Management Practices

Practices to Reduce Transmission

Lymphocytes may be found in almost all body fluids, including blood, colostrum and saliva. Any contact with these bodily fluids from an infected animal could transfer the disease, but only if the infected lymphocytes can get through the skin or mucus membrane barriers and enter into the new host’s blood stream. The following are simple ways to help reduce transmission of BLV in your herd.

Sleeve Changes: 

Failure to change bloodied examination sleeves between cows following artificial insemination or reproductive examination is an identified risk factor for the hematogenous transmission of BLV. Results of a Michigan management study indicated that the number of reproductive examinations per cow was positively associated (P= 0.03) with BLV prevalence (15).

Single-Use Needles:

Re-using hypodermic needles for cattle is a documented method of transmitting bovine leukemia virus (BLV) and other diseases such as anaplasmosis. Using single-use needles for all injections is an important part of any BLV control program.

Calf Management:

BLV can also be transmitted vertically across the placenta from a BLV-positive cow to her calf (4 – 18% of cases).  Infection can also occur by blood exchange during birthing and by ingestion of contaminated colostrum or milk. Management practices also associated with an increase in the risk of BLV transmission include gouge-type dehorning and not disinfecting tattoo pliers between cattle (17,20-26).