Animal Health - Bovine Viral Diarrhoea
BVD (Bovine Viral Diarrhoea) is a highly infectious viral disease spread through body fluids and excretions damaging cattle health, fertility and productivity, and sometimes resulting in death.
Up to 60% of herds in New Zealand have been recently affected by BVD. This can cost individual farmers from $7,000 up to $90,000 for a major outbreak.
Monitoring through bulk milk and individual testing helps inform you of your herd’s exposure to BVD infections and assists in identifying a PI (Persistently Infected) animal. The sooner you manage BVD on farm the less on-going costs will be incurred through reduced production and other health and fertility issues.
Consequences of BVD can be serious:
- Temporary infertility of bulls
- Reduced cow fertility e.g. long returns
- Abortions and still births
- Premature calves and congenital defects
- Ill-thrifty calves with reduced growth rates
- Increased vet costs
- Animals that die young
- Increased incidence of mastitis and high somatic cell counts
Stages of infection:
Has not been exposed to the BVD virus. Has low to no antibodies against BVD and therefore has very little natural immunity to infection.
TI (Transiently Infected) Animals
An uninfected (naïve) animal can become a Transiently Infected (TI) animal when in contact with BVD virus. A TI animal will shed the BVD virus for approximately four weeks. During the period of transient infection an animal will produce antibodies and develop immunity. At this stage the BVD virus infection will be cleared and the immune animal will no longer be a source of infection.
An animal that has antibodies to BVD virus. Immunity is not life-long. The antibody level will wane over time
PI (Persistently Infected) Animals
A PI animal is created when its mother is exposed to BVD in the first four months of pregnancy and it will be a born carrier of the BVD virus. A PI animal will shed large amounts of the BVD virus throughout its entire life. A PI cow will always give birth to a PI calf.
Risks of Infection:
Natural Mating Bulls
Un-tested and unvaccinated natural mating bulls can be a major source of BVD on farm, so it is important to have them tested for BVD prior to using them. Transmission of the BVD virus to pregnant cows may result in the next generation of animals being persistently infected (PI).
People, cows or machinary
Cattle coming on to the property, including their fetuses.
People coming on to the farm as well as any contaminated equipment and vehicles.
Heifers and carry-over cows that have returned to the farm after grazing off the farm.
A neigbouring herd
It is not uncommon for a herd to become infected after contact with neighbours’ cattle across boundary fences.
Animal Health and Genemark DNA parentage solutions
Genemark DNA Parentage Verification
LIC Diagnostic's Animal Health Testing will determine if your herd is carrying any abnormalities that could result in ill health, loss of production, fertility problems, or even death.
Genemark DNA parentage testing takes the ‘guess-work’ out of matching calves to their dam and sire. Our accredited IANZ laboratories use the latest in scientific technology to confirm the parentage of your animals.
- Whole Herd Testing
- Individual Animal Testing
- A2 Testing
- Freemartin Testing