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- Three-day stiffsickness (TDS) is a viral cattle disease transmitted by biting insects, posing a significant threat to reproduction and milk production in cattle.
- Outbreaks of TDS are closely linked to high rainfall and environmental conditions that lead to increased numbers of biting insects.
- The disease primarily affects bulls during the breeding season, causing stiffness and pain that can result in temporary infertility for up to six weeks.
- TDS has a substantial impact on milk production, particularly in dairy cows, where infected animals may experience a drastic decrease in milk output or even dry off.
- Vaccination is the primary preventive measure against TDS, with livestock producers advised to vaccinate their animals before the wet season to build immunity.
While three-day stiffsickness (TDS) is known to have a low mortality rate, it does have a high incidence rate. Biting insects are the main transmitters of this viral cattle disease, which is of economic importance to South African producers due to the serious impact it has on especially reproduction and milk production in cattle.
Outbreaks are closely linked to environmental conditions marked by high numbers of biting insects. High rainfall regions are therefore more prone to annual disease outbreaks, and drier regions to a lesser extent. Where rainfall is above normal in the traditionally drier areas, large outbreaks may occur due to lower herd immunity resulting from less exposure.
The disease reporting system by veterinarians across the country clearly points to this seasonal disease pattern, says Dr Danie Odendaal, director of Veterinarian Network. According to the system, TDS occurs three to four months earlier in the winter rainfall regions as it coincides with spring and summer’s wet and warm conditions.
Due to the disease coinciding with the main summer breeding season in the summer rainfall regions, reproductive losses and a decrease in milk production, especially in dairy cows, can be substantial.
Identifying TDS
It is difficult to distinguish TDS from certain other deadly diseases this time of year, as the signs are very similar. It must be distinguished from diseases that require immediate and correct treatment, such as redwater, anaplasmosis, and heartwater. Animals with TDS are often lethargic, ingest less feed, and keep to themselves. These animals are stiff and will be unable or unwilling to walk. This is due to high levels of inflammation and pain in the joints and muscles. They will often lie down, unable to get up, especially in the case of heavy bulls. Symptoms usually last only a few days, and animals recover quickly – hence the name three-day stiffsickness.
However, a disease state arises when the virus targets the cells lining the smaller blood vessels, causing a drop in the body’s free calcium levels. The biggest impact of TDS is seen in the breeding season, especially in bulls. Sick bulls are unable to breed due to stiffness and pain. The fever reaction also inactivates sperm, and bulls can end up being infertile for around six weeks. One- and two-year-old heifers and bulls are most prone to contracting TDS.
Mature animals will often lie down. Periods of low immobility tend to affect the blood supply to and nerves in the legs, and animals may often never get up by themselves again.
This disease’s biggest impact on production is a rapid, drastic decrease in milk production. Cows in the last third of lactation may dry off. A small percentage of in-calf cows or heifers may experience a loss in milk due to abortions. Dairy cattle can also develop atypical TDS which affects the lungs (pulmonary emphysema), resulting in subcutaneous air bubbles between and behind the shoulder blades.
Treatment and prevention
Since TDS is caused by a virus, there is no primary treatment. Symptomatic treatment, including the administration of anti-inflammatories and calcium, is necessary for managing pain and inflammation. Antibiotics are recommended for preventing secondary bacterial infection in especially the lungs. The infected animal must have access to feed and water.
Livestock producers must vaccinate their animals against this disease, as it increases the animal’s resistance and lowers exposure. Producers should consult their local veterinarian about a vaccination programme before the wet season commences. It takes animals at least two weeks to build up immunity against a viral disease. However, TDS itself develops over a much shorter period and vaccinating animals at the last minute is therefore a waste of money.
Heifers, and young and breeding bulls can be vaccinated before the start of the wet season. Dairy cattle, feedlot animals, and valuable breeding stock can also be immunised.
A booster dose must follow the first vaccination, especially in young cattle. Administer the first vaccinations before or during the start of the wet season and the booster dose as soon as the first cases of the disease emerge in the area. It takes at least two weeks after the first vaccination for animals to build up immunity, and only a few days for the animal to reactivate a protective immune response after having received the booster dose.
Private companies currently produce effective vaccines against the disease, but be sure to follow your herd veterinarian’s advice when administering it. – Christal-Lize Muller
For more information, email Dr Danie Odendaal at vnet1@absamail.co.za.
