Cattle farmers in South Africa face a hidden enemy in sexually transmitted diseases (STDs) that can wreak havoc on herd productivity and economic well-being.
Dr Geoff Brown, a veterinary specialist in animal reproduction, sheds light on the prevalent diseases, the impact of STDs, and strategies for control.
According to Brown, there are only two true venereal diseases in cattle in South Africa.
The first, Tritrichomonas foetus, is a single-celled organism with a unique appearance. “If you look at it under a microscope, it moves with an awkward, twitching, jerky motion. I always joke that it looks a bit like a three-legged spider trying to climb out of a slippery bathtub.”
The second is Campylobacter foetus, sometimes referred to as Vibrio foetus, which is a bacterium.
These seemingly harmless organisms pose a significant threat to cattle reproduction.
“Neither of these conditions is hazardous to the life of the cattle, but they both cause the death of the embryo and abortion in cattle,” he explains.
The problem lies in the subtlety of the impact. “This is not dramatic and is often missed,” he warns. Early pregnancy loss often occurs unnoticed, with minimal blood or foetal discharge. The farmer’s first clue might be a lower calving rate which is a significant economic blow.
“As you can imagine, fewer calves means less saleable product for the farmer,” Brown emphasises.
Mating and beyond
Mating is the primary route of transmission but contaminated artificial insemination (AI) equipment or infected semen can also be culprits. However, Brown highlights the crucial role of farm biosecurity management.
“The most important reason for the spread of these diseases is a failure of proper farm access control, where cattle from neighbouring farms are able to wander onto the farm through broken fences. Introducing untested bulls is another major risk factor.”
Since early detection is critical, Brown emphasises the importance of meticulous record-keeping. “Ensure that you accurately identify and keep careful records of all your animals. Written records are much better than records committed to memory,” he advises.
A defined breeding season, followed by a pregnancy diagnosis by a veterinarian, further aids in early identification. Biosecurity measures like maintaining good fences and controlling animal movement are also essential.
Diagnosing venereal diseases typically involves testing bulls, the primary carriers. A sample of cells is collected from the sheath cavity, housing the penis, and analysed in a laboratory using two methods:
- Culture method: While less sensitive, a positive culture confirms the presence of the live organism. However, Brown emphasises the importance of collecting a good sample over multiple weeks to increase accuracy due to the possibility of low organism numbers in carrier bulls.
- Polymerase chain reaction (PCR): This highly sensitive technique detects the organism’s DNA if it is present.
Related stories
- Record-keeping: Know the ins and outs of your cattle
- Vaccinations and pregnant cattle: Safeguard two lives at once
Vaccination: A tool with limitations
Vaccines exist for both diseases but Brown advises against routine vaccination without consulting a veterinarian.
“[Vaccines] are fantastic tools that can form part of a management programme for the elimination of a disease from an infected herd. However, they are not very effective in bulls, and even in cows, their duration of protection is short.”
Veterinary advice is crucial for determining the most appropriate course of action.
No threat to humans
Brown says these two diseases do not pose any threat to humans. “These two diseases are very specific to cattle. They do not pose a risk to other livestock or humans and are certainly not a cause for concern regarding human health.”
While he focuses on the two most significant venereal diseases, he acknowledges the existence of viral diseases with similar transmission routes. However, he emphasises that their impact pales in comparison to tritrichomoniasis and vibriosis.
A multi-pronged approach
The fight against venereal diseases in cattle requires a multi-pronged approach. Understanding the nature of these diseases and their impact helps farmers implement a combination of strategies:
- Meticulous record–keeping;
- Controlled breeding seasons;
- Biosecurity measures;
- Bull testing;
- With strategic veterinary advice, cattle farmers can significantly reduce the risk of venereal diseases.
Brown concludes by advocating for artificial insemination as a potential alternative to bull breeding.
“Eliminating the use of bulls entirely is a very good way to reduce the risk of venereal disease transmission,” he says. However, he acknowledges the importance of careful planning and the synchronisation of oestrous cycles for successful implementation.
ALSO READ: Sunlight and seawater: Try sea farming if it floats your boat
Sign up for Farmer’s Inside Track: Join our exclusive platform for new entrants into farming and agri-business, with newsletters and podcasts.
