A major portion of the text in this manual are taken from the Kansas Swine Nutrition Guide and gratitude is expressed to the many individuals who worked to put it together. Gratitude is also expressed to the many individuals who have worked to make this guide unique and applicable to the North Carolina Swine Industry. The North Carolina Cooperative Extension Service and the author hope that this is a valuable asset to the swine producer regardless of size. We hope that it can be used as an educational tool as well as a nutrition guide. Should you have information that you believe could or should be incorporated into this manual, please don't hesitate to contact Extension Swine Husbandry. All comments are welcomed.
Efficient and profitable swine production depends upon an understanding of the concepts of genetics, environment, herd health, management, and nutrition. These factors interact with each other, and their net output determines the level of production and profitability. Feed represents 60 to 75 percent of the total cost of pork production. Therefore, amino acids, carbohydrates, vitamins, minerals, and water must be provided and balanced to meet the pig's requirements. Thus, a thorough knowledge of the principles of swine nutrition is essential in order to maintain a profitable swine enterprise.
Improvements in production have led to changes in nutrient recommendations in order to maximize performance. These requirements are continually changing and this publication is revised periodically to keep up with the latest developments and changes in technology. The purpose of this publication is to provide the latest recommended nutrient allowances and answer some of the more frequently asked questions concerning swine nutrition. Suggestions made in this guide may not be applicable to swine production in other regions of the country.
There is some variation among the Lang Grant Universities in nutrient level recommendations. The main reason for the differences is the amount of added nutrients beyond the National Research Council (NRC) minimum requirement. The NRC periodically reviews and publishes estimates of the nutritional requirements for swine. These requirements are based on pigs fed under experimental conditions with normal health and performance. Many of the requirements are based on feeding a corn-soybean meal diet.
In this publication, the nutrient recommendations have been increased beyond the NRC levels to add a margin of safety for each of the essential nutrients. In addition, with improved record-keeping programs, there are data to suggest that feed intake may not be as great as previously estimated. Although a pig's requirement for a specific nutrient may be the same, if it is not eating the estimated amount, the nutrient density of the diet must be increased in order to meet its daily nutrient requirement. Our purpose is to reduce the risk of nutrient deficiencies that might occur because of differences in ingredient quality, genetics, health, environment, and performance on individual farms.
Several factors affect a pig's requirement for a specific nutrient. These factors influence feed intake, which will require changing the concentration of the nutrient in the diet to meet the pig's requirement on an amount-per-day basis. Some of these factors are:
Environmental temperature or weather
Breed, sex, and genetic background of pigs
Health status of the herd
Presence of molds, toxins, or inhibitors in the diet
Availability and absorption of dietary nutrients
Variability of nutrient content in the feed
Level of feed additives or growth promotants
Energy concentration of the diet
Level of feeding, such as limit feeding vs. ad libitum
Environmental temperatures and housing conditions play in important role in determining the pig's nutrient needs for maintenance. Pigs housed in outside dirt lots are exposed to greater temperature changes than those housed in confinement facilities and may have greater maintenance needs. In addition, research has indicated that pigs of different sex, breeds, or genetic background may have different capacities for production, thus different nutrient requirements. It is reasonable to expect that a sow weaning 27 pigs per year would have a higher requirements than one weaning only 15 pigs per year.
Feed quality, including processing methods; nutrient availability and variability; and the presence of molds, toxins, or anti-nutritional factors will influence pig performance and feed costs. Herd health status and the presence and level of feed additives or growth promotants will also alter nutrient utilization. Finally, factors affecting feed intake such as level of feedings or energy density of the diet will alter requirements.
In general, as measures are taken to increase production (i.e., growth rate or pigs per sow per year, etc.), increasing the nutrient fortification of the diet may be required to meet these challenges in pig production. Error! Reference source not found. and Error! Reference source not found. list typical growth rates, carcass traits, and sow performance, as well as goals for future production values. As an industry, producers need to be aware of the past as well as keep an eye on the future in order to remain competitive and profitable.
There are basically four systems of preparing diets for a swine operation. The goal for a nutrition program should be to provide each pig at the feeder with quality feed at a cost-effective price. This is not the same as least cost per ton of feed produced. The four systems of diet preparation include:
Complete Feed. Complete feeds are prepared and delivered by a commercial mill as a ready-to-feed product. Although convenient, complete feeds are usually the most expensive. Additionally, flexibility is limited when specific diet changes are needed.
Grain and Supplement. Mixing producer-raised grain and supplement has been popular for a long time. In most cases, a basic 40 percent protein supplement is added to grain to provide the proper nutrients. This system may be more expensive than the base mix system.
Base Mix Program. Base mixes contain all needed ingredients except grain and protein and usually account for 2.5 to 5 percent of the diet by weight. Bases mixes are a cost-effective way to make swine diets on the farm and fit well with many portable feed systems. Base mixes also work well with volumetric and stationary mills. The terminology "premix" is often used erroneously by some feed companies to describe their base mix products.
Premix Program. Premixes offer the greatest opportunity for specifically tailored diets at a lower cost. Accuracy in preparation and ingredient care are critical in good premix diet formulation. When equipment and personnel allow, a premix program is suggested as the most precisely designed and cost-effective diet preparation system. Premixes of vitamins and trace minerals are added with macro minerals (dicalcium phosphate, limestone, and salt) to a protein and grain mixture.
As a producer assumes more responsibility for mixing his own feed, costs may be decreased. However, very often the producer is unaware of the increased demands associated with on-farm feed preparation. The producer must supply additional facilities, labor, and quality control over a wide range of feed ingredients. This includes nutrient variability, vitamin and mineral stability, as well as adequate storage, processing, and mixing of diets. Therefore, before considering changing from one level of diet formulation to the next, the producer must be aware of the advantages and disadvantages of on-farm feed preparation.
In addition to increasing responsibility for quality control, management, labor, and diet formulation, there will be increased capital investment (i.e., storage bins, mixing and weighing equipment, tractors, etc.) with on-farm mixing. Very often, these costs are underestimated, and it is important to emphasize that these services are provided when complete feed is purchased.
However, as you move from complete feed to a premix program, you increase diet flexibility. Diets can be specifically formulated to fit your operation and facilities, genetics, and environment. But probably the biggest advantage with taking more responsibility in mixing your own feed is a reduction in feed cost. This is accomplished by not paying someone else to ensure quality diet formulation.
Carbohydrates and fats in the diet supply most of the pig's caloric needs. Today, energy requirements are expressed as kilocalories (kcal) of digestible (DE or metabolizable energy (ME) per pound of feed. Digestible energy is defined as the amount of energy in the feed minus the energy lost in the feces and urine.
Energy sources for swine are the cereal grains; corn, milo, wheat, barley, and their by-products. In addition, fat, which contains 2.25 times the amount of energy as cereal grains, is often used to increase the energy density of swine diets. Most common cereal grains and fats are quite palatable and digestible. However, cereal by-products tend to be more variable; therefore, their use in swine diets may be limited. Although cereal grains will provide carbohydrates to meet the pig's energy needs, they must be supplemented with amino acids (protein), vitamins, and minerals to meet the pig's requirements for these nutrients.
When formulating swine diets using the common cereal grains, producers do not balance for a specific energy level in the diet, because the pig will often eat to meet its energy requirement. However, when low-energy feeds are used, pigs are limit-fed (sows and gilts), or external factors limit feed intake, dietary energy levels must be checked to ensure adequate intake.
Both grains are excellent energy sources in swine diets. In North Carolina, however, milo is often a more economical source of energy. Because the energy content of corn is slightly higher than that of milo, feed efficiency of pigs fed corn diets will be slightly better than that of pigs fed milo, but average daily gains will be the same.
A general recommendation for swine diets is to replace corn with milo on a pound-for-pound basis or on a lysine basis. One disadvantage of milo is that it can be more variable in nutrient content than corn because of growing conditions. In addition, because a milo kernel is smaller and harder than a corn kernel, fine grinding, (1/8 or 5/32" screen) or rolling is suggested for best utilization.
Wheat
Wheat is an excellent feed grain for swine, but usually is
not competitively priced with milo or corn. Wheat can replace
all or part of the corn or milo in a swine diet on a pound-for-pound
basis without affecting performance. Because wheat is slightly
more lysine and phosphorus than corn and milo, the amount of soybean
meal and dicalcium phosphate can be reduced in the diet. Research
shows that soft ed winter wheat is comparable in feeding value
to hard red winter wheat for finishing pigs. Because wheat tends
to flour when processed, it should be coarsely ground (3/16"
screen) or rolled. If ground too finely, feed intake may be decreased
and performance lowered.
Barley
Barley also contains more lysine than milo or corn. However,
it contains less energy and more fiber. Therefore, pigs fed barley-based
diets will tend to have 5 to 10 percent poorer feed efficiency.
Fine grinding (600 to 700 microns) of barley diets improves the
feeding value for growing/finishing pigs, but when energy intakes
is critical, barley diets are not recommended.
Oats
Oats also have more lysine than either milo or corn, but again,
their high fiber content limits their application in swine diets.
Oats should not exceed 30 percent of the diet growing/finishing
pigs. Because of the high fiber content of oats and barley, they
may be best used in sow gestation diets, if economically priced.
The amount of feed per unit of grain (feed efficiency) is not the most important factor in formulating swine diets. Cost per unit of gain is more important; therefore, it is necessary to use the most economical energy sources in swine diets. The relative feeding values listed in Table 3 can be used to calculate the most economical energy source. For example, if corn costs 5.0 cents per pound, milo is a better value when it costs less than 4.8 (5.0 X 96 percent) cents per pound.
Fats and oils such as lard, choice white grease, beef tallow, corn oil, and soybean oil contain about 2.25 times as much metabolizable energy as most of the cereal grains. Research indicates that the addition of 1 to 5 percent fat to growing-finishing swine diets will improve feed conversion and often average daily gain with no adverse effect on carcass quality. A reduction in the amount of dust will be evident and wear on mixing equipment and augers will be reduced with 2 to 3 percent added fat.
Addition of fat above 5 percent will further improve feed conversion, but physical handling problems such as bridging in the feeders and caking in the mixer may limit the use of these higher levels. Diets containing fat may become rancid during prolonged storage or when feed is exposed to high temperatures. Therefore, an antioxidant such as ethoxyquin, BHT, or BHA should be added to fat before mixing it into the rations.
Adding fat to swine diets is a matter of economics. Fat additions will usually increase the cost of the diet, which must be offset by an increase in pig performance. Several commercial supplements and complete feeds contain added fat. New commercial products that contain dried fat may reduce part of the mechanical problems of adding liquid fat on the farm, but the economic feasibility of using these products must be evaluated. Fat products that have limestone as the carrier should be avoided, because the calcium will decrease the digestibility of the fat.
Research with sows suggest that feeding a diet with 5 percent added fat at a rate of 5 lb/day for 10 days before farrowing has the potential to improve pig survivability if preweaning survival is below 8C percent. The reasons for the increase in survival rate appear to be increases in milk yield and milk fat content.
The potential benefits of fat addition must be evaluated in terms of economic considerations. When calculating what price you can pay for adding fat to a swine diet, the following equation can be used:
percent improvement in feed efficiency needed to offset added diet cost
For example, if adding fat will increase diet cost by 5 percent, you must get at least a 5 percent improvement in feed efficiency before it is economical. Fat may be added in summer diets to increase the energy density of the feed to offset low feed intake due to high temperatures. Feed efficiency is usually improved 2 percent for each 1 percent increment of added fat in growing-finishing pig diets.
Recent research shows that not all fat sources give similar improvements in pig performance, especially for baby pigs. This may be a result of the fat source's fatty acid profile or impurities from the rendering process. In general, fat sources such as soybean oil and choice white grease are considered higher quality than tallow and yellow grease. Evidence indicates that blends of soybean oil and coconut oil support excellent performance in baby pigs. Waste cooking oils may be used in swine diets but should also be checked for quality.
Fat sources of questionable quality should be analyzed for moisture, impurities, and unsaponafiable material (MIU), as well as free fatty acids. Moisture should not exceed 1 percent, free fatty acids 15 percent, impurities .5 percent, unsaponifiable material 1 percent, and total MIU 2.5 percent. If two fat sources are blended together, moisture should not exceed 1 percent, free fatty acids 30 percent, impurities .5 percent, unsaponifiable material 3.5 percent, and total MIU 5 percent.
There is no perfect feed ingredient that can be fed to pigs by itself. Some feeds, if added to the diets in excess amounts, will decrease performance. Some less commonly fed feedstuffs, such as millet and rye, should not exceed the recommended levels shown on Table 4.
Under adverse weather conditions, such as drought, floods, or early frosts, low test weight or sprout-damaged grain may be available for use in swine diets. As the degree of sprout damage increases or test weight decreases, the energy content of the grain is decreased. Therefore, the pig will need to eat more feed to meet its energy requirement. Although average daily gain will usually not be affected, feed efficiency will become poorer. Research has shown that his occurs when milo drops below 45 pounds per bushel test weight and wheat is below 50 pound test weight.
Furthermore, milo with up to 40 percent sprout damage can be effectively used by growing finishing pigs. When the test weight of milo and wheat drop below 45 and 50 pounds, respectively, or there is more than 40 percent sprout damage, average daily gain will begin to be affected. Blending low test weight or sprout-damaged grain (up to 50 percent) with normal grain is an effective way to utilize weather-damaged grain. It is extremely important to recalibrate volumetric mixing equipment when feeding low test weight grains.
Profitability the biggest disadvantage to weather-damaged grain is the increased potential for mold or aflatoxin contamination because of high moisture content. Therefore, weather damaged grains should always be tested for molds and aflatoxin and, if contaminated, these grains should not be fed to starter pigs or the breeding herd. If contaminated grains are used, they should be blended with normal grain and fed only to growing-finishing pigs in limited amounts. Several mold inhibitors have been shown to improve pig performance when mold-contaminated grains are fed.
The pig does not have a specific requirements for crude protein, but rather for the individual components or sub-units that make up protein, called amino acids. Proteins are made up of several different combinations of approximately 20 different amino acids. During the process of digestion, proteins are broken down into individual amino acids that are absorbed into the bloodstream. The amino acids are then incorporated into new protein molecules. When formulating diets with commonly available grains and protein sources, the level of crude protein typically used to describe the diet usually will contain adequate amounts of amino acids to meet the pig's requirement. However, it is important to remember that this is not always true when using synthetic amino acids and alternative or by-product feed ingredients, and that the dietary levels of amino acids should always be checked. It is becoming increasingly important to specify lysine levels when formulating and evaluating swine diets.
If a diet is inadequate in any essential amino acid, protein synthesis cannot proceed beyond the rate at which that amino acid is available. This is called a limiting amino acid. Another way of describing a limiting amino acid is thinking of protein as a rain barrel and the amino acids as the individual staves making up the barrel. If one stave (amino acid) is shorter than the others (limiting), the barrel can only be filled to the level of the shortest stave. In the pig, a deficiency of one or more amino acids will result in depressed growth rate, poor feed conversion, unthriftiness, or reduced reproductive performance. Therefore, protein quality can be defined as how closely the essential amino acids in the protein source come to meeting the pig's estimated requirement for those amino acids.
The 10 essential amino acids that must be provided in swine diets are: lysine, threonine, tryptophan, methionine (and cystine), isoleucine, histidine, valine, arginine, and phenylalanine (and tyrosine). Most cereal grains are limiting in lysine, tryptophan, and threonine. Therefore, when evaluating feed ingredients, these amino acids, especially lysine, are most important in determining protein quality.
When substituting other protein sources for soybean meal, it is important to consider the maximum level at which the new feed ingredient can replace soybean meal without seriously affecting performance. Table 5 is a list of alternative protein sources that can be used in starter, growing-finishing, gestation, and lactation diets to replace all or part of the soybean meal. By using this table, you can determine the maximum replacement rate of the feed ingredient for soybean meal. For example, corn gluten meal can replace 25 percent of the soybean meal protein in the diet.
Protein sources are classified into two major categories: animal (tankage, meat and bone meal, fish meal, or dried skim milk) and plant (soybean meal, cotton seed meal, or corn gluten meal). Soybean meal is usually the most economical source of high quality protein available to North Carolina swine producers. It is the only plant protein that compares with animal protein that compares with animal protein in terms of quality of amino acid content and ratio and ban be sued as the only protein source in most swine diets. Therefore, there is no need to have both animal and plant protein sources in a swine diet, with the exception of starter diets, which should contain dried whey and (or) dried skim milk.
Producers in North Carolina and other states may have the choice of buying either 44 percent or 48.5 percent crude protein soybean meal. The primary difference is that 44 percent soybean meal is made by adding soy hulls to 48.5 percent soybean meal. In addition to the lower fiber content, transportation costs may favor buying the 48.5 percent soybean meal.
In order to determine the relative feeding value of alternative protein sources, it is important to compare the lysine level in the new protein source to soybean meal. The relative feeding values of some alternative protein sources are listed in Table 6. This can be used to determine the comparative economic value of the protein source as a partial or complete replacement to 44 percent soybean meal. These feeding values were calculated by dividing the lysine content of the feed ingredient by that of 44 percent soybean meal (2.90 percent lysine) and multiplying by 100 to put them on a percentage basis.
Assuming that 44 percent soybean meal can be purchased at $250 per ton, what would a ton of 48.5 percent soybean meal be worth? Because the lysine content of 48.5 percent soybean meal is 3.12 percent and 44 percent soybean meal has 2.90 percent lysine, 48.5 percent soybean meal has 108 percent the feeding value of 44 percent soybean meal (3.12/2.90 X 100 = 108 percent). Therefore, if 108 percent is multiplied by the cost of 44 percent soybean meal (108 percent X $250), 48.5 percent soybean meal is of greater value than 44 percent soybean meal if it costs less than $270 per ton.
This section lists some of the more common substitutes for soybean meal in swine diets. Very often, these feed ingredients may appear to be economical compared to soybean meal. However, there are often many hidden costs or disadvantages in using these feed ingredients that are not reflected by their price. These include storage costs, anti-nutritional factors, product variability, fiber content, spoilage, and under-or over-processing. These factors are especially problematic in by-product protein sources. Because by-product feed ingredients tend to vary more in composition, proper information regarding chemical composition is necessary to ensure optimum pig performance.
Cottonseed Meal
Cottonseed meal ranks second in production compared to soybean meal. However, its use in swine diets is limited because of the deleterious effects produced by the residual free gossypol (toxic substance produced by fungi) found in the pigment glands of the seed. Although fairly high in protein, cottonseed meal is low in lysine and tryptophan. It is recommended that cottonseed meal replace no more than 50 percent of the soybean meal or protein supplement in the diet. At this inclusion rate, it is unlikely that the total diet will contain over .01 percent free gossypol. Pig performance begins to be reduced at gossypol concentrations of .04 percent of the diet. Solvent-extracted, gossypol-free cottonseed meal can be used to replace 75 percent of the protein source in growing-finishing diets when balanced on a lysine basis.
Canola Meal
Canola meal, or what is sometimes referred to as rapeseed meal, is the by-product of vegetable oil processing from rapeseed. Because it is well adapted to cool-season growing conditions, rapeseed is produced primarily in Canada and the northern states. Since its oil contains a high level of unsaturated fatty acids, production is expanding throughout the United States. Canola meal averages between 35 and 40 percent crude protein and has less lysine but more sulfur-containing amino acids than soybean meal.
Some varieties of rapeseed contain high levels of a toxic compound, glucosinolate, which effects thyroid functioning. However, new cultivars of low-glucosinolate rapeseed (µ1 mg/g) have been developed and are commonly referred to as canola meal to distinguish it from the older varieties of high-glucosinolate rapeseed. It is not advisable to feed meals from the cultivars of rapeseed. Reduced palatability, high fiber, and low digestible energy have been causes of slightly poorer performance of pigs fed diets containing canola meal. Canola meal can be used to replace up to 50 percent of the protein from soybean meal in growing-finishing and sow diets without adversely affecting performance.
Sunflower Meal
Sunflower meal is produced by extraction of the oil from sunflower seeds. Because of its high fiber content (22-24 percent), it should be used in limited quantities in swine diets. Sunflower meal is relatively low in lysine yet high in sulfur-containing amino acids in comparison to soybean meal. Sunflower meal containing high levels of oil will produce soft pork because of the oil's unsaturated fatty acid content. It appears that sunflower meal may replace up to 25 percent of the protein in the diet for growing-finishing pigs.
Meat and Bone Meal
Meat packing by-products often are economically feasible to add to swine diets. In general, meat and bone meal is an excellent source of calcium and phosphorus. However, it is often very low in tryptophan and methionine. Since there is considerable variation in the type and quality of the raw materials used, there is potential for greater variation in the quality of meat and bone meal. Tankage has a crude protein value of 60 percent, but if the raw materials used to make tankage are inadequate to meet this protein level, small amounts of blood meal or other poor-quality protein sources are added. Excessive heating during the processing of tankage may also decrease its digestibility and value as a protein source. Therefore, it is recommended that meat and bone meal or tankage should not exceed 25 percent of the protein supplement.
Raw Soybeans
Raw soybeans, especially weather damaged or low test-weight beans, are often attractive alternatives to add to swine diets. However, raw soybeans contain high quantities of trypsin inhibitors, which block normal protein digestion in pigs. As the pig becomes older, its susceptibility to trypsin inhibitor decreases. Therefore, raw soybeans may be used in gestation diets (but not lactation) without adversely affecting performance. If raw soybeans are to be sued in diets for young pigs, it is important to heat the beans to inactivate the trypsin inhibitor. New varieties of soybeans are under development in which the trypsin inhibitor has been genetically selected against, which would allow for greater use in growing pig diets.
Home processing by roasting or extruding of raw soybeans, if done properly, results in excellent sources of protein. On-farm roasting or extruding yield "full-fat" soybeans, which, in some instances, are among the cheapest means of adding fat to swine diets. Because of the economic relationship between soy oil and soybean meal and the cost of other fat sources and incorporating them into your feed mill, it may be more economical to utilize full-fat soybeans instead of selling the beans and buying back soybean meal.
Because whole or full-fay soybeans have less protein and lysine than soybean meal (32 to 37 percent protein and 2.1 to 2.4 percent lysine), it is necessary to add 20 to 25 percent more whole soybeans than soybean meal to have similar protein level in the diet. At the same time, this will supply approximately 3 percent added fat to the diet, which will improve feed efficiency approximately 3 to 5 percent. Whole soybeans have an approximate feeding value of 90 to 95 percent that of soybean meal. The following equation can be used to determine if feeding full-fat soybeans is economically justified:
A = .86Y + .17Z - (S + C),
where:
A = cost advantage per ton of full-fat product
Y = cost of one ton of 44 percent soybean meal
Z = cost of one ton of feed grade fat
S = cost of one ton of soybeans
C = cost of processing one ton of soybeans
If it is feasible to feed full-fat soybeans, A will be greater than zero.
High-lysine corn can refer to at least two varieties of corn that contain higher lysine levels than normal corn. The first commecial high-lysine corn was Opaque-2 corn. However, a new variety of corn was developed in Latin America and may be found in the U.S., it is referred to as quality protein maize (QPM). The differences between opaque-2 and QPM are significant, especially with regard to appearance and handling. Opaque-2 corn is a variety of corn that has been selected for improved protein and is higher than regular corn in all essential amino acids except leucine. Because the lysine content is higher in opaque-2 and QPM corn than that of normal corn (.40 and .38 vs. .24 percent, respectively), diets using opaque-2 or QPM corn should be formulated on a lysine basis. The major disadvantages of opaque-2 corn are reduced yields and decreased kernel durability, which are not reportedly problems with the QPM variety.
Excessive heat will reduce the availability of the amino acids, particularly lysine, in feed ingredients. If your soybean meal or dried whey looks darker than usual or has a burnt smell, it is possible that the protein quality has been reduced.
Synthetic amino acids, if added properly, can reduce feed costs and maintain pig performance. Lysine and methionine are the two feed-grade amino acids most commonly added to swine diets. However in the future, synthetic threonine and tryptophan may be available at prices low enough to add to swine diets. Research has demonstrated that supplemental lysine can reduce the amount of soybean meal needed in swine diets. Therefore, adding synthetic lysine can reduce the crude protein level of the diet without affecting performance.
The most common source of synthetic lysine is L-lysine monohydrochloride, which is 78 percent lysine. In diets for pigs over 50 pounds body weight, 100 pounds soybean meal can be replaced by the addition of 3 pounds L-lysine HCl and 97 pounds grain per ton. If the 3 pounds L-lysine HCl and 97 pounds grain are cheaper than 100 pounds soybean meal, the diet costs would be reduced by using supplemental lysine. In sow diets, 50 pounds of soybean meal can be replaced by 48.5 pounds of grain and 1.5 pounds of L-lysine HCl.
Protein sources vary greatly in quality and quantity. Protein quality is directly dependent on the content of the most limiting amino acid relative to the pig's requirement. If a diet is not balanced correctly, a shortage of one of the essential amino acids will reduce growth rate and performance. An amino acid imbalance may occur if a second limiting amino acid is added to a diet when the first limiting amino acid is still deficient. This will result in a reduction in feed intake and reduced pig performance.
On the other hand, when a diet is balanced for the most limiting amino acid (usually lysine), other amino acids are usually in excess of the pig's requirement. Some commercial companies are using the concept of amino acid balance or ideal protein in their sales promotions. This refers to formulating a diet in which all amino acid levels are very similar to the pig's requirement without excesses. However, there is not scientific information to indicate that the excesses of amino acids that occur naturally in milo- or corn-soybean meal based diets will have a detrimental effect on pig performance.
Suggested amino acid recommendations are usually based on the amount of an amino acid required to maximize rate of gain. However, slightly higher levels of amino acids will further improve feed efficiency and carcass leanness. This is because the higher amino acid levels allow the animal to deposit greater amounts of lean tissue rather than fat. Because it takes less energy to deposit lean than fat, feed efficiency is improved. Slightly higher levels of amino acids may be economical to producers who market their hogs on a lean value system, where there is incentive for producing lean pork. In this situation, increasing the lysine content of finishing diets by .05 to .1 percent is suggested.
On an amount-per-day basis, barrows and gilts require similar amounts of amino acids. However, because gilts typically consume 1/2 pound less feed per day than barrows, they may not eat enough to fully meet their requirements. Although sometimes difficult to accomplish on the farm, split-sex feeding offers some feeding and marketing alternatives. Split-sex feeding involves sorting gilts from barrows and feeding each separate diets. Because gilts consume less feed than barrows, their diets can be fortified with extra amino acids for growth rate and feed efficiency as well as calcium and phosphorus for bone development, if they are going to be retained for the breeding herd.
Marketing programs taking advantage of the better feed efficiency of gilts can also be used with split-sex feeding. In general, feed gilts a diet containing .10 percent more lysine than the diet for barrows. Suggested lysine levels for producers who split-sex feed are listed in Table 7.
Pigs are like people, and when the weather gets hot, their appetite decreases. During the summer months, it is advisable to provide drip cooling or cool-zones to keep pigs cool. Increasing the energy and amino acid levels of the diet will also help to offset decreased feed intake. With increased amino acid and energy levels in the diet, the pig will still be consuming the required amounts of each nutrient regardless of the reduced intake, helping to prevent summertime stall-out. A typical recommendation is to increase the lysine level of the diet .10 percent during the warm months of the year (see Table 7).
Although two protein sources may contain the same amounts of a certain amino acid, because of some difference in the chemical structure of the protein, processing method, or anti-nutritional factor, not all of that amino acid may be available to the pig. This is especially true for certain by-product feed ingredients or feed ingredients that have been over-processed.
More and more information about amino acid availability is being published for a variety of by-product feed ingredients, such as cotton seed meal, meat and bone meal, and blood meal. If you are using a high percentage of these feed ingredients, you may want to consider balancing the diet on an available amino acid basis. However, if you are using milo or corn and soybean meal, there is probably no need to worry about amino acid availability.
A pig will adjust its feed intake to meet its energy requirement. When the energy density of the diet increases, a pig will tend to eat less feed. Thus, in diets with added fat, it is important to increase the concentration of amino acids. This way, the pig will consume approximately the same amount per day even though feed intake is less.
Although there is little information on what is the optimum calorie:protein ratio for pigs, it may be possible to extrapolate ratios from standard grain-soybean meal diets to those with high levels of added fat (> 5 percent). A typical grain-soybean meal-milk product diet will have approximately 3.7 g lysine/Meal metabolizable energy, whereas a grower and finishing diet will contain approximately 2.5 and 2.0 g lysine/Meal metabolizable energy, respectively.
Minerals constitute a small percentage of the swine diet, but their importance to the health and well-being of the pig cannot be over-emphasized. Minerals have been classified into two types: macrominerals and microminerals. Macrominerals (major minerals) that are commonly added to swine diets are calcium, phosphorus, sodium, and chloride (magnesium and potassium are also required but are adequately supplied by grains). Microminerals (minor or trace minerals) or primary concern are zinc, copper, iron, manganese, iodine, and selenium.
Functions of minerals are diverse, ranging from structural functions in some tissues to a wide variety of regulatory functions. The increasing trend toward confinement rearing of pigs, without access to soil or forage, increases the importance of meeting dietary mineral requirements.
Other trace minerals are essential for chicks or laboratory animals and may be required by swine. These include molybdenum, cobalt, fluorine, chromium, nickel, silicon, vanadium, tin, and arsenic. Whether these elements will be of practical significance awaits further research. Most of them are believed to be present in adequate quantities in natural feed ingredients. However, the use of simpler swine diets with fewer ingredients may necessitate consideration of their importance in the future.
Minerals should not be added haphazardly. The old adage, "if a little is good, more is better," is not true when adding minerals to swine diets. If minerals are added without reason, more harm than good can occur. All minerals have a toxic level.
Some minerals, particularly calcium, if added in excess, will interfere with absorption of other nutrients. As an example, calcium interferes with zinc absorption and results in a skin disorder called parakeratosis. A combination of a high level of calcium (over 0.9 percent) and marginal zinc level can result in this condition. Never mix additional minerals with a commercial supplement, unless the need is specified on the tag.
These two elements are important in skeletal structure development, but their presence in soft tissues is also vitally important. Both aid in blood clotting, muscle contraction, and energy metabolism. About 99 percent of the calcium and 80 percent of the phosphorus in the body are found in the skeleton and teeth. Therefore, deficiency of calcium and phosphorus will result in impaired bone mineralization, reduced bone strength, and poor growth.
Young pigs with a deficiency of calcium and phosphorus will have clinical sings of rickets. Mature pigs eating a deficient diet will remove calcium and phosphorus from the bone (osteoporosis), decreasing bone strength. This can result in a condition called "Downer Sows" and can be prevented by proper diet formulation.
The ingredients used in swine diets vary widely in mineral content. Most cereal grains are particularly low in calcium. Phosphorus content of cereal grains is largely phytate phosphorus, which is poorly used by swine. Several researchers are currently evaluating the availability of phosphorus in cereal grains. A range of 8 to 60 percent of phosphorus availability has been reported in cereal grains, but for practical purposes, an availability of 30 percent is a reasonable estimate.
Feeds of animal origin, such as meat and bone meal, tankage, or fish meal, are quite high in calcium and phosphorus. Thus, the level of supplemental calcium and phosphorus must be recalculated as feeds of animal origin replace soybean meal in the swine diet.
The standard ingredients for supplying supplemental calcium are limestone or oyster shell. Phosphorus is primarily supplied by dicalcium phosphate or monocalcium phosphate. Table 8 lists a number of feed ingredients that may be used to supply calcium and phosphorus. Note that many of the sources supply both calcium and phosphorus, so the quantity of limestone in the diet must also be adjusted. It is extremely important to check the nutrient specifications of these mineral sources, because the level of calcium and phosphorus may be different from the above values.
Phosphorus is the second most expensive nutrient and most expensive mineral added to swine diets. It is possible to reduce the total cost of a diet by evaluating the cost of the supplemental phosphorus. For example, if the -- cost of dical (21 percent calcium, 18 percent phosphorus) is $20 per 100 pounds and monocalcium phosphate (18 percent calcium, 21 percent phosphorus) is $25 per 100 pounds, which is the cheapest source of phosphorus? The cost of phosphorus per pound is divided by the percentage of phosphorus to determine the cost per pound of actual phosphorus.
For example:
Dicalcium Phosphate
20¢/pound = $1.11/lb phosphorus
18 percent of actual phosphorus
Monocalcium Phosphate
25¢/pound = $1.19/lb phosphorus
21 percent of actual phosphorus
Therefore, the dical would be a cheaper source of phosphorus.
Because the amounts of calcium and phosphorus can vary in products commonly called "dical," producers need to know how to adjust the amount of dical and limestone in their swine diets. In the suggested diets (Tables 18, 19, 20, and 22, pages 25-28), 21 percent phosphorus "monocal" was used for formulation. In adjusting the amounts of monocal or dical and limestone to achieve the desired levels of calcium and phosphorus, the following example may be helpful:
The diet has 30 lbs of monocal (21% P; 18 % Ca) and 10 lbs of limestone (38% Ca). You can purchase 18% phosphorus and 21% Ca dical at a lower price per unit of phosphorus.
Determine phosphorus levels:
lb of monocal × 21% = 6.3 lb of phosphorus supplied by monocal.
lb ¸ 18% = 35 lb of dical (18% P) needed to replace 30 lb
of monocal (21% P).
Determine calcium levels:
30 lb of monocal × 18% = 5.4 lbs. of calcium supplied by
monocal.
35 lb of dical × 21% = 7.35 lbs. of calcium supplied by dical.
Needed amount of limestone:
lb of Ca - 5.4 lb of Ca = 1.95 lb of extra ca.¸
38% Ca = 5.15 fewer lb of limestone needed.
Results:
lb of monocal (21% P; 18% Ca) and 10 lb of limestone can be substituted
for 35 lb of dical (l8% P; 21% Ca) and 4.85 lb of limestone.
The optimum levels of calcium and phosphorus for various ages of pigs are shown in Table 24 (page ). For maximum performance, minimum dietary levels of each are necessary, as well as the correct ratio of one to the other. The desired ratio of l.0 to 1.3 calcium to 1.0 total phosphorus is a grain soybean meal diet is preferred, although if the phosphorus level is adequate, a calcium:phosphorus ration of 2:1 will not affect performance.
Levels of calcium and phosphorus adequate for maximum gain in body weight are not necessarily sufficient for maximum bone development. Borderline deficiency may go unnoticed in the growing-finishing pig, but cause serious consequences in those pigs saved for breeding purposes. With split-sex feeding, replacement gilts can be fed higher levels od calcium and phosphorus (.75 and .65, respectively) for maximizing bone development.
Swine producers have reported leg weaknesses and abnormalities that impair the breeding effectiveness of young replacement animals. Many of the leg problems can be attributed to structural unsoundness. However, inadequate dietary calcium and/or phosphorus can impair bone mineralization and result in weaker bones. With replacement gilts, it is not advisable to limit feed the finishing diet, which may reduce calcium and phosphorus intakes.
Calcium carbonate, commonly called ground limestone, is used routinely to aid in improving the flowability of soybean meal during processing. In the past, a value of .20 to .25 percent calcium has been observed in soybean meal, but for the past few years, the calcium level has increased dramatically. A new level of .50 percent calcium for soybean meal should be used in formulating diets.
Salt, a combination of sodium and chloride, must be added to all swine diets. Grains and plant protein supplements are low in sodium and chloride, but the needs of the growing-finishing pig can be met by adding .25 percent salt to the diet. When a diet deficient in salt is fed to growing pigs, depressed performance will be evident within a few weeks. Recent research suggests that for breeding stock, .5 percent added salt is adequate.
High levels of salt can be tolerated, if adequate drinking water is available. However, if water is restricted, as little as .2 percent dietary salt has resulted in toxicity symptoms.
The baby pig is born with a limited supply of iron, and because the sow's milk is also low in iron, supplemental iron is a must. The commonly used sources of iron to prevent anemia in newborn pigs are injectable and oral products. Injectable iron is the preferred method of anemia prevention. An intramuscular injection of 200 mg of iron dextran given at 1 to 3 days of age will prevent the anemia problem. Because the concentration of iron sources may vary,k it is important to evaluate products based on a cost/mg iron basis.
Most producers will give an iron injection within the first 3 days of life. Need for a second injection depends on the amount of iron available to the baby pigs during the lactation period and how much was given in the first injection. The baby pigs can receive iron orally from consuming creep feed or sow feed or from the sow's feces. Over 90 percent of the injected iron from the initial treatment is utilized over the first 3 weeks. If less than 20 mg of iron is given in the first injection, a second iron shot may be needed. Need for a second injection also depends primarily on blood hemoglobin concentration, a rapid and reliable indicator of the iron status of the pig. Blood hemoglobin levels of 10 mg/100 ml or above indicate adequate iron status. Hemoglobin levels of 8 to 9 mg/100 ml indicate a borderline anemia condition, whereas a value of 7 or below indicates an anemic condition. If blood hemoglobin levels fall below the 10 mg/100 ml level, a second iron shot is advisable.
For many years, swine producers have been giving iron injections in the ham. When iron injections are given in the ham, permanent staining of the meat has been observed. Because ham is one of the higher value cuts of pork, it is highly recommended that iron injections be given in the neck.
A chelated or complexed mineral is bound to a compound that helps stabilize the mineral. Many claims have been made for the benefit of chelated and complexed minerals. One is the greater physical stability, which reduces the tendency for trace minerals to segregate in the feed. Another claim is for less oxidation of vitamins and minerals and greater availability. Recent research has shown that chelated minerals will be 0 to 15 percent more available. However, their cost may be two to three times greater than those of nonchelated minerals. Therefore, the costs of chelated and complexed minerals must be examined before adding them to swine diets.
The need for supplemental selenium is related to vitamin E intake. In fact, supplemental selenium has become more important with decreased use of pasture as a source of Vitamin E, artificial drying of grains that causes partial destruction of vitamin E and increase in the incidence of mulberry heart disease in North Carolina swine herds. The amount that may be added to swine diets is regulated by the U. S. Food and Drug Administration and is limited to 0.3 ppm (.27 g/ton) for all swine. Research shows that increasing the supplemental selenium level to .3 ppm will improve pig performance.
Iron, copper, manganese, zinc, iodine, and selenium are the trace minerals that should be added in a mineral premix. Table 9 lists the various chemical forms in which the trace minerals are available. Most trace minerals are not generally supplied as pure chemicals, but as either ores or industrial by-products. Sulfate trace mineral forms are usually more reactive in the premix and possibly reduce the potency of the more susceptible vitamins and reduce the shelf life of the entire premix.
A suggested trace mineral premix with specified amounts and mineral sources appears in Table 10. This single premix can be used in diets for all ages of swine by adjusting the inclusion rate (3 lbs/ton for sow, starter, and grower diets; 2 lbs/ton for finishing diets).
Vitamins are required for normal metabolic function; development of normal tissues; and health, growth, and maintenance. Some vitamins can be produced within the pig's body in sufficient quantities to meet its needs. Others are present in adequate amounts in feed ingredients commonly used in swine diets. However, several vitamins need to be added to swine diets to obtain optimal performance. Vitamin needs are more critical today than in previous years because of the use of simple diets containing fewer ingredients and confinement facilities.
Vitamins that should be added to swine diets can be divided into two groups--fat-soluble and water-soluble. The fat-soluble vitamins that are generally added are A, D, E, and K. The water-soluble or B-complex vitamins, which may be deficient in a corn- or milo-based diet, are pantothenic acid, riboflavin, niacin, choline, and vitamin B12. The recommended levels of addition are shown in Table 24. In addition, recent research shows that additions of folic acid and biotin may improve sow and litter performance when added to gestation and lactation diets. There is no need to supplement diets for growing-finishing swine with biotin or folic acid.
Green leafy plants, grasses, and alfalfa are excellent sources of vitamins for swine. However, with increased confinement rearing and continual usage of pastures and outside lots, very often little plant material is available. In addition, with fewer ingredients used in diet formulation, there is no longer the variety of feed ingredients to supply added vitamins. Finally, vitamin content of grains and protein sources may be unavailable or lost during storage. Therefore, when formulating swine diets, it is recommended to specify all vitamin and trace mineral levels as "added" levels. This helps to eliminate some of the confusion and difficulty in determining availability and concentrations in feed ingredients.
Because the natural sources of the vitamins may not be present in swine diets, it is recommended that a vitamin supplement be added. Synthetic vitamins are produced by many companies and are sold individually or in various combinations. Synthetic vitamins may be more accessible than some of the natural sources of vitamins.
A suggested vitamin premix is listed in Table 11. This premix is designed to be fed to all ages of pigs by adjusting its inclusion rate. Therefore, it is necessary to use a sow add pack (Table 12) for gestation and lactation diets. Although this single premix is over-fortified on certain vitamins for pigs depending on age, there is less potential for vitamin potency losses during long storage.
Even though the vitamin premix is correctly formulated before leaving the manufacturer, it does not necessarily mean that it will have adequate levels of vitamins to meet the pig's daily dietary requirements. Premix abuse can contribute to borderline vitamin deficiencies. Table 13 show factors that affect vitamin stability. Some vitamins are much less stable than others; therefore, care of the vitamin premix is extremely critical for optimum performance. To maintain vitamin potency, it is recommended that vitamins be stored in a dry, cool, dark place. Because vitamins are hygroscopic (absorb moisture) vapor barriers such as plastic-lined sacks will aid in reducing moisture levels, especially when the humidity is high. If trace minerals are present in combination with the vitamins in the premix or base mix, storage time should not exceed 60 days. However, if vitamins or minerals are kept separate, they may be stored up to six months.
Choline is important in nerve function, protein synthesis, and structural development. Choline in the strict sense is not a vitamin because pigs can synthesize sufficient choline for their needs, provided that specific chemical substances are available. However, as a safety factor, supplemental choline is recommended. Choline is one of the most expensive vitamins added to premixes. It may represent 10-25 percent of the cost of vitamin supplementation. The cost of choline in gestation diets can be justified by the increase in the number of live pigs born and weaned when it is added at the rate of 500 grams per ton of complete feed.
In the past, the cause of spraddle legs in baby pigs has been attributed to a deficiency of choline. Recent research indicates that choline deficiency is not a major factor in this condition. The cause(s) of spraddle legs is not fully understood, but it may involve several factors including: Genetics, management, slick flooring, mycotoxins, and a virus or combination of viruses.
Although the requirement for choline has not been defined, 100 grams per tone of complete feed is recommended to prevent a possible choline deficiency in growing-finishing pigs.
There is much debate as to how much vitamin E should be added to swine diets. This is a result of the many factors that influence vitamin E concentrations and requirements. Some of these include: artificial drying of grains, storage time and conditions, unsaturated fatty acids, and selenium concentrations. Because of the high incidence of Mulberry Heart Syndrome in North Carolina swine herds, at least 40,000 IU/ton of vitamin E should be added to sow and nursery pig diets.
Although vitamin K occurs in many natural feedstuffs and is also synthesized by intestinal microflora of the pig, a deficiency can be caused by low stability and moldy feeds. Deficiency characteristics are hemorrhaging and prolonged blood clotting time, but can also include blood-tinged urine, lameness, and listlessness. When specifying vitamin K requirements, it is important to indicate menadione, which is the active form of the vitamin.
Several experiments have been conducted to determine the value of supplemental vitamin C or ascorbic acid in swine diets. The majority of the research indicates that vitamin C supplementation will not improve pig performance.
Biotin and folic acid are two water-soluble vitamins that have been studied to evaluate their influence on overall reproductive performance. Biotin deficiency has been associated with foot lesions and toe cracks in sows. However, research is contradictory, with some experiments finding benefit from biotin additions and others not. The availability of biotin in grain may be a possible factor for these discrepancies. Therefore, 200 mg/ton biotin is recommended to be added to sow gestation and lactation diets as an insurance factor.
Folic acid participates in many enzymatic reactions that appear to be essential in assuring embryo survival. Research indicates that the addition of 1500 mg/ton of complete feed will increase the number of pigs born alive by approximately one pig per litter.
In the last 10 to 15 years, vitamin and trace mineral additions have become increasingly important because of changes in feeding, housing and management systems. Some of the more important changes include:
Increased confinement production has denied swine access to soils and grazing crops, which provided vitamins and minerals.
Increased use of slotted floors has prevented recycling of feces, which may be high in B-vitamins and vitamin K that are synthesized by microorganisms in the large intestine.
Reduced use of multiple protein sources in diets. If multiple protein sources are used, they often complement each other in providing the vitamin and mineral needs of swine.
Reduced daily feed intake during gestation. Dietary vitamin and mineral concentrations must be increased as daily feed intake is decreased. With the trend towards moving sows from outside gestation lots into environmentally controlled buildings, maintenance requirements and feeding levels will be lowered. Therefore, to prevent shortages with decreased feed intake, vitamin and mineral requirements should be expressed on an amount/day basis rather than percentages.
Earlier weaning of pigs. There is increasing pressure to wean pigs at an earlier age. Three to 4-weak weaning is commonplace. As weaning age decreases, the quality of the diet with respect to all nutrients becomes more critical.
Bioavailability of nutrients in heat-dried grains and feed ingredients appears to vary widely. Inhibitors and molds in feed may result in reduced absorption, increasing requirements for certain vitamins.
Water is so common we seldom think of it as a nutrient, but it is probably the most essential and the cheapest of all nutrients. Depriving hogs os water reduces feed consumption, limits growth and feed efficiency, and causes lactating sows to produce less milk. Water affects many physiological functions necessary for maximum animal performance. Among these are temperature regulation, transport of nutrients and wastes, metabolic processes, lubrication, and milk production.
The water requirements of swine are variable and governed by many factors. Water accounts for as much as 80 percent of body weight at birth and declines to approximately 50 percent in a finished market animal. The need for water is increased when a pig has diarrhea. High salt intake, high ambient temperature, fever, and lactation also markedly increase water requirement.
Water requirement has a relationship to feed intake and to body weight. Under normal conditions, swine will consume 2 to 5 quarts of water per pound of dry feed or 7 to 20 quarts of water per 100 pounds of body weight daily. A rule of thumb is that self-fed hogs will consume 1.5 to 2 times as much water as feed.
Temperature will affect water intake. Additional energy is required to warm liquids consumed at temperatures below that of the body. Lactating sows must have unlimited access to water ( about 5 gallons a day) if they are to milk adequately, and suckling pigs past 3 weeks of age need water in addition to that in sows' milk for optimum performance. Free access to water located near feeders is desirable.
Recent research shows that water flow rate has little effect on growing-finishing pig performance. However, pigs will take longer to drink when water flow rate is reduced. Suggested water flow rates based on phases of production are listed:
Nursing pigs and hot nursery pigs:
1 cup (250 cc) of water per minute
Pigs from 25 to 50 lb (nursery):
2 cups (500 cc) of water per minute (1 pint)
Pigs from 50 125 lb (grower):
3 cups (750 cc) of water per minute
Finishing hogs, 125 lb to market:
4 cups (1000 cc) of water per minute (1 quart)
Sows and boars:
2 quarts (2,000 cc) of water per minute.
There has been renewed interest in wet feeding, and several "wet" feeders are available. Research with starter pigs indicates that wet feeding results in poorer feed efficiency. However, research with finishing pigs has shown a slight improvement in feed conversion. Probably the biggest concern with wet feeding is the increase potential for spoilage and mold problems from wastage. Therefore, if using wet feeders, feeder management and cleaning will be increased.
Saline waters are found occasionally throughout the United States and cause concern about their use as drinking water for humans and livestock. Minerals most commonly found in ground and surface waters are sulfates, chlorides, bicarbonates, and nitrates, which form salts with calcium, magnesium, or sodium. The combined concentrations of these minerals are called total dissolved solids. Heavy applications of fertilizers to fields, contamination of runoff water by animal wastes, and severe drought can increase the potential for water quality problems.
Sulfates. Sulfate salts are of special concern because of their laxative effects. Some effects of high levels of sulfates in drinking water for swine are: (1) diarrhea, (2) poor gains and feed efficiency, (3) nervousness, (4) stiffness of joints, (5) increased water consumption, and (6) decreased food intake. Researchers have reported an increase in scouring of growing pigs consuming water containing 3,000 parts per million sulfates, but gain and feed efficiency were not affected. This level of sulfates did not adversely affect reproductive performance of sows.
Nitrates/Nitrites. Nitrites impair the oxygen carrying capacity of the blood by reducing hemoglobin to methemoglobin. The conversion of nitrate to nitrite in water is necessary for toxicity to occur. Research indicates that approximately 100 ppm nitrate nitrogen is generally safe. However, 300 ppm nitrate nitrogen can result in toxicity.
Total Dissolved Solids. It appears that for swine, moderate contamination of water supplies by sulfates or nitrates may be intensified by concentrations of other dissolved minerals. Total dissolved solids (TDS) measures minerals that contribute to the salinity of the water, such as sodium chloride, and calcium and magnesium salts. High TDS may lower the toxicity levels for sulfates and nitrates. Approximately 5,000 parts per million appears to be the maximum safe level of total dissolved solids in drinking water for swine without adverse affect on performance.
The use of feed additives in swine diets has been extensive in the United States for more than 40 years. Feed additives are used by most swine producers because of their demonstrated ability to increase growth rate, improve feed utilization, and reduce mortality and morbidity from clinical and subclinical infections.
In general, additives available for swine producers fall into five classifications: (1) antibiotics, (2) chemobiotics or chemotherapeutics, (3) anthelmintics or dewormers, (4) copper compounds, and (5) probiotics.
An antibiotic is a compound synthesized by living organisms, such as bacteria or molds, which inhibits the growth of another. Chemibiotics are compounds similar to antibiotics but they are produced chemically rather than microbiologically. Anthelmintics or dewormers are compounds added to swine diets, generally for short intervals, to help control worm accumulation.
Copper compounds (copper sulfate) have growth-stimulating value similar to antibiotics. They are also effective as a therapeutic treatment for intestinal disorders that do not respond satisfactorily to antibiotics or chembiotics. Probiotics, which means "in favor of life," have an opposite effect to antibiotics on the microorganisms of the digestive tract. It has been theorized that probiotics increase the population of desirable microorganisms instead of directly killing or inhibiting undesirable organisms.
There are many feed additives on the market, and they differ widely in chemical composition and mode of action. Selection of a specific feed additive and the level needed for optimal response will vary with the existing farm environment, management conditions, and the stage of the production cycle.
It is highly recommended that an accurate diagnosis and an antibiotic sensitivity test be performed to determine what compounds would be effective. In the long run, the initial expense of a sensitivity test will be of great value because unnecessary drugs and inadequate levels will be avoided.
Producers who are planning to use a feed additive for treatment or prevention of a disease should consult their veterinarian or other professional who has training in the pharmacodynamics and efficacy of drugs. Some drugs (example--nitrofurazone is still approved but seldom of value in outbreaks of swine dysentery) are not as effective as others.
Certain drugs will appear to be a good treatment based upon a sensitivity test, but will be unsatisfactory because the drug has limited absorption from the intestine. Furazolidone and neomycin often appear to be good drugs against organisms causing pneumonia, but neither are absorbed to any degree from the intestine. Rotation of antibiotics, evaluation of different antibiotics, or use with approved mixtures may be advisable, if the response to a feed additive appears to be diminishing.
Because antibiotics are expensive and their use is coming under greater scrutiny by health authorities and the public, their indiscriminate use should be avoided. Antibiotics should not be used to replace good management.
Level of usage depends upon the type of additive and the purpose of the compounds. Table 14 lists some of the common feed additives. Note that many additives have two level--one for prevention and one for treatment. Always consult manufacturer's direction before mixing. In addition, the Food and Drug Administration has proposed that the subtherapeutic use of certain antibacterial compounds in feed be restricted and withdrawal periods observed. Thus, it is important to recognize that approved usage of any feed additive and withdrawal periods are subject to change, and it is imperative to keep updated on any changes.
Certain feed additives must be withdrawn from the feed prior to slaughter at varying intervals to ensure residue-free carcasses. Some withdrawal periods for commonly used feed additives are listed in Table 14. Be sure to read the feed tags to determine withdrawal time.
The response to feed additives is greatest in starter (10 to 50 lb) diets. The response to feed additives is less during the finishing period (125 lb to market weight) than it is at younger ages. Because of the expense of antibiotics and the expected improvement in performance, their use in finishing diets is questionable.
Herds that have experienced problems with conception rates and litter size have often been helped by the addition of antibiotics to brood sow diets. However, the routine feeding of antibiotics to the breeding herd is discouraged, unless there is a history of reproductive problems.
The use of copper sulfate as a growth promotant in swine has become widespread in the United States and Europe. Research has shown that when 125 to 250 ppm of actual copper (1 to 2 lb of copper sulfate per ton) is added to starter pig diets, an improvement in growth and feed efficiency and a reduction in mortality is observed. When a combination of supplemental copper and antibiotics is fed in starter diets, improved performance is observed compared with the addition of antimicrobial agents alone. Copper sulfate can be added to starter pig diets but is not recommended for use in the finishing phase.
Cooper sulfate increases corrosion, thereby reducing the longevity of galvanized woven wire floors and feeders. It also has been shown to decrease the bacterial degradation of manure in lagoons. Copper, when fed in excess of 300-500 ppm (2.5 to 5.5 lb of copper sulfate per ton), may be toxic, particularly if the diets are low in zinc and iron.
Probiotics are organisms that, rather than killing pathogenic bacteria like antibiotics, help stimulate proliferation of desirable organisms. Probiotics can be classified into two types--live microbial cultures and nonviable fermentation products of microbes. The most common microorganisms included in probiotic products are Lactobacillus, Streptococcus, and Bacillus, a bacterium that normally inhabits the digestive tract of healthy animals. It has been theorized that these bacteria remove waste products and inhibit the growth of certain undesirable bacteria.
Numerous research reports indicate little if any benefit of probiotics on pig performance. Therefore, their use in swine diets is not recommended and economically unjustified.
Producers are bombarded with products and additives that promise improvements in growth performance, sow production, etc. Claims are often too good to be true and, can be best described a "wiffle dust." When evaluating new products, use common sense and ask to see the results of scientific testing. Products are often promoted based on testimonials. If you have any questions concerning the use of a product, contact your county agent, Extension specialist, veterinarian, or swine consultant for an impartial and objective evaluation.
Grinding is the most common method of feed processing for the swine producer and nearly all feed ingredients will be subjected to some type of particle size reduction. Particle size reduction increases the surface area of the grain, allowing for greater interaction with digestive enzymes, improving feed efficiency. It also improves the ease of handling and mixing characteristics. However, fine grinding will increase the energy costs of feed processing and may result in the feed bridging in feeders and bulk bins. increased dustiness, and the potential for gastric ulcers. Therefore, the increased costs of fine processing must be offset by the resulting improved feed conversion.
Confusion exists concerning the optimum particle size of swine diets because of broad classification like "fine, medium, and coarse," used to define particle size. In addition, different grains, because of their kernel size and shape, will produce a different particle size when ground through the same screen. At present, considering improvements in feed efficiency, processing costs, incidence of gastric ulcers, and potential for bridging, an average particle size of 700 to 800 microns is recommended.
In addition, fine (700 microns) grinding of high-fiber feed ingredients has been shown to improve their feeding value. As a rule of thumb, if there are whole kernels in your feed, it is probably not ground fine enough,a nd you may be losing 5 to 8 percent in feed efficiency. Results of over 1,500 samples analyzed at Kansas State University since 1985 indicate that 70 percent of the samples are over 800 microns in particle size.
This is one of the most frequently asked questions concerning particle size reduction. Either mill is capable of producing the desired particle size. However, there are advantages and disadvantages that must be considered to determine the best mill for your operation. Hammermills have greater capacity per unit horsepower, and it is easy to change from grinding one grain to another by changing screens. However, a hammermill requires more energy than a roller mill and will produce a higher percentage of fines and dust.
A roller mill requires about 28 percent less energy to produce a 700-micron particle size than a hammermill, but if grain types are to be changed frequently, the roller mill will need to be adjusted for each grain. For processing grain with a hammermill, screen size will vary based on type of grain. Corn and wheat may be processed through a hammermill equipped with a 3/16-inch screen, whereas a 1/8-inch screen is recommended for processing milo, barley, and oats. By using these screens with the respective grain, a 700- to 800-micron particle size should be achieved.
Condition of screens and rollers will be critical in grinding efficiency and maintaining optimum particle size. Screens and hammers need to be checked at least monthly for wear and replaced if there are holes in the screen or if the holes become funnel-shaped. Hammers can also be reversed or replaced if they become worn.
In roller mills, three criteria are essential in producing a 700- to 800-micron particle size: (1) the rolls should be moving with a differential drive of one roll moving 50 to 75 percent faster than the other to produce a shearing action that will help "cut" the kernel rather than crush it; (2) the rolls should have corrugations to help slice the grain, with the desired corrugations per inch of roll being 8 to 10 for corn, 10 to 12 for wheat, barley, and oats, and 12 to 14 for milo; (3) the corrugations should have a 1- to 2-inch spiral to increase the shearing potential and eliminate fines. Magnets are important to remove any metal objects from the grain and increase the longevity of hammers, screens, and rollers. Both hammermills and roller mills should be checked periodically for wear.
There are many different methods for processing feed for pigs. In addition to grinding, the most common forms of feed processing are pelleting, extruding, and roasting.
Pelleting. Pellets can be made of different lengths, diameter, and degree of hardness. The ingredients of the diet will influence the hardness of the pellet and pellet quality. Various studies suggest a 3 to 10 percent improvement in growth rate and feed efficiency when pigs are fed pelleted diets rather than a meal. This appears to result from less feed waste with pelleted feeds. Pelleting appears to improve the nutritional value of high-fiber feed ingredients to a greater extent than that of low-fiber ingredients. This may be a result of increasing the bulk density of the feed. However, as energy costs increase, the economics of pelleting swine feeds may be change. The increased diet cost must be offset by the improved feed efficiency or other productive measure of pigs fed the pelleted diet. Of future importance is the potential benefits that pelleting produces by sanitizing the feed. This aspect has yet to be examined in swine production and may play an intergral part in future production systems.
Extrusion and Roasting. Extrusion processing involves the application of heat, pressure, and (or) steam to an ingredient or diet. Extruders are sometimes used for on-farm processing of soybeans. If properly heated, this is an easy way to add fat to swine diets and utilize home grown soybeans. Recent research shows that moist, extruded, soy protein concentrate is an excellent protein source for baby pigs.
Because of volume and tonnage, extrusion of complete feeds is usually not economically justified based on performance of pigs fed extruded complete feeds. Furthermore, extrusion increases the bulkiness of the diet, making it more difficult for the pig to consume enough feed to meet its nutrient requirements.
Roasting can also be used to process home-grown soybeans. This can also be an alternative method for adding fat to swine diets. However, roasting temperature and times must be checked to ensure adequate processing. The added cost of the extruded, or roasted products must be the ultimate consideration in determining the feasibility of their use in swine diets.
Other Processing Methods. Several alternative processing methods are available to swine producers. Steam flaking, micronizing, and other processing methods often do not improve pig performance enough to justify the added expense of processing. When evaluating the expense of feed processing methods, the following equation will determine if it is justified:
percent improvement in feed efficiency needed to offset added diet cost
High-moisture grain is similar in feeding value to regular grain on a dry matter basis. Rate of gain and feed efficiency, when compared on an equivalent dry basis, have been essentially the same for pigs fed high-moisture or dry grains in a complete diet. Some studies with high-moisture grains and free-choice supplement have indicated that under- or over-consumption of protein supplement is a problem. It is recommended that high-moisture grain be included in a complete ground and mixed diet. The amount of supplement needed for proper diet formulation is influenced by the amount of moisture in the grain (Table 15).
The use of high-moisture grain in a swine feeding system is an economic decision rather than a nutritional one. Although using high-moisture grain adds flexibility in timing of harvest and eliminates the need to dry grain, storage facilities can be costly and management to prevent spoilage is critical. Fresh feed must be mixed every 1 to 2 days to prevent spoilage of the mixed feed in the feeders. Thus, the various costs involved should be carefully studied for each individual case before a sound decision can be made.
If you plan to use an organic acid preservative, the high-moisture grain should be treated as soon as possible after harvest, especially during warm weather. Rate of acid application varies with the moisture content of the grain and the intended length of storage. The higher the moisture content of the grain, the greater the amount of acid needed for proper preservation. Table 16 gives the recommended rates for 100 percent propionic acid for a maximum storage period of 1 year. These rates are listed for corn, but would be suitable for other grains. The acid application preserves the grain by inhibiting mold growth. The acid reduces the Ph of the grain below the mold requirement and also kills the grain germ.
As outlined in the introduction of this guide, swine producers have several options for mixing feed. In general, there is a trend towards taking more of the responsibility for mixing feed. This generally lowers feed costs and increases the flexibility a producer has in mixing several different diets, but more time, labor, and facilities will be required.
Probably the biggest concern is that the producer must now take on the added responsibility of quality control to ensure a properly formulated and mixed diet. It is difficult to determine the size of operation for which it is profitable to assume mixing and formulation responsibilities. This will also vary with the preference and goals of the producer.
A commonly suggested tonnage at which one should consider replacing purchased complete feed or supplements with soybean meal and base mixes or premixes is between 500 to 750 tons per year. To calculate the distribution of your feed costs, it is estimated that a sow and her pigs (assuming 18.5 pigs per year) will require 7.3 tons of feed per year. This includes boar feed as well. Of that 7.3 tons, the feed will be distributed as follows:
Diet % of Total Starter I 1 percent Starter II 2 percent Starter III 3 percent Grower I 13 percent Grower II 20 percent Finisher 45 percent Gestation 10 percent Lactation 6 percent
By multiplying your present feed costs per phase by the projected tonnage, you can quickly see where the bulk of your feed dollars go. This often helps to determine the cost comparison between feeding programs. Comparing these values to your actual usage is also a useful diagnostic indicator to see if you are feeding the correct feed for the correct period of time, i.e., not overfeeding one phase and underfeeding another.
In addition to particle size reduction, the producer must also be concerned about whether or not the feed is being mixed properly, and ingredients must be accurately weighed. A preferred way to accomplish this is with a gravimetric scale, rather than a volumetric meter. If a volumetric meter is used, it must be recalibrated often, because bushel weights change frequently. With a premixing system, only scaled, batch mixing operations, not volumetric mills, should be used.
Mixers and mixing time vary considerably. Mixing times for horizontal mixers are approximately 5 minutes. Worn ribbons or paddles will increase the time necessary to adequately mix a batch of feed. Vertical mixers and on-farm grinder-mixers generally required approximately 15 minutes to mix a batch of feed. Tests have shown that over-filling mixers greatly increases the amount of time needed for mixing. Worn ribbons and screws will also contribute to increased mixing times. Very often, manuals underestimate the amount of time necessary for feed mixing.
A mixing test is a sure way of knowing the correct mixing time for your mixer. Mixing efficiency can be measured by taking several samples of feed from one batch cycle and analyzing them for salt content. The variation between samples in salt content is used as an indicator of properly mixed feed (10 percent). If feed is under-mixed, this will be more of a problem for young pigs because they eat only a little feed. Larger pigs, however, by virtue of their greater feed intake, may be less susceptible to marginally mixed feed.
The sequence in which feed ingredients are added to a mixer may influence mixing efficiency and feed uniformity. Ingredients should be added in the following order: (1) half of the grain; (2) protein sources, vitamins, minerals and feed additives; (3) the remainder of the grain.
There is a common misconception that feed, if mixed too long, can become "unmixed." Tests indicate that feed reaches a "steady state" of being mixed and remains at or near that point for an extended period of time. However, during transportation of mixed feed or ingredients it is possible that segregation of ingredients may occur.
As you assume more responsibility for mixing your own feed, quality control will be vital to avoid use of inferior feed ingredients. A stringent and tough quality control program will help in this effort. Quality control programs will vary based on the size of the operation and tons of feed used. However, the following is a suggested program indicating the items to check and how often. These are only suggestions, and you may check them more or less frequently as you see fit.
Particle size. Based on the tonnage processed per year, particle size should be checked very 400 to 500 tons of feed processed. If you notice whole kernels or even half kernels, these can be indicators of a hole in a screen or worn hammers or rollers.
Mixing efficiency. Mixers should be checked for proper mixing times when they are first installed, then updated periodically as screws, augers, and paddles become worn. This can be once every year or two, depending on tonnage mixed.
Grains. Moisture content and test weight will be most critical as indicators for determining grain quality. In addition, foreign materials and presence of molds or other contaminants that can occur because of improper storage should be noted. A moisture tester and a blacklight (for aflotoxins) can be practical means for on-farm testing of grain quality. Protein content can also be checked to determine quality.
Soybean meal. Soybean meal is the most common protein supplement used. Standards are established for protein, fiber, moisture, and calcium. The purchaser is entitled to price adjustment should these criteria not meet set standards. However, this price adjustment does not happen automatically. The producer must have the soybean meal analyzed and request a price adjustment.
When purchasing a new load, request an official sample and ask the company for a written description of the content. Then send the sample to a refereed analytical laboratory for analysis. You may decide to take a duplicate sample for analysis when it is unloaded. Generally, 48.5 percent soybean meal will have less fiber and be a more consistent protein source than 44 percent soybean meal. Other protein sources are often variable in nutrient content and should be analyzed for protein content as an indicator of amino acid content. This variation is often a hidden cost of using alternative protein sources.
Whey and fish meal. Because these ingredients are often added to baby pig diets, quality is essential. Specify "edible grade" dried whey and "select menhaden" fish meal. These producers often have excellent and predictable nutrient quality.
Dicalcium phosphate and limestone
A common problem for producers is formulating their diet with dicalcium phosphate (21 percent Ca and 18 percent P) and buying monocalcium phosphate (18 percent Ca and 21 percent P). Always check feed tags and ingredient labels.
Complete supplements, base mixes, and vitamin and trace mineral premixes. Check periodically for certain nutrient content. Generally, this will include screening for two to four nutrients and rotating the nutrients checked with each batch. Check the more expensive nutrients such as protein, phosphorous, vitamin E, and riboflavin.
Fats and oils. Rancidity may be the biggest problem with fat and oil sources. If questionable, check for free fatty acids and MIU (moisture, impurities, and unsaponafiable material). A high quality fat source is essential in formulating swine diets.
When storing fats or oils for long periods of time, stabilize them with an antioxidant, such as ethoxyquin, BHT, or BHA.
Complete diets. If a stringent quality control program is followed on all incoming ingredients and processing, there should be little need to check the final product. However, periodically checking one or two of your diets on a rotational basis is a good way to double check your system. Check for moisture, protein, and possibly calcium and phosphorus.
The preceding items are typically the more expensive nutrients and are most likely not to exceed minimum requirements.
Fill out a diet formulation sheet, including prices and as much diet content information as possible. Feed tags and a complete ingredient description should be included when possible. These records can provide important historical information about your operation's feeding program.
Check your calculated nutrient composition and compare it to those suggested by North Carolina State University.
Check your diets frequently. Again, check the tonnage used by each phase of production to make sure you are not over-feeding a diet. Also, continually check prices of your diets and cost per cwt of pork sold.
Nutrient composition can vary within each specific batch of feed to such a degree that chemical composition can be significantly altered based on a non-representative sample. A composite sample that is representative of the complete batch mix is the key to successfully determining nutrient concentrations. Sampling is a step-wise procedure that must be scrutinized heavily to ensure that proper samples are obtained. First, identify the most practical method of sampling based on the mixing system, feeding program, and the purpose of the sample.
Samples taken to determine mixing efficiency are not composite and must be analyzed individually, whereas samples taken to determine crude protein, calcium, amino acids, etc., must be composite to determine average composition. Thus, the first step is identification of sampling location. The following locations are acceptable for obtaining samples:
Mixer. Samples can be taken using a grain trier/probe from separate locations within the mixer; approximately 10, 1-lb samples should be taken and combined into one composite sample for chemical analysis or kept separate for mixing efficiency tests. The most common method of sampling a mixer is to obtain 10 samples at the discharge outlet while unloading the mixer. Take care to avoid sampling the initial output as well as the final output, because these can be extremely variable.
Bulk feed. Take samples during the loading or unloading process and at timed intervals to ensure a representative sampling. Use an in-line, automatic sampler while moving the product to a bin or while loading a truck or car. However, grab samples may be obtained while unloading the product at the destination. The samples can be combined for chemical analysis or kept separate for mixing efficiency tests.
Sacked feed. Samples should be obtained using a bag trier/probe. Samples taken by hand, with a cup or with a dipper, are most common, but often fail to provide the best possible sample. Ten, 1/2 lb samples should be obtained, but deviation may be necessary depending upon the number of sacks in the lot. The bag should be laid horizontally and probed diagonally from end to end. From lots of 1 to 10 bags, sample all bags; and from lots greater than 11 bags, sample 10 bags. Samples should be combined for chemical analysis and are probably not best used for mixing efficiency tests.
Variation is calculated nutrient concentrations and actual analyzed values are affected by many factors. Some of these include: sampling error, inadequate mixing, inadequate calibration of scales or volumetric mixers, and storage losses. In addition. certain tolerances are allowed for accuracy of specific lab analyses. The 1990 official publication of the Association of American Feed Control Officials lists the following analytical variations as guidelines for helping officials make routine decisions on acceptability of feed ingredients.
Table 1. Analytical Variation
Item % Moisture 12 Protein (20/x + 2) Fat 10 Fiber (30/x +6) Calcium (14/x + 6) Phosphorus (3/x + 8) Riboflavin 30
In these examples, x equals the percent guarantee, i.e., if the protein guarantee is 10 percent, the analytical variation is 20/10 + 2 = 4 percent. This means that the sample must contain between 9.6 and 10.4 percent protein to be acceptable. Analytical variation is not reported for amino acid analysis, but variation from 20 to 30 percent can be anticipated.
Yes, because individual feed ingredients will vary testing results will aid in diet formulation. An alphabetical list of commercial analytical laboratories appears in Table 17. This listing is for information only and does not constitute an endorsement of the labs listed nor a discredit to any lab inadvertently omitted from the list. Contact the lab of your choice for a price list and for instructions on size of sample, sample methods, and mailing.
An open formula is a listing of ingredients and nutrient concentrations supplied in a complete feed, protein supplement, base mix, or premix. This information is listed on the feed tag and readily available to the producer. It can be used to compare prices based on nutrient specifications to ensure that they meet the pig's requirements. Closed formulas do not provide nutrient specifications, making it virtually impossible to determine cost/unit nutrient or the nutrient levels provided in the diet.
To make sound economic and management decisions concerning feeds and feed ingredients, the use of open formulas in swine diet formulation is strongly encouraged.
Bids for the feed business of a swine operation can be conducted on complete feeds, supplements, base mixes, or premixes. The format for setting up a bidding system is simple, with the producer working with his nutritionist, veterinarian, or consultant to set up guidelines for nutrient specification. These guidelines are then submitted to interested feed manufacturers, who will submit a bid for the producer to consider, it is essential that the producer follow these few steps to ensure the fairness of the bidding procedure.
Write extremely clear and narrow nutrient specifications so that products cannot be misrepresented.
List all essential nutrients that must be included in the product to be bid on. Make sure you do not leave out any nutrients. This is a common mistake made by producers. Any additional nutrients or ingredients that a feed company includes in the product are extras with no nutritional or economic value.
List all nutrient levels per pound or ton that must be guaranteed in the product. These guaranteed levels (maximums or minimums) will be used in the quality control program. A common mistake is that producers will specify 500 grams of choline chloride when they want 500 grams of choline. In a bidding process, 500 grams of choline chloride (50 percent choline) would leave the final diet 50 percent short on meeting the pigs' choline requirement.
List the desired ingredient sources for each of the nutrients. This is essential to provide uniform product comparisons.
Include any desired mixing directions, nutrient carriers, or information that will help the feed company meet the customer's needs. This may also include medications and the desired levels.
Pellets less than 20% meal in farm bin
$2.5 per 5% unit difference above 20% (i.e., $2.5 - 25% fines, $5 - 30% fines, etc.)
Maximum particle size of 700 microns in pelleted feed
Maximum particle size of 900 microns in mash feed
$2.5 per 50 microns above max. (i.e., $2.5 - 50 microns above, $5 - 100 microns above, etc.)
Maximum moisture of 13%
$5 per .5% unit above 13% (i.e., $2.5 - 13.5%, $5 - 14%, etc.)
Individual products are expected to meet minimum and not exceed maximum nutrient specifications.
For amino acids, the per ton credit is established at $10 per 5% deviation below the recommended minimum.
For nutrients other than amino acids, the per ton credit will be $2.5 per 5% above or below recommended maximums and minimums, respectively.
A 5% analytical variation is allowed before compensation. Thus, if the analyzed content falls within 5% of the specified min. or max., then no credit is to be given.
The credit will be computed by calculating the percentage unit deviation of the analyzed sample from the analytical min. or max. For example, if the specified maximum on Ca is .9% and if it analyzed 1.1%, the analytical max. is .95%. Thus there is .15% unit deviation or 3 credit units above analytical max., and the per ton credit is $7.5.
Credit = (Analyzed - Analytically Allowed) Specified .05 Credit Value
Where:
Analyzed = Laboratory value in % unless specified otherwise
Analytically Allowed:
For maximums = (max.) + (max. .05)
For minimums = (min.) + (min. .05)
Specified = Nutrient specification min. or max.
Credit Value = per ton $ credit for each 5% deviation
Yes! Nursery diets should contain specifications on specfic ingredients. A suggested list of alternative ingredients is specified under each diet. These are only guidelines and ingredient quality will dramatically affect how ingredients are used in swine diets.
Gastric ulcers occurring around the esophogeal opening in the stomach have been identified as a major problem in swine production. Many researchers have identified an association between the incidence of gastro-esophogeal ulcers and fineness of grind, pelleting, wheat feeding, and added fat. There is most likely a high relationship between the amount of fat, pelleting, and wheat feeding and the incidence of ulcers, but these factors do not result in ulcers consistently. Because wheat is lower in energy than corn, fat is added to attain the same digestible or metabolizable energy content as a corn-based diet. Also, pelleting allows for the inclusion of bulkier ingredients, which are typically lower in energy than the ingredient they replace. As a consequence, when pelleting one typically sees higher fat diets which are typically ground very fine to attain good pellet quality and bulk density.
Several other possiblilities for the high incidence of gastric ulcers in North Carolina may include the amount of non-esterified fatty acids found in the fats fed. Research has shown that these non-esterified fatty acids, alcohols, and volatile fatty acids can cause deterioration of the stomach lining. Coupling these issues with the fact that feed intake can vary greatly in North Carolina. When intake is reduced, stomach acid production may be very high and coupled with the many other factors, results in deterioration and ulceration of the stomach lining.
To prevent problems with gastric ulcers, diets should not contain excessive amounts of added fat. Also, the use of higher fiber ingredients, such as wheat middlings may help alleviate the problem. The use of antioxidants in your fat tanks will reduce the potential for rancidity, and help to reduce antioxidant losses in the feeds. Some forms of vitamine E serve as antioxidants in the feed and can easily be rendered useless if dietary fat is not stabilized. However, most currently available forms of vitamin E, such as alpha-tocopherol acetate, do not become functional until the enter the animal. Feeding a coarse ground feed may also alleviate some ulcer conditions, but changes in feed efficiency should be weighed against mortality and mobidity rates.
It is important that new-born pigs receive colostrum during the first 24 hours post-farrowing. Colostrum contains the antibodies necessary for building up the baby pig's disease resistance. Bovine colostrum can be administered in addition to the sow's colostrum and can be easily stored in an ice cube tray and thawed as needed. Commercial colostrum products are available, but little research is available to currently recommend their use.
Equalizing litters within 24 to 48 hours and transferring pigs so that litters contain pigs of similar weight can improve pig survival. Commercial milk replacers can also be sued to provide supplemental milk during lactation or the first few days post-weaning. A good milk replacer should contain at least 24 to 28 percent protein and 8 to 10 percent fat. Homemade milk replacer can be made from the following:
One quart milk
One raw egg
One pint half and half
4 cc neomycin
Research shows that very little creep feed will be consumed before 3 weeks of age. Often, more creep feed is wasted than consumed before then. It is recommended that creep feed be fed three to four times per day to keep a fresh diet in front of the baby pig. Pan or floor feeding may aid in increasing the consumption of creep feed. Feeders should only be used if they allow adequate access to the feed. Because of the feed wastage problems with creep feeding one should consider using a diet slightly less expensive than your first phase nursery diet. If you are considering the use of creep feeds, you should conduct a test using a minimum of two to three farrowing groups and a minimum of 30 to 40 sows per treatment.
Usually, when pigs are weaned at 3 to 4 weeks of age, they will go through an adjustment period. In many cases, newly weaned pigs will just maintain their body weight for the first week after weaning. Severe growth depression may result from poor ventilation, poor santitation, and poor diet selection. Although the starter diet can significantly improve performance, environmental factors can easily overshadow the benefits of a good diet.
It is beneficial to review some of the reasons why problems often develop shortly after weaning so any environment or management problems can be corrected.
There is physical stress at weaning time. Because the baby pigs are being transferred from a diet high in lactose to a diet largely consisting of very complex starch. Also, there is a physical change between liquid and dry feed, although some dry feeds can yield the same performance as liquid feeds.
The baby pig has a relatively under-developed digestive tract at 3 weeks of age and must adjust to dietary changes.
The baby pig has a limited ability to produce antibodies, which it primarily obtained from its mother during lactation.
With a sparse hair coat and relatively little body fat, the baby pig has a limited heat regulating mechanism.
Baby pigs are forced to make a social adjustment--going from the security of their dam to new environments with new pen mates.
Phase feeding is a term used to describe the feeding of several diets for a relatively short period of time in order to closely meet the pig's nutrient requirements. When one diet is fed for along period of time, it is usually under the young pig's nutrient requirements and over fortified for the older pig. By phase feeding, you may minimize this over- and under-feeding and provide a more economical feeding program for the pig (Table 18).
Because the baby pig undergoes more dramatic changes in digestive development, the most common application of phase feeding is for starter pigs. By phase feeding, you can match the baby pig's nutrient requirements and digestive capabilities with the most economical diet possible, yet get maximum performance in the nursery. Although these diets are expensive, the low amount of feed used and excellent feed efficiency justifies the cost.
Scheduled feeding is not a unique concept, however it is a very important aspect of North Carolina Swine Production. The ability to alot a specified amount of feed to a group of pigs is extremely important in controlling feed costs. The use of a feeding schedule will allow trained professionals assist you in determining a feeding program which will maximize profits. Table ? demonstrates a nursery feeding schedule based on the recommended diets. One can easily evaluate the benefit of a particular starter diet, and conduct "What-If" analyses.
Some people feel that slower growth rate in the nursery will be made up in the growing-finishing phase by compensatory gain. This concept originates from the belief that during a time of nutrient stress, the animal becomes more efficient at utilizing nutrients once the restriction is removed. The result would be more efficient growth after the restriction phase. This philosophy is flawed by the fact that if the animal was capable of achieving the increased efficiency after stress, it should be capable of achieving it without the stress. This is supported by current research showing that every additional pound a pig weighs coming out of the nursery will result in fewer days to market.
Dried whey and dried skim milk are by-products of the cheese and fluid milk industry. Whey contains most of the water-soluble components of milk, including lactose, lactalbumin and lactoglobulin protein, minerals and water-soluble vitamins. Dried whey contains approximately 70 percent lactose (milk sugar), whereas dried skim milk contains 50 percent. Whey is vacuum-condensed to a semi-solid and then further dried, either by spray or roller drying. Dried skim milk contains less lactose but more milk proteins and is more expensive than dried whey. Therefore, dried skim milk is usually used only in diets for pigs less than 15 pounds.
Recent research shows that both dried whey and dried skim milk can be added to diets of pigs weaned between 3 and 5 weeks of age and significantly improve performance. Research also shows that milk products need to be fed for only 20 to 3 weeks after weaning or until the pig is 25 to 30 pounds. It appears that spray-dried whey is slightly better than roller-dried whey. The reasons for improvement in pig performance from feeding whey and dried skim milk appear to be improvement in feed intake, protein quality, and the high digestibility of milk proteins and carbohydrates.
There are some differences between various sources of dried whey. If whey is excessively heated, it will result in a brownish color, indicating caramelization of the sugar (lactose). This lowers the feeding value of the product. White color is desirable, although some good quality whey may have a pinkish of yellowish color from carry-over of the cheese color.
There are several forms of dried whey products such as partially delactosed whey, partially demineralized whey, and partially delactosed and partially demineralized whey. The amount of lactose and/or minerals removed from the dried whey will affect the actual amount of protein and ash present. Delactose whey is not recommended for use in baby pig diets.
There are some mechanical problems (such as bridging in the feeders and clogging in the feeding system because of moisture absorption) when feeding a 20 percent dried whey diet in meal form. Therefore, diets containing large amounts of milk products (> 20 percent) should be pelleted.
In a farrow-to-finish operation, grower diets represent approximately 30 to 35 percent of the feed usage. The growing pig (50 pounds) is still in the growth phase in which it is depositing lean tissue at a fast rate. Therefore, high levels of lysine and other amino acids are necessary to promote maximum lean growth. The grower phase (50 to 120 pounds) has been broken down into two phases, 50 to 80 pounds and 80 to 120 pounds, to better meet the pig's requirements (Table 19).
Finishing feed will represent approximately 45 to 50 percent of the feed usage on a farrow-to-finish operation, so decisions to change or modify finishing diets must be made based on economics. Finishing pigs are more subjected to changes which affect feed intake, therefore feeding programs which include summer vs. winter diets, and (or) split-sex feeding can be economically justified (Table 20).
During gestation, the recommended feeding method for gilts and sows is a limited feeding program. However, it should be emphasized that a limit-feeding program is limiting only the energy intake and not other nutrients, such as protein, minerals, and vitamins. The energy is limited in order to keep sows from becoming too fat. Excessive feeding of gilts and sows leads to increased costs and interferes with the potential to maximize reproductive efficiency.
Sows that are overfed immediately after breeding or throughout gestation often suffer high embryonic mortality, producing smaller litters than sows fed proper amounts. Sows that become too fat have a tendency to have more farrowing difficulties and crush more pigs. This is especially true during the summer, when the sows are subject to heat stress.
Diets for the pregnant female must meet her daily requirements for all essential nutrients (Table 24). During normal (spring/fall) weather conditions, about 6,000 kcal of metabolizable energy per head per day will keep sows in good condition. However, this energy intake may need to be adjusted up or down depending on the condition of the sow and as the weather changes. This is usually accomplished by increasing or decreasing the amount of feed given to the sows daily.
For sows and gilts in confinement, under ideal environmental conditions, 5,000 kcal of metabolizable energy per head per day may be sufficient. During the winter, the sow should have about 7,500 kcal metabolizable energy per head per day. A good indicator of condition during gestation is weight gain. A sow should gain 75-100 lb and a gilt 100-125 lb during gestation. Sow condition is a critical indicator of performance, thus high-producing sows may require higher feeding rates to maintain adequate body condition.
The daily allowance for protein is .5 pound, lysine 9 g, Ca 16 g, and P 14.5 g. This allowance can be met by feeding 4 pounds of a 14 percent crude protein diet per day. During the summer, feed intake may be reduced to about 3.5 lb per head per day. In this case, the protein in the diet must be increased to about 16 percent to meet the .5 lb per head per day requirement, assuming amino acid levels are adequate. Feeding levels lower than 4 pounds will also require an increase in the levels of minerals and vitamins to maintain proper amounts on a daily basis.
Daily nutrient requirements for females during gestation are given in Table 21. It is important to consider that sow and gilt requirements are expressed as amount-per-head-per-day, not as a percentage as with a growing pig. Suggested gestation diets are in Table 22.
The success of limit-fed gilts and sows depends upon controlling the intake of each female. Care must be taken to see that each one gets her share. Individual sow feeding stalls are an effective device for controlling boss sows. If sows are group fed, it is imperative that the grain be spread across a larger area to reduce the amount of fighting and to ensure that all animals get the calculated energy requirement.
Interval feeding during gestation is a possible alternative to limit=feeding. Interval feeding is accomplished by feeding the sows every other or every third day. Of course, the amount fed is adjusted accordingly. For an example, instead of feeding 4 pounds each day during gestation, 8 pounds is fed every 2 days. With interval feeding, it is necessary to have sufficient feeder space. Research results have shown that a minimum of 2 to 6 hours out of every 72 hours is an adequate feeding time. Interval feeding is not recommended for gilts.
Sows during lactation should be full-fed in order to obtain maximum milk production (Table 23). A sow will normally consume 9 to 15 pounds per day. This intake will depend upon a diet composition, sow's condition, previous gestation diet, and environmental temperature of the farrowing facilities. For maximum milk production, it is recommended that the sow be maintained in an environment of 60-70oF. At higher temperatures, a reduction in feed intake will be evident.
Feed ingredients with a high fiber content such as beet pulp, oats, and wheat bran, may be used as laxatives to keep sows from becoming constipated. However, they also reduce the energy density of the diet and limit sow energy intake. Chemical laxatives, such as magnesium, potassium, or sodium sulfate, may be a preferred method of controlling constipation problems. The recommended level of magnesium sulfate (Epsom Salts) is 10 to 20 pounds per ton or top dressing about 1 to 2 tablespoons per feeding. Suggested lactation diets are listed in Table 22.
In smaller swine operations, it may not be practical to use two different diets for the sow herd. Therefore, the lactation diet, if properly formulated, can be fed during gestation at the rate of 4 to 6 pounds per sow per day. Feed cost will be higher if the lactation diet is fed during gestation.
Boars can be fed a grain-soybean meal diet fortified similarly to a gestation diet. The daily feeding rate has to be changed to reflect differences of season, condition, and workload of the boar. Boars under heavy use should be fed 6 pounds per head per day.
In this publication the nutrient recommendations have been increased beyond those of the NRC (National Research Council) (see Table 24). This adds a margin of safety for each of the essential nutrients.
Several nutrient requirements for developing breeding herd replacements are different from those for growing-finishing market hogs. Table 25 provides suggested levels for amino acids, vitamins, and minerals for replacement gilts and developing boars.
In formulating diets to meet the recommended nutrient requirements of swine, it is necessary to know the nutrient composition of each ingredient used. Compositions of ingredients commonly used in swine diets are given in Table 26.
Individual ingredients can vary widely in composition because of the variation in species or variety, storage conditions, climate, soil moisture, and agronomic differences. Variations in chemical analytical procedure also affect values obtained. Therefore, the values given are an average and are subject to interpretation.
Jeff_Hansen@ncsu.edu or (919)515-4467!
Notes: Information presented here represents the views of the Authors, and may not represent the views of North Carolina State University. The information provided herein is intended to be used for educational purposes and may not be reproduced without the consent of the Authors!