Impacts of BLV

BLV is a Silent Threat

Persistent lymphocytosis is associated with immune disruption and inadequate defense against pathogens and opportunistic infections. Animals with persistent lymphocytosis may not show any apparent clinical signs, but it has been shown that these animals have depressed immune systems.

Decreased Milk Production:

As BLV-infected cows age, they exhibits lower milk production than non-infected herd mates. In general, a higher BLV herd prevalence is associated with a lower rolling herd average, and infected cows have a lower predicted 305-day mature equivalent milk yield. Also, genetically superior animals infected with BLV under-perform their estimated genetic potential.

Decreased Cow Longevity:

BLV-infected cows are likely to be removed from the herd earlier than non-infected herd mates (i.e., have a lower herd longevity). As such, BLV-infected cows often have a lower economic return due to a shortened productive life.

Decreased Reproductive Success:

BLV-infected cows need to be bred more times to obtain a pregnancy and have longer calving intervals. In rare cases, BLV-infected cows may develop tumors in the uterus resulting in the inability to become pregnant.

Increased Slaughter Condemnation:

Tumor development may occur in animals with high levels of virus. These tumors are the main reason for carcass condemnation at slaughter by USDA inspectors.

Decreased Animal Welfare:

Consumer perception and animal welfare issues may be raised with knowledge of heightened BLV prevalence on United States dairy farms.

Negative Economic Impact:

It is challenging to estimate the true economic impact of BLV, given the multitude of underlying and confounding factors. In 2017, our team estimated an annual loss of approximately $283 per milking cow, resulting in a $2.7 billion national deficit due to BLV.