IACUC Learning Module - Swine | Previous Next |
Pigs are referred to as swine, porkers or hogs.
The Latin word "porcine" is also used in reference to pigs.
Intact males are called boars and castrated males are called barrows.
Females are called sows if they have been bred, or gilts if they have never bred.
The young are called piglets.
Farm breeds have the disadvantage for research facilities of rapid growth rate; from a birth weight of 1 kg they may reach 100 kg at four months of age and a mature weight of greater than 200 kg. White colored farm breeds include the Yorkshire and Chester White, both with erect ears, and the Landrace, with ears that fall over the eyes. The Spotted Poland China is a white pig with black spots. The Duroc is reddish brown and the most popular breed in the USA. Most commercial pig farmers cross several breeds together so there is great variation in color.
There are several miniature breeds commonly used in research facilities in the USA. The Yucatan is slate grey, exceptionally docile, with a short snout and blocky build and there are two strains, the minipig with an adult weight of 80 kg and the micropig which only reaches 50 kg. The Sinclair Hormel breed is slightly larger (90-140 kg) and is white in color. Another white minipig is the Hanford which appears much like a small (80 kg) Yorkshire. The Vietnamese pot bellied pig has not been used in many research facilities.SOCIAL BEHAVIOR
Pig are gregarious and social. Whenever possible, pigs should be housed in groups of from two to eight pigs. When pigs must be individually housed, be certain they can see, hear and touch other pigs through a fence or cage.
Pigs establish a dominance order early in life with their litter mates, which continues throughout their life. However, most pigs are not housed with only their own litter mates. Therefore, any addition or loss of a member to the established group will result in fighting and threats until they determine a new dominance hierarchy. Once the dominance between two individuals is established, subsequent encounters consist of only grunts and threatening postures. The most dominant pig can usually be determined by watching which pig pushes the other pigs on their shoulders or flank, and makes the pigs move away. This hierarchy is fairly stable; the dominant pig can be removed from the group for at least up to a month and upon reintroduction to the herd, still retain the "top" position.
Occasionally, more serious fighting with teeth grinding, foaming of the mouth and biting will occur in a group; this is more common in groups of noncastrated males and may be reason to separate the animals. Adult boars may be very aggressive and should be housed alone. Some boars will pace back and forth, chomping their jaws, slobbering and squalling, a behavior called ranting. Complete isolation, unable to see, hear or smell, from other boars or sows may be required to quiet such behavior.SIGNS of ILLNESS
A normal pig will be awake and alert for many, short periods, for a total of about twelve hours out of twenty-four, and be drowsy or completely asleep the other twelve hours. Therefore,
it is quite normal to look into a room with pigs and see the entire group quietly lying around.
A depressed or sick pig may be off alone, in a corner, and when it does stand, it may have it's head and ears more dropped than normal.
If one pig looks "different" from the group, please report this to the veterinary care staff. Of course, obvious signs of illness, such as an extended neck with trouble breathing, diarrhea, lameness, or any other unusual behavior should be reported as well.WARNINGS to HANDLERS
Because most people have not worked with pigs, or kept them as pets, it may be difficult to "read" facial expressions and body language. Therefore, use care when first working with these animals. Unfortunately, you may not recognize behaviors which signify that a pig is becoming defensive or aggressive, until it is too late!
It must be stressed that pigs, although usually safe and fun to work with, may be dangerous! This is especially true with pigs that weigh over 60 kg, their shear size makes them unsafe. Never enter a room of pigs without knowing your escape route.
A normal behavior for pigs is the "rooting" movement, wherein pigs tuck their heads low and then quickly raise up their head, trying to "root up" whatever they are pushing with their snout. They will do this with their food and water buckets, they will do this along the bottom edges of the pen, and they may do this to human handlers. Pigs have strong jaws and sharp teeth. Often the incisor teeth are snipped off at the farm, but the remaining teeth can still inflict serious damage when they root up the leg. Another dangerous situation may occur when a pig puts their head down, sniffs the person's feet and then suddenly lifts up, jerking the person off balance.
Please understand that these warnings are an exception to the rule. When properly handled and conditioned to their human caretakers, pigs are curious, gentle and affectionate animals. In fact, some Americans have full grown "farm" pigs living in their homes, often being trained to use a toilet. Further confirmation of their "loveableness" is the continual gain in popularity of the Vietnamese pot bellied pig as a companion animal.
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