Man and pig
* The pig is farmed in a wide range of farming conditions around the world, except in Moslem countries. It evolved mainly in China and Asia, and our New Zealand Kunikuni pig shows all the traits of these early Chinese ancestors.
* The many types of wild ancestor of the modern pig were domesticated to provide meat and they took well to confinement and being omnivorous and were useful to clean up human waste and garbage.
* If was the first animal apart from the hen, to be subjected to very intensive housing and management.
* Pigs have now become fashionable pets in some modern cultures.
Pig senses
Sight
* Pigs are forest dwellers and nocturnal feeders in the wild.
* Their eyes are highly developed and they can see colour like other higher mammals.
* Their sight can be greatly reduced by their floppy ears which act as protection when rooting in scrub.
* The pig's other well-developed senses compensate for any limitations in vision.
* Sight is important in reproduction as the boar uses visual clues as to the oestrous state of the sow.
Smell
* The pig has an acute sense of smell, exploited by man in hunting truffles.
* It has a well-developed olfactory lobe in the brain.
* The design of the pig's nose and strong neck give it very powerful rooting abilities.
* Feral pigs use scent to follow trails and can smell feed and carrion from a considerable distance.
* They can locate each other in the wild by smell when spaced out foraging.
* Smell and taste are thought to be important in recognition, as at first meeting pigs sniff each other in the face, along the line of the jaw and around the eyes and ears.
* Smell is very important in piglets to find their own chosen teat for sucking.
Hearing
* Pigs have extremely good hearing and clearly recognise a wide range of sounds used in communication between them.
* They can be easily panicked by unfamiliar sounds - which can cause major problems in intensive housing e.g. when jet planes fly over or thunder.
* They must be able to sense very low pitched sound by reports of their early reactions to earthquakes.
Taste
* Pigs have clear taste preferences.
* Creep feed for piglets is sweetened with sugar to encourage intake.
* Mature pigs love apples - they're a great means of getting a pig to follow you.
Vocalisation
* Pigs use a wide range of sound to communicate - probably developed because they evolved as forest dwellers.
* Young piglets squeak, grunt, bark and squeal.
* Older pigs use various grunts and squeals to indicate hunger, thirst, alarm, fear, terror, affection, calling a litter to suckle, courtship, and many others.
* Pigs respond very well to human communication, and soon seem to learn what human sounds mean. One researcher suggested that "uff uff" uttered with the lips and your face level and close to the pig was very successful in establishing friendship. To move pigs forward "choo choo" achieved interesting results.
* Pigs squeal can reach 112 decibels which can damage human hearing and stress the animals. Wearing ear muffs, especially at feeding time is essential in large intensive operations. A level of 85 decibels should be the limit aimed for in housing.
* The terror squeal of pigs when held by a nose strop is also damaging to hearing.
Social behaviour
* Pigs are very social animals but do not show tight herding behaviour. You soon learn this when trying to drive pigs!
* Wild pigs that are hunted are very nocturnal; otherwise they can be active at any time. Pigs farmed intensively are diurnal and active during the day because of the husbandry system.
* As they are den-living animals, social contact developed at birth is very important for the rest of the pig's life. Pigs enjoy the close company of mates.
* They develop a social rank very early within their litter by vicious blows with their needle teeth while fighting for teats. Farmers clip these teeth off to prevent damage to other piglets and to the sow.
* Pigs have many ways of communicating with each other - sound is the most important because of the bush environment in which they evolved.
* Twenty different calls have been identified - 6 of which can be identified by man such as the grunt, bark and squeal.
* Body language is also important at close quarters, especially in courtship.
* Feral pigs are usually found in groups of about 8 made up of 3 sows and their offspring. Males tend to be solitary.
* Groups of wild pigs have their own home range, and these can overlap with other bands of pigs.
* Pigs don't have sweat glands over their body so wallowing is a common behaviour in feral pigs in warm conditions. However, they'll also wallow and enjoy mud in cold climates.
* If water is deep enough outdoor pigs will swim.
* There is little social grooming in pigs as we know it in other animals. This is surprising as they enjoy rubbing and scratching so much. But they do nuzzle each other along the flank and back - areas they can't reach on their own.
* Lone pigs scratch these parts against objects in their territory.
* Pigs yawn like other farm animals, and this is often combined with stretching the back leg and closing the eyes.
* Pigs also shake themselves after a period of rest, especially if they've been lying in a group.
* Pigs regularly "tuck in" with their mates and by wriggling settle right down into the bedding.
* When growing pigs have selected their own temperatures, they chose warm afternoon temperatures and quite cool conditions at nights when they lie huddled with their mates for warmth.
* Pigs show a lot of play behaviour, and it's very common in young pigs when they leave the nest or lying area.
* They show great play behaviour especially when they go into a new environment as part of their exploration.
* Social play usually consists of fighting with selected littermates. Often one animal runs away eliciting a chase by mates.
* A piglet playing by itself will whirl round trying to scratch itself and may jump up and down on the spot.
* Pigs are great investigators and play by lifting and moving objects on the ground and throwing them in the air.
* With their sensitive nose, rooting is a favourite pastime and treasured finds are carried away with other pigs in pursuit.
Pig learning ability
* Pigs learn quickly and show great variation in their ability to learn and solve problems.
* Teaching pigs can be done easily by using mild electric shock avoidance, audio signals and feed rewards.
* They have been taught to control their heating and lighting regime - which saves human labour and reduce costs.
* This learning ability is moderately inherited so you could increase this trait in a herd through selection.
* Pigs quickly learn all the details of a new environment because of their well-developed exploratory behaviour. When tested in a maze, pigs are smarter explorers than any other farm animal. Depriving them of this natural ability can cause great stress as seen in pigs kept in barren concrete environments with no bedding to chew.
Pig-human interaction
* There is now plenty of research to show the benefits of pigs that have a strong relationship or bond with their human minders.
* The pigs have clearly been "tamed" and have responded to good handling.
* Taming is best done by quiet and gentle handling of young pigs at feeding time.
* Lay your hand on the pig's had or back, talk gently and scratch or stroke the animal. The best areas to touch are behind the ears, shoulders, along the back and down the sides.
* Pigs soon learn to enjoy this contact and will often lie down to enjoy it. Complete taming can be done in 2-3 weeks after which they will come when called.
Dunging behaviour
* Pigs are probably the cleanest and most orderly farm animal if their environment allows this, and if they have learned appropriate behaviours during their early rearing.
* Pigs defaecate and urinate regularly throughout the day and night in intensive housing although they rest a lot between 7pm and 6am the following morning.
* By 3 days old, piglets have learned not to dung where they sleep. After this age further dunging behaviour is learned from their dam - habits they maintain throughout life. A "dirty" sow that dungs and urinates on her bed will produce "dirty" piglets that do the same.
* Good dunging habits can be encouraged by a few management practices:
* When changing pigs from one pen to another, give them a run for a while before they enter the new pen. This will let them empty out and their first urge in the new pen will not be to defaecate and urinate.
* After moving, dampen the dunging area of the new pen, and put some dung from the old pen on it.
* Pigs that are scouring should have the problem fixed as they will have less control of their faeces and where it goes.
* If there are too few pigs in the pen, use temporary barriers to reduce space in the sleeping area so they are forced to dung elsewhere. Put fresh bedding on the sleeping area.
* A false roof maintaining warmth over the sleeping area will encourage them to rest there and they'll hopefully be less keen to foul the area.
* Cleaning their pen at night may help if the problem exists. After cleaning the fouled area, put some bedding and feed on it.
* Pen shape and the position of the feed and water sources can affect where pigs eliminate. Try moving troughs until the pigs modify their habits.
Abnormal pig behaviour
* Pigs show a long list of abnormal behaviour where stress is the major underlying cause.
* Tail biting
* Ear biting
* Cannibalism - killing and eating pen mates
* Belly nibbling
* Tongue rolling
* Rubbing the nasal bone
* Rubbing snout
* Hyperactivity
* Massaging the anus
* Vacuum chewing
* Biting pen bars
* Rocking back and forward when tethered
The “runt“ pig and its problems
* It's difficult to describe in precise terms what a runt is. It's not necessarily a small piglet, as these can be the result of poor nutrition.
* These nutritional runts are commonly seen in large litters where pigs are not weaned until 5 or 8 weeks.
* Piglets can be runts because of their position in the uterus, where for some reason they have been deprived of nutrients. These runts never catch up, even with extra feeding as they are physiologically under-developed.
* As litter sizes increases and competition for milk and feed increases, the problem the runt has to survive and grow increases. Commercial pig farmers often see euthanasia as a cost-effective solution.
Moving pigs
* Pigs are den-living, home-loving animals and do not show any flocking/herding response when moved.
* In the wild, frightened pigs scatter and crouch in the undergrowth, or race back to their den. Domestic pigs still show this behaviour.
* They just don't like being moved - especially from their darkened den into bright outside light.
* Loading and unloading are the most stressful part of transport when pigs are pushed, dragged by their ears, have their tails pulled, or goaded physically or electrically. (Note that electric prodders should not be used on pigs in New Zealand).
* Suggestions for loading and transport of pigs:
* Select the pigs for market the night before, and hold them in an unfamiliar pen.
* Reduce feed before transport but not water.
* Move them in the early morning.
* Don't attempt to rush, abuse or punish them.
* They'll go better up a ramp or along level ground.
* Avoid having to move them down a ramp.
* Keep ramp sides fully covered so they can't see through.
* Spread some bedding along their path you want them to go.
* Spread some feed or slices of apple along the path and up the ramp.
* Use a hand-held pig board to approach them - this also protects your legs. Use any solid barrier to bring up behind them.
* Don't do anything like pulling ears or tails that will make them squeal. Use a canvas slapper so as not to bruise them.
* To move an awkward individual - put a plastic bucket over its nose and eyes and reverse it along.
Transporting pigs
* Transport can be very stressful for pigs. Here are some recommendations to reduce stress:
* Don't transport pigs that are not familiar with each other.
* Provide plenty of ventilation in the truck.
* Avoid transporting when temperatures exceed 28 C.
* Avoid long parking periods on hot sunny days. Always park in the shade.
* Avoid physical exertion and excitement before and during transport.
* Do not feed during the 12 hours before transport.
* Put the pigs direct from their pen on to the truck.
* Transport the following pigs separately:
* Young piglets
* Sows with piglets
* Adult boars
* Unfamiliar groups of pigs
* Sows in advanced pregnancy
The female
* Puberty can be affected by breed, season of the year, and social environment (e.g. crowding) but especially by live weight.
* Mixing during transport sometimes triggers puberty where the transport stress is thought to trigger reproductive hormones.
* Contact with males will also stimulate first oestrus. However if exposure is too early or for too long, the gilts may become accustomed to the boar's presence and not react.
* To exploit this male effect, expose the gilt to the boar at about 160-175 days of age, and 60-90% of then should show oestrus within 10 days after exposure.
* Most breeds of gilts today come into oestrus between 170-220 days of age, when they have been moved from their finishing pens at around 90kg live weight.
* Weaning a litter will trigger the sow to come in oestrus. She usually cycles 4-5 days after removal of her litter.
* For best results, make sure the gilts are kept totally from within sight, smell or sound of the boar.
* Rearing gilts with contemporary male pen mates does not seem to advance their age of puberty.
* In general practice, gilts are mated and their third heat, when weighing about 118kg. However mating them at their second heat has economic advantages.
Signs of oestrus
Sows and gilts in oestrus show any combination of the following signs:
* Swollen and reddened vulva about 2-6 days beforehand.
* Mucous discharge from the vagina.
* Restlessness and a poor appetite.
* Females coming into heat may sniff the genital area of their pen mates.
* They may ride others and stand to be ridden.
* They will show a feature unique to pigs - the "stance reflex" where they arch their backs , stand rigidly when pushed from behind, and allow a person to sit astride them.
* Prick-eared breeds carry their ears erect and held back.
* Oestrus pigs make a characteristic grunt and seek other pigs while go around searching for a boar.
Mating
* The female pig assumes a major role in mating by searching for the male and converting social contact into sexual behaviour.
* "Standing heat" when the female will stand for copulation lasts around 48 hours (range of 38-60 hours). Some sows can stay on heat for up to 120 hours.
* The first heat is usually shorter and sows have longer receptive periods than gilts.
* Length of oestrus is also affected by breed, season and management system such as if sows are group our individual housed.
* Ovulation occurs during the second half of the oestrus period, so it's best for the boar to serve the sow twice - at the start and end of the standing heat period.
* Females not mated will cycle every 21 days (range of 19-24 days).
* Gestation in the modern hybrid pig kept intensively averages 115 days (range 108-122 days).
* The "standing reflex" of the sow where she will not move when weight is applied to her back increases as the oestrus period advances.
* The sow is stimulated by the boar and his pheromones from his body, especially his frothing mouth and the gelatinous exudates from his prepuce.
* The order of priority of these stimuli seems to be smell, sound, sight with physical contact last.
* Some sows show a preference for a particular boar and this can cause inconvenience in breeding programmes.
* When the boar is too large and heavy and risk damaging the sow (as mating can take a very long time), the female is best held in a crate where the boar's front legs rest on the sides of the crate to take some of his weight.
* Gilts may often only stand for a boar in the presence of another female in the mating pen, or with a familiar pig in an adjoining area. However, if these support pigs are nearing oestrus, they'll only distract the boar from the job in hand.
* It's a good idea to mate gilts to an old experienced boar and mate old sows with a young boar.
Female behaviour before birth
* Sows show great variation in their behaviour approaching birth. This depends mainly on age, previous experience, breed, strain and the husbandry system.
* Sows carrying a litter of more than 11 pigs will have a 5-day shorter gestation than those carrying average litters of 9-10 piglets.
* To avoid stressing the sow, she should be transferred to her farrowing quarters about a week before birth. This will allow them to settle in and reduce stress levels.
* Stressed sows (especially inexperienced ones) will have higher piglet mortality through overlaying and even attacking piglets.
* Heavily pregnant sows spend most of their time resting, sleeping and feeding.
* As gestation length varies widely, recognising the signs of approaching birth is very important, to ensure the welfare needs of the sow are met.
* Sows are nest builders - and they need to express this desire in intensive farming. A sow starts to nest build 3-7 hours before farrowing, and after giving birth she stays in the nest for 24 hours, nursing every 45 minutes.
Signs of birth
* The vulva swells and becomes redder, especially obvious in white skinned pigs about 4 days before birth (range 1-7 days). In black pigs you will only see the vulva starting to look like a swollen prune.
* The udder swells, becomes firm and colostrum can be obtained by gentle massage up to 24 hours before farrowing. Rubbing the front teats usually stimulates the sow to lie down.
* Increased restlessness. The sow gets up and lies down or changes side more frequently, twitches the tail, and chews the pen railings.
* She also urinates, defaecates and drinks more.
* The sow chews up the bedding (when provided) and makes the nest. She paws the ground, especially where no bedding is provided. This is a key sign.
* There will be a discharge of blood, birth fluid from the sow and green-brown faecal meconium pellets originating from the piglets.
* Respiration will increase from about 54 breaths/minute 24 - 12 hours before birth, to 90/min 12 - 4 hours before birth, reducing to 25/min at about 24 hours after farrowing. This together with intermittent low grunting and jaw chomping is common.
* Sow rectal temperatures rises from about 39 - 39.5 C four hours prior to farrowing. They then stay elevated (around 40 C) for up to 24 hours after farrowing.
Behaviour during birth
* During birth, the sow lies on one side, and in the intervals between piglets she may change sides, stand or sit in a dog-sitting posture. These movements risk crushing or overlaying the piglets.
* Studies showed that the average time to produce a whole litter averaging 11 piglets was 2 hours 53 minutes, or 15.3min/piglet.
* But these times vary greatly with a range from 3.6 min/piglet to 44.6 min/piglet.
* Normally 55-75% of piglets are born head first and 25-45% back legs first.
* Abdominal straining is more often seen before the birth of the first pig, and less common with the remainder.
* As the sow strains, her tail is often pulled back away from the vulva, and delivery of a piglet is often accompanied by vigorous tail swishing and expulsion of gas from the rectum.
* Paddling with the legs while lying down is common.
* The sow usually just lies still as each piglet is born, and she attracts them to her head end by special grunts. She doesn't stand up and lick them and chew their birth sack like other species. She also cannot turn to lick them as they are born like a bitch as she is not as flexible.
* After the piglets are born, the sow stands up and often urinates.
* Usually the foetal membranes start to be expelled during the birth phase and they may appear in two of three lumps. Most of it is shed after the last piglet is born.
* Four hours is normally needed to expel the complete afterbirth but this varies widely from 21 minutes to 12-13 hours.
Early sow and piglet behaviour after birth
* About 70% of piglets are born with their umbilical cords still attached and attached to the foetal membranes still inside the sow's genital tract.
* The cord can be stretched considerably before breaking and this helps to prevent haemorrhage.
* It takes from 1 to 30 minutes for piglets to free themselves form their cords which became shrivelled within 4-5 hours after birth. The sow rarely chews the end of a piglet's cord.
* After a brief period of 5-10 seconds of not breathing, the piglet gives 5-6 gasps and a cough. This is followed by about 20 seconds of rapid shallow panting followed by regular rhythmic breathing.
* Most piglets attempt to stand within one minute of birth, and within two minutes they can stand freely and start searching for the teats, or anything that sticks out that feels like a teat - e.g. the point of the sow's vulva.
* There's a wide interval of 3 - 153 minutes/piglet (average of 10-15) between birth and the first milk intake. Piglets clearly vary enormously in their ability to find a teat although some are greatly restricted by the trailing cord.
* Nuzzling is a very important behaviour used in teat-seeking.
* Piglets show a very clear preference for the front teats of the sow, which generally have more milk than the rear ones.
* So the first-born piglets get the best (front) teats, which they claim and fight for until a suckling order is established.
* The front teats are longer with more space between them and they have a greater clearance above ground level than the rear teats, so the piglet can grip them more easily.
* Clearance generally declines up to teat number 6, and as the sow ages the udder becomes more pendulous and her ability to expose the bottom teats is reduced.
* The risks of piglets being kicked by the hind feet are also greater when suckling the rear teats. There is also a danger of being kicked by the front feet.
* So the front-suckling piglets grow faster and consequently maintain their social rank in the litter.
* Piglets sort out a hierarchy in the first few days, and a clear social order is established after a week.
* As milk letdown is very rapid (about 20 seconds) and occurs about once an hour, there's little opportunity for piglets to share teats. But if space allows, they may suckle more than one teat.
* Normally breeders select females with a minimum of 12 functional teats, and preferably 14-16. In older sows, wear and tear and mastitis may reduce the number of functional teats.
* Piglet suckling behaviour moves through the following stages:
* Jostling for position along the sow's belly to find the teat.
* Squealing while jostling.
* Nosing the udder.
* Slow sucking.
* Rapid sucking.
* Final slow sucking and udder nuzzling.
* The sow's grunting increases greatly up to the slow sucking stage which is a clear signal to the piglets that letdown is imminent. Letdown starts 25-35 seconds after this signal.
* The squeal of isolated, lost, or handled piglets will alert and stress the sow and she may interrupt her suckling behaviour to investigate. So don't pick up stray piglets during suckling time.
* Piglets sleep for about 15-16 minutes every hour.
* In the wild, the sow and her piglets join the herd after a week.
Fostering piglets
* When sows are farrowed separately but in batches, litter sizes can be adjusted by taking piglets from large litters and giving them to sows with plenty of milk and small litters.
* Care is needed as sows vary in their acceptance of foster piglets.
* Best results are obtained if piglets from both sows are the same age and under one week old before teat preferences have been established.
* For success- remove all the piglets from the sow that is going to be given the extras.
* Wait till they are really hungry and she is anxious to have them back.
* Rub the rear ends of the removed piglets over the anogenital area of the strangers to be added. The sow usually smells this area.
* Use the afterbirth for this job if it's still available.
* Then put them all with the sow and watch to make sure she lets them all suckle and accepts them.
* Fostering will probably disrupt the whole nursing process, because of renewed competition for teats. You'll see this in the uneven growth of the litter up to weaning.
* When sows farrow together in the open, piglets seem to mix freely from birth without any problems. The main concern for the farmer is to make sure that each sow has a similar number of piglets.
* Behaviour of dry sows It's important that dry sows have their diets carefully controlled to ensure their nutritional needs are carefully monitored and met.
* The need to have strict control over a sow's diet has led to the development of systems that restrict their movement, and these have large behavioural and welfare implications.
The systems used are:
* Sow stalls - the sow is held in a narrow stall, allowing her to move to and fro but not turn round. There is total environmental control.
* Sows tethered in stalls by a neck strap or a strap around her chest. She cannot turn round. There is total environmental control.
* Sows at pasture in groups with communal shelters.
* Sows at pasture in individual runs or tethered to individual kennels.
* Sows in groups of 6-10 in a yard with kennel-type shelter and individual feeders.
* There is an active national campaign in many countries (including New Zealand) to make sow stalls and tethering illegal because of the stress it causes the animals. This practice has been banned in some European countries.
* Sows in stalls and tethered sows tend to develop "bar biting" when they bite the front bars of the stall, and also show a "paddling" behaviour often seen by bored tethered animals.
* Research has shown that even in stalls, providing some straw gave some enrichment to their existence.
* The ultimate in luxury, (judged with an anthropomorphic view) is to keep dry sows in large yards in deep straw. But sows can have savage fights to establish a social order when housed loosely, and it adds greatly to costs of production. This is a classical example of what the domestic contract should provide.
The male
* In the wild or in extensive pig keeping systems, the male pig, (unlike males in other species) does not initiate sexual behaviour. He waits for initial signals from the female.
* Boars reach puberty about 6 months of age, but are generally not used for service till 7-8 months old. These ages can vary a lot depending on the feeding level.
* They start learning their courting behaviour and show elements of sexual behaviour while still suckling and as part of play with pen mates. They develop these behaviours even more if mixed with strangers.
* Boars reared in isolation are much slower to develop successful courting behaviour. Group reared boars are better than those reared in individual pens, and intensive stocking will encourage aggression as well as sexual behaviour.
* Boars reared intensively in homosexual groups maintain this relationships for many months after parting, and they can often show abnormal sexual behaviour.
* The boar's courting ritual includes:
* Chasing the sow.
* Nuzzling her head, flanks, shoulder and anogenital area.
* Occasional pushing or leaning on the sow to test her state.
* Drinking her urine.
* He urinates frequently.
* He grinds and chomps his teeth salivating and frothing at the mouth.
* This courting ritual has an important effect on improving the conception rate of the sows being mated. In outdoor pigs boars often have rings inserted in their noses to stop them rooting up the pasture. This affects their courting ritual when it comes to nuzzling the sow and causing a negative response.
* When the boar mounts, he rests his belly along the sow's back and grasps her with his forelegs. Inexperienced boars will head mount, side mount and dismount frequently before intromission (penis entering the vagina).
* Ejaculation occurs when the cork-screw penis of the boar locks in the sow's cervix. This can take considerable time - averaging about 7 minutes but it can last up to 25 minutes.
* The boar thrusts and rests many times and eventually ejaculates up to 500 ml of sperm. Other farm species produce a 5-15 ml ejaculate.
Boar behaviour and handling
* Treat all boars with respect and treat them as individuals.
* Handle them carefully and de-tusk them every 6 months (with veterinary advice).
* Remove the front accessory claws to protect the sow from injury during mating (with veterinary advice).
* Don't overwork the boar - one boar to 20 sows is most common.
* Four services a week are plenty till the boar is 12 months old. Don't let him serve more than 6 times a week as this will lower his fertility and subsequent litter size from the sows mated.
* Too frequent use of a boar as a teaser to locate sows coming into heat, may frustrate him too much and he may not serve when needed.
* Mate young boars to old sows in peak oestrus, and old boars to gilts.
* Don't let young boars get injured during their early matings.
* After layoffs of longer than a month, libido may drop and a boar may need the stimulus of an old sow in peak oestrus that has already been served by another boar.
* Spreading some ejaculate from another boar along the sow's back will help to stimulate a boar.
* Take the sow on heat to the boar so he doesn't waste time investigating a new environment. Otherwise he'll waste time in an elaborate ritual of urinating, rubbing scent from his body on the walls, marking the territory with salivary foam and fight the sow to establish dominance.
* Boar pens should provide a good foothold for the boar but not so rough as it will cause foot problems.
* Boars should be kept within sight, sound and smell of sows. However this assumes the boar is the dominant animal in the herd. He may be considerably stressed with other boars near by, as in the wild each boar would be solitary.
* Boars get very large and need regular exercise to keep fit. It's a good idea to have a system where the boar walks daily to the sow's accommodation to help stimulate oestrus and identify sows on heat.
* Regular quiet handling by the stockperson is ideal, walking behind with a pig board for protection, and talking in quiet reassuring tones.
Boars and Artificial Insemination (AI)
* AI in pigs is now well established in commercial pig improvement and is a specialist operation.
* At AI centres boars are trained to mount dummy sows and serve into an artificial vagina as this is less complicated than using a live sow.
* Boars may be harder to train if they have mated sows first. But again this varies with the personality of the boar.
* Gentle, reassurance by the stockperson is the secret of success to get a good semen sample from the boar.
* Boars will show courting behaviour to the dummy by nuzzling its flank and rear end.
* Libido varies greatly between boars, and is related to frequency of use.
* Boars can be stimulated more by giving them false mounts, or by observing a collection from another boar.
* It's a good idea to allow the sow or gilt 10-20 minutes contact (through a pen) with a boar after insemination.
Behaviour of housed boars
* In less intensive systems where sows are kept in straw yards (and not in stalls), boars often run with them and few problems arise.
* If a boar is put in among a group of unfamiliar loose-housed sows, he will waste time investigating the environment and not checking for sows on heat.
* In intensive pig farming, the boar does not spend time in social contact with sows and opportunities to consort with females are decided by the human in charge.
* Here, sometimes the boar pens are arranged between pens of six loose-housed sows to achieve maximum physical presence of the male.
* In other systems, including where sows are tethered or in stalls, the boar is walked daily in front of them to test for oestrus.
* When boars walk behind stalled sows a boar may be confused by the fact that they are immobile and hence displaying an invitation to be mounted. This can be very time-wasting.
* It's well established that depriving boars and sows full opportunity to indulge in their full courting behaviour affects pregnancy and litter size.
Boar behaviour problems
* Serving into the rectum instead of the vagina can be a problem. Avoid this by supervising young boars in their early work to make sure they are aligned correctly.
* Extremes of heat may affect the boar's enthusiasm. Delay his work till evening.
* Masturbation by coiling the penis inside the diverticulum of the prepuce. Make sure the boar's penis has actually entered the sow and he is not masturbating.
* Boars that masturbate persistently should be culled although the prepuce can be surgically removed.
* Some boars behave normally up to the point of mounting and then squat down on the floor and ejaculate. Great care is needed to help these boars achieve success as they may persist in this habit.
* Aggression. Boars are always potentially dangerous and need to be handled with care. Nervous and aggressive boars should be culled. Some boars will show aggression with strangers but not with their regular handlers.
* When strange boars meet, they strut shoulder to shoulder, head raised and hair bristling along their backs. Deep grunts, jaw chomping and mouth frothing continues.
* In a fight, boars face each other with their shoulders in opposition and apply sideways pressure. They circle around, biting and slashing at each other with their tusks. They may charge each other with mouths wide open and bite. The loser turns and runs away squealing.
* Subsequently after a win, the winning dominant boar need only grunt to get submission. Newly-mixed boars fight less if they are both put in a strange environment.
Weaning
* In the wild, pigs are weaned at around 14-17 weeks old.
* Farmed pigs were traditionally weaned at 8 weeks of age, but in more intensive systems weaning is done at 3, 4 or 5 weeks.
* Even weaning at 24 hours after birth after the piglets have had their colostrum has been studied. But current opinion among pig behaviorists and welfarists is that piglets cannot effectively cope with weaning before 3 weeks old.
* In some intensive systems, young pigs are kept very intensively in wire-floored tiered cages from weaning at 7 days. At about 7kg live weight, the pigs in these systems proceed to grow and fatten in "flat deck' cages on mesh floors.
* The development of very early weaning systems is based on getting the sow pregnant to produce more pigs per year as weaning stimulates the sow to return to oestrus.
* Abrupt weaning is now considered to be preferable to removing pigs gradually. Again this is to achieve higher production from the sow.
* The more intensive the system is for growing pigs after weaning, the greater is the need for skilled care by the stockperson. There also needs to be a good smoke alarm system and back up for power breakdowns.
* Studies of highly-intensive systems have shown wide variation from pigs showing stress behaviours, to pigs adapting well without stress. Clearly the person in charge who controls the pigs' environment is the key factor.
The stress of weaning
* Removal of their mother and hence their source of feed, warmth, security and comfort.
* They lose their normal clues for feeding given by the sow's vocal messages.
* They may be mixed with strange pigs from other litters and in a strange pen.
* Competition for feed, water, sleeping space and dunging area may be increased.
* They will face new bacterial challenges and diseases.
* They may be subject to rough handling, transport, markets, veterinary inspection and treatment.
* They will experience climatic change with cold temperatures and draughts being especially dangerous.
Reducing weaning stress
* Piglets can cope with one or two of these stressors, but more that this leads to poor growth for up to 14 days after weaning.
* The settling down period of pigs at weaning seems to be around 3 weeks.
* The major aim is to ensure pigs are eating adequate amounts of correctly balanced dry feed before weaning. Flavour and physical form of this feed is important to encourage high intake.
* Getting the pigs used to the lower temperature of the fattening accommodation is important. The sow's nest is around 28 C and they have to get used to temperature in the growing pens of 19C and eventually below this.
* Avoid erratic temperatures, as this will cause pigs to huddle and fight for positions to keep warm.
* Provide adequate trough space, again to stop intense competition and fighting.
* Adequate lying space and a comfortable bed are important as growing pigs in intensive housing spend around 60-70% of their time resting/sleeping. Constant standing or restlessness will lead to fatigue and poor performance.
Behaviour of growing pigs
* Poor growth and poor feed conversion inevitably will have a large behavioural component, especially in intensive systems.
* There are many factors involved in poor performance, and the skill is to determine which of them can be changed, with the welfare of the animal as well as profit very much in mind.
* The physical form of the diet is important. Pigs generally prefer wet to dry feeds, but dry feeds keep pigs occupied for longer.
* Scattered feed takes longer to eat than feed in troughs - again keeping pigs occupied for longer. It also saves the costs of troughs and fighting over trough space.
* Providing adequate trough space is of major importance, and prevents aggression and stress.
* Feed offered ad lib will keep pigs fully occupied but restriction is often needed to control growth and performance. For example pregnant sows, as opposed to lactating sows, need their diets restricted to prevent them getting too fat. Obesity lowers subseqent lactation performance.
* Pigs perform well on once-a-day feeding but feeding time is a good time to inspect pigs. Reduced appetite is a good early sign of potential health problems.
* So it's important in large intensive systems to use time saved on chores to be spent on animal inspection.
* This is especially the case as systems become even more automated where light levels are reduced. Increasing the lights for inspection will then activate the pigs, so there is a dilemma here.
* Increasing stocking density/pen is an easy way to get more throughputs in a pig unit. It can have devastating effects on pig welfare.
* This approach can cause a major upset in social order leading to bullying, tail and ear biting, disease, low feed conversion efficiency and low profits.
* Pigs highly stocked in pens spend more time feeding, standing and walking, and less time resting and sleeping.
* Contented pigs are recumbent for up to 19 hours a day. They drowse for 5 hours and sleep about 6-7 hours.
* Pen floors have an important role in pig comfort and behaviour. They should provide a good non-slip, non-abrasive surface with no protruding edges, and not harbour bacteria or parasites. They should be impervious to water and be easily cleaned.
* The pig's cloven hoof was designed to walk on earth, so slatted and perforated floors can cause damage and discomfort.
* When social orders have been sorted out by fighting, all that is needed is a loud grunt and a feint with the snout by the dominant pig to maintain this order.
Mixing growing pigs
* To reduce stress, mix pigs from 3-4 litters before weaning so they know eachother.
* Don't put newly mixed pigs in too large a pen, as they'll stay in their original groups, they'll not mix and they'll fight to defend territory.
* Put all the pigs to be mixed in a strange pen.
* Distract them by giving them straw or paper sacks to chew, or spray them with a strong-smelling fluid.
* Provide adequate trough space and feeding and drinking opportunities.
* Mix them at dusk when identification of rivals will be more difficult.
* Keep pigs in close weight ranges and remove any sick animals or any being severely molested.
* The fewer pigs there are in a single group, the tighter they can be packed.
* In general, vices are more common in large groups in large houses where social orders are more are more complex, and maintaining them causes more aggression and stress.
* Don't change diets at the time when pigs are mixed.
* Feed pigs ad lib diets for 2-3 weeks after mixing to avoid digestive upsets. Most producers feed ad lib for up to 10 weeks of age. Feed restriction should be delayed until the pigs have sorted out a new social order.
* Provide plenty of feed and trough space.
* Opinions on mixing sexes vary. Generally, if they have a good environment, sex does not cause problems. There may be some mounting in the last 4-5 weeks before slaughter.
Water for growing pigs
* Water is provided from bowls, metal nipples or metal drinking straws. Pigs are very quick to learn how to operate them.
* The watering device is a great plaything for bored pigs, so it will be subject to rubbing, nuzzling and chewing. Rigid construction is essential.
* Place the water source near a dunging area or drain or above a food trough because of spillage.
* Make the pigs have to reach up to get at nipples when drinking.
* Don't put water sources in positions where pigs will bruise themselves. Put them in a corner.
* Be consistent in the choice of drinkers provided.
1. Overlaying piglets by the sow
* This is a serious problem and accounts for 20% of all piglet deaths.
* The greatest risk to piglets is during the first week of life and especially during the first few hours of birth when a restless sow gets up and lies down a lot.
* The causes of high overlaying losses are complex and obviously involve the piglets and the sow. It's often difficult to apportion blame.
Factors in the sow:
* Previous experience
* Age
* Breed and strain
* Lameness
* Leg and joint problems
* Obesity
* Skin parasites
* Mastitis and udder problems
Factors in the piglet.
Piglets that are most likely to be crushed are usually one of the following:
* Dull
* Weak
* Inactive
* Uncoordinated
* Suffer from coma
* Chilled
* Starved
* Have very low birth weights
* Have very high birth weights
* Are runts from litters
* Have splayed legs
Possible cures/Prevention
* Provide a heat lamp in an area protected from the sow to attract the piglets away from her after suckling.
* Place highly palatable feed pellets near the lamp to start the piglets eating.
* This is most easily organised when the sow farrows in a crate, rather than free in a hut or pen. Sows usually lie with their teats towards the heat lamp.
* Farrowing pens should all have rails about 200mm from the floor and 200mm from the wall.
* Cull sows that persistently show this behaviour.
2. Savaging piglets by the sow
* This is more common in inexperienced gilts with their first litter than in sows.
* A sow may snap and injure an odd piglet, but seldom savages the whole litter.
* The first piglet born is most likely to be savaged as it seems that the sow is frightened by it's movement and high-pitched squeak, associated with the birth process. Usually after the sow has sniffed the piglet, all is well.
* Most sows accept human presence at birth, but strangers of unfamiliar noises may upset and frighten the sow and she may savage some piglets.
* Sows that savage litters without very good reason are culled. Gilts may be given another chance but the fear is that the trait may be genetic and these animals should not be bred from.
Possible cures/Prevention
* Check that the cause was not a "one-off" such as fright or panic and make sure it is not repeated.
* Cull any female that shows the vice more than once.
* Check the genetics of the female incase it could be an inherited trait.
3. Stress in pigs
Many factors have been identified as the causes of stress in pigs. These are all products of bad husbandry and/or poor stockpersonship:
* Chilling
* Overheating
* Physical injury
* Poor sanitation
* Poor ventilation
* Overcrowding
* Bullying
* Dampness and draughts
* Genetic makeup
* Weaning
* Castration
* Lack of feed and water
* Nutritional deficiencies
* Internal and external parasites
* Disease
* Loss of appetite
* Noise
Possible cures/Prevention
* Try to sort out which of the above is the main cause and change the management to avoid future problems.
* Veterinary advice should be part of any changes.
4. Aggression - fighting in pigs
* Aggression in pigs has been classified into three kinds - acute, chronic and abnormal.
* "Acute" - fighting to establish a social order, especially when strange pigs are mixed.
* "Chronic" - fighting to maintain an established order.
* "Abnormal" - serious fighting that has very big economic implications.
* Tail biting.
* Ear biting.
* Cannibalism.
* Sudden savaging of a group member.
* Sows attacking each other.
* Sows savaging their young.
* Domestic pigs unlike wild pigs are kept in monocaste social groups of the same sex, age and size. This may in fact make it harder and more stressful for pigs to form stable social groups when the combatants are physically equal.
* Newly-acquainted pigs seem to fight for 24-48 hours to establish a linear dominance hierarchy, usually with the largest pig at the top and the smallest at the bottom. Note that it may not always be the biggest pig that becomes the top dominant animal. Once this is established, fighting is greatly reduced but not totally eliminated.
* When unfamiliar pigs are mixed, fighting seems to start the feed runs out.
* Fighting will nearly always occur when a pig removed for treatment is returned to the group. Top rank pigs can be returned without problems but any pigs lower in the social order will need to be returned before about a maximum of 3 days. The key to success is to know what the pig's social rank is before removing it and acting accordingly
Possible cures/Prevention
* Check the environment to make sure it is not too hot or too cold, that the air is fresh and that the pigs have a dry warm area to rest.
* Provide plenty of feeding and watering space. Hunger is often the cause of aggressive biting which can blow up into more serious aggression.
* Make sure pigs are all of similar size in the group.
* Provide bedding for newly mixed pigs to chew - at least for a period of about 1½ hours.
* If pigs are removed from their group for any reason, try to put them back before 3 days. If they are the smaller members of the group, put them back sooner and watch that they are not victimised.
5. Tail biting and possible causes
* This has developed since pigs were kept intensively.
* Usually starts 4-22 days after weaning.
* May be associated with ear biting.
* There are many possible causes are put forward yet little is still known about it. The so-called "solution" is seen as removing the tail which should not be done before the causes are determined and rectified.
Causes are usually:
* Behavioural - boredom, breakdown of dominance order or excess social contact.
* Nutritional - low fibre, low bulk, and deficiencies of a whole range of nutrients.
* Environmental - poor ventilation leading to high humidity, high temperatures, high ammonia and carbon dioxide, lack of bedding, and not enough feed or watering points.
* Disease - skin mange, internal parasites and various infections.
* Teething problems.
Possible cures/Prevention
* Check ventilation to prevent build up of foul air.
* Check pigs are not too cold (below 15C) and not too hot (above 28C).
* Remove badly bitten pigs from the group and isolate them.
* Daub the tails with Stockholm tar, creosote, disinfectant, lice of mange wash as a repellant.
* Provide toys - hanging chains, paper sacks, straw, balls, stone filled cans, or anything you can think of to provide occupational therapy and keep the pigs busy.
* Reduce the stocking rate in the pens - don't exceed 120kg live weight/m2 of floor space.
* Group pigs on the basis of size. Often a small pig in a group is the aggressor and not the biggest one.
* Move the problem pigs to another pen. This may fix the problem, or it can make them worse!
* Change the feeding system or the physical form of the feed. For example moving from meal to pellets may help, or the reverse may work.
* Keep mixing of pigs to a minimum as it may trigger fighting and make the problem worse.
* Dock about 2cm from the piglet's tail at birth.
* Change from flop-eared to prick-eared breeds as the incidence in the latter is sometimes less.
6. Cannibalism
* This may develop from tail biting.
* It often starts by pigs attacking wounds, prolapsed rectums, sick pigs and the like.
* Pigs in a pen will chase and attack the suffering pig till it is killed - when they continue their cannibalism.
* The attacked pig must be removed.
* The remaining pigs must have a change to their environment - eg provide straw, altering the temperature, providing toys.
Possible cures/Prevention
* See suggestions for tail biting.
7. Gastric ulcers
* These increase as pigs are kept more intensively - clearly a stress induced problem.
Possible cures/Prevention
* Try to find the cause and remove it - but may not be easy.
* Investigate infections, intoxication, stress, gastric acidity, digestive upsets, hormones, seasonal changes, feeding methods (especially ad lib systems), housing and many more.
8. Nose rubbing (belly rubbing)
* Weaned pigs may develop the habit of nuzzling other pigs as they lie resting.
* Groups of wild pigs have their own home range, and these can overlap with other bands of pigs.
* Pigs don't have sweat glands over their body so wallowing is a common behaviour in feral pigs in warm conditions. However, they'll also wallow and enjoy mud in cold climates.
* If water is deep enough outdoor pigs will swim.
* There is little social grooming in pigs as we know it in other animals. This is surprising as they enjoy rubbing and scratching so much. But they do nuzzle each other along the flank and back - areas they can't reach on their own.
* Lone pigs scratch these parts against objects in their territory.
* Pigs yawn like other farm animals, and this is often combined with stretching the back leg and closing the eyes.
* Pigs also shake themselves after a period of rest, especially if they've been lying in a group.
* Pigs regularly "tuck in" with their mates and by wriggling settle right down into the bedding.
* When growing pigs have selected their own temperatures, they chose warm afternoon temperatures and quite cool conditions at nights when they lie huddled with their mates for warmth.
* Pigs show a lot of play behaviour, and it's very common in young pigs when they leave the nest or lying area.
* They show great play behaviour especially when they go into a new environment as part of their exploration.
* Social play usually consists of fighting with selected littermates. Often one animal runs away eliciting a chase by mates.
* A piglet playing by itself will whirl round trying to scratch itself and may jump up and down on the spot.
* Pigs are great investigators and play by lifting and moving objects on the ground and throwing them in the air.
* With their sensitive nose, rooting is a favourite pastime and treasured finds are carried away with other pigs in pursuit.
Pig learning ability
* Pigs learn quickly and show great variation in their ability to learn and solve problems.
* Teaching pigs can be done easily by using mild electric shock avoidance, audio signals and feed rewards.
* They have been taught to control their heating and lighting regime - which saves human labour and reduce costs.
* This learning ability is moderately inherited so you could increase this trait in a herd through selection.
* Pigs quickly learn all the details of a new environment because of their well-developed exploratory behaviour. When tested in a maze, pigs are smarter explorers than any other farm animal. Depriving them of this natural ability can cause great stress as seen in pigs kept in barren concrete environments with no bedding to chew.
Pig-human interaction
* There is now plenty of research to show the benefits of pigs that have a strong relationship or bond with their human minders.
* The pigs have clearly been "tamed" and have responded to good handling.
* Taming is best done by quiet and gentle handling of young pigs at feeding time.
* Lay your hand on the pig's had or back, talk gently and scratch or stroke the animal. The best areas to touch are behind the ears, shoulders, along the back and down the sides.
* Pigs soon learn to enjoy this contact and will often lie down to enjoy it. Complete taming can be done in 2-3 weeks after which they will come when called.
Dunging behaviour
* Pigs are probably the cleanest and most orderly farm animal if their environment allows this, and if they have learned appropriate behaviours during their early rearing.
* Pigs defaecate and urinate regularly throughout the day and night in intensive housing although they rest a lot between 7pm and 6am the following morning.
* By 3 days old, piglets have learned not to dung where they sleep. After this age further dunging behaviour is learned from their dam - habits they maintain throughout life. A "dirty" sow that dungs and urinates on her bed will produce "dirty" piglets that do the same.
* Good dunging habits can be encouraged by a few management practices:
* When changing pigs from one pen to another, give them a run for a while before they enter the new pen. This will let them empty out and their first urge in the new pen will not be to defaecate and urinate.
* After moving, dampen the dunging area of the new pen, and put some dung from the old pen on it.
* Pigs that are scouring should have the problem fixed as they will have less control of their faeces and where it goes.
* If there are too few pigs in the pen, use temporary barriers to reduce space in the sleeping area so they are forced to dung elsewhere. Put fresh bedding on the sleeping area.
* A false roof maintaining warmth over the sleeping area will encourage them to rest there and they'll hopefully be less keen to foul the area.
* Cleaning their pen at night may help if the problem exists. After cleaning the fouled area, put some bedding and feed on it.
* Pen shape and the position of the feed and water sources can affect where pigs eliminate. Try moving troughs until the pigs modify their habits.
Abnormal pig behaviour
* Pigs show a long list of abnormal behaviour where stress is the major underlying cause.
* Tail biting
* Ear biting
* Cannibalism - killing and eating pen mates
* Belly nibbling
* Tongue rolling
* Rubbing the nasal bone
* Rubbing snout
* Hyperactivity
* Massaging the anus
* Vacuum chewing
* Biting pen bars
* Rocking back and forward when tethered
The “runt“ pig and its problems
* It's difficult to describe in precise terms what a runt is. It's not necessarily a small piglet, as these can be the result of poor nutrition.
* These nutritional runts are commonly seen in large litters where pigs are not weaned until 5 or 8 weeks.
* Piglets can be runts because of their position in the uterus, where for some reason they have been deprived of nutrients. These runts never catch up, even with extra feeding as they are physiologically under-developed.
* As litter sizes increases and competition for milk and feed increases, the problem the runt has to survive and grow increases. Commercial pig farmers often see euthanasia as a cost-effective solution.
Moving pigs
* Pigs are den-living, home-loving animals and do not show any flocking/herding response when moved.
* In the wild, frightened pigs scatter and crouch in the undergrowth, or race back to their den. Domestic pigs still show this behaviour.
* They just don't like being moved - especially from their darkened den into bright outside light.
* Loading and unloading are the most stressful part of transport when pigs are pushed, dragged by their ears, have their tails pulled, or goaded physically or electrically. (Note that electric prodders should not be used on pigs in New Zealand).
* Suggestions for loading and transport of pigs:
* Select the pigs for market the night before, and hold them in an unfamiliar pen.
* Reduce feed before transport but not water.
* Move them in the early morning.
* Don't attempt to rush, abuse or punish them.
* They'll go better up a ramp or along level ground.
* Avoid having to move them down a ramp.
* Keep ramp sides fully covered so they can't see through.
* Spread some bedding along their path you want them to go.
* Spread some feed or slices of apple along the path and up the ramp.
* Use a hand-held pig board to approach them - this also protects your legs. Use any solid barrier to bring up behind them.
* Don't do anything like pulling ears or tails that will make them squeal. Use a canvas slapper so as not to bruise them.
* To move an awkward individual - put a plastic bucket over its nose and eyes and reverse it along.
Transporting pigs
* Transport can be very stressful for pigs. Here are some recommendations to reduce stress:
* Don't transport pigs that are not familiar with each other.
* Provide plenty of ventilation in the truck.
* Avoid transporting when temperatures exceed 28 C.
* Avoid long parking periods on hot sunny days. Always park in the shade.
* Avoid physical exertion and excitement before and during transport.
* Do not feed during the 12 hours before transport.
* Put the pigs direct from their pen on to the truck.
* Transport the following pigs separately:
* Young piglets
* Sows with piglets
* Adult boars
* Unfamiliar groups of pigs
* Sows in advanced pregnancy
The female
* Puberty can be affected by breed, season of the year, and social environment (e.g. crowding) but especially by live weight.
* Mixing during transport sometimes triggers puberty where the transport stress is thought to trigger reproductive hormones.
* Contact with males will also stimulate first oestrus. However if exposure is too early or for too long, the gilts may become accustomed to the boar's presence and not react.
* To exploit this male effect, expose the gilt to the boar at about 160-175 days of age, and 60-90% of then should show oestrus within 10 days after exposure.
* Most breeds of gilts today come into oestrus between 170-220 days of age, when they have been moved from their finishing pens at around 90kg live weight.
* Weaning a litter will trigger the sow to come in oestrus. She usually cycles 4-5 days after removal of her litter.
* For best results, make sure the gilts are kept totally from within sight, smell or sound of the boar.
* Rearing gilts with contemporary male pen mates does not seem to advance their age of puberty.
* In general practice, gilts are mated and their third heat, when weighing about 118kg. However mating them at their second heat has economic advantages.
Signs of oestrus
Sows and gilts in oestrus show any combination of the following signs:
* Swollen and reddened vulva about 2-6 days beforehand.
* Mucous discharge from the vagina.
* Restlessness and a poor appetite.
* Females coming into heat may sniff the genital area of their pen mates.
* They may ride others and stand to be ridden.
* They will show a feature unique to pigs - the "stance reflex" where they arch their backs , stand rigidly when pushed from behind, and allow a person to sit astride them.
* Prick-eared breeds carry their ears erect and held back.
* Oestrus pigs make a characteristic grunt and seek other pigs while go around searching for a boar.
Mating
* The female pig assumes a major role in mating by searching for the male and converting social contact into sexual behaviour.
* "Standing heat" when the female will stand for copulation lasts around 48 hours (range of 38-60 hours). Some sows can stay on heat for up to 120 hours.
* The first heat is usually shorter and sows have longer receptive periods than gilts.
* Length of oestrus is also affected by breed, season and management system such as if sows are group our individual housed.
* Ovulation occurs during the second half of the oestrus period, so it's best for the boar to serve the sow twice - at the start and end of the standing heat period.
* Females not mated will cycle every 21 days (range of 19-24 days).
* Gestation in the modern hybrid pig kept intensively averages 115 days (range 108-122 days).
* The "standing reflex" of the sow where she will not move when weight is applied to her back increases as the oestrus period advances.
* The sow is stimulated by the boar and his pheromones from his body, especially his frothing mouth and the gelatinous exudates from his prepuce.
* The order of priority of these stimuli seems to be smell, sound, sight with physical contact last.
* Some sows show a preference for a particular boar and this can cause inconvenience in breeding programmes.
* When the boar is too large and heavy and risk damaging the sow (as mating can take a very long time), the female is best held in a crate where the boar's front legs rest on the sides of the crate to take some of his weight.
* Gilts may often only stand for a boar in the presence of another female in the mating pen, or with a familiar pig in an adjoining area. However, if these support pigs are nearing oestrus, they'll only distract the boar from the job in hand.
* It's a good idea to mate gilts to an old experienced boar and mate old sows with a young boar.
Female behaviour before birth
* Sows show great variation in their behaviour approaching birth. This depends mainly on age, previous experience, breed, strain and the husbandry system.
* Sows carrying a litter of more than 11 pigs will have a 5-day shorter gestation than those carrying average litters of 9-10 piglets.
* To avoid stressing the sow, she should be transferred to her farrowing quarters about a week before birth. This will allow them to settle in and reduce stress levels.
* Stressed sows (especially inexperienced ones) will have higher piglet mortality through overlaying and even attacking piglets.
* Heavily pregnant sows spend most of their time resting, sleeping and feeding.
* As gestation length varies widely, recognising the signs of approaching birth is very important, to ensure the welfare needs of the sow are met.
* Sows are nest builders - and they need to express this desire in intensive farming. A sow starts to nest build 3-7 hours before farrowing, and after giving birth she stays in the nest for 24 hours, nursing every 45 minutes.
Signs of birth
* The vulva swells and becomes redder, especially obvious in white skinned pigs about 4 days before birth (range 1-7 days). In black pigs you will only see the vulva starting to look like a swollen prune.
* The udder swells, becomes firm and colostrum can be obtained by gentle massage up to 24 hours before farrowing. Rubbing the front teats usually stimulates the sow to lie down.
* Increased restlessness. The sow gets up and lies down or changes side more frequently, twitches the tail, and chews the pen railings.
* She also urinates, defaecates and drinks more.
* The sow chews up the bedding (when provided) and makes the nest. She paws the ground, especially where no bedding is provided. This is a key sign.
* There will be a discharge of blood, birth fluid from the sow and green-brown faecal meconium pellets originating from the piglets.
* Respiration will increase from about 54 breaths/minute 24 - 12 hours before birth, to 90/min 12 - 4 hours before birth, reducing to 25/min at about 24 hours after farrowing. This together with intermittent low grunting and jaw chomping is common.
* Sow rectal temperatures rises from about 39 - 39.5 C four hours prior to farrowing. They then stay elevated (around 40 C) for up to 24 hours after farrowing.
Behaviour during birth
* During birth, the sow lies on one side, and in the intervals between piglets she may change sides, stand or sit in a dog-sitting posture. These movements risk crushing or overlaying the piglets.
* Studies showed that the average time to produce a whole litter averaging 11 piglets was 2 hours 53 minutes, or 15.3min/piglet.
* But these times vary greatly with a range from 3.6 min/piglet to 44.6 min/piglet.
* Normally 55-75% of piglets are born head first and 25-45% back legs first.
* Abdominal straining is more often seen before the birth of the first pig, and less common with the remainder.
* As the sow strains, her tail is often pulled back away from the vulva, and delivery of a piglet is often accompanied by vigorous tail swishing and expulsion of gas from the rectum.
* Paddling with the legs while lying down is common.
* The sow usually just lies still as each piglet is born, and she attracts them to her head end by special grunts. She doesn't stand up and lick them and chew their birth sack like other species. She also cannot turn to lick them as they are born like a bitch as she is not as flexible.
* After the piglets are born, the sow stands up and often urinates.
* Usually the foetal membranes start to be expelled during the birth phase and they may appear in two of three lumps. Most of it is shed after the last piglet is born.
* Four hours is normally needed to expel the complete afterbirth but this varies widely from 21 minutes to 12-13 hours.
Early sow and piglet behaviour after birth
* About 70% of piglets are born with their umbilical cords still attached and attached to the foetal membranes still inside the sow's genital tract.
* The cord can be stretched considerably before breaking and this helps to prevent haemorrhage.
* It takes from 1 to 30 minutes for piglets to free themselves form their cords which became shrivelled within 4-5 hours after birth. The sow rarely chews the end of a piglet's cord.
* After a brief period of 5-10 seconds of not breathing, the piglet gives 5-6 gasps and a cough. This is followed by about 20 seconds of rapid shallow panting followed by regular rhythmic breathing.
* Most piglets attempt to stand within one minute of birth, and within two minutes they can stand freely and start searching for the teats, or anything that sticks out that feels like a teat - e.g. the point of the sow's vulva.
* There's a wide interval of 3 - 153 minutes/piglet (average of 10-15) between birth and the first milk intake. Piglets clearly vary enormously in their ability to find a teat although some are greatly restricted by the trailing cord.
* Nuzzling is a very important behaviour used in teat-seeking.
* Piglets show a very clear preference for the front teats of the sow, which generally have more milk than the rear ones.
* So the first-born piglets get the best (front) teats, which they claim and fight for until a suckling order is established.
* The front teats are longer with more space between them and they have a greater clearance above ground level than the rear teats, so the piglet can grip them more easily.
* Clearance generally declines up to teat number 6, and as the sow ages the udder becomes more pendulous and her ability to expose the bottom teats is reduced.
* The risks of piglets being kicked by the hind feet are also greater when suckling the rear teats. There is also a danger of being kicked by the front feet.
* So the front-suckling piglets grow faster and consequently maintain their social rank in the litter.
* Piglets sort out a hierarchy in the first few days, and a clear social order is established after a week.
* As milk letdown is very rapid (about 20 seconds) and occurs about once an hour, there's little opportunity for piglets to share teats. But if space allows, they may suckle more than one teat.
* Normally breeders select females with a minimum of 12 functional teats, and preferably 14-16. In older sows, wear and tear and mastitis may reduce the number of functional teats.
* Piglet suckling behaviour moves through the following stages:
* Jostling for position along the sow's belly to find the teat.
* Squealing while jostling.
* Nosing the udder.
* Slow sucking.
* Rapid sucking.
* Final slow sucking and udder nuzzling.
* The sow's grunting increases greatly up to the slow sucking stage which is a clear signal to the piglets that letdown is imminent. Letdown starts 25-35 seconds after this signal.
* The squeal of isolated, lost, or handled piglets will alert and stress the sow and she may interrupt her suckling behaviour to investigate. So don't pick up stray piglets during suckling time.
* Piglets sleep for about 15-16 minutes every hour.
* In the wild, the sow and her piglets join the herd after a week.
Fostering piglets
* When sows are farrowed separately but in batches, litter sizes can be adjusted by taking piglets from large litters and giving them to sows with plenty of milk and small litters.
* Care is needed as sows vary in their acceptance of foster piglets.
* Best results are obtained if piglets from both sows are the same age and under one week old before teat preferences have been established.
* For success- remove all the piglets from the sow that is going to be given the extras.
* Wait till they are really hungry and she is anxious to have them back.
* Rub the rear ends of the removed piglets over the anogenital area of the strangers to be added. The sow usually smells this area.
* Use the afterbirth for this job if it's still available.
* Then put them all with the sow and watch to make sure she lets them all suckle and accepts them.
* Fostering will probably disrupt the whole nursing process, because of renewed competition for teats. You'll see this in the uneven growth of the litter up to weaning.
* When sows farrow together in the open, piglets seem to mix freely from birth without any problems. The main concern for the farmer is to make sure that each sow has a similar number of piglets.
* Behaviour of dry sows It's important that dry sows have their diets carefully controlled to ensure their nutritional needs are carefully monitored and met.
* The need to have strict control over a sow's diet has led to the development of systems that restrict their movement, and these have large behavioural and welfare implications.
The systems used are:
* Sow stalls - the sow is held in a narrow stall, allowing her to move to and fro but not turn round. There is total environmental control.
* Sows tethered in stalls by a neck strap or a strap around her chest. She cannot turn round. There is total environmental control.
* Sows at pasture in groups with communal shelters.
* Sows at pasture in individual runs or tethered to individual kennels.
* Sows in groups of 6-10 in a yard with kennel-type shelter and individual feeders.
* There is an active national campaign in many countries (including New Zealand) to make sow stalls and tethering illegal because of the stress it causes the animals. This practice has been banned in some European countries.
* Sows in stalls and tethered sows tend to develop "bar biting" when they bite the front bars of the stall, and also show a "paddling" behaviour often seen by bored tethered animals.
* Research has shown that even in stalls, providing some straw gave some enrichment to their existence.
* The ultimate in luxury, (judged with an anthropomorphic view) is to keep dry sows in large yards in deep straw. But sows can have savage fights to establish a social order when housed loosely, and it adds greatly to costs of production. This is a classical example of what the domestic contract should provide.
The male
* In the wild or in extensive pig keeping systems, the male pig, (unlike males in other species) does not initiate sexual behaviour. He waits for initial signals from the female.
* Boars reach puberty about 6 months of age, but are generally not used for service till 7-8 months old. These ages can vary a lot depending on the feeding level.
* They start learning their courting behaviour and show elements of sexual behaviour while still suckling and as part of play with pen mates. They develop these behaviours even more if mixed with strangers.
* Boars reared in isolation are much slower to develop successful courting behaviour. Group reared boars are better than those reared in individual pens, and intensive stocking will encourage aggression as well as sexual behaviour.
* Boars reared intensively in homosexual groups maintain this relationships for many months after parting, and they can often show abnormal sexual behaviour.
* The boar's courting ritual includes:
* Chasing the sow.
* Nuzzling her head, flanks, shoulder and anogenital area.
* Occasional pushing or leaning on the sow to test her state.
* Drinking her urine.
* He urinates frequently.
* He grinds and chomps his teeth salivating and frothing at the mouth.
* This courting ritual has an important effect on improving the conception rate of the sows being mated. In outdoor pigs boars often have rings inserted in their noses to stop them rooting up the pasture. This affects their courting ritual when it comes to nuzzling the sow and causing a negative response.
* When the boar mounts, he rests his belly along the sow's back and grasps her with his forelegs. Inexperienced boars will head mount, side mount and dismount frequently before intromission (penis entering the vagina).
* Ejaculation occurs when the cork-screw penis of the boar locks in the sow's cervix. This can take considerable time - averaging about 7 minutes but it can last up to 25 minutes.
* The boar thrusts and rests many times and eventually ejaculates up to 500 ml of sperm. Other farm species produce a 5-15 ml ejaculate.
Boar behaviour and handling
* Treat all boars with respect and treat them as individuals.
* Handle them carefully and de-tusk them every 6 months (with veterinary advice).
* Remove the front accessory claws to protect the sow from injury during mating (with veterinary advice).
* Don't overwork the boar - one boar to 20 sows is most common.
* Four services a week are plenty till the boar is 12 months old. Don't let him serve more than 6 times a week as this will lower his fertility and subsequent litter size from the sows mated.
* Too frequent use of a boar as a teaser to locate sows coming into heat, may frustrate him too much and he may not serve when needed.
* Mate young boars to old sows in peak oestrus, and old boars to gilts.
* Don't let young boars get injured during their early matings.
* After layoffs of longer than a month, libido may drop and a boar may need the stimulus of an old sow in peak oestrus that has already been served by another boar.
* Spreading some ejaculate from another boar along the sow's back will help to stimulate a boar.
* Take the sow on heat to the boar so he doesn't waste time investigating a new environment. Otherwise he'll waste time in an elaborate ritual of urinating, rubbing scent from his body on the walls, marking the territory with salivary foam and fight the sow to establish dominance.
* Boar pens should provide a good foothold for the boar but not so rough as it will cause foot problems.
* Boars should be kept within sight, sound and smell of sows. However this assumes the boar is the dominant animal in the herd. He may be considerably stressed with other boars near by, as in the wild each boar would be solitary.
* Boars get very large and need regular exercise to keep fit. It's a good idea to have a system where the boar walks daily to the sow's accommodation to help stimulate oestrus and identify sows on heat.
* Regular quiet handling by the stockperson is ideal, walking behind with a pig board for protection, and talking in quiet reassuring tones.
Boars and Artificial Insemination (AI)
* AI in pigs is now well established in commercial pig improvement and is a specialist operation.
* At AI centres boars are trained to mount dummy sows and serve into an artificial vagina as this is less complicated than using a live sow.
* Boars may be harder to train if they have mated sows first. But again this varies with the personality of the boar.
* Gentle, reassurance by the stockperson is the secret of success to get a good semen sample from the boar.
* Boars will show courting behaviour to the dummy by nuzzling its flank and rear end.
* Libido varies greatly between boars, and is related to frequency of use.
* Boars can be stimulated more by giving them false mounts, or by observing a collection from another boar.
* It's a good idea to allow the sow or gilt 10-20 minutes contact (through a pen) with a boar after insemination.
Behaviour of housed boars
* In less intensive systems where sows are kept in straw yards (and not in stalls), boars often run with them and few problems arise.
* If a boar is put in among a group of unfamiliar loose-housed sows, he will waste time investigating the environment and not checking for sows on heat.
* In intensive pig farming, the boar does not spend time in social contact with sows and opportunities to consort with females are decided by the human in charge.
* Here, sometimes the boar pens are arranged between pens of six loose-housed sows to achieve maximum physical presence of the male.
* In other systems, including where sows are tethered or in stalls, the boar is walked daily in front of them to test for oestrus.
* When boars walk behind stalled sows a boar may be confused by the fact that they are immobile and hence displaying an invitation to be mounted. This can be very time-wasting.
* It's well established that depriving boars and sows full opportunity to indulge in their full courting behaviour affects pregnancy and litter size.
Boar behaviour problems
* Serving into the rectum instead of the vagina can be a problem. Avoid this by supervising young boars in their early work to make sure they are aligned correctly.
* Extremes of heat may affect the boar's enthusiasm. Delay his work till evening.
* Masturbation by coiling the penis inside the diverticulum of the prepuce. Make sure the boar's penis has actually entered the sow and he is not masturbating.
* Boars that masturbate persistently should be culled although the prepuce can be surgically removed.
* Some boars behave normally up to the point of mounting and then squat down on the floor and ejaculate. Great care is needed to help these boars achieve success as they may persist in this habit.
* Aggression. Boars are always potentially dangerous and need to be handled with care. Nervous and aggressive boars should be culled. Some boars will show aggression with strangers but not with their regular handlers.
* When strange boars meet, they strut shoulder to shoulder, head raised and hair bristling along their backs. Deep grunts, jaw chomping and mouth frothing continues.
* In a fight, boars face each other with their shoulders in opposition and apply sideways pressure. They circle around, biting and slashing at each other with their tusks. They may charge each other with mouths wide open and bite. The loser turns and runs away squealing.
* Subsequently after a win, the winning dominant boar need only grunt to get submission. Newly-mixed boars fight less if they are both put in a strange environment.
Weaning
* In the wild, pigs are weaned at around 14-17 weeks old.
* Farmed pigs were traditionally weaned at 8 weeks of age, but in more intensive systems weaning is done at 3, 4 or 5 weeks.
* Even weaning at 24 hours after birth after the piglets have had their colostrum has been studied. But current opinion among pig behaviorists and welfarists is that piglets cannot effectively cope with weaning before 3 weeks old.
* In some intensive systems, young pigs are kept very intensively in wire-floored tiered cages from weaning at 7 days. At about 7kg live weight, the pigs in these systems proceed to grow and fatten in "flat deck' cages on mesh floors.
* The development of very early weaning systems is based on getting the sow pregnant to produce more pigs per year as weaning stimulates the sow to return to oestrus.
* Abrupt weaning is now considered to be preferable to removing pigs gradually. Again this is to achieve higher production from the sow.
* The more intensive the system is for growing pigs after weaning, the greater is the need for skilled care by the stockperson. There also needs to be a good smoke alarm system and back up for power breakdowns.
* Studies of highly-intensive systems have shown wide variation from pigs showing stress behaviours, to pigs adapting well without stress. Clearly the person in charge who controls the pigs' environment is the key factor.
The stress of weaning
* Removal of their mother and hence their source of feed, warmth, security and comfort.
* They lose their normal clues for feeding given by the sow's vocal messages.
* They may be mixed with strange pigs from other litters and in a strange pen.
* Competition for feed, water, sleeping space and dunging area may be increased.
* They will face new bacterial challenges and diseases.
* They may be subject to rough handling, transport, markets, veterinary inspection and treatment.
* They will experience climatic change with cold temperatures and draughts being especially dangerous.
Reducing weaning stress
* Piglets can cope with one or two of these stressors, but more that this leads to poor growth for up to 14 days after weaning.
* The settling down period of pigs at weaning seems to be around 3 weeks.
* The major aim is to ensure pigs are eating adequate amounts of correctly balanced dry feed before weaning. Flavour and physical form of this feed is important to encourage high intake.
* Getting the pigs used to the lower temperature of the fattening accommodation is important. The sow's nest is around 28 C and they have to get used to temperature in the growing pens of 19C and eventually below this.
* Avoid erratic temperatures, as this will cause pigs to huddle and fight for positions to keep warm.
* Provide adequate trough space, again to stop intense competition and fighting.
* Adequate lying space and a comfortable bed are important as growing pigs in intensive housing spend around 60-70% of their time resting/sleeping. Constant standing or restlessness will lead to fatigue and poor performance.
Behaviour of growing pigs
* Poor growth and poor feed conversion inevitably will have a large behavioural component, especially in intensive systems.
* There are many factors involved in poor performance, and the skill is to determine which of them can be changed, with the welfare of the animal as well as profit very much in mind.
* The physical form of the diet is important. Pigs generally prefer wet to dry feeds, but dry feeds keep pigs occupied for longer.
* Scattered feed takes longer to eat than feed in troughs - again keeping pigs occupied for longer. It also saves the costs of troughs and fighting over trough space.
* Providing adequate trough space is of major importance, and prevents aggression and stress.
* Feed offered ad lib will keep pigs fully occupied but restriction is often needed to control growth and performance. For example pregnant sows, as opposed to lactating sows, need their diets restricted to prevent them getting too fat. Obesity lowers subseqent lactation performance.
* Pigs perform well on once-a-day feeding but feeding time is a good time to inspect pigs. Reduced appetite is a good early sign of potential health problems.
* So it's important in large intensive systems to use time saved on chores to be spent on animal inspection.
* This is especially the case as systems become even more automated where light levels are reduced. Increasing the lights for inspection will then activate the pigs, so there is a dilemma here.
* Increasing stocking density/pen is an easy way to get more throughputs in a pig unit. It can have devastating effects on pig welfare.
* This approach can cause a major upset in social order leading to bullying, tail and ear biting, disease, low feed conversion efficiency and low profits.
* Pigs highly stocked in pens spend more time feeding, standing and walking, and less time resting and sleeping.
* Contented pigs are recumbent for up to 19 hours a day. They drowse for 5 hours and sleep about 6-7 hours.
* Pen floors have an important role in pig comfort and behaviour. They should provide a good non-slip, non-abrasive surface with no protruding edges, and not harbour bacteria or parasites. They should be impervious to water and be easily cleaned.
* The pig's cloven hoof was designed to walk on earth, so slatted and perforated floors can cause damage and discomfort.
* When social orders have been sorted out by fighting, all that is needed is a loud grunt and a feint with the snout by the dominant pig to maintain this order.
Mixing growing pigs
* To reduce stress, mix pigs from 3-4 litters before weaning so they know eachother.
* Don't put newly mixed pigs in too large a pen, as they'll stay in their original groups, they'll not mix and they'll fight to defend territory.
* Put all the pigs to be mixed in a strange pen.
* Distract them by giving them straw or paper sacks to chew, or spray them with a strong-smelling fluid.
* Provide adequate trough space and feeding and drinking opportunities.
* Mix them at dusk when identification of rivals will be more difficult.
* Keep pigs in close weight ranges and remove any sick animals or any being severely molested.
* The fewer pigs there are in a single group, the tighter they can be packed.
* In general, vices are more common in large groups in large houses where social orders are more are more complex, and maintaining them causes more aggression and stress.
* Don't change diets at the time when pigs are mixed.
* Feed pigs ad lib diets for 2-3 weeks after mixing to avoid digestive upsets. Most producers feed ad lib for up to 10 weeks of age. Feed restriction should be delayed until the pigs have sorted out a new social order.
* Provide plenty of feed and trough space.
* Opinions on mixing sexes vary. Generally, if they have a good environment, sex does not cause problems. There may be some mounting in the last 4-5 weeks before slaughter.
Water for growing pigs
* Water is provided from bowls, metal nipples or metal drinking straws. Pigs are very quick to learn how to operate them.
* The watering device is a great plaything for bored pigs, so it will be subject to rubbing, nuzzling and chewing. Rigid construction is essential.
* Place the water source near a dunging area or drain or above a food trough because of spillage.
* Make the pigs have to reach up to get at nipples when drinking.
* Don't put water sources in positions where pigs will bruise themselves. Put them in a corner.
* Be consistent in the choice of drinkers provided.
1. Overlaying piglets by the sow
* This is a serious problem and accounts for 20% of all piglet deaths.
* The greatest risk to piglets is during the first week of life and especially during the first few hours of birth when a restless sow gets up and lies down a lot.
* The causes of high overlaying losses are complex and obviously involve the piglets and the sow. It's often difficult to apportion blame.
Factors in the sow:
* Previous experience
* Age
* Breed and strain
* Lameness
* Leg and joint problems
* Obesity
* Skin parasites
* Mastitis and udder problems
Factors in the piglet.
Piglets that are most likely to be crushed are usually one of the following:
* Dull
* Weak
* Inactive
* Uncoordinated
* Suffer from coma
* Chilled
* Starved
* Have very low birth weights
* Have very high birth weights
* Are runts from litters
* Have splayed legs
Possible cures/Prevention
* Provide a heat lamp in an area protected from the sow to attract the piglets away from her after suckling.
* Place highly palatable feed pellets near the lamp to start the piglets eating.
* This is most easily organised when the sow farrows in a crate, rather than free in a hut or pen. Sows usually lie with their teats towards the heat lamp.
* Farrowing pens should all have rails about 200mm from the floor and 200mm from the wall.
* Cull sows that persistently show this behaviour.
2. Savaging piglets by the sow
* This is more common in inexperienced gilts with their first litter than in sows.
* A sow may snap and injure an odd piglet, but seldom savages the whole litter.
* The first piglet born is most likely to be savaged as it seems that the sow is frightened by it's movement and high-pitched squeak, associated with the birth process. Usually after the sow has sniffed the piglet, all is well.
* Most sows accept human presence at birth, but strangers of unfamiliar noises may upset and frighten the sow and she may savage some piglets.
* Sows that savage litters without very good reason are culled. Gilts may be given another chance but the fear is that the trait may be genetic and these animals should not be bred from.
Possible cures/Prevention
* Check that the cause was not a "one-off" such as fright or panic and make sure it is not repeated.
* Cull any female that shows the vice more than once.
* Check the genetics of the female incase it could be an inherited trait.
3. Stress in pigs
Many factors have been identified as the causes of stress in pigs. These are all products of bad husbandry and/or poor stockpersonship:
* Chilling
* Overheating
* Physical injury
* Poor sanitation
* Poor ventilation
* Overcrowding
* Bullying
* Dampness and draughts
* Genetic makeup
* Weaning
* Castration
* Lack of feed and water
* Nutritional deficiencies
* Internal and external parasites
* Disease
* Loss of appetite
* Noise
Possible cures/Prevention
* Try to sort out which of the above is the main cause and change the management to avoid future problems.
* Veterinary advice should be part of any changes.
4. Aggression - fighting in pigs
* Aggression in pigs has been classified into three kinds - acute, chronic and abnormal.
* "Acute" - fighting to establish a social order, especially when strange pigs are mixed.
* "Chronic" - fighting to maintain an established order.
* "Abnormal" - serious fighting that has very big economic implications.
* Tail biting.
* Ear biting.
* Cannibalism.
* Sudden savaging of a group member.
* Sows attacking each other.
* Sows savaging their young.
* Domestic pigs unlike wild pigs are kept in monocaste social groups of the same sex, age and size. This may in fact make it harder and more stressful for pigs to form stable social groups when the combatants are physically equal.
* Newly-acquainted pigs seem to fight for 24-48 hours to establish a linear dominance hierarchy, usually with the largest pig at the top and the smallest at the bottom. Note that it may not always be the biggest pig that becomes the top dominant animal. Once this is established, fighting is greatly reduced but not totally eliminated.
* When unfamiliar pigs are mixed, fighting seems to start the feed runs out.
* Fighting will nearly always occur when a pig removed for treatment is returned to the group. Top rank pigs can be returned without problems but any pigs lower in the social order will need to be returned before about a maximum of 3 days. The key to success is to know what the pig's social rank is before removing it and acting accordingly
Possible cures/Prevention
* Check the environment to make sure it is not too hot or too cold, that the air is fresh and that the pigs have a dry warm area to rest.
* Provide plenty of feeding and watering space. Hunger is often the cause of aggressive biting which can blow up into more serious aggression.
* Make sure pigs are all of similar size in the group.
* Provide bedding for newly mixed pigs to chew - at least for a period of about 1½ hours.
* If pigs are removed from their group for any reason, try to put them back before 3 days. If they are the smaller members of the group, put them back sooner and watch that they are not victimised.
5. Tail biting and possible causes
* This has developed since pigs were kept intensively.
* Usually starts 4-22 days after weaning.
* May be associated with ear biting.
* There are many possible causes are put forward yet little is still known about it. The so-called "solution" is seen as removing the tail which should not be done before the causes are determined and rectified.
Causes are usually:
* Behavioural - boredom, breakdown of dominance order or excess social contact.
* Nutritional - low fibre, low bulk, and deficiencies of a whole range of nutrients.
* Environmental - poor ventilation leading to high humidity, high temperatures, high ammonia and carbon dioxide, lack of bedding, and not enough feed or watering points.
* Disease - skin mange, internal parasites and various infections.
* Teething problems.
Possible cures/Prevention
* Check ventilation to prevent build up of foul air.
* Check pigs are not too cold (below 15C) and not too hot (above 28C).
* Remove badly bitten pigs from the group and isolate them.
* Daub the tails with Stockholm tar, creosote, disinfectant, lice of mange wash as a repellant.
* Provide toys - hanging chains, paper sacks, straw, balls, stone filled cans, or anything you can think of to provide occupational therapy and keep the pigs busy.
* Reduce the stocking rate in the pens - don't exceed 120kg live weight/m2 of floor space.
* Group pigs on the basis of size. Often a small pig in a group is the aggressor and not the biggest one.
* Move the problem pigs to another pen. This may fix the problem, or it can make them worse!
* Change the feeding system or the physical form of the feed. For example moving from meal to pellets may help, or the reverse may work.
* Keep mixing of pigs to a minimum as it may trigger fighting and make the problem worse.
* Dock about 2cm from the piglet's tail at birth.
* Change from flop-eared to prick-eared breeds as the incidence in the latter is sometimes less.
6. Cannibalism
* This may develop from tail biting.
* It often starts by pigs attacking wounds, prolapsed rectums, sick pigs and the like.
* Pigs in a pen will chase and attack the suffering pig till it is killed - when they continue their cannibalism.
* The attacked pig must be removed.
* The remaining pigs must have a change to their environment - eg provide straw, altering the temperature, providing toys.
Possible cures/Prevention
* See suggestions for tail biting.
7. Gastric ulcers
* These increase as pigs are kept more intensively - clearly a stress induced problem.
Possible cures/Prevention
* Try to find the cause and remove it - but may not be easy.
* Investigate infections, intoxication, stress, gastric acidity, digestive upsets, hormones, seasonal changes, feeding methods (especially ad lib systems), housing and many more.
8. Nose rubbing (belly rubbing)
* Weaned pigs may develop the habit of nuzzling other pigs as they lie resting.
* It may appear is if they are navel sucking but it's more likely to be nuzzling in the flank area and along the teat line.
* It may be accompanied by nursing grunts.
* Persistent rubbing may cause ulcers and destruction of the tissue (necrosis).
Possible cures/Prevention
* This is powerful thrusting by dominant pigs, after weaning, eg by high-rank males.
* It occurs sporadically and can spread quickly through a group, and trigger off other vices like tail and ear biting.
* The solution is to change environmental factors till you find something that does the trick.
By Dr Clive Dalton
* Persistent rubbing may cause ulcers and destruction of the tissue (necrosis).
Possible cures/Prevention
* This is powerful thrusting by dominant pigs, after weaning, eg by high-rank males.
* It occurs sporadically and can spread quickly through a group, and trigger off other vices like tail and ear biting.
* The solution is to change environmental factors till you find something that does the trick.
By Dr Clive Dalton
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