In animal production, animal diseases remain one of the factors that affect the quality and quantity of the products.
Bovine viral diarrhea is a disease spread with 95% of dairy herds and about 60% are actively infected at any given time. Active infection is caused by direct contact with persistently infected (PI) cattle.
Disease management
PI cow show high levels of virus in body fluids which is a source of BVD spread. Find and eliminate PI cattle to prevent new one from being created on farm and this is done through monitoring , culling off and bio security which include strict vaccination.
Similarly, monitoring involves testing for BVD antibodies in blood, milk which indicate past PI exposure and in this, the higher the antibody the more recent and wide spread PI has been. BVD virus in blood , milk, tissue means an animal is a PI or transiently infected and for positive BVD virus tests, work with the vet to confirm a PI animal.
Cull PI animals immediately since it cant be cured or can be a source of infection for others. For dairy herd, bulk milk antibodies increase 2-3 times per year and if antibody is high, pre test for BVD virus to see whether there is a PI in the herd.
Additionally, make sample milk for virus testing when all cows are contributing to vat and ask vet to organise testing packages for BVD. If antibody is high, work with vet to investigate and eliminate PI contact before mating.
Finding milk PI and accurate records prevent PI from entering milking herd and for replacement calves, PI animals and reject positive animals for purchased animals and leased animals. Make sure service bulls are vaccinated before mating in each season.
Finally monitoring and bulk milking cows show how control measures are working and other bio security measures include strategic vaccination.
