Ask the Vet

Ask the Vet

Q: Last year, I purchased some replacement heifers from a number of different farms and, at the time, didn’t spend too much time thinking about herd bio-security.  Is it too late to think about this?

Purchasing stock from a well-known and trusted source is always recommended.  Many farms sell animals on as BVD or IBR vaccinated, for example.  However, if you don’t know the disease or vaccine status of bought-in animals, it isn’t too late to do some tests to establish this.  Bulk milk screening, in the form of DairyCheck (available via your vet) will reveal whether your herd has been exposed to/has an active infection for BVD and IBR.  These are probably the main diseases to consider at this stage as both are pretty much endemic in the UK dairy herd, hard to spot, and easily spread when infected animals are brought into a herd.

Results to the end of December, for this Intervet-subsidised scheme showed that of all samples submitted for BVD, 63% had a result showing current active infection. Test results showing recent exposure, but not necessarily infection were given by a further 27%.

Of samples submitted for IBR, 40% tested positive for current active infection while an additional 32% showed previous exposure to the virus.

Q. How significant an impact can these two diseases have, and is it worth considering vaccination?

Both IBR and BVD can sometimes go unnotices in a herd for some time, spreading to more animals and affecting milk yield and reproductive performance.  In adult cows, IBR infection can be associated with a severe and prolonged milk drop, reduced fertility and abortions. The virus is usually shed in secretions from the respiratory tract but can also be spread in the semen of infected bulls.  Once an animal has become infected it remains so, and these animals can shed virus at any time in their lives when stressed.  Movement of such animals into a herd is often the source of new infections. 

IBR symptoms inlude:

• Fever
• Milk drop
• Discharge from the nose and eyes
• Coughing
• Pneumonia
• Abortions (at 6-8 months of pregnancy)
• Occasionally death

BVD meanwhile affects different herds, and animals, in different ways.  Symptoms can range from a drop in fertility, unexplained abortions or calves that are best described as ‘poor-doers’.

Both diseases can be effectively controlled with Bovilis® BVD and Bovilis® IBR vaccines, provided a vaccination programme is worked out with your vet as the infection level or existing status of the herd will determine this. 

Consult your vet to find out more about the Bovilis® DairyCheck BVD and IBR screening service.