November, 1997 ^. Volume 20, Number 10

Dr. Robert Harrell recently joined the Department of Animal Science as Assistant Professor in the area of swine nutrition. He was raised on a swine and grain farm in central Illinois and received his B.S. and M.S. degrees in Animal Science from Southern Illinois University in Carbondale, IL. He continued his studies at Cornell University and received his Ph.D. degree in nutrition in 1997. His dissertation work focused on the Insulin-like Growth Factor system in growing pigs and how it is regulated by age and nutritional factors. Dr. Harrell plans to focus his research program on the regulation of nutrient utilization for growth and lactation with the ultimate goal of improving efficiency of pork production. In addition to his research, he will be teaching courses in swine management and animal science. He is officed in room 319 Polk Hall and can be reached at (919) 513-1117, or via the e-mail address Bob_Harrell@ncsu.edu.

Eric van Heugten

Sufficient quantity and quality of drinking water is essential for the health and efficient production of pigs. If there is any doubt concerning the quality of the drinking water, samples need to be collected to analyze the water and verify it is acceptable for animals. Many factors can affect the quality of water, including microbiological, physical and chemical factors.

Microbiology

There are a variety of microorganisms that can be contained in the water. Salmonella spp, Vibrio cholera, Leptospira spp and Escherichia coli have been reported to occur most frequently. Bacteria using inorganic ferrous iron as an energy source can be particularly problematic, because they produce a reddish slime that can plug waterlines and nipple waterers. Pathogenic protozoa and eggs or cysts of intestinal worms can also be encountered.

Physical Measures

Physical measures primarily include color, odor, flavor and clarity. They should be considered red flags that could indicate a problem with the water. If any of the physical measures appears out of the ordinary, then a further evaluation of the water is recommended.

Chemical Measures

A variety of chemical tests are available to determine the quality of water. Of these, Total Dissolved Solids (TDS), pH, iron, hardness, and nitrates/nitrites are a good initial screening. If any of these tests prove unsatisfactory, further analysis (sulfate, chloride, sodium, potassium, calcium, magnesium and manganese for example, if TDS is too high) needs to be conducted to specify the nature of the contamination.

TDS

The TDS is a measure of the total concentration of inorganic matter dissolved in the water. It is also referred to as salinity and commonly involves calcium, magnesium and sodium in the bicarbonate, chloride or sulfate form. The following table provides recommendations for acceptable levels of TDS.

pH

Usually the pH of groundwater falls within the acceptable range of 6.5 to 8.5. However, pH can have an effect on certain water treatments. For example, chlorination of water is impaired at a high pH and some drugs delivered through the water may not be soluble above or below a certain pH.

Hardness

The hardness of water (calcium and magnesium) can cause problems because of accumulation of scale in the water delivery system. In addition, certain drugs (OTC) can be inactivated by high levels of calcium, magnesium and also iron. However, hardness of water is not a problem for pig health and performance.

Chloride

Chloride levels in water above 250 - 500 ppm can cause a brackish taste which may result in low water intake. Iron

Iron can promote growth of certain bacteria and result in precipitation of iron compounds. Although there is no health risk, iron concentrations of 2 to 3 ppm can plug up water nipples. At a concentration of 5 ppm or greater, OTC added to the water can be inactivated. Water refusal or low water intake may occur at levels of 10 ppm or greater.

Sulfates

Sulfates are laxative agents and can cause diarrhoea, particularly in young pigs, at high levels.

Nitrates and Nitrites

Pigs are relatively tolerant to nitrates and nitrites. Nitrates in the water often indicate bacterial contamination. These nitrates can be converted to the more toxic nitrites. The effect of very high levels of nitrates and nitrites on pig performance is shown in the table below.

Water Quality Recommendations

The table below lists some published recommendations for water quality. Values in the Dutch guidelines that fall between the "no risk" and "risk" category pose no problem if it concerns only one measurement. However, if three or more measurements fall into that area, it may be recommended to not use the water, or to do additional analysis.

Upper limits for concentrations of potentially toxic substances in drinking water are listed in the following table:

Improving Poor Quality Water

Some water problems can be resolved by water treatment. For example, water softeners can be used, which replace calcium and magnesium with sodium. This may reduce problems with plugging of water nipples, but will not affect TDS. Chlorination is used to disinfect water, but its effectiveness is dependent on a variety of factors and may, therefore, not be a reliable method. No other methods that are cost effective are available.

Water Testing

Water testing is available through the NCDA laboratory. Forms and further information can be obtained from the county extension office.

Eric van Heugten

A Swine Health Summit will be held November 12-13, 1997 at the Williamsburg Marriott in Williamsburg, VA. It is sponsored by the National Pork Producers Council, in cooperation with the National Pork Board.

Purpose of the Summit:

Diseases affect production efficiency and profitability. As a result, maintenance of swine health is critical to the continued growth and profitability of the U.S. pork industry. It is becoming increasingly more important for producers to have access to the latest information in order to maintain and improve the health of their herds. At this meeting, leading experts will discuss the latest challenges and technologies. What You Will Learn:

The Swine Health Summit helps producers address the challenging issues related to herd health. Expert speakers discuss the latest challenges and technologies. Producers will gain knowledge about the latest technologies so they can change and improve their own operations, as well as develop a long-term direction and approach to their herd health situations.

Topics to be covered include: selling quality pork, biosecurity, PRRS, SEW pigs, porcine respiratory disease complex and maintaining antibiotic effectiveness. Contact the National Pork Producers Council to register by phone at 515-223-3525 or 1-800-667-1436.

Todd See

The thirteenth annual Carolina Swine Nutrition Conference will be held November 11, 1997 at the Sheraton Imperial Hotel in the Research Triangle Park. Sponsored by the Carolina Feed Industry Association, the program features speakers representing the universities of Missouri, Illinois and Georgia, as well as industry.

Topics include: young pig nutrition, sow feeding, added value grains and ingredient & product monitoring. Contact Owen Robertson, Sec.-Treas., 2116 N. Shoreline Drive, Sanford, NC 27330, 919-776-3054 to register.

Todd See

Culling a breeding female can be very satisfying you congratulate yourself that you have averted another disaster by removing an animal that you are sure will fail to raise another litter, and besides, by culling her now you have shortened her suffering. However: Just how sure are you that she will not raise another litter? What are the economic consequences? Answering these questions suddenly makes the whole issue of culling guidelines very complicated and warrants a better understanding of the reasons sows are culled and how those rates need to change. From an economic perspective, a sow should stay in the herd as long as the expected profit from her next litter is higher than the lifetime average of a replacement gilt. The only exception to this rule is when she is prematurely culled to alleviate her suffering. Many people chose to categorize reasons for culling into voluntary and non-voluntary. I believe this division is counterproductive because it implies that the sows are in charge of culling when, in reality, the farm manager must retain full control and accept economic responsibility for all management decisions on the farm. The challenge is to understand your farm's wastage rate and the economic factors involved. In most cases, the system will profit from decreasing wastage and increasing sows' longevity in the herd. Understanding the definitions used to describe culling rates is the first step.

Annual Removal Rate: This rate is defined as the number of animals removed from the herd during a year divided by the average inventory and expressed as a percentage. This rate includes all causes and is the one usually quoted to define a herd's culling rate. In PigCHAMP records it is the rate quoted on the performance monitor as "Culling Rate".

Proportionate Removal Reasons: These proportions are commonly reported because they reflect the relative importance of the various reasons of sow wastage, e.g., "reproductive failure is the main reason for culling". This is the figure usually reported in studies examining the issue. In PigCHAMP records it is reported on the Removal Analysis report under "Reasons".

Reason-Specific Rate: This rate reflects the probability that a breeding female will be culled for the specified reason in a set period. It is the number of females culled for that specific reason expressed as a percentage of the average female inventory for the period. Unlike proportionate removal reasons this rate is independent of the other reasons sows are culled. It better reflects the risks sows face.

Parity-Specific Rate: This rate is similar to the reason-specific rate but it reflects the risk of females never making it to the next parity. It is the number of females culled by parity expressed as a percentage of the average female inventory for that parity. It is useful in economic analyses of lifetime productivity of sow herds. In PigCHAMP records it is reported on the Removal Analysis report, stratified by parity, as the percentage of "Gilts and Sows Culled".

Morgan Morrow

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Last modified August 5, 2000.