A worrying 65% of herds tested positive for IBR infection, 69% positive for Leptospirosis and the majority of herds tested showed evidence of previous BVD exposure, according to the 2008 results of Intervet/Schering-Plough Animal Health’s subsidised milk testing service DairyCheck.
The service, which is offered via veterinary practices, is a bulk milk screening facility capable of showing whether a herd is negative or positive for certain infectious diseases. This can indicate whether the disease is currently present or if cattle have been exposed previously. For many herds, it is these hidden infections that could be causing most damage to performance and yield. Above expected levels of mastitis, lower milk yields and poor fertility can all be the legacy of rumbling either BVD, IBR or Leptospirosis infections.
"It can be a case of ’out of sight, out of mind’," explains vet adviser Ruth Vernon. "However, after the initial infection, cows may appear healthy, but their immune systems may not be working properly. This results in herd performance that is always below expected levels."
Services such as DairyCheck offer a subsidised way of identifying a herd’s health status, before taking the appropriate action. A written interpretation is completed by the lab, which is then sent to your vet. This is then the basis of a discussion to develop the best course of action, and re-testing can then be used to monitor the herd’s disease status in future months and years.
"The majority of herds will show either infection or previous exposure after which your vet can come up with a programme of action including vaccination, blood testing to identify carriers, and culling," Mrs Vernon adds. "When the news is good – and on average around 33% of DairyCheck tested herds were found to be clear of all three diseases – your vet can advise on ways to keep your naïve herd clear.
"This involves paying attention to biosecurity and making sure that any bought-in animals are blood tested. Quarantine is essential before they join the main herd, and vaccination programmes may also need to be considered."
