This BLV Herd Profile shows low prevalence in first lactation, with an increase in later lactations. From this you can surmise the majority of ongoing transmission is happening in the milking herd.
With USDA estimating 94% of all dairy herds in the United States are infected with Bovine Leukemia Virus (BLV); chances are you have it! While it’s true that BLV is incurable, it is not unmanageable.
The easiest and most cost-effective step to start managing BLV is to estimate an overall herd prevalence with a BLV Herd Profile. A BLV Herd Profile is established by testing milk samples (DHI or hand-stripped) of the 10-most-recently-fresh cows in the first, second, third and fourth and greater lactation groups. With individual-animal results, a lactation-specific prevalence is calculated showing the percentage of cows in each lactation group that tested positive.
The BLV Herd Profile is useful for understanding herd risk, determining where to implement management changes and in monitoring the infection rate of the herd. If the herd has low prevalence and does not detect any positive cows, consider conducting a whole-herd BLV test and segregate or cull positive cows to eliminate the disease from the herd. With higher prevalence, or if culling/segregating positive animals is not practical, implement management changes known to reduce prevalence. The BLV Herd Profile helps identify where in the production cycle cows are becoming infected, enabling you to target management changes.
To ensure progress, ongoing testing and management strategies should be developed. In low-prevalence herds, follow up could be as simple as completing a BLV Herd Profile, annually, with routine ELISA screenings on incoming fresh cows to keep prevalence low. When herd prevalence is higher, follow up may include an annual BLV Herd Profile, testing all incoming fresh cows to find new infections; and follow-up testing of all positive cows which identifies the most contagious (super-shedders) animals so action can be taken to slow/eliminate the spread.
The BLV Herd Profile does not require whole herd testing and samples can be submitted through routine DHI, making it the most cost effective and easiest first step to managing BLV. As easy as this first step is, you don’t have to go it alone; the CentralStar team provides follow-up consultation to answer questions and discuss next-step management strategies.
Learn more by watching this on-demand webinar with Dr. Don Niles and leading Michigan State University researcher, Dr. Tasia Kendrick.