Study on Genetic Variation of Microsatellite and Their Association with Mastitis Occurrence in Crossbred Cattle

In present study, the polymorphism at five microsatellite loci BM302, BM4505, BMS2684, CYP21 and DIK20 were investigated for finding their association with the somatic cell counts (SCC) in crossbred cattle. Total 130 animals were tested using california mastitis test (CMT) and somatic cell count (SCC) to screen animals for mastitis. Total 83 alleles were found in all five microsatellites where 23 alleles (9 in BM302, 3 in BM4505, 2 in BMS2684, 8 in CYP21 and 1 in DIK20) were differing significantly in case-control animals. Total number of genotypes for BM302, BM4505, BMS2684, CYP21 and DIK20 were 148, out of which 11 were differing significantly in case-control animals. The allele size ranges for BM302, BM4505, BMS2684, CYP21 and DIK20 were 146 bp to 166 bp, 212 bp to 252 bp, 82 bp to 108 bp, 180 bp to 228 bp and 164 bp to 196 bp, respectively. The polymorphism information content/heterozygosity/allelic diversity for BM302, BM4505, BMS2684, CYP21 and DIK20 were 0.88/0.92/0.89, 0.91/0.53/0.91, 0.81/0.56/0.82, 0.91/0.65/0.92 and 0.82/0.60/0.84. The genotypes ‘146/158’, ‘148/156’, ‘148/158’, ‘150/164’, ‘152/164’, and ‘152/166’ at BM302, ‘238/238’ at BM4505, ‘186/186’ and ‘196/196’ at CYP21 and ‘174/186’ and ‘180/192’ were differing significantly in case-control animals. It revealed that the information observed in the present study was valuable and it may be helpful for improving mastitis resistance in crossbred cattle.