Volume 75 (2025) Issue: 2025 No#4

Seropositivity of the bovine leukosis virus and its effect on the presence of subclinical mastitis in specialized dairy herds in three high tropical regions of Antioquia

Author(s): Caterine López-Sánchez, Cristian C. Rúa-Giraldo, Juan Pablo Arismendy Morales, Cristina Úsuga-Monroy, Albeiro López-Herrera

Keywords:compositional quality, diagnosis, infection, milk, production, profitability

Bovine leukosis virus (BLV) negatively affects the immune health of cattle, increasing their susceptibility to diseases such as subclinical mastitis, a common condition in dairy cows that generates significant economic losses due to decreased milk production, treatment costs, and culling of animals. The aim of this study is to evaluate the relationship between BLV seropositivity and subclinical mastitis in 200 cows from 20 specialized herds in the Aburrá Valley, north and east of Antioquia, Colombia. Milk and blood analyses were performed using the California mastitis test (CMT), somatic cell count (SCC) by flow cytometry, and BLV detection by ELISA. The results showed a 68% seropositivity to BLV, an average SCC of 168.350/mL, and a CMT index of 0.42. A high positive correlation (90%) was found between SCC and CMT, indicating the effectiveness of CMT as a diagnostic tool to assess mammary health. Furthermore, the negative correlation (-20%) between SCC and milk production evidences the impact of mastitis on productivity. The significant relationship between BLV seropositivity and increased SCC (P=0.00129) confirms the immunosuppressive effect of BLV, which predisposes cows to subclinical mastitis. In conclusion, bovine leukosis increases the susceptibility of cows to develop subclinical mastitis by weakening their immune system, compromising the general health of herds, and generating economic losses, highlighting the importance of the CMT as an efficient, rapid, and economical method for its diagnosis.