What are the effects of BTV in cows?
Bluetongue causes fever (temperatures up to 40oC), nasal discharge, swelling and ulceration of the mouth, swollen teats, runny eyes, lethargy, drooling saliva, and swelling of the head and neck. In dairy cattle there can be huge losses in milk yield and a reduced resistance to other diseases such as mastitis, metritis and lameness. It can be hard to spot in cows as infection is often subclinical (many animals show no visible signs), so regular stock inspection is necessary – particularly around the nose and mouth, and the coronary band – to catch signs early. Secondary bacterial infections (commonly respiratory disease) often follow bluetongue infection. Cows can remain viraemic (infectious) for up to 60 days.
