Bovine Viral Diarrhea (BVD) is a viral disease of cattle caused by the Bovine Viral Diarrhea Virus (BVDV) . The virus is widespread, and most herds are at risk for infection. Cattle of all ages are susceptible to acute infection, but since colostral antibodies are effective in preventing infection in young animals, the disease is seldom seen before 3 months of age when management includes adequate feeding of colostrum from immune dams. The clinical presentation can range from inapparent or subclinical infection to acute and severe enteric disease. The clinical symptoms include lethargy, anorexia, mild oculonasal discharge, diarrhea, mild oral erosions and ulcers. In severe cases, the calf may die. BVD is currently one of the costliest diseases of cattle. Abortions, infertility, and/or embryonic deaths associated with BVD lead to significantly reduced reproductive performance and increased premature culling. These symptoms are especially marked if one or more BVDV carriers are in the herd. Animals that develop acute diarrhea and fever may die or have long, costly recovery periods with decreased milk production and/or growth.
BVD must be distinguished from other viral diseases that produce diarrhea and mucosal lesions. These include malignant catarrhal fever, bluetongue, and rinderpest. Although persistently infected cattle are important in transmission of BVDV, the virus also may be spread by biting insects, fomites, semen, biologic products, and other animals, including swine, sheep, goats, camelids, and possibly wild ruminants.
Controlling BVD in the herd is important to prevent economic losses. Accurate, rapid results are needed to know how to treat affected animals and protect the other members of the herd. Whole herd screening and individual samples can be used for testing. Testing strategy depends on the situation. The Scottish Government is supporting an ambitious industry-led scheme to eradicate BVD from Scotland, and BVDFree England is a voluntary industry-led scheme, working to eliminate Bovine Viral Diarrhoea (BVD) from all cattle in England by 2022.
