Demonstration of a new method to eliminate bovine leukemia virus from your dairy herd by targeting culling of the most infectious cattle

Project Overview

Project Type: Research and Education
Funds awarded in 2023: $249,999.00
Projected End Date: 10/31/2026
Grant Recipient: Michigan State University
Region: North Central
State: Michigan
Project Coordinator:
Dr. Tasia Kendrick
Michigan State University


No commodities identified


No practices identified

Proposal abstract:

The sustainability of the U.S. dairy industry is threatened by an increasing prevalence of bovine leukemia virus (BLV), now infecting almost all U.S. herds and almost half of U.S. dairy cows. BLV acts by interfering with the cow’s immune system, leaving animals with increased vulnerability to common cattle diseases and conditions. In addition to causing lymphoma, this retroviral cousin of HIV/AIDS has recently been recognized as reducing milk production, decreasing cow lifespan, decreasing vaccine efficiency, exacerbating heat stress, and increasing rates of mastitis and lameness. This epidemiologic puzzle has only been revealed in the last 15 years. Additionally, animal suffering and BLV-associated human mammary cancer are recent concerns shaking consumer confidence in dairy products.

Over 20 countries have eradicated BLV by simultaneously culling all infected cattle. This approach is economically impossible for the U.S. where almost half of the cows are infected. The recent development of a BLV qPCR assay determines the concentration of BLV provirus (PVL) in a blood sample. Animals with higher PVL can be thousands of times more infectious than herd mates with a lower PVL. We have recently shown on four pilot U.S. herds that BLV prevalence was dramatically decreased by removing only those cattle with the highest PVL (Figure 1 and 2).

The proposed project, “Demonstration of a new method to eliminate BLV from your dairy herd by targeting culling of the most infectious cattle” will recruit Organic Valley Cooperative membership farms to determine the ease and return on investment for our control method. We will enroll farms of different size, management style, and geographic location. Annually, all milking cows will be ELISA tested and positive animals will be assayed for PVL. Using PVL, the most infectious cows will be targeted for culling. Annual reports will monitor each herd’s new infection rate and average PVL.

Dissemination of project outcomes to producers, veterinarians, industry representatives, extension experts, and researchers will be a major component of project outcomes. We will encourage participating producers to share their experiences, outcomes, and successes in BLV control. The results of the project will be used for our many educational materials and programs.

The project will demonstrate to both organic and conventional dairy producers that BLV can now be effectively controlled without an economically catastrophic immediate culling of all infected animals. With their value-added products, Organic Valley Cooperative is well positioned to implement and advocate a new standard of BLV-free milk production.

Project objectives from proposal:

We aim to inform the U.S. dairy industry about BLV’s economic impact and demonstrate a comparatively low-cost control program. Study outcomes include: (1) producers learning BLV control by targeted culling in their own herd with the potential for complete eradication; (2) participants gaining increased knowledge, awareness, and skills to control BLV; (3) creation and dissemination of educational materials and programs for expert and novice audiences; and (4) constructing a community with shared goals during the project and beyond. Production of BLV-free milk will decrease dairy production losses, improve animal welfare, remove human health concerns, and better compete with milk alternatives.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.