NCSU Extension Swine Husbandry 2001
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March, 2000 ^. Volume 24, Number 2

When it comes to producing pigs profitably, growers often underrate the value of managing feed and feeders, water and waterers. Optimizing feed and water intake is one way for a producer to achieve greater growth rates in the pig facility.

Distinguishing between feed intake and feed disappearance is an important aspect of evaluating a feeder. The difference between the amount of feed that the pig actually consumes and the amount that disappears from the feeder is waste. Feed waste typically runs from 3 to 6 percent with well-designed feeders, but under some conditions it may be as high as 15 to 20 percent.

Waterers should be managed to maximize water intake by the animals while minimizing waste. Wasted water represents the loss of a valuable resource and increases the amount of liquid waste that the facility must store and recycle. Storing and recycling, in turn, equate to loss.

Maximizing feed and water utilization and minimizing their waste directly affect profits through enhanced animal performance and a reduction of the waste stream (volume and unused nutrients). By providing high-quality feeders and waterers and maintaining proper adjustment of these devices throughout the finishing period, the grower himself can improve his bottom line.

Feed disappearance

A pig's genetics and sex set the baseline for feed intake. Significant differences exist between high- and low-intake genetic lines as well as between barrows and gilts. In addition, feed formulation and processing play key roles in the pig's feed intake and amount of feed waste. However, several management practices also influence intake and waste:

• Healthier pigs generally have higher feed intakes and growth rates.

• Water intake is positively related to feed intake. Any limitation on water consumption, whether it be the design of the watering device or the quality of the water, will result in some feed intake reduction.

• Heat stress and/or excessive competition at the feeder tends to limit feed consumption.

• Feeder design has much to do with the level of feed waste, although not everyone agrees on the best design. Pigs are nibble feeders and tend to eat many times per day. Feeder design problems can be found by observing feeding behavior. Pigs should be comfortable standing perpendicular to the trough. If the pig has to turn sideways or gets a mouthful of feed and then backs out to chew, there are likely feeder design problems. Design factors influencing feed intake include width, depth, and headroom of the tray. Inadequate headspace for the natural eating motions results in more spilled feed and poor feed conversion. The height of the tray lip, the presence of solid partitions, and the type of adjustment mechanism also affect wastage. A decision to purchase new feeders should be based on economic incentives relative to feed efficiency.

• Feeder adjustment definitely influences waste. The general recommendation is to adjust most typical feeders so that at least 50 percent and possibly 75 percent of the feeder tray bottom is visible or not covered with feed. Here is how to make the adjustment:

1. After the feeder is cleaned and disinfected between pig herds, close the adjustment mechanism and then add feed.

2. Open the mechanism or gate just enough to allow feed to flow into the trough. If the gate is on the inside of the feeder, the adjustment can be looser. Gates on the inside are affected more by the amount (weight) of feed inside and tend to require more adjustment.

3. Shake the feeder/feeder adjustment mechanism to assure feed flow.

4. Proper adjustment will result in very limited feed in the tray bottom.

5. Routinely use a hook to reach under the feeder gate and dislodge any caked feed instead of raising the gate excessively.

Feed quality

Although the feed-quality-control program is most often the responsibility of others, the grower must be alert to problems that might originate at the feed mill or in bins and feeders on the farm. Feed should be inspected as part of the daily walk-through of the unit. The grower should be on the lookout for:

•Moldy feed that is caked or clumped in bins and feeders. Bins and feeders should be managed to assure the turnover or cleanout of older feeds. The detection of a moldy odor may be your first indication of problems. Try to determine the source of moisture that is supporting the growth of molds in the feed and take appropriate action to prevent reoccurrence. If the feeder is the source of mold growth, clean out the damaged feed and dispose of it properly. If the feed bin is the source, the feed may have been delivered with mold growth or the bins may be leaking or sweating. Some molds produce toxins that may result in such classic symptoms as feed refusal, possible vomiting, or swollen vulvas in gilts. All moldy feed is not toxic to pigs, but it most certainly will lead to reduced intake and diminished pig growth.

•An unusual amount of foreign material or trash (corn stalks, fiber-like material, dirt, or metal fragments) in the feed. If this is the case, the most common source is the feed mill. Make the appropriate personnel aware of the problem. Pigs will sort out most foreign material, but this problem raises questions relative to feed quality.

Water

Water is not only essential for survival, it is also a critical nutrient for growth. Addressing the pig's water needs can be done from a supply-and-demand perspective. If enough good quality water is supplied to meet the pig's biological needs, performance will not suffer. But if the pig's demand for water exceeds the available supply, the pig will not grow and develop to its genetic potential. Here are factors to be considered in supplying water to pigs:

•Temperature greatly influences the pig's water needs because pigs use water to help reduce body heat. When the environmental temperature rises from 59 to 95 degrees, the water needs of a 75-pound pig can increase by 57 percent and that of a 250-pound pig by 63 percent.

•Water systems should be checked regularly for any signs of contamination. The quality of the water may affect intake, nutrient digestibility, and pig performance. The mineral content and microbial safety of the water source should be routinely monitored. Total dissolved solids (TDS) should not exceed 6,000 to 7,000 parts per million. In-line filters and traps can help improve water quality on some farms.

•Watering devices should be checked and maintained frequently to prevent leaks, and screens should be cleaned to assure adequate flow to the pig. The recommended flow from a nipple drinker is 750 milliliters per minute (ml/min) for a growing pig and 1,000 ml/min for a finishing pig. Flow rate can be checked by using a measuring container to collect the water flowing from drinkers for one minute and comparing it to the recommended rate for the age of pig and type of waterer.

•Pigs will remain at waterers for only a limited amount of time. This means there must be an adequate number of waterers available per pen and the flow rate must be adequate to satisfy the pig's need quickly.

•Note that stray voltage on watering devices frequently limits a pig's water intake. This electrical charge can be measured with a good voltmeter and an isolated ground. As little as 0.5 to 1 volt may reduce water intake under certain conditions. Check with your electric utility company for assistance in solving this problem.

•Gate-mounted nipple waterers should be frequently adjusted to a height just above the pig's shoulder to prevent injuries and carcass bruising.

•Consider replacing older equipment with water-saving drinkers. Standard fixed nipple waterers tend to result in excessive water waste, especially during warm weather. Swinging nipple waterers may reduce water use by 10 to 25 percent compared to fixed nipples. Some modern bowl-type nipple drinkers may reduce water disappearance by 20 to 35 percent compared to standard fixed nipples.

•Sometimes supplying water to the growing pig can be confounded by the need to reduce the amount of liquids entering the manure management system. Integrating the drinker nipple into the feeder (wet/dry type) has resulted in a 33 percent reduction in liquid manure production, which equates to reduced waste of water and feed combined.

—Todd See

LIQUID DIETS FOR EARLY-WEANED PIGS

A recent study at North Carolina State University (Kim et al., 2001) evaluated the effect of a liquid diet on the performance of early-weaned pigs and found it significantly improved growth both short-term and long-term.

In the experiment, 240 pigs were weaned at 11 days of age, weighing an average of 8.66 pounds. Half the pigs were put in a conventional nursery, and the other half were placed in a specialized commercial nursery building.

Each of the two groups of weanling pigs received either a pelleted diet or a liquid milk replacer diet. The diets were exactly the same in ingredient and nutrient composition, so the physical form of the diet was the only variable studied. Although nursery environment was one of the factors of interest to the investigators, this summary will focus only on the effects of diet physical form on performance of pigs that were housed in a conventional nursery. Thus results of this comparison would have a direct application to swine producers.

In the study, pigs were fed the pelleted or liquid diet for 14 days immediately after weaning. After that, all pigs were switched to pelleted diets for another 3 weeks in the nursery, followed by meal diets for the remaining 2 weeks in the nursery and meal diets during the grower-finisher period. The only time the animals received a different treatment was for the first 2 weeks after weaning. The pigs were followed all the way through to market weight to evaluate whether liquid feeding for 2 weeks would have a long-term benefit on pig growth performance.

Using the liquid milk replacer diet for 14 days immediately after weaning improved daily gain by 54 percent compared to the pelleted diet (Table 1). Feed intake improved by 26 percent, as did feed efficiency, by 23 percent. These improvements were especially pronounced during the first 3 days after weaning when the pigs fed liquid diets grew 0.55 pounds per day (lbs/day) and the pigs fed pelleted diets grew 0.14 lbs/day.

As time progressed, this improvement in gain decreased. But the advantage in growth rate due to liquid feeding was maintained throughout the rest of the nursery phase and during the grower-finisher phase. For the entire growth period, daily gain and feed intake improved by 4 percent each when pigs had been fed liquid diets for 2 weeks in the nursery. In addition, pigs reached market weight of 240 lbs an average of 4 days sooner than the pellet-fed animals (Table 1).

The authors concluded that feeding liquid diets is beneficial in early-weaned pigs and that the advantage is maintained until market weight is reached. They further suggested that feeding liquid diets selectively to pigs having lighter weaning weights could potentially reduce variation in market weight as well as reduce days to market.

Full-scale use of liquid diets in conventional nurseries will depend on the availability of user-friendly and economical delivery systems.

Reference

Kim et al., 2001. Journal of Animal Science, vol. 79, pp.427-434.

—Eric van Heugten

ON-FARM PERFORMANCE TESTING
The following breeders with validated herds have tested animals in the past 30 days.

Breeder	Address	Breeds
Bob Ivey*	314 N.C. 111 S, Goldsboro 27530	L, D, H, Y, CW, X
Wesley Looper*	4695 Petra Mill Rd., Granite Falls 28630	L, D, H, Y, X
Thad Sharp, Jr., & Sons	5171 N.C. 581 Hwy., Sims 2788030	D, Y, X
Tommy Spruill	Rt. 1, Box 149, Columbia 27925	L, X
Swan Acre Farm	1060 Main Street, Swan Quarter 27885	X
Thomas Farms	8251 Oxford Rd., Timberlake 27583	X
UCPRS (Swine Dev. Center)	Rt. 2, Box 400, Rocky Mount 27801	X
*Real-Time Ultrasound

Frank Hollowell
David Lee

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Last modified February 22, 2001.

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