Biting, chewing and suckling are the sins of the pig world.
Known as vices, these aggressive behaviours are unrelated to herd hierarchy and often harm other animals.
Left to their own devices, and given proper resources, pigs don’t spend much time chewing or mouthing each other. But place them in close quarters indoors and they can develop bad habits to replace a few of their natural behaviours that might have occurred in the wild.
Tail, ear and vulva biting, belly-nosing and navel sucking are all problems created through modern pig confinement management systems.
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Researchers say solutions to these vices lie in the pigs’ own natural tendencies and behaviours that cause the problems in the first place.
Tina Widowski of the University of Guelph studies and teaches animal behavior and says some vices are more easily solved than others.
“For some vices there has been a lot of research and we have developed a few ways of approaching the issues,” she said.
Sigmund Freud believed many human behavioural problems start at a young age and begin with the mother, a theory that may also apply to pigs.
Separating piglets from their sows too early increases incidences of belly nosing and navel sucking, although not all piglets will be attracted to the bellies of their pen mates.
Belly nosing causes lesions on target animals and can lead to umbilical hernias. Victims may need attention ranging from antibiotics to euthanasia. Even mildly injured animals fail to gain as rapidly as their barn mates.
Offenders also suffer because they spend time trying to coax milk from their pen mates instead of eating and drinking from feeders.
The behaviour mimics the massaging activity that piglets use on sows’ udders when attempting to call down additional milk.
Speaking at the Saskatchewan Pork Symposium that was held in Saskatoon on Nov. 8, Widowski said there are solutions.
“Twelve-day weaners are twice as likely to develop nosing problems than 21-day (weaned) animals. Wean later,” she said.
However, some of the other known pig stressors, such as drafts, overcrowding, mixing and transporting, don’t seem to cause belly nosing.
She told producers that bowl drinkers are better than nipple drinkers because it appears to help piglets adjust to their new feed sources.
Research at the University of Saskatchewan’s Prairie Swine Centre in Saskatoon has shown that baby bottle nipples attached to boards in rows and mounted near waterers or feeders can dramatically reduce the vice.
Another suggestion is to add a pliable surface at the back of the pen for piglets to nose.
As well, liquid feeding systems or the addition of water to dry feed to create gruel reduces the problem.
John Patience, who heads the swine centre, said research has also shown the problem occurs in weaner pens where all the feeders are not working or are set too tightly.
“When there is no feed, it may cause piglets to use their begging behaviour of nosing on other pen mates.”
Tail biting is not as well understood as nosing behaviour. It can occur in the nursery but mainly happens during the grower-finisher stage of production.
It causes severe injury in its second stage, once blood is drawn, but begins with relatively innocent light chewing on the tails of other pigs.
Once the tail is damaged, it becomes a target for the attention of pen mates and can lead to cannibalism. Blood is a popular flavour for pigs. In testing at the University of Guelph, blood-soaked ropes mounted in pens are constant targets for the animals.
As tails disappear into the stomachs of pen mates, infections often set in and can spread rapidly up the spines of victimized animal. Pigs that suffer the attacks have reduced rates of gain, require greater medical attention, often have large cutouts at slaughter and in many cases die before shipping.
Widowski said in the past the practice was blamed on a failure of the feed ration, but research and practical experience has shown that it is related to discomfort.
Patience said an epidemic of tail biting occurred in one of the swine centre’s barns at Elstow, Sask., and the solution was found in tightening the airflow in the building and repairing automated lighting systems.
Widowski said again it comes down to animal behaviour.
“Pigs need chewable substrates. They need to be able to chew and shred something. Shredded cloth, tubing or rope, however, doesn’t mix well with automated manure handling systems, but having alternative oral toys makes a big difference.”
Increased space per animal also helps.
Genetic studies have shown that floppy-eared pigs such as Landrace tend to tail bite more than prick-eared pigs such as Large Whites. Leaner animals also bite more than those with more back fat, which may also be related to genetics.
Ear biting behaviours may have some of the same causes as tail chewing. As well, there may be different causes for the different kinds of ear biting: earlobe and tip.
Like nosing, it often begins in the nursery and earlobe damage may be an attempt at suckling. Tip biting may be a result of discomfort due to temperature, feed management or crowding.
Some researchers suggest ear tip necrosis, in which ear tips turn black and drop off, is often misdiagnosed as biting, but may be a form of PVC2 or porcine circovirus two.
Vulva biting among group-housed sows can be a severe problem when too few watering stations or feeders are available. Feeding twice per day and moving pigs to the farrowing barns earlier will usually reduce this problem.
