Fighting a Cow Virus Profitably

By Levy Randolph

The little-known bovine leukemia virus (BLV) infects most of America’s dairy herds. In a typical infected herd, over 40% of the cows have BLV.  MSU assistant professors Melissa McKendree (of Agricultural, Food and Resource Economics [AFRE]) and Tasia Taxis Kendrick (of Animal Science) are working to help herd owners manage the disease as profitably as possible.

BLV is a retrovirus that lives in the blood of cows. The blood-borne pathogen can be transferred whenever there is blood-to-blood contact between animals, such as when needles are reused. The disease is related to retroviruses of other mammals, including HIV in humans. BLV can cause enzootic bovine leukosis, which can cause a cancer of the lymphatic tissue.

“BLV lives in the B-Cells in the blood, and it hides,” Kendrick says. “I call it the silent killer because you won’t know the animal has it, but it’s living in the B-Cells that are related to the immune system. Which, in turn, leads to a compromised immune system where farmers are treating other ailments without knowing that BLV is the underlying cause.”

Dairy farmers have asked the research team two questions: Where is the virus coming from, and What is the impact on cost?  Kendrick’s research tackles the first question.  McKendree’s research tackles the second one.

For the past two years, McKendree and her master’s student, Drew Frommelt, have been analyzing farm financial records to understand how BLV infection affects farm milk revenue, drug costs, and the success rate of breeding attempts to determine how BLV affects cow profitability.

“The impact of our research is that we will have an estimate, on a per cow basis, of how a producer’s bottom dollar is impacted by a cow with or without BLV,” McKendree explained. “The outputs from our models will be used to develop a decision tool, which will allow producers to enter their own farm data and see how their farm will be impacted over the course of 10 years.”

“We are aiming to be the first economic BLV study to estimate the effects of BLV on partial profitability,” Frommelt said. “BLV is a very complicated disease, and while there may never be a straightforward answer to the disease, we are hoping this research is a starting point for other research on the economic viability of mitigating the disease.”

The results of this project should provide good news for dairy farmers in the battle against BLV. While it is not quick nor easy to eliminate the disease, it is possible to reduce prevalence and to minimize the impact of the disease.

The research team shares more about BLV and the impact of their research, in this video interview.

Although BLV has neither a cure nor a vaccine, it is a controllable and preventable disease. Michigan State University Extension is committed to continue to research and learn more about BLV so that farmers can apply that knowledge to their herd management. For more information about BLV, visit the MSU Bovine Leukemia Virus website.

The whole-herd scan project is funded by USDA Agricultural and Food Research Initiative competitive Grant no. 2020-67015-21562 from the USDA National Institute of Food and Agriculture. The economics portion of this project is funded by the Michigan Alliance for Animal Agriculture (AA-21-163).