All cattle breeds in South Africa can be affected and LSD usually occurs during the wet summer and autumn months, when flies are in abundance.
It’s a notifiable disease, which means the state vet must be informed, as there are specific control schemes.
LSD causes emaciation (loss of body condition because of unwillingness to eat); temporary or permanent loss of milk production; lowered or complete loss of fertility in bulls and cows; abortion; and permanent damage to hides.
Up to 45% of a herd can get infected and the mortality rate may reach 10%. LSD can also spread through the saliva of infected animals when using the same drinking trough.
Signs of LSD include the following:
- Skin nodules and ulcers: These range from 0,5cm to 5cm in size and can vary from a few to hundreds. They occur anywhere on the skin, including the nose, udder and vulva in cows, and the scrotum in bulls;
- Legs become swollen and develop sores;
- Enlarged lymph nodes;
Pneumonia/coughing as a result of infection of the respiratory tract (the windpipe and lungs);
- Nasal discharge;
- Infertile cows and infertile bulls (due to infection of the testes);
- Mastitis, reducing milk production;
- Excessive salivation.
Confirmation from a vet
A basic diagnosis can be made from the presence of the lesions on the skin and in the mouth. In the case of long-haired animals, feel for the nodules on the skin, or wet the hair to see the nodules more easily.
Diagnosis can only be confirmed through a vet, who will have skin samples tested at a lab. Some other diseases cause similar signs in cattle.
If you suspect LSD in your herd, inform the state vet so that the disease can be confirmed.
He will then help you to control the disease. If animals have been protected, you will suffer no production or financial losses due to the ill effects of the disease.
Prevention through vaccination
The attenuated Neethling strain vaccine contains weakened LSD virus. When this vaccine is administered, the animal will develop protective antibodies (white blood cells) which resist the actual virus.
Vaccinate all cattle once a year, preferably before the summer rain to ensure good protection.
Animals that have had the disease and have recovered are immune and do not have to be vaccinated.
Calves under six months old born to cows that have been vaccinated or have had the disease, do not need to be vaccinated. However, when they are six months old, they have to be vaccinated annually.
There may be a swelling at the site where the injection is given, and a temporary drop in milk production, but the swelling will disappear after a few weeks with a return to normal milk production.
Read the instructions on the vaccine label. If you have any questions or need assistance with vaccination, contact your state veterinarian or animal health technician.
Source: Lindsay Thomas. ‘Lumpy-skin disease: a disease of socio-economic importance’, Directorate Communication Services in co-operation with ARC-Onderstepoort Veterinary Institute