This spring, in our practice in south Wexford, we have seen a number of herds presenting with persistently infected (PI) Bovine Viral Diarrhoea (BVD) calves. This is disappointing in the fourth year of the BVD eradication programme.
The virus can cause a host of issues from subclinical infections where no clinical signs are apparent to diarrhoea, immuno-suppression, infertility, embryo loss, abortions and deformities.
The PI calves are created when the dam is infected with the BVD virus between day 30 and day 120 of gestation. These PI calves are unlikely to survive, but are very effective in spreading the disease while alive, contributing to creating more PI calves. These can consequently have a very negative impact on herd health in a naive herd and cause serious and dramatic economic loss.
Dams that are infected by the virus from these PI calves during gestation can have early embryonic deaths, abortion, stillbirths and give birth to weak or deformed calves.
Cows infected by the virus may display signs of inappetence, reduced milk production and increased temperatures. Younger stock show signs of fever and diarrhoea and are vulnerable to other opportunistic viruses and bacteria.
Entry and spread occurs in several ways:
Purchasing in-calf cows or heifers which are carrying a PI calf (called Trojan animal). Purchasing animals which have a BVD infection and joining immediately with the herd. From neighbouring farms where stock are grazing in adjacent pastures with boundaries which allow nose-to-nose contact or where breakouts or breakins may occur. Vaccination is an important tool in controlling BVD and protecting herds. The best time to have the vaccination course completed by is a month before the start of the breeding season.
Improved boundary fences, improved biosecurity, quarantine of recently purchased stock and testing of introduced animals for BVD are measures which can reduce the risk of the virus entering the herd.
Consult your vet if you have received a positive PI result to organise a BVD herd investigation and discuss control measures and vaccination.
Seamus Allis works at AHC Veterinary, Taghmon and Wellingtonbridge, Co Wexford, part of XLVets. Visit www.xlvets.ie for more.
This spring, in our practice in south Wexford, we have seen a number of herds presenting with persistently infected (PI) Bovine Viral Diarrhoea (BVD) calves. This is disappointing in the fourth year of the BVD eradication programme.
The virus can cause a host of issues from subclinical infections where no clinical signs are apparent to diarrhoea, immuno-suppression, infertility, embryo loss, abortions and deformities.
The PI calves are created when the dam is infected with the BVD virus between day 30 and day 120 of gestation. These PI calves are unlikely to survive, but are very effective in spreading the disease while alive, contributing to creating more PI calves. These can consequently have a very negative impact on herd health in a naive herd and cause serious and dramatic economic loss.
Dams that are infected by the virus from these PI calves during gestation can have early embryonic deaths, abortion, stillbirths and give birth to weak or deformed calves.
Cows infected by the virus may display signs of inappetence, reduced milk production and increased temperatures. Younger stock show signs of fever and diarrhoea and are vulnerable to other opportunistic viruses and bacteria.
Entry and spread occurs in several ways:
Purchasing in-calf cows or heifers which are carrying a PI calf (called Trojan animal). Purchasing animals which have a BVD infection and joining immediately with the herd. From neighbouring farms where stock are grazing in adjacent pastures with boundaries which allow nose-to-nose contact or where breakouts or breakins may occur. Vaccination is an important tool in controlling BVD and protecting herds. The best time to have the vaccination course completed by is a month before the start of the breeding season.
Improved boundary fences, improved biosecurity, quarantine of recently purchased stock and testing of introduced animals for BVD are measures which can reduce the risk of the virus entering the herd.
Consult your vet if you have received a positive PI result to organise a BVD herd investigation and discuss control measures and vaccination.
Seamus Allis works at AHC Veterinary, Taghmon and Wellingtonbridge, Co Wexford, part of XLVets. Visit www.xlvets.ie for more.
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