Materials and methods Experimental animals and DNA isolationDeoni cattle are medium-sized dual-purpose Bos indicus cattle found in parts of the Maharashtra, Karnataka, and

The hypothalamic gonadotropin-releasing hormone receptor (GnRHR) plays an essential physiological role in reproductive function. In this investigation, we studied genetic variation in the entire coding region of GnRHR gene using PCR-SSCP technique in 250 Bos taurus (Holstein Friesian, Jersey) and Bos indicus (Malnad Gidda, Deoni) bulls. The genetic variants in GnRHR gene were determined by PCR-SSCP technique by using 5 sets of primers. SSCP analysis of fragment 1, comprising exon 1, and fragment 3, comprising exon 2, revealed 2 SSCP patterns in all breeds under study, while fragment 2 of exon 1 and fragment 4, comprising exon 3, revealed 3 patterns in Malnad Gidda; Holstein Friesian and Deoni breeds showed 2 SSCP patterns. In Jersey bulls, fragment 4 showed 3 patterns. The fragment 5 comprising exon 3 was monomorphic in all 4 breeds under study. SNPs were confirmed by direct sequencing.

A study was undertaken to analyze associations between HSP70 genetic variants of promoter region with heat tolerance and performance in Deoni (Bos indicus) cattle using PCR-SSCP technique. The analysis revealed three SSCP patterns, viz. AA, AB and BB with frequencies of 0.712, 0.254 and 0.034, respectively. Sequence analysis of representative samples of each pattern showed 7 SNPs, which included four transitions (A859G, A1046G, C1257T and G1294A) and 3 transversions (A897C, A1127C and G1166T). Cows with different SSCP patterns showed similar production and reproduction performances. The studies on physiological parameters and calculation of Heat tolerance coefficient (HTC) of individual cows indicated that Deoni cows maintained at Bengaluru were not under heat stress even after 6 h of exposure to sun during summer (March to May).