HANDLING AND MOVING PIGS

Proper care and handling of pigs can prevent millions of dollars of economic loss in all aspects of the pork industry. The National Pork Board’s Trucker Quality Assurance Program provides excellent information that should be known by anyone who works with or handles pigs. Improper handling contributes to skin injuries, bruising, and even sudden death. Bruising alone results in $48 million in trim loss on market hogs, and the productivity of sows and nursery pigs also can suffer if they are improp-erly handled.

Understanding the natural instincts and behavior of the pig will help producers handle them properly and use proper management techniques. Pigs have a strong natural urge to escape. If they see even small gaps between pens, alleys, ramps, side gates, chutes, or anywhere else, pigs may try to escape. When trying to escape, pigs often injure themselves. Pigs also have a natural tendency to follow each other and maintain visual or bodily contact. In addition, pigs are easily frightened. Watch for and remove dangling chains, loose ramps and boards, and slippery floors; and cut down on extreme bright lights, darkness, and loud noises. Other things that frighten pigs include shadows, water puddles, shiny objects, flapping or moving objects, and sunlight shining through a crack or hole. Don’t get pigs excited. Excited pigs are more difficult to move than calm pigs. Improper use of electric prods can cause severe stress, heart attacks, and death. Use other methods like clapping, whistling, hurdle boards, or flags to move pigs. Stock whips should never be used, and electric prods should be used minimally.

Figure 1. Flight Zone and Point of Balance (Source: National Pork Board)

An understanding of the flight zone and point of balance (Figure 1) will help you move animals more easily. The flight zone is the animal’s personal space. The size of the flight zone is determined by the wildness or tameness of the animal. Completely tame animals have no flight zone, and people may touch them. When you enter this space, the pig will move away. Stand at the outside edge of the flight zone. To drive a pig forward, stand at an angle behind the animal, but not directly behind it. The point of balance is at the animal’s shoulder. All species of livestock will move forward if the handler stands behind the point of balance. They will back up if the handler stands in front of the point of balance.

Move pigs in small groups of three to five animals at a time, and move slowly. Pigs naturally follow one another, so direct the first pig in the correct direction and the others will follow. Do not attempt to move a group by standing behind all of them and crowding them or yelling.

Always try to avoid aggressive handling of pigs. Here are some examples of aggressive handling:

• Use of electric prods
• Loud noise and yelling
• Moving pigs too fast
• Moving pigs in groups that are too large
• Overcrowding
• Stationary periods that are too long

An animal handler also must recognize signs of pig stress, which, in turn, can help to prevent metabolic acidosis. Metabolic acidosis is often associated with taking pigs from their inactive lifestyle and imposing upon them the sudden exertion required when they attempt to escape aggressive handling. Pigs that have never been out of their pens, or that have had very little contact with people, may be more excitable during movement and more prone to the onset of metabolic acidosis when handled aggressively. Signs of stress are:

• Open mouth breathing
• Vocalization (squealing)
• Blotchy skin
• Stiffness
• Muscle tremors
• Increased heart rate
• Increased body temperature

For more information on the Trucker Quality Assurance Program, contact the National Pork Board or your Cooperative Extension Service office. The article is adapted from the National Pork Board’s Trucker Quality Assurance Participant Guide.

—Todd See

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A NEW LOOK AT PHOSPHORUS DIGESTIBILITY

Formulation of swine diets to incorporate phosphorus traditionally has been based on either the total level of phosphorus present in ingredients or the available phospho-rus levels in the ingredients. Available phosphorus levels are determined by measuring total tract digestibility of phosphorus in the ingredients and comparing it to a standard phosphorus source, typically monosodium phosphate. In this assay, it is assumed that monosodium phosphate is 100 percent available to the pig and that the availability of the test ingredient is expressed relative to this standard. In some countries outside the US, the digestibility of phosphorus is not adjusted to this standard, but is expressed only as digestible phosphorus.

The variation in phosphorus availability within single ingredients can be relatively large. For example, phosphorus digestibility in corn has been reported to range from a minimum of 12 percent to a maximum of 48 percent. For soybean meal, the range is 21 to 39 percent. Even for dicalcium phosphate, a phosphorus source that is generally considered very available, the availability has been reported to range from 32 to 96 percent.

A recent paper by Shen and coworkers (Use of the regression analysis technique to determine the true phos-phorus digestibility and the endogenous phosphorus output associated with corn in growing pigs. J. Nutr. 132:1199-1206) describes a new method of expressing phosphorus digest-ibility for ingredients. The authors suggest that endogenous losses of phosphorus be accounted for when measuring phosphorus digestibility. Endogenous losses are those produced by the pig itself (from mucus, sloughed-off cells, and enzymes produced by the animal) and represent a major route of phosphorus excretion. Thus, after correcting for endogenous phosphorus losses, the true digestible phos-phorus content of an ingredient can be calculated.

Shen and coworkers determined the true digestible phosphorus content of corn by evaluating P digestibility in four diets. These diets were formulated with purified ingredients that contained no phosphorus but did contain graded levels of corn at 18, 36, 54, and 72 percent of the total diet. Corn was the only source of phosphorus, and the diets contained 0.07, 0.15, 0.22, and 0.28 percent phosphorus on a dry matter basis.

To calculate the endogenous losses of phosphorus, the authors plotted the apparent digestible P (g/kg of dry matter intake) with the dietary levels of P (Figure 1). Endogenous losses can be estimated from this graph if a linear relation-ship between these parameters exists and can be determined as the intercept, where 0 percent dietary phosphorus would be present (endogenous phosphorus was 0.67 g/kg DM or 0.067 percent).

Figure 1. Linear relationship betwen apparent digestible phosphorus and dietary phosphorus

Apparent digestibility of phosphorus was negative for the diet that contained the lowest level of phosphorus (Table 1). This means that the pigs excreted more phospho-rus in their feces than they consumed. The reason for this is that the endogenous losses of phosphorus contributed greatly to the amount of phosphorus in the feces, whereas the diet only provided a very small amount of phosphorus.

Endogenous phosphorus excretion for this diet was 101 percent, relative to phosphorus intake. As the phosphorus level in the diet increased, the endogenous losses contrib-uted relatively less phosphorus to the total excreted levels in the feces, and the apparent digestibility of phosphorus in the diets increased. Shen and co-workers suggested that the large variation in phosphorus digestibility or availability observed in the literature may be due largely to variation in total phosphorus content of the ingredients studied, especially in ingredients that are particularly low in phosphorus, such as corn. In those cases, endogenous losses become relatively more relevant, and adjustments should be made to account for these losses. When adjusting for endogenous phosphorus losses, digestibility would be expressed as true phosphorus digestibility, which is the digestibility of feed ingredients only, without any phosphorus contributions from the animal.

When correcting for endogenous losses, true digestibility measurements can be compared with apparent values that are not corrected (Figure 2). True phosphorus digestibility is not affected by dietary phosphorus content, whereas apparent digestibility varies greatly, depending on dietary phosphorus.

Figure 2. Apparent and true phosphorus digestibility

The researchers suggest that true phosphorus digestibility measurements are superior to traditional measurements because they are not dependent on ingredient variability in total phosphorus content. They further suggest that the present data on apparent phosphorus digestibility or availability underestimate the true digestive utilization of phosphorus in corn by approximately 35 percent. Thus, formulating on true digestible phosphorus values can reduce overfeeding of phosphorus and subsequently reduce phosphorus excretion of pigs. This in turn can reduce the cost of the diet and provide for reduced levels of phosphorus entering the environment.

—Eric van Heugten

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

Breeder	Address	Breeds
Caswell Farm Unit	2415 W. Vernon Ave., Kinston 28501	X
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
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 and David Lee

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Last modified November 8, 2002.

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