Читать книгу Farm Animal Medicine and Surgery - Graham R Duncanson - Страница 99

BVD type 1 disease, caused by Bovine viral diarrhoea virus 1 (BVDV 1) is normally associated with reproductive problems in adult cattle. There is also a BVD type 2 disease which can cause acute illness in cows and is usually fatal. The cows feel ice cold to the touch and have a low rectal temperature. They have profuse watery diarrhoea and death follows in a few hours. There is no treatment but there is a vaccine.

Cows infected with BVD type 1 during very early pregnancy will reabsorb the embryo and return to service. Cows infected in early and middle pregnancy will produce calves which are persistently viraemic (i.e. persistently infected (PI) calves). These calves may develop mucosal disease, which is invariably fatal. The calves or yearlings will be ill, sometimes with a fever. They will have erosions around the mouth and will be totally anorexic. A heparinized blood (Green top Vacutainer) test will reveal virus positive animals, i.e. PI calves, even before they manifest clinical disease.

See also ‘Bovine viral diarrhoea virus (BVDV)’ as a cause of abortion under ‘Diseases of the Reproductive System’ below.