Diagnostic Laboratory Rounds


ises, it is not a good idea to allow the animal out of the carrier. I was on a flight that was delayed for over 3 hours because a cat had been released from his carrier and be- came lost in the mechanical spaces of the airplane. A most uncomfortable situation all the way around for pet, owner and passengers. Owners believe their animals are always under their con- trol. We’ve all seen the reality. Remind clients that for the safety of their animals, pets should remain in their carrier. Food scraps and trash are readily available, there are many infections to which a pet can easily be exposed. Tere are many travelers who do not like pets or have severe allergies to dogs or cats. While we all love our pets, be cognizant of other travelers and their comfort as well as the rules of the airlines.


The following article is being reprinted to correct an inadvertent omission.


BVD: To Test of Not to Test Jami Carroll Breathitt Veterinary Center


Bovine viral diarrhea (BVD) is a common viral disease that causes respiratory and reproductive problems in cat- tle and other ruminants. It can be transmitted in many ways including a congenital infection (in utero) or after birth. Congenital infections may cause resorption, abor- tion, stillbirth, or live birth of calves that may be per- sistently infected (PI). A PI animal may or may not show symptoms but can continue to shed virus throughout its life, which may become a source of infection for others in the herd.


Symptoms of BVD include respiratory and intestinal is- sues, birth defects, and low reproductive success. Animals exhibiting any or all of these symptoms should certainly be tested, but exhibition of symptoms is not the only rea- son to test. Herds that have contact with outside animals, either domestic or wild, should also be tested regularly. Failure to vaccinate should also lead you to test your herd. It is recommended that all new animals be tested before being introduced into a herd to prevent introducing a PI animal.


Tere are several assays available for testing for BVD. Vi- rus neutralization (VN) tests are used to detect antibod- ies in serum. VN can be performed on any age animal and will detect an antibody titer resulting from natural infection, exposure or vaccination. If the animal has an antibody titer, testing a convalescent sample a few weeks later can be done to determine whether the titer is due


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to past exposure/vaccination or if the animal has an active infection. Even though VN testing may take a week or sometimes more to perform, it is a very sensitive test for measuring antibody levels. VN is not a good option when looking for a PI animal though, since PI animals do not produce antibodies to BVD.


ELISA-based antigen testing is a very cost-effective meth- od of identifying a BVD PI animal. At typically less than $5 per sample, it is a good option for whole-herd testing. Tis two-hour test can be used to detect viral antigens in both serum and/or ear notches. Due to possible inter- ference of maternal antibodies, only serum from pre-co- lostral newborn calves or animals over the age of three months is suitable for use in this test. Ear notches can typically be collected by the farmer and can be used to test animals of any age. It is important for farmers who will be collecting ear notches to be well trained in the process. Ear notches should either be greater than 1 cm on one side or greater than 1 mm and less than 1 cm on at least one dimension for accurate results.


PCR assays are also available for BVD testing. Tough often costly, this is the most sensitive test for detection of virus. PCR assays can be used as confirmatory tests for samples deemed positive or suspect by other assays.


Testing an animal pre-sale is beneficial to insure the best pricing for the animal. Land and Livestock Post reported recently that animals from BVD negative herds have sold for premiums in some markets. While it may sound cost- ly, whole-herd testing for BVD can be quite beneficial. In the state of Kentucky, BVD is considered a reportable disease, meaning you cannot sell, give away or transport the animal without approval from the state veterinarian. Te positive animal must be quarantined until slaughter, at which time it is possible to obtain a permit for trans- port to slaughter. It’s possible for a test costing less than $5 to make the difference in getting top price for an an- imal and losing a calf crop due to a single PI animal. We recommend you test early, and test often. 


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