Halting BVDV Before it Hampers Your Cattle Production
Is Bovine Viral Diarrhea Virus (BVDV) hampering your operation? BVDV affects cows of all ages and in every herd size by suppressing their immune system and making them more susceptible to respiratory and reproductive diseases. If you’re wondering how you can be getting more out of your herd, BVDV is the place to start. Let’s look into exactly what this disease is, why farmers need to monitor it, and how and when to test for it.
What is Bovine Viral Diarrhea (BVD)?
BVD is a complex viral disease that is caused by the Bovine Viral Diarrhea Virus. It presents as a high-fever illness (105+ degrees) with bloody diarrhea and often leads to pneumonia. Antibiotics are ineffective because of the viral nature of the disease. While some animals are back to themselves in a week or two, BVD leads to abortions and stillborn calves, increased calf morbidity, poor milk production, lower reproductive performance and more.Infected pregnant animals may lose their calf, depending on how far along they are, and open heifers may not be able to conceive. Some pregnant animals who get exposed between 30 and 120 days of pregnancy end up with a persistently infected (PI) calf who carries the virus and sheds BVD for the rest of its life. While these PIs make up only .4% of a herd, they initiate far larger long-term losses.
Dr. Jim Rhoades is a Sr. Professional Services Veterinarian for the Americas with IDEXX Laboratories and explains the invisible danger of PIs: “When cows are exposed in the first trimester, the calf doesn’t recognize the virus as a foreign invader. Their body thinks it’s part of them, so they don’t fight it like human bodies fight a cold or a splinter – they actually protect it. Think of it like a Trojan horse that regenerates inside of itself.”
As a result, PIs look healthy. Their body thinks the virus is normal because of when they developed it in gestation. However, they don’t perform as well in the long run and worse – they spread the virus to other animals 24/7/365.
Ways BVD Infiltrates a Herd
The best way to ensure you aren’t introducing a persistently infected calf into a herd is by testing them at birth. If they test positive for BVDV, it’s best to remove them immediately. But there are a few other ways BVD can make its way into and around the herd:- Lack of vaccination
- Purchasing new animals at auction
- Introducing new animals without isolation
- Not testing new animals (including calves)
Economic Impacts of Undetected BVD
BVD may not appear to be as much of a challenge as other livestock health concerns, especially if you’ve vaccinated your herd, but according to Dr. Rhoades, this is the most costly disease in cattle. “A lot of people don’t pay any attention to it until something dies or gets sick,” says Dr. Rhoades. “The biggest impact of BVD isn’t mortality – it’s performance.”In a starter feedlot study, 21,743 heads found only .4% prevalence of persistently infected animals (just 86). However, that small group of PIs led to loss in the exposed population of $93.52 per head (or $41.84 with outliers removed). It’s because infected animals show reduced potential weight gain, less reproductive efficiency, and a diminished return on feed. A weaning calf might look healthy at 500 lbs but could be 600. The healthier they are, the faster they grow and when cattle sell by the pound, you may not even realize what you’re missing out on until you test.
Another way to think about lost earnings is with missing calves. Dr. Rhoades knows of another farm with 400 cattle who tested and found 18 positive for BVD. They removed the 18 and now test annually, and their production has gone through the roof for pregnant animals. Imagine if they get 80 extra calves a year at $1,400 a piece, they gain $112,000 more that year on the same inputs.
BVD Testing Requirements for Expo Cattle
The most likely way BVD reintroduces itself in a herd is by buying it. That’s why the Ohio Beef Expo introduced a new requirement for all sale, display, and show cattle to have a negative BVD test before they arrive at the show. The Ohio Cattlemen’s Association followed suit with its BEST Show rules.Vaccines can decrease the duration, severity and frequency of a disease, but they can’t block exposure. These Expo requirements, however, can break the transmission cycle and increase biosecurity for all producers if otherwise healthy-looking PIs cannot attend.
BVD Testing Made Easy with IDEXX
For around $6 per test, your operation can break the cycle of BVDV infection. The SNAP BVDV Antigen Test Kit from IDEXX is perfect for on-farm or veterinary clinic use with results in just 20 minutes. This easy-to-use ear notch kit includes 25 test devices, conjugate, tubes and pipettes. The ear notch sampling can be done any time, but it’s smart to do it when you tag the animal. It’s nearly fool-proof with more than 99% accuracy, too.One consistent test user was able to cut antibiotic usage by more than 75%, and their death loss dropped by 81%. They also saw a 40% increase in weight gain. Another study Dr. Rhoades mentioned saw a 20% increase in pregnancy rate after eradicating BVD from the herd. “They didn’t even know their numbers were low, they just thought that was normal because they’ve done what Grandpa always did,” says Rhoades. “Their feed, genetics, and other costs were all the same, but they achieved a lot more out of it after discovering the BVD issue.”
You may not have to test every animal, either. Always start with a calf, and if they’re negative, the dam is automatically negative. Only test the dam if the calf is positive. After that, remember it’s still important to test cows without calves, bulls, and pets to fully identify the disease.
