Effect of supplementation of several coated vitamins and chelated trace minerals on reducing the incidences of subclinical mastitis in crossbred cows

摘要

Two hundred and fifty five crossbred cows were selected, having a history of sub-clinical mastitis (SCM) and clinical mastitis (CM) in previous lactation. Seventy eight crossbred cows were served as control, and the remaining were fed daily 10 g supplement containing chelated Cu, Zn, Cr, vitamins E and A along with iodine for 4 weeks prior to calving. Milk and blood samples were collected for analysis of SCC, Na, K, CI, pH, EC, neutrophil count, FRAP activity etc. Out of 177 experimental cows, only 36 (20%) showed signs of SCM and CM with Mastect strip and CMT which was confirmed by SCC in milk (average 7.26xl05 cells/ml milk). However, 67 animals (86%) out of 78 in control group were affected by SCM as indicated by the higher SCC in milk (average 10. llxlO5 cells/ml milk), which was later aggravated to CM. Milk pH, EC, Na and CI content in milk were higher (PO.05) in animals affected by SCM than the normal animals. In experimental group, of 141 animals SCC was within the normal range (1.22-2.36xl05 cells/ml milk) and no signs of SCM or CM were observed. Milk lactose, protein, SNF and FRAP activity were higher in unaffected as compared to mastitic animals. On supplementation of vitamins and chelated minerals, blood neutrophil count decreased, whereas, immunoglobulin and FRAP activity increased significantly (P<0.05). It was found that feeding vitamins and chelated minerals based supplement during pre-partum period could significantly reduce the incidences of SCM and CM in crossbred cows.