Prevalence of Bovine Leukemia Virus Antibodies in US Dairy Cattle

Abstract

Objective To estimate current US herd-level and animal-level prevalence of bovine leukemia virus (BLV) in dairy cows and characterize epidemiologic features. Design Cross-sectional observational study design and survey. Animals 4120 dairy cows from 103 commercial dairy herds in 11 states across the US. Procedures Milk samples were collected from dairy cows through routine commercial sampling and tested for anti-BLV antibodies by antibody capture ELISA. Based on the ELISA results of a sample of an average of 40 cows per herd, within-herd apparent prevalence (AP) was estimated by a directly standardized method and by a lactation-weighted method for each herd. Within-herd AP estimates were summarized to give estimates of US herd-level and animal-level AP. Differences in AP by lactation, region, state, breed, and herd size were examined to characterize basic epidemiologic features of BLV infection. Results 94.2% of herds had at least one BLV antibody positive cow detected. The average within-herd standardized AP was 46.5%. Lactation-specific AP increased with increasing lactation number, from 29.7% in first lactation cows to 58.9% in 4th and greater lactation cows. Significant differences were not observed based on region, state, breed, or herd size. Conclusions and Clinical Relevance These results are consistent with a historical trend of increasing prevalence of BLV among US dairy cattle. Given the findings of other studies on the negative impacts of BLV infection on milk production and cow longevity, these findings are clinically relevant for veterinarians counseling dairy clients on the risks of BLV to their herds.

Risk of Transmission of Bovine Leukosis Virus (BLV) Using Semen from Seropositive Bulls in In Vitro Produced Embryos

“…Recently, a study looked at the infection rate and found 38% of beef herds, 84% of all dairy herds, and 100% of large-scale dairy herds are infected with the virus [7]. In the USA, incidence of BLV infection has been estimated as high as 94.2% of dairy herds [7,8]. The high prevalence of BLV infection "suggests that the cost of testing and culling of seropositive animals may not be a cost effective method to control the disease" [7.].…”

“…Symptoms include swollen lymph nodes, weight loss, decreased milk production, anorexia, and limb paralysis. Roughly 29% of infected cattle [8,12]. Diagnosing BLV infected cattle can be done by simply testing serum for virus-specific antibodies [13].…”

Infrared milk pasterizer as a component of success in the Animal leukemia control

“…During pathological processes in the body of a lactating animal, a number of pathogenic microorganisms are released with milk, that can cause serious harm to the consumer (Chaffer et al, 1999). It should also be noted that these microorganisms often have high antibiotic resistance (Hadzevych et al, 2019).…”

“…One of the most common and dangerous diseases of oncogenic origin among cattle is leukemia (Frie et al, 2017;LaDronka et al, 2018). Bovine leukemia virus is leukemogenic in at least two mammalian species, it is widespread in commercial dairy herds, and can infect a wide range of in vivo hosts and cells, including human cells, in vitro (Ferrer, Kenyon and Gupta, 1981).…”

“…An effective technological stage in the control of animal leukemia and prevention the possibility of its further spread, is milk pasteurization (Baumgartener, Olson and Onuma, 1976). This method is widely used not only in veterinary medicine, but also in humane medicine (Gayà and Calvo, 2018), in the processing industry (Stabel, 2003).…”