It’s still early in the breeding season – and not too late to take precautions against sexually transmitted diseases in cattle that cause infertility. Now is the time to test bulls for diseases such as vibriosis and trichomoniasis.
By Nico van Burick, senior journalist at African Farming and Landbouweekblad
Dr Dave Midgley, CEO of the Ruminant Veterinary Association of South Africa (RuVASA), says many farmers only bring their bulls and cows together in November or December. That’s why testing is so important at this stage.
He says 82 veterinarians recently attended RuVASA’s monthly disease notification meeting, where trichomoniasis and vibriosis were discussed – because now is the time to test bulls before they are placed with cows. Concerns were also raised about vaccine shortages.
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Vaccine Shortages
Midgley says that although the well-known vaccine Vibrin is temporarily out of stock, there are alternative products farmers can discuss with their veterinarians. Positive cases have been reported on several farms, which is driving up demand for vaccines.
Claude Cloete, a farmer from Dordrecht in the Eastern Cape, says vaccines are not currently available in his area, which is a big problem for him as now is the time for his bulls to be tested and vaccinated. He believes the shortage extends beyond his immediate area.
The company Zoetis, which imports Vibrin, has declined to comment at this stage.
Midgley explains that when a fertile bull inseminates a cow carrying pathogens of a sexually transmitted disease, the infection can prevent the cow from becoming pregnant, something the farmer usually discovers only much later.
“These are not state-controlled diseases,” he says, “but they can have a serious impact on cow fertility and ultimately the farm’s profitability. The farmer who doesn’t have calves doesn’t have an income – that’s why prevention is so important.”
Some vaccines available can be used for both treatment and prevention. Every local vet looks at the herd’s history, Midgley says. “If conception rates are low, the first thing to investigate is the bulls released to the cows.”
He adds that only about 3% of bulls are used in a herd, for example, three bulls for every 100 cows. Focusing on these bulls and keeping them free of disease is a way to reduce risks – like taking out insurance or burning firebreaks.
If one bull is infected, it can also spread the disease to other bulls if they service the same cows. This can cause a conception rate of 90% to suddenly drop to 30% or 40%.
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Biosecurity and Planning Ahead
Midgley warns that farmers should also monitor bulls owned by farm workers, bulls on loan or animals that may have broken through fences – all of which could spread infection. These risks should be included in the farm’s biosecurity plan, along with testing and vaccination programmes for both prevention and treatment.
He urges farmers to keep track of vaccine availability and plan ahead. The vaccine is not a treatment on its own, he says, but it strengthens the immune system and forms part of a broader treatment plan.
Until Vibrin is back in stock, an autogenous vaccine – developed in collaboration with a farmer’s private or herd veterinarian – can be used as an alternative.
Also read: Is biosecurity South African agriculture’s weakest link?
