What is Bovine Pestivirus?
Pestivirus is a viral infection of cattle that is common in beef and dairy herds throughout Australia. Recent investigation has shown that in Australia the bovine Pestivirus syndrome may take two different forms.
- Mucosal disease: a syndrome that occurs sporadically in weaned and adult calves as a result of foetal infection during the first 3-4 months of gestation. This results poor calf development and poor weaning weights. Feed lot cattle can have reduced feed conversion and poor daily gains, high morbidity and some mortality.
- Bovine Pestivirus syndrome: infections of pregnant females not exposed to the virus previously, resulting in reproductive loss.
How is the virus spread?
Transmission of Pestivirus is usually from direct contact with a persistently infected carrier animal or its excretions and secretions. The virus has been isolated from the saliva, tears, ocular and nasal discharges, urine, faeces, milk and semen of persistently infected animals.
Persistently infected animals within a herd are the main source of infection in that herd. These animals occur if:
- A susceptible female is infected during day 25-125 of gestation and maintains the pregnancy to term. Any calf born after the dam is infected at this time is born persistently infected, however 50% of females infected at this stage of pregnancy abort.
- All offspring from persistently infected females are born persistently infected.
Infection occurs mainly when cattle are in close contact, such as during mustering, yarding and transport, however the virus can also be spread by flies, during branding and even via nose pliers. Another less important source of transmission is transiently infected animals. Transiently infected animals are those that are infected with the virus after birth. These animals can infect others for 4-7 days after they themselves are infected.
What are the signs of Bovine Pestivirus?
Endemic Pestivirus can manifest itself within a herd with few clinical signs so long as persistently infected calves infect replacement heifers and bulls prior to joining. Persistently infected animals often present as the poor doers in a herd developing mucosal disease before two years of age. However, some persistently infected animals can survive for many years without clinical signs.
Reproductive signs of Pestivirus infection occur when heifers or cows are first exposed to the virus during pregnancy, although exposure to the virus can also reduce conception rates. When the dam is exposed to the virus during pregnancy the virus has the ability to cross the placenta and infect the foetus. Depending on the stage of pregnancy, infection of the foetus may result in early foetal loss (infertility), abortions or stillbirths. Calves that develop to term are born persistently infected or with congenital abnormalities. Calf losses of 25-50% can occur in recently infected herds.
Cattle exposed to the virus soon after birth develop a sub-clinical infection. Although these cattle develop few signs of infection, the ability of their immune system can be reduced resulting in higher levels of productivity loss.
How is Bovine Pestivirus diagnosed in cattle?
A suspicion of Pestivirus may arise in a herd after a history of either unexplained abortions, an increased incidence of stillbirths and/or premature births, birth of congenitally abnormal calves or the occurrence of one or more cases of the mucosal disease syndrome. However, confirmation of Pestivirus can only be achieved by laboratory blood testing.
Sampling 10 females from your heifers, second calf cows and older cows will give an accurate picture of the disease in your herd and allow an informed management plan to be formulated.
Control of Bovine Pestivirus with Pestigard™
Pestigard™ is the first vaccine for the prevention of Bovine Pestivirus in cattle in Australia.
For the active immunisation of cattle against Bovine Pestivirus and to reduce reproductive losses due to Bovine Pestivirus.
- Bovine Pestivirus is a widespread disease throughout Australian cattle herds causing significant productivity loss by affecting the reproductive performance of the herd or increasing susceptibility to other common diseases.
- The introduction of a Pestigard™ vaccination program will reduce reproductive loss caused by Bovine Pestivirus. Pestigard™ will also stimulate active immunity against Bovine Pestivirus which will assist in the reduction of losses associated with the Bovine Respiratory Disease (BRD) complex where Bovine Pestivirus is implicated.
- A Pestigard™ vaccination program can be conveniently integrated into existing management practices.
- Dose rate 2mL
- Pack Size 100mL - 50 doses
- Pack Size 250mL - 125 doses
Dosage and Administration
- The recommended dose for cattle of all ages is 2ml.
- Two doses of Pestigard™ should be administered 4-6 weeks apart with annual boosters thereafter.
Exposure of young cattle will develop a sub-clinical infection within the herd boosting immunity and decreasing reproductive losses in the breeder herd. Although not all animals are guaranteed of being exposed, it is a management tool available to decrease the effects of Pestivirus.
Increased susceptibility to other common diseases
Bovine Pestivirus normally has little effect on healthy adult cattle. However, when cattle become stressed, such as in an intensive grazing, feedlot or saleyard situation, an infection with Bovine Pestivirus may place cattle at a greater risk of contracting other illnesses. Through its immunosuppressive effects, Bovine Pestivirus is a major factor predisposing cattle to infection with other viruses and bacteria that in combination can manifest as Bovine Respiratory Disease (BRD) complex.
More information is available from the Pfizer Animal Health website.