Effect of supplementing certain vitamins and chelated trace minerals on reducing incidence of sub-clinical mastitis in crossbred cows

Abstract

Crossbred cows (93) having a history of sub-clinical mastitis (SCM) and clinical mastitis (CM) in previous lactation were selected from 57 farms in Sabarkantha district of Gujarat. Twenty crossbred cows from 12 farms served as control, and the remaining (n=73) were fed daily 10 g supplement per animal containing coated vitamins E and A, chelated copper (Cu), zinc (Zn), chromium (Cr), along with iodine(I), for 4 weeks prior to calving. Milk samples were collected post calving on day 10, 30, 60 and 90 for analysis of somatic cell counts (SCC), sodium (Na), potassium (K), chloride (Cl) content, pH and electrical conductivity (EC). Blood samples were also collected for neutrophil count, measurement of immunoglobulin and ferric reduction anti-oxidant power (FRAP). The milk producers were provided with Mastect strip for weekly checkup of SCM. Out of 73 supplemented cows, only 15 (21%) showed signs of SCM and CM with Mastect strip and California mastitis test, which was confirmed by SCC in milk (average 7.26×105 cells/ml milk). However, 16 animals (80%) out of 20 in control group were affected by SCM as indicated by the SCC (average 10.11×105 cells/ml milk), which was later aggravated to CM. Milk pH, EC, Na and Cl content in milk were higher in animals affected by SCM than the normal animals. In supplemental group, SCC in 58 (79%) animals was within the normal range (1.22–2.36×105 cells/ml milk) and no signs of SCM or CM were observed. Milk lactose, protein, solids-not-fat (SNF) content and FRAP were higher in unaffected as compared to mastitis affected animals. On feeding the supplement, blood neutrophil count decreased, whereas, immunoglobulin and FRAP activity increased significantly (P<0.05). The inference could be drawn that feeding a vitamins and chelated minerals based supplement 4 weeks prior to calving could significantly help in reducing the incidence of SCM in crossbred cows.