Bovine leukosis virus, bovine viral diarrhea, and bovine neosporosis seroprevalence in specialized dairy herds in Antioquia-Colombia

Abstract

Enzootic bovine leukosis (EBL) is a chronic infectious disease caused by the bovine leukosis virus (BLV), a Deltaretrovirus. Bovine viral diarrhea (BVD) is an infectious disease caused by a pestivirus. Bovine neosporosis is caused by the obligate intracellular parasite Neospora caninum (Nc). These pathogens can have horizontal (postnatal) or vertical (transplacental) transmissions and affect the productive and reproductive performance of infected bovines. This work aimed to detect BLV, BVD, and Nc seroprevalence in specialized dairy cattle from the north, east, and Aburrá Valley regions of the Department of Antioquia, the highest in milk production regions in Antioquia. A total of 599 blood samples, obtained from 53 specialized dairy cattle herds, were evaluated by the ELISA test. The results revealed a seroprevalence of 41.13% for BLV (242/599), 28.48% (163/599) for Nc, and 22.7% (132/599) for BVD. Regarding the regional seroprevalence evaluation, BLV was found in 47.02% of the samples from the east, 36.87% from the north, and 46.02% from the Aburrá Valley. Nc was found in 31.03% of the samples from the east, 24.26% from the north, and 36.63% from Aburrá Valley. BVD was found in 21.62% of the samples from the east, 25.03% from the north region, and 10.39% of the samples from the Aburrá Valley. It is highlighted by these results that the north region, with the highest milk production in Antioquia, had the lowest BLV and Nc seroprevalences but the highest seroprevalence of BVD. BLV has increased in Antioquia in recent years, and as an immunosuppressive infection, opportunities for other pathogens are created by it. A significant statistical difference was found in the average prevalence of the pathogens according to the municipality, cattle breed, and region of origin of the sample. The seroprevalence of these pathogens in specialized dairy herds in Antioquia can be classified as medium-low. However, it is recommended that biosecurity practices should be maximized to avoid the spread of these pathogens due to the variability detected in the region, municipality, breed group, and herd age. The rapid and efficient diagnosis of these three pathogens through reliable methodologies will allow for the control of dissemination in dairy herds.

Keywords: Antibodies; Dairy herds; ELISA; Epidemiology; Milk-producing municipalities; Variability.

Image 1

Geographical location of the study regions in the department of Antioquia

Fig. 1

Seroprevalence of BLV, BVD, and Nc in the main breeds used in specialized dairy production in Antioquia (Colombia). Different letters depict statistical differences (p < 0.05). JER Jersey, HO Holstein, SR Swedish Red, JH Jersey × Holstein, AYR Ayrshire, SRHO Swedish Red × Holstein, AYRHO Ayrshire × Holstein, SB Swedish Brown, SBHO Swedish Brown × Holstein, NN unidentified breed, Other Other breeds, Nc Neospora caninum, BVD bovine viral diarrhea, BLV bovine leukosis virus

Fig. 2

Seroprevalence of BLV, BVD, and Nc according to age (months) and parturition number (1–3, 4–6, and more than six births) in specialized dairy cows from the Department of Antioquia (Colombia). Different letters depict statistical differences (p < 0.05)