Influence of pathogens specific subclinical mastitis on oxidative status and mineral metabolism of yak

Yaks are the lifeline of the tribal nomadic herdsmen/ highlanders. The present investigation was carried out to study the alteration of milk and serum micro-minerals with antioxidant status in sub-clinically affected yak. A total 420 mammary quarters from 120 yaks were screened for intramammary infection (IMI). Out of 420 mammary quarters of yaks, 62 were found positive for subclinical mastitis. Out of 62 quarters, 19, 16 and 15 quarters were found to be positive for Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Streptococcus agalactiae (S. agalactiae) respectively. A total 48 quarters were selected for this study. 12 clinically healthy quarters and 12 each quarter from S. aureus, E. coli and S. agalactiae infected mammary quarters were selected and formed Group I, II, III and IV respectively. Oxidative stress was measured on the basis of estimation of malondialdehyde (MDA), ceruloplasmin and nitric oxide (NO) in serum. Serum copper, cobalt, zinc and iron were also estimated. The serum malondialdehyde (MDA) and ceruloplasmin level was significantly (p < 0.05) higher in infected groups as compared to healthy quarters. Maximum nitric oxide (NO) activity was exhibited in S. aureus group followed by E. coli group and S. agalactiae group infected quarters. Among the infected quarters, lowest and highest concentrations of minerals were found in S. aureus infected quarters and E. coli infected quarters respectively. Alterations of milk mineral profiles were more significant in S. aureus group as compared to other groups whereas serum mineral profiles were having significant alteration in between all the groups.