Aim:Out of various members of heat shock protein (HSP) superfamily which act a molecular chaperon by binding to the denaturing protein thus stabilizing them and preserving their activity, HSP70 are of major importance in thermotolerance development. Thus, present investigation aimed at a screening of HSP70 gene for polymorphisms and possible differences in thermotolerance in Tharparkar breed of cattle.Materials and Methods:A 295 bp fragment of HSP70 gene was subjected to polymerase chain reaction-single-strand conformation polymorphism (SSCP) followed by sequencing of different SSCP patterns in 64 Tharparkar cattle. A comparative thermotolerance of identified genotypes was analyzed using heat tolerance coefficients (HTCs) of animals for different seasons.Results:Three SSCP patterns and consequently two alleles namely A and B were documented in one fragment of HSP70 gene. On sequencing, one single-nucleotide polymorphism with G > T substitution was found at a position that led to a change of amino acid aspartate to tyrosine in allele A. It was found that in maintaining near normal average rectal temperature, genotype AA was superior (p≤0.01). Genotype AA, thus, was found to be most thermotolerant genotype with the highest HTC (p≤0.01).Conclusion:The polymorphism at HSP70 is expected to be a potent determinant for heat tolerance in cattle, which may aid in selection for thermotolerance in cattle.

HighlightsThe estimates of heritability for body weight from birth to 12 months age ranged from 0.10 to 0.43.The estimates of heritability for average daily gain (ADG) during various growth phase varied from 0.04 to 0.41.The heritability estimates of survival potential for post-weaning period to 12 months of age varied from 0.18 to 0.39.The genetic trend of body growth traits at 9 months of age and 12 months of age was positive.

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Birth weights and subsequent body weights of individual kits of New Zealand White rabbits were analysed to estimate the impact of direct additive genetic, maternal additive genetic and permanent environmental litter effect on growth traits i.e. birth weight (BW), 15th day body weight (15dW), 30th day body weight (30dW), 90th day body weight (90dW) and 180th day body weight (180dW). The variance components and genetic parameters were estimated using Sire Model and two different animal models. Effect of litter size was significant on all the growth traits except 90dW. Kits born in winter season had significantly higher BW, 30dW and 90dW than the kits born in summer season. The heritability estimate for BW ranged from 0.266 (Sire Model) to 0.540 (Animal Model 2). The permanent effect of litter (c 2 ) was highest (0.288Á0.310) just before weaning at 30dW and decreased after weaning. The effect of indirectly inherited maternal genetic effect (m 2 ) was present at early juvenile stage of growth (15dW, 30dW and 90dW) and was nil for 180dW. Selection for better growth would be more reliable at 180dW because at this age both c 2 and m 2 became lower than in previous stages of growth. Using Animal Model 1, repeatabilities of doe effects on BW, 15dW, 30dW, 90dW and 180dW were 0.35, 0.44, 0.40, 0.35 and 0.01, respectively. Animal Model 1 was better than Animal Model 2 in partitioning of variances when the maternal genetic variance (s 2 m ) was very low or zero.

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