Always investigate abortion cases
Always investigate abortion cases
INFECTIOUS abortions in cattle can occur due to about 32 different organisms.
But in practice, vets only need diagnose about a third of these, according to Richard Murray of the Liverpool University vet school.
He explained that to be worth identifying, infectious agents must reduce herd health, fertility or productivity or be transmissible to people. There must also be a reliable lab test for it. "And, when you cant do anything about it, why spend money going after a diagnosis."
But he believes that it is important to investigate abortion with a clinical examination of the cow and foetus. Taking samples from the foetus is also worthwhile, even when these are only stored for diagnosis at a later date should it be deemed necessary.
This can save on the £30 fee for lab tests for every cow which aborts. But for a cost of £10 the material can be kept to allow further investigations if more abortions occur, said Dr Murray.
The primary causes of abortion include bacteria – such as brucella abortus, salmonella, leptospirosis hardjo and campylobacter – neospora, bovine viral diarrhoea, bovine herpes virus-1 and fungal abortion.
"Fungal abortions were responsible for 2% of positive diagnoses in 1999. These can occur because of the cattle environment or come from silage."
Investigations of about 5500 abortions in 1999 showed a positive diagnosis in 29% of cases. A third of these were neospora caninum and a quarter were leptospirosis hardjo, he added.
It is important to investigate cows which abort and the foetus, says Richard Murray.