BVD Colorado’s Voluntary BVD Control Program

Bovine Viral Diarrhea (BVD) review BVD may infect cattle of any age. BVD is a disease that diminishes production and in the individual impacts multiple body systems including the reproductive, respiratory, digestive and immune systems. Clinical signs can vary from pneumonia, abortions, stunted calves, stillbirths, PI calves, weak calves, unthriftiness, increase disease susceptibility and full blown disease characterized by a watery diarrhea that frequently leads to death.

BVD types The virus presents in different forms, cytopathic, noncytopathic, type 1, type 2, type 1a, 1b,…………… 2a, 2b……………..etc., etc., etc. All of this makes for confusion when selecting vaccines and testing for the disease. The virus may exist in multiple species and transmission from one to the other may occur

Transmission and Sources of BVD Transmitted by, ingestion, inhalation, insects, carried on boots and vehicles Sources transient infected animals including wildlife Persistently infected animals are the main source of infection. PI’s shed viruses in high numbers and infect others, even if they are vaccinated. PI calves result from the dam being exposed during the first third of pregnancy

BVD INFECTION DURING GESTATION persistent infection abortion, stillbirth infertility congenital defects repeat breeding immune response d 0d 283d 125d 150d 58d 90

Keys to controlling BVD Understand “persistently infected” (PI) animals as they relate to BVD. Not be willing to live with one or more PI calves in a herd. Not be willing to keep a PI calf as a replacement heifer or breeding bull. (don’t sell them either) Commit to finding BVD PI cattle in the herd

Can you pick out the PI calf?

BVD Review BVD can cause a variety of clinical and subclinical reproductive, enteric, and respiratory syndromes and immune suppression. BVD is unique in that a fetus that is infected from its transiently or persistently viremic dam prior to formation of a competent immune system can become persistently infected (PI) with the virus. PI animals will shed BVD from body secretions throughout their life. PI animals are considered the primary reservoir for BVD in both cow herd and feedlot situations.

BVD Review (continued) A current estimate is that about 10% of beef cow herds have at least 1 PI animal, and about 0.25 to 1% of calves born are PI. Veterinarians/Producers should have a surveillance strategy to determine level of herd risk for the presence of PI animals (High vs. Low Risk). Herds that are considered high risk for containing PI animals should utilize laboratory tests to do whole-herd screening to find all PI animals and then remove them.

Financial impact of BVD $10.00 to $24.00 per breeding animal (conservative estimate based on value of the cow and the lowered calf crop) a 200 head cow herd would lose $2000 to $4800 per year. In the feedlot economic impact can be tremendous.$21,000 to $100,000 have been lost in a few weeks by local feedlots.

Colorado’s BVD Program Colorado’s BVD program is strictly voluntary What will the program do: Improve reproductive performance Improve calf performance Lower treatment costs Lower death loss Provide a more marketable commodity

BVD PI Myth 1 PI calves will be killed by MLV vaccination Fact – Controlled experiments have not been able to induce morbidity or mortality in PI calves following MLV vaccination. However, case reports indicate that MLV vaccination can cause a PI animal to become moribund or to die - though far less than 100% are negatively affected..

BVD PI Myth 2 PI calves will be thin, have a rough haircoat, and be a poor-doer Fact – While many PI animals are unthrifty, reports have indicated up to 50% will appear normal and may enter the breeding herd or feedlot pen in excellent condition. PI calves cannot be identified visually.

BVD PI Myth 3 Calves are PI because their dam is PI Fact – Recent research has shown that 7% of PI calves’ dams were PI, the other 93% of calves have dams with a normal immune response to BVDv and are not persistently infected.

BVD PI Myth 4 The greatest cost associated with a PI calf is the death of that calf Fact – The reproductive loss associated with lower pregnancy proportions, more abortions, and higher calf mortality are the greatest economic costs of exposure to PI animals. In addition, increased morbidity, treatment costs, treatment failure, and reduced gain in feedlot or stocker pen mates greatly exceed the cost of PI death in feeder cattle.

BVD PI Myth 5 BVDv problems will always be obvious Fact – If BVDv was introduced into the herd via a PI animal several years previously, after an initial period of noticeable losses, the herd may currently experience only low reproductive loss and BVDv-associated morbidity. This low loss however, may not be compatible with economic sustainability.

BVD PI Myth 6 BVD won’t affect my herd because I vaccinate Fact – The tremendous amount of virus secreted by a PI calf can overwhelm a level of immunity that is protective under less severe exposure. There are documented cases of herds with vaccination protocols in place for several years that have endemic BVDv because of the presence of PI animals. VACCINATION ALONE WILL NOT SOLVE BVDv PROBLEMS

That’s all I’ve got to say!!!