Serological and haemato-biochemical insights into bovine leukosis in dairy cattle in D.I. Khan, Pakistan

Bovine leukosis is an economically important disease of dairy cattle caused by the bovine leukaemia virus (BLV). The study aimed to determine the seroprevalence, haemato-biochemical effects, and risk factors pertinent to the prevalence of bovine leukosis in Holstein–Friesian purebred dairy cattle in the D.I. Khan region of Pakistan. A total of 192 sera were assayed using an enzyme-linked immunosorbent assay. Overall, 31.3% (60/192) cattle were detected as seropositive. There was a marked increase in total leukocyte count (11.29 ± 0.48×103/μl), lymphocytes (5.73 ± 0.42%), monocytes (0.81 ± 0.06%), haemoglobin (11.09 ± 0.46 g/dl), red blood cells (7.23 ± 0.37 ×106/μl), and packed cell volume (31.75 ± 1.48%) in seropositive cattle. Serum biochemical parameters in seropositive cattle showed a marked increase in the liver enzymes, alanine transaminase (24.25 ± 1.03 U/l) and aspartate aminotransferase (49.33 ± 3.31 U/l), with a marked decrease in glutathione peroxidase (1365.63 ± 12.03 (U/l) and superoxide dismutase (2.14 ± 0.13 U/ml) activity. A significant association of age, pregnancy, breeding method, milk yield, and health status of seropositive animals with bovine leukosis was also recorded. The prevalence was higher in animals which were older, pregnant, artificially inseminated, low milk producers, and had a history of ailments. The current study found that bovine leukosis virus could cause changes in internal homeostasis, oxidative stress, and liver dysfunction, all of which should be considered during a control regimen. It was concluded that bovine leukosis was moderately prevalent in the D.I. Khan region in Pakistan.