As most people in the cattle industry know, there are certain diseases and illnesses that can cause real damage to a producer’s numbers, both on the hoof and on a spreadsheet. One such disease is Bovine Viral Diarrhea (BVD).
BVD is caused by the bovine viral diarrheal virus (BVDV) and is one of the most prevalent illnesses in the livestock industry on a global scale. There are numerous clinical signs of BVD, including reduced fertility, a decline in milk production, infection of unborn fetuses and of course, diarrhea.
According to the USDA, BVDV is a member of the pestivirus genus. There are four recognized species within the pestivirus genus. These species are BVDV-1, BVDV-2, border disease virus of sheep and classical swine fever virus, previously known as hog cholera virus.
There are two forms of BVDV infection – acute and chronic.
Animals that have recently acquired BVDV demonstrate an acute strain of the illness, and animals that have had symptoms for a long period of time (several months) are considered chronic.
“Some of the signs of acute infection are fever, lethargy, loss of appetite, ocular discharge, nasal discharge, oral lesions, diarrhea, and decreasing milk production.
Chronic infection may lead to signs of muscular disease, noted the USDA. Signs of the disease in newborn calves are birth defects that include anything from failure to nurse to tremors to ataxia; calves exhibiting these symptoms, unfortunately, often die.
So how could a herd potentially contract BVDV?
According to the U.S. Department of Agriculture, BVDV transmission may occur vertically (i.e., before birth), leading to congenital infection of the fetus, or the transmission may occur horizontally (i.e., after birth).
Congenital infections may cause resorption, abortion, stillbirth or live-birth. Congenitally infected fetuses that survive in utero infection (i.e., the live-births) may be born as BVDV-infected calves. The BVDV infection in these calves will persist during the entire life of the calf, and they will shed BVDV continuously in the farm environment. BVDV can be shed via manure, saliva, tears, urine, nasal discharge and semen.
Luckily for producers, there are steps that can be taken to minimize the risk of BVDV within their herd.
Increasing antibodies is one such way. This helps cattle that contract acute BVD shed less virus, and shed the virus for a shorter period of time.
Feeding calves high-quality colostrum and vaccinating older cattle helps to increase their antibodies. Another strategy is to identify and remove persistently infected animals from the herd, as they shed far more of the virus that acutely infected animals.
Providing ample room for your cattle to move around and decreasing pasture density is also a strategy to reduce BVDV risk.
BVD and BVDV are, unfortunately, something that cattle producers have to be aware of at all times. But with some preventative measures and good observation, you can lower your herd’s risk of contracting this disease.
