The successful breeding and rearing of pigs requires finding the right balance of several key factors:
- husbandry practices
- disease management
Choosing the right genetics for your situation is vital, as it is important to get the breed and type of pig that suits your environment, type of husbandry practices, and the level of nutrition. Many of the modern breeds of pigs have fast growth rates to give minimal back fat, but this type of pig needs to be kept in a modern piggery environment and fed on commercially prepared feed in order to do well.
If you want to run your pigs outdoors with minimal labour input and require them to forage for part of their diet, you need to match the type of pig to this environment i.e. go for a type of pig that is hardy and slower growing.
Selecting for large litter numbers is an obvious way to increase profitability, but it must be matched by the sow’s mothering ability, the health and nutrition of the sow, and the suitability of the environment for the young piglets, or else the mortality rate of the piglets will cancel out the extra piglets born.
The husbandry practices you use will have a big impact on how successful your breeding and rearing will be. Many modern piggeries have strict boar to sow ratios, use group mating, artificial insemination, or supervised matings. They strictly monitor return rates and fertility, as well as carrying out routine tasks such as vaccinations, tail docking, clipping milk teeth, worming and early weaning.
Running a boar with the sows may mean that you don’t know which sow is breeding and when, whereas with supervised matings you can keep records of mating dates, and monitor the fertility and pregnancy rates.
If you want to wean piglets early to breed the sow again to maximise litters per sow per year, you need to have the management practices that enable this to be done successfully.
Good animal welfare is also tied in with good husbandry – providing optimal conditions for the pigs, taking action when problems occur, and carrying out activities in a manner that is appropriate.
The physical environment that the pig lives in has a significant impact on its growth rate, general health and levels of disease. They need access to clean drinking water, and fed in a way that allows each pig to have its share of food.
Pigs like to be able to cool off in summer when the temperature and humidity rises, and use wallowing behaviour as a cooling mechanism. If the pigs are unable to wallow in mud or water to cool off, they can become heat stressed.
Pigs love to keep warm in winter, and like to cuddle up to other pigs to stay warm. The like a dry and draft-free environment, particularly if there is some bedding to snuggle in to. The much prefer to sleep on a wood floor rather than directly on concrete.
Pigs are very susceptible to disease related to overcrowding – poor ventilation can significantly increase the risk of pneumonia, particularly if they are confined to a small area where there are high ammonia levels from urine. Very damp conditions also tend to result in more cases of scours in piglets.
The ideal environment if a pig is kept indoors is to use a type of flooring or deep litter system that assists waste disposal, with good insulation of the walls and ceiling but with sufficient air flow and air quality to manage humidity and reduce ammonia levels.
Outdoor pigs should be provided with sufficient shelter that enables them to stay warm and dry in winter conditions. In summer they should have access to shade and a wallow.
One of the most important components in a pig’s growth rate and reproductive success is good nutrition. Pigs need a balanced diet, particularly with sufficient protein and a range of other nutrients to be healthy. They also have a relatively high water intake compared to other species.
Protein is the most extensive part of the diet, and there is a tendency to keep the intake of protein down to reduce feed costs. A poor diet, particularly when combined with health problems, caused poor growth rates and reduces reproductive efficiency.
Commercial diets are formulated to contain all the basic essentials, but it is also important to feed the correct amount and type of feed to the appropriate age of pig. Younger piglets require a higher protein level ( 15-16 %) whereas the maintenance diet for a sow is lower (13-14 %). Nutritional needs change throughout the life of the pig – piglets need a higher protein diet that is easy to digest, the nutritional requirements of a sow increase during late pregnancy and lactation, while adults can cope with a maintenance diet high in roughage.
If the diet is made up of a mixture of sources of food, it is important to assess the diet to ensure that it covers the basics – enough protein of the right type (e.g. dairy or fish protein), sufficient carbohydrates for energy, and enough of the key vitamins and minerals. High fibre diets such as pasture vegetable supplements provide bulk, but do not always provide the optimum levels of protein and carbohydrate.
A poor diet will usually result in a reduced growth rate, poorer reproductive performance, and increased disease problems.
See also Feeding Your Pigs. (Downloadable fact sheet.)
Pigs as a species are particularly prone to a range of diseases including pneumonia, gastrointestinal tract infections, and skin problems. Most of the important aspects of disease management are providing an environment, adequate nutrition and a level of husbandry that prevents disease escalating to a problem level. When disease does occur, it is important to know what has contributed or caused the disease, what can be done to treat it, and how to prevent further problems.
One important way of managing disease is by keeping to a stocking density that doesn’t increase disease rates. Pigs run outdoors do better if they are moved to fresh ground every two years, as the parasite levels and bacterial contamination in the environment builds up over time. Use of movable farrowing arcs and fresh bedding for farrowing sows can assist farrowing hygiene, and reduce the levels of disease that piglets are exposed to.
In a pig population with sows farrowing all year round diseases such as pneumonia and scours tend to cycle through the young pig population, often maintaining disease at a level that will provide a source of infection to the next batch of piglets.
Generally, the more intensive the stocking rate the more reliance there is on vaccination, use of antibiotics and worming to manage disease.
Where there are a large number of pigs present on a property, or a high risk of disease outbreaks, vaccinations should be given routinely. The most common vaccines used are Leptospirosis (abortion), Parvovirus (abortion), and Erysipelothrix (arthritis) every six months. Other diseases that can be vaccinated against include E. coli scours, and the Mycoplasma and Haemophilus pneumonias.
There are a range of viruses and bacteria causing pneumonia, bronchitis, and nasal cavity infections. Rapid or laboured breathing usually means a very serious illness, and needs immediate treatment. Coughing may be caused by bronchitis or pneumonia but may also be due to lungworm infection.
In general, pneumonia is usually the main cause of death in weaner age or grower pigs. It often occurs as outbreaks, usually with a large proportion of the younger pigs affected. Pigs don’t usually show many obvious symptoms unless the pneumonia is well advanced, so by the time they are noticeably unwell they are usually severely affected. Deaths can occur rapidly.
Diarrhoea can be caused by dietary upsets or infections and in some cases such as in very young piglets it can be so severe or serious that it is life threatening.
Dietary causes – sudden change in diet, undiluted milk, or too much fat in the diet.
Infectious causes – E. coli bacteria scours, Rota virus and other miscellaneous viruses and bacteria. Infections can cause a serious outbreak with a whole litter affected.
Internal parasites in rare cases can cause diarrhoea but are usually only a contributing factor and not the main cause.
If pigs with diarrhoea are quieter than normal, have a reduced appetite, or have blood in the diarrhoea, they need prompt treatment with antibiotics and electrolyte oral fluids.
Postweaning Multisystemic Wasting Syndrome (PMWS)
This disease is now widely spread through the pig population in New Zealand, but only a small proportion of piggeries have clinical disease. It is thought to be caused by a virus, but it has a suppressant effect on the immune system.
The disease is usually seen in weaner pigs from 5-6 weeks of age to about 14 weeks of age. PMWS tends to be a slow and progressive disease, with a high fatality rate at about 6-8 weeks of age. The weaner pigs lose weight and gradually become emaciated. They often have pneumonia or diarrhoea associated with the disease. Typical signs of the disease include piglets in poor condition, enlarged lymph nodes, and sudden death. Commercial piggeries with a history of the disease use a vaccine to help control the disease.
The infection is caused by a bacteria, and can cause kidney problems, generalised illness, or can cause sows to abort if they develop the infection during early pregnancy. Leptospirosis can also be caught from other animals such as rats and mice that are often associated with piggeries and stored feed.
Although infections of the Leptospirosis bacteria are not common in pigs, it is recognised as a health hazard to people dealing with pigs and cattle. It is recommended that all pigs exhibited at shows be vaccinated against Lepto. The initial vaccination is given at weaning, followed by a booster four weeks later, then every six months.
There are three main infectious agents that can cause abortions in sows or the birth of very weak piglets – Leptospirosis, Parvovirus, and Toxoplasmosis. Where a large number of pigs are kept it is often advisable to vaccinate against Lepto and Parvovirus. Always handle any stillborn piglets or aborted material with care because of the risk of Lepto. Toxins of certain fungi in cereal-based food can also cause abortions.
Infection in the mammary glands can occur where the glands are swollen, hot and painful. The most common times that mastitis occurs are within a few days of farrowing, or at weaning time. Treatment with antibiotics is usually needed to clear the infection. Following mastitis there is usually quite a reduction in the amount of milk produced, so if mastitis occurs at farrowing time there may not be sufficient milk produced by the sow to keep the piglets alive.
These occur mainly in winter time as lice breed more in cold weather. The infection can be picked up from other pigs such as at shows or from new pigs introduced onto the property. Lice are host specific, so pigs will only get pig lice breeding on them, the lice don’t breed on other species of animals. The lice are rather large and brown and move around when disturbed. The lice lay their eggs on the hair on the sides of the lower neck and at the back of the legs – the eggs look like cream spots stuck to the hair.
Treatment can be using a topical insecticide such as louse powder, or a systemic treatment such as an Ivomec injection. Appling oil to the skin and coat of the pig can also help kill off the lice. The treatment will need to be repeated at least once three weeks later to kill any further lice that may have hatched from the eggs.
Occurring mainly in summer, mange usually looks like crusty reddened areas especially around the head and legs. In piglets it can be very severe, as they don’t have much immunity to it, so they can end up with dry crusty areas all over their body as well as general symptoms of poor growth rate and ill thrift. Treatment is a topical insecticidal wash or Ivomec injection.
This is a fungal infection common in young piglets – it occurs as crusty areas, mainly on the legs. Treat with a topical Iodine solution.
There are four main types of worms in pigs – intestinal roundworms, stomach worms, lungworms, and kidney worms. The most common one that causes a problem is intestinal roundworms in young pigs. Ivomec injection or oral wormers can be used to treat worms. A suggested worming programme is to treat all piglets for worms routinely at weaning, treat one month later, then again three months later. Adults are ideally treated twice a year, with sows treated pre-mating and pre-farrowing.