Posted from High Plains Journal: Lubbock
Prevent the creation of BVD-PI calves
Contrary to popular opinion, BVD does not stand for bad veterinarian disease. It stands for bovine viral diarrhea, and it can be very costly for cow-calf producers and feedlot operators.
Speaking at the BVD Forum in Kansas City, Missouri, April 7, Dan Grooms, a professor in the College of Veterinary Science at Michigan State University, said BVD can cost producers $14 to $25 in decreased return per beef cow, and feedlot owners can lose $41 to $93 per animal exposed to BVD. The morbidity rate for feedlot calves exposed to persistently infected animals is almost double the rate for non-PI exposed calves.
Derrell Peel, a professor at Oklahoma State University Department of Agricultural Economics, said the economic impact of BVD is $20 to $30 per beef cow, $45 to $55 per dairy cow and $20 to $45 per stocker/feedlot animal. The impact for the industry as whole is $1.54 to $2.59 billion.
BVD is a viral infection of cattle that can mutate and change rapidly and have adverse consequences. Clinical outcomes related to BVD include abortions, early embryonic death and congenital defects.
The disease can lead to persistently infected animals, although many of these die at a young age due to secondary infections. Approximately 93 percent of calves that test positive for BVD do not have a PI dam but a PI cow will always give birth to a PI calf.
“PIs are lifetime shedders of BVD,” Grooms said.
A PI animal can look normal but is generally a poor performer. Peel said a lot of the loss may not even be noticed by producers because PI calves that survive past weaning become someone else’s problem.
The challenges for effective BVD control include failure to recognize the disease, failure to recognize the costs associated with the disease, little incentive to identify and remove PI animals from the herd, the cost of testing for the disease, the nature of the disease and the impact of BVD on other diseases.
“You can’t see what you are not looking for,” Peel said.
Dr. Dan Givens, a veterinarian at Kansas State University’s College of Veterinary Science, said most BVD-PI animals occur in the cow-calf segment of the industry. There is no good way to test a calf for BVD until it is on the ground. At this point the producer is only six months away from the selling the animal and then it is halfway through the production process. Givens wondered if it reasonable to expect one segment of the industry to shoulder all of the costs for testing and control of this disease.
“BVD is one of the few disease that is easy to blame on someone else,” Givens said.
It is estimated that 10 percent of herds in this country will have a PI-infected animal. However, a recent survey of producers with over 200 cows said that while they had knowledge of the disease, they were not testing for it. Givens said the absence of evidence is not the evidence of absence.
Givens said producers should undertake pre-breeding tests before bulls are turned in with the cows. They should test calves on the ground, bulls and all cattle without calves. Pl-positive cows and calves should be removed from the herd and be sold for slaughter.
“All of the tests can be done reliably if done correctly,” Givens said.
Richard Kerr, laboratory manager at Daisy Farms in Texas, said his associates do intensive testing of all animals on the dairy. They found three BVD positive animals in 2014 but none since.
Brian Keith, a stocker and cow-calf operator from Allen, Kansas, said he tests every calf that comes off the truck. Within 12 to 24 hours of arrival he knows which calves are “hot.” Keith manages 10,000 acres of summer grass and all cows and bulls are PI tested.
Darrell Busby, manager of the Tri-County Steer Carcass Futurity in Iowa, collects ear notches for samples. He said his associates found three positives from three different animals and all three calves died. Busby said they have had only one positive animal they know of that made it to 1,000 pounds.
The key to controlling BVD is to prevent the creation of PI calves, according to Bob Larson, chair of Food Animal Production Medicine at K-State’s College of Veterinary Medicine. This means improving head immunity, improving immunity of dams and keeping pregnant cows away from at risk cattle. As little as one hour with a PI animal will transmit the virus to susceptible cattle.
Doug Rich can be reached at 785-749-5304 or firstname.lastname@example.org.
The Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) offers a variety of tests to assist practitioners diagnosing Bovine Viral Diarrhea (BVD). For persistently infected (PI) calves or cows, TVMDL recommends the following tests:
In addition, TVMDL offers a Bovine Viral Diarrhea Test Selection Guide. Please view it HERE.
For more information on TVMDL’s test services, visit tvmdl.tamu.edu/tests/.