By Dr Sello Maboe
Animal diseases are estimated to be responsible for about 20% of losses in a farming operation. This is not limited to loss through animal deaths – it also includes productivity lost while animals are ill, the cost of prevention and treatment, man hours spent on caring for sick animals, pregnancy losses, and fertility impairment.
What Exactly Is Lumpy Skin Disease?
Lumpy skin disease (LSD) is one of those economically important diseases whose impact cannot be ignored. It is also a notifiable disease in South Africa, meaning all cases, even if suspected, must be reported to the nearest state veterinarian. LSD is a fairly predictable livestock disease that can be prevented with a minimum investment of a few rand per vaccine dose. Also known as knopvelsiekte, it’s a viral disease of cattle, characterised by the development of lumps or nodules on the skin surface of affected animals.
LSD commonly occurs during wet summer and autumn months when biting flies and mosquitoes are about in great numbers. Recent research has demonstrated that ticks can transmit the disease as well. This suggests a greater likelihood of picking up LSD outside normal seasonal parameters. This is particularly so in areas that experience warmer winters where ticks survive and show some activity, although limited.
How Would I Recognise The Disease?
Typical lesions can range from a few to several thousand and can be up to 5cm in diameter. These lumps or nodules occur on the skin, including in the form of oral ulcers. Enlarged lymph nodes are very common at the onset. Affected animals may also present with swollen legs and be reluctant to move. Nasal and eye discharges and salivation are very common.
Pneumonia and/or coughing is also common in infected animals due to infection of the respiratory tract, possibly worsened by other opportunistic pathogens. In some cases, there is a drop in milk production (more noticeable in dairy animals) as a result of mastitis that may occur following infection. Over time, affected animals may lose weight, possibly exacerbated by painful mouth lesions that make it difficult to feed.
How Does It Affect Me As A Farmer?
Severely affected animals (up to 10% of those infected) may die, especially those suffering opportunistic infections at the same time as LSD. It is important to note that losses due to disease are not always as a result of death. For example, when exposed raw lesions from the infection develop secondary complications, the animal may have to receive treatment with antibiotics and anti-inflammatories.
Depending on the fly activity, blowfly strike may be another complication requiring treatment. Sick animals will generally perform below their full potential. The fever related to the onset of the disease may cause some pregnant animals to abort. Breeding bulls also suffer negative reproductive impact as a result of infection.
Even though bulls are known to recover from LSD, full recovery is never guaranteed. Other losses may relate to loss of breeding opportunities, especially for farmers that follow strict short breeding seasons. Bulls may only recover when the breeding season has passed. All these losses have a direct and indirect financial impact on the farmer, whether this is through animal mortalities, treatment costs for secondary complications or reproductive losses. This disease can also become a trade barrier – even at a local level – as visibly sick animals are not attractive to prospective buyers.
How Can I Prevent Or Minimise Losses?
• Vaccination
Lumpy skin disease is preventable by highly effective vaccines available in the country. This includes the OBP Neethling strain vaccine that has been on the market for 50 years. Annual vaccination should be carried out in spring, before the start of the rainy season. Animals receiving the vaccine for the first time should be given a booster dose four to six weeks after the first injection. Vector control in susceptible animals helps manage infection pressure. This is mainly achieved using dips and other approved external parasite control remedies.
• Treatment
While it is generally accepted that antibiotics do not kill viruses, they are often a valuable intervention to manage secondary infections. Other supportive interventions may also include provision of milled feed to help with animals that may be reluctant to feed because of mouth ulcers from the disease.
Speak to your local veterinarian or animal health technician regarding basic vaccination programmes that can make a difference to your livestock operation. Dr Sello Maboe is the technical and marketing manager at Onderstepoort Biological Products. Email him at sello.maboe@obpvaccines.co.za
