Identifying the threats that endemic diseases pose to the Irish suckler beef industry, vet Doreen Corridan outlined key methods for control and eradication.
Developing an on-farm health scheme was the first point of call, she told delegates.
“The first step is to keep disease out by improving biosecurity. Spread of disease can be over fences, by people, equipment and vermin.”
This has further advantages, Ms Corridan explained. “Producers wanting to market elite genetics need to gain elite health status. Not only is it an insurance policy, but it strengthens sales of bulls and breeding females to a guaranteed market.”
But, each programme has to be farm specific, and production objectives, disease prevalence and farm conditions have to be considered.
“Where a disease like Johne’s is concerned, it is key to establish current herd status before putting a testing programme in place. This will involve annual testing and culling of reactors when found.”
Stages of disease could be lengthy, with a silent infection lasting up to two years and clinical disease anywhere between two and 10 years. “When a herd tests positive, six-monthly testing and culling is the only option. Remove the positives and their progeny and identify those animals at risk,” she adds.
With BVD, which affects 80% of Irish beef herds, identifying the persistently infected (PI) animal is crucial. Blood test all cattle, remove any PI animals and implement a whole-herd vaccination plan, she advised.
“The PI is the virus factory, an animal which may not show signs, but transmits the disease. This is why it is essential to test before bringing new stock into the herd, particularly when buying bulls and replacements.”
Disease screening allows an assessment to be made of the actual incidence of disease, she said. “Once this process is completed, producers can then go through accreditation procedures.”