Pig Health

Physical problems in intensive piggeries

Intensive confinement of pigs produces some major health problems as well as physical discomfort. In addition, growing suffer a number of surgical mutilations in the industry in general. To see references for this document you can click on any of the reference numbers in the text.

An average of 10.4% of breeding sows die in a year ( 1 ), the main causes of death being gastrointestinal accidents such as twisted gut, and kidney/urinary tract infections ( 2,3 ). In addition, some sows are destroyed on-farm due to arthritis/severe lameness, abscesses and fractures/spinal traumas ( 2 ).

Sows have an average of 2.2 litters before they die or are sold off for slaughter, even though they reach their reproductive peak in the fourth to sixth pregnancy ( 4 ). Another indication that sows are killed off at a young age is that there are 7 gilts (young females) for every 10 sows in the breeding herd, a sow replacement rate of 72.3% ( 1 ). One expert has stated that a reasonable replacement rate would be 35-40%, and that in general mortality should not be over 3% ( 5 ). Clearly the industry falls far short of this level, which has led to a Sow Wastage Project being set up to investigate the causes.

Major issues include skeletal problems due to lack of exercise, lung problems due to polluted air, and infections due to contact with excrement in crowded conditions.

Skeletal problems

Around 10% of all sows are culled each year due to lameness ( 6,7 ).

Growing pigs also suffer leg problems due to abnormal cartilage development. In a Queensland study, 11% of young males raised to 90kg were killed due to leg weakness, with 6% removed before the end of the study because they couldn't stand ( 8 ).

Other studies have also found marked cartilage damage in confined growing pigs, with almost all pigs affected to some extent ( 9,10 ).

Exercising on a treadmill has been shown to improve leg condition and walking ability ( 11,12 ). Similarly, putting pigs out to pasture improves their walking ( 13 ), indicating the importance of exercise in preventing these problems. Intensive confinement fails to allow the amount of exercise necessary for healthy bones and joints.

Bursitis is inflammation of the fluid-filled bursa sacs in the joints. Bursitis is much more common in growing pigs kept on bare floors without bedding such as straw ( 14-15 ). Similarly, foot lesions are more common without bedding ( 14 ).

Concrete or mesh floors without bedding also produce skin abrasions, especially among piglets in farrowing crates. As one group of Australian researchers has observed: ( 16 ) " Skin necrosis from concrete floors or full wire mesh occurs variously on knees, hocks, fetlocks, elbows, coronets and heels ". A South Australian Department of Agriculture and Fisheries Bulletin (10/79) has also observed that: " Skinned and infected knuckles are common in young pigs run on concrete ".

A number of studies have observed high levels of leg wounds and foot lesions in piglets kept on hard floors ( 14,17-19 ). Such injuries are not only painful, but can also allow entry to the micro-organisms that cause arthritis. Damage is reduced by giving piglets sufficient bedding, such as chopped straw or shredded paper ( 20-21 ).

Thus, the lack of exercise and bare, hard floors in intensive farms produce both major health problems as well as physical discomfort.

Lung diseases

One writer has observed ( 22 ):
" If city factories operated with the dust levels of the average Australian piggery the industrial health inspectors would be down on them severely ".

He noted that dust levels in some piggeries were 4 times higher that those allowed for industrial safety. With so many animals crowded into sheds where the air contains dust, ammonia from droppings, and micro-organisms, it is no wonder that lung diseases are a problem.

In a survey of 3 South Australian slaughterhouses, 47% of pigs had pneumonia and 14% pleurisy ( 23 ). In the South Australian Pig Health Monitoring Scheme the incidence of pneumonia varied from 50% to 90% between 1990 and 1995 ( 24 ). In Queensland 22% of herds are infected with pleuropneumonia, and it has been described as " a major disease in the Australian pig industry " ( 25 ). In the Victorian Pig Health Monitoring Scheme the incidence of pleurisy and pneumonia decreased only slightly from 1996 to 1998, with pleurisy affecting at least 30% and pneumonia at least 60% of pigs in each year ( 26 .)

The incidence of enzootic pneumonia has been linked to the conditions in intensive sheds. One writer has said: ( 27 )
" The disease is most severe when pigs are maintained in over-crowded, dusty, poorly ventilated environments".

One of the advantages of more spacious and naturally ventilated shelters such as the Ecoshelters for growing pigs is a low rate of disease, especially lung disease ( 28 ).

Other infectious diseases

Around one quarter of sow deaths are due to kidney/urinary tract infections ( 2,3 ). In close confinement, sows have to lie in areas soiled with excrement, from which they can pick up such infections. Free ranging pigs use a dunging area well away from their resting and feeding areas, so there is much less risk of disease.

Proliferative enteritis (PE) is an infection of the small intestine found mainly in young pigs. They suffer diarrhoea and reduced growth rate. In the South Australian Pig Health Monitoring Scheme, 35% of herds were found to be infected with PE. Within a herd, 5-25% of pigs were affected ( 29 ). In a survey of pig farmers in Victoria, 56% had PE or the more e severe PHE in their herd ( 30 ).

One writer has noted:
" Clinical disease is more frequently observed in intensive piggeries than under extensive systems " ( 31 ), and others have observed: " Proliferative enteritis (PE) is a disease of intensively reared pigs " ( 32 ).

The incidence of PE is low among growing pigs in Ecoshelters ( 28 ). Similarly, the Farm Animal Welfare Council in the UK has noted that sows kept outdoors have fewer diseases: ( 33 )
" In general, pigs in outdoor units have high health status due to low stocking density and reduced infectious challenges. Whilst treatment may be more difficult outdoors, one advantage of this method of pig-keeping is that infection dilution occurs in the open air and lower stocking densities and stress levels tend to keep the animals in better condition: so outdoor pigs are generally healthier than those kept indoors ".

Surgical mutilations

There are several surgical operations that are commonly carried out in the pig industry, all without any sort of pain relief, including:

For a non-veterinarian to carry out such painful procedures without any anaesthetic would be illegal if done to animals other than farm animals.

Tail docking

Piglets routinely have most of their tails cut off to leave less for other pigs to potentially bite. The Scientific Veterinary Committee of the European Commission stated in its 1997 report on The Welfare of Intensively Kept Pigs:
" Tail docking is likely to be painful when it is carried out and it has been demonstrated that in a proportion of animals it leads to neuroma formation and hence prolonged pain " ( 34 ).

Donald Broom, Professor of Animal Welfare at Cambridge University, concluded:
" ... it is likely that a pig with a neuroma in its docked tail region will have frequent or continuous pain throughout its life " ( 34 ).

As was shown in the document Evidence of suffering in intensive piggeries , tail biting is an animal husbandry problem and suggests poor welfare. It is alleviated by eliminating overcrowding, providing straw bedding, and eliminating any other stressors such as dust, ammonia or poor nutrition. The Scientific Veterinary Committee agreed that the problem of tail biting should be solved through better management, not a painful surgical procedure.
" The problem of injury following tail biting should be solved by improved management rather than tail docking " ( 34 ).

Teeth clipping

When piglets are only a few days old their eye teeth are cut with clippers almost to gum level to stop them lacerating the sow's udder or the faces of litter mates. The Scientific Veterinary Committee stated that teeth clipping causes immediate and some prolonged pain, and therefore concluded:
" It seems unlikely that the causing of pain in every tooth of every piglet could be justified by the relatively minor advantages which occur as a result of the practice " ( 35 ).

Castration

Once all male growing pigs were routinely castrated, which causes severe pain and distress. The aim was to prevent boar taint in the meat when the animals reached sexual maturity. Although pigs are now being slaughtered at a younger age, some still have boar taint produced by the male hormones. The answer is not to cut off the trsticles, but to use new vaccines such as Improvac, which stimulat the immune system to produce antibodies against gonadotropin releasing factor, thus stopping the testes from producing the male hormones involved in boar taint. Pigs are saved the pain of castration, but also grow better and fight less ( 36 ).

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