Common pig diseases every farmer should watch out for

By Janine Ryan | 29 October 2024 | 1:00 pm

In this article, we discuss some of the most common viral pig diseases in South Africa, and what farmers should do to prevent and/or treat these diseases to ensure a happy and healthy herd.

Herd health refers to the overall well-being, disease resistance, and productivity of a group of pigs within a farm or production facility. For pig farmers, herd health is a critical aspect of managing their operations effectively and ensuring the profitability and sustainability of their businesses.

A pig farming operation will never be productive or profitable if the herd is sick. As a herd consists of individual animals, it is essential that farmers monitor the health of all of their animals, and act timeously to prevent an outbreak of disease within the herd.

There are a number of common pig diseases in South Africa, some of which are treatable, while others are not. That is why, in most cases, prevention is better than cure, and the article will thus explore the measures that farmers must take to prevent infection.

African swine fever

Not to be confused with African swine flu, African swine fever (ASF) is a notorious disease of pigs in South Africa that most pig farmers will be aware of. It is highly contagious and infects wild and domesticated pigs.

ASF has a high mortality rate, and as it is caused by a virus, antibiotics will not cure the disease.

The World Organisation for Animal Health says that ASF spreads easily amongst a herd through the direct contact of infected animals with healthy animals. Healthy animals could also

become infected through contact with contaminated objects, such as feed troughs and other equipment.

The virus can also spread through tick vectors or contaminated pork products. Infected wild boars or feral pigs can contribute to the spread of ASF over long distances. The virus is very resilient in the environment and can live for extended periods in pig products and feed.

Preventive measures such as strict biosecurity protocols, movement restrictions, surveillance, and early detection are essential to limit the spread of ASF. Timely reporting and collaboration between authorities, farmers and veterinary professionals are crucial in containing outbreaks and preventing further dissemination of the virus.

Death can occur within seven to 10 days of infection.

As there is no effective treatment or vaccine available to treat ASF, the US Department of Agriculture (USDA) recommends that farmers implement strict biosecurity measures, which include:

-culling infected and exposed pigs to prevent further spread;

-the proper disposal of carcasses to prevent scavenging by other animals;

-cleaning and disinfecting of affected premises and equipment;

-movement restrictions on pigs and pig products to prevent the spread of the virus to other areas; and surveillance and monitoring of pig populations to detect new cases.

Quarantine new pigs before introducing them to the general herd for around 10 to 14 days.

Porcine Reproductive and Respiratory Syndrome

Porcine reproductive and respiratory syndrome (PRRS) is a viral disease that affects pigs, causing significant economic losses in the industry. The disease manifests differently depending on the age and immune status of the pigs, as well as the strain of the virus involved. PRRS primarily affects the reproductive and respiratory systems of pigs.

The disease spreads through direct contact between infected and susceptible pigs, as well as through contaminated objects, personnel, and airborne transmission. There is no specific treatment for PRRS, and control measures focus on prevention.

The USDA says the symptoms of reproductive PRRS in sows include abortion (sows may experience late-term abortions or give birth to weak piglets); giving birth to weak piglets (piglets born from infected sows may be weak, often exhibiting difficulty in breathing or failure to thrive); and decreased fertility (infected sows may show reduced fertility or irregular oestrus cycles).

In growing pigs, symptoms may include coughing, laboured breathing, nasal discharge, fever, lethargy, and loss of appetite. Pigs generally begin to show symptoms after two to seven days.

There is no specific treatment for PRRS. As with ASF, prevention is thus better than cure, and farmers are urged to maintain good hygiene, such as keeping the pigs’ environment clean.

Proper nutrition and hydration are also important to support the immune systems of pigs. In the case where farmers might suspect infection, remove the suspected pig from the herd and isolate the animal to prevent the spread of infection.

Farmers should implement strict biosecurity protocols, such as controlling access to the farm, disinfecting equipment, and quarantining new animals.

The importance of nutrition for a healthy herd

Nutrition is a cornerstone of profitable pig production, influencing every aspect of pig growth, health and performance.

By prioritising nutrition and implementing sound dietary management practices, pig producers can enhance productivity, efficiency and profitability, while promoting the well-being of their animals and the sustainability of their operations.

Providing pigs with a balanced and nutritious diet ensures that they grow efficiently and reach their maximum genetic potential for growth and performance.

Proper nutrition supports muscle development, body composition and overall health, leading to faster weight gain and improved feed conversion efficiency.

Nutrition influences the reproductive performance of sows and boars, impacting fertility, conception rates, litter size, and the health of piglets. Adequate nutrition during gestation and lactation is essential for supporting foetal development, milk production, and the survival and growth of piglets.

A well-balanced diet strengthens the pigs’ immune system, making them more resistant to diseases and infections. Essential nutrients such as vitamins, minerals and amino acids play a key role in immune function, helping pigs fight off pathogens and recover from stressors more effectively.

Nutrition affects the quality characteristics of pork, including meat composition, marbling, tenderness, flavour and juiciness. Proper dietary management can enhance meat quality attributes desired by consumers, leading to higher market value and profitability for pork producers.

Efficient nutrient utilisation and feed conversion efficiency are critical for optimising feed costs and minimising production expenses. Formulating diets that meet pigs’ nutritional requirements while minimising wastage and excess nutrient excretion can help maximise feed efficiency and profitability.

Balanced nutrition contributes to environmental sustainability by reducing nutrient excretion and minimising the environmental impact. By optimising nutrient utilisation and minimising feed waste, producers can mitigate nutrient run-off, minimise greenhouse gas emissions and promote sustainable farming practices.

Porcine parvovirus

Porcine parvovirus (PPV) is a viral disease that affects pigs. PPV is transmitted through direct contact with infected pigs or their bodily fluids, such as saliva, nasal secretions, faeces and urine. It can also spread through contaminated equipment, clothing, or the environment.

In reproductive sows, the symptoms of PPV infection in pigs, as described in various veterinary sources, include:

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Infertility;

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Embryonic death;

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Mummification of foetuses;

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Stillbirths;

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Reduced litter size.

In piglets, symptoms may include:

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Diarrhoea;

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Respiratory distress;

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Weakness;

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Reduced growth; and

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Increased mortality.

Symptoms may vary in severity depending on factors such as the age and immune status of the pigs, as well as the presence of concurrent infections.

As with ASF and PRRS, there is no cure, and farmers are advised to monitor their herds to detect illness. Farmers are again advised to implement strict biosecurity measures to prevent exposure to the disease, and to isolate sick animals.

Classical swine fever

Classical swine fever (CSF), also known as hog cholera, is a highly contagious viral disease.

It can cause severe illness and death in infected animals. CSF is highly contagious and can spread rapidly within pig populations through direct contact between infected and susceptible animals, as well as through contaminated feed, equipment, or clothing. The virus can also be transmitted by ticks and other vectors.

The symptoms of CSF include fever, loss of appetite, depression and weakness, coughing, difficulty breathing, diarrhoea and vomiting, and neurological symptoms such as tremors, convulsions and incoordination. CSF can also cause reproductive problems in sows, including abortion, stillbirths, and infertility.

Control and prevention of CSF rely on strict biosecurity measures, including herd isolation, proper sanitation, and surveillance programmes, as discussed before.

Transmissible gastroenteritis

Transmissible gastroenteritis (TGE) is a viral disease that affects the gastrointestinal tract of pigs, causing diarrhoea, vomiting and dehydration, particularly in piglets. It is caused by a coronavirus known as the transmissible gastroenteritis virus.

The virus primarily targets the cells lining the small intestine, leading to severe damage and resulting in diarrhoea, vomiting, dehydration, and often high mortality rates, especially in young piglets.

TGE spreads primarily through direct contact with infected pigs or their bodily fluids, such as saliva, faeces, and nasal secretions. The virus can also spread indirectly through contaminated

objects, equipment, or surfaces. It is a significant concern in the swine industry due to its potential for causing severe economic losses.

Symptoms include severe diarrhoea, vomiting, and dehydration (look for sunken eyes, lethargy and weakness). TGE can cause significant mortality, especially in piglets under two weeks of age.