Estimates of co(variance) components were obtained for weights at birth, weaning and 6, 9 and 12 months of age in Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Mathura, India, over a period of 28 years (1976 to 2003). Records of 5530 lambs out of 169 rams and 1631 ewes were used for the study. Analyses were carried out by restricted maximum likelihood (REML), fitting six animal models, including various combinations of maternal effects. Heritability estimates for weight at birth, weaning and 6, 9 and 12 months of age were 0·09, 0·21, 0·06, 0·10 and 0·14, respectively. Maternal heritability of body weight declined from 0·07 at birth to 0·02 at weaning. The maternal permanent environmental component contributed 10 to 11% to the total variance for all traits except weight at 12 months. A significant large negative genetic correlation was observed between direct and maternal genetic effects on weaning weight, suggesting the presence of antagonistic environmental, as well as perhaps genetic, effects in daughter and dam. Results suggest that maternal additive effects were only important in early stages of growth, whereas a permanent environmental maternal effect existed at all ages up to 9 months, probably as a carryover effect of maternal influences present at weaning. Modest rates of genetic progress appear possible for all weights, but the presence of an antagonism between direct and maternal effects on weaning weight would complicate attempts to improve both by selection.
Background: The domestic goat is one of the important livestock species of India. In the present study we assess genetic diversity of Indian goats using 17 microsatellite markers. Breeds were sampled from their natural habitat, covering different agroclimatic zones.
Polymorphism in the beta-LG gene in the Indian goat was investigated by the SDS-PAGE and PCR-RFLP method. SDS-PAGE was carried out in 1098 samples belonging to 8 different breeds of Indian goats. The electrophoretic pattern in the beta-LG locus showed the presence of AA and AB genotypes with frequencies of 0.81 and 0.19, 0.89 and 0.11, 0.50 and 0.50, 0.80 and 0.20, 0.84 and 0.16, 1.00 and 0.00, 0.98 and 0.02 and 0.950 and 0.050 in Jamunapari, Barbari, Marwari, Sirohi, Jakhrana, Beetal, Local UP and Local MP goats, respectively. A total of 358 individuals belonging to 13 different genetic groups were analyzed by the PCR-RFLP method. The amplified product was observed as 426 bp and the restriction digestion with SacII revealed three genotypes, namely S1S1, S1S2 and S2S2 at the beta-LG locus. The frequency of the S2S2 genotype ranged from 0.42 to 1.00 in the population. An analysis was carried out in Jamunapari and Barbari goats to observe the effect of the beta-LG genotype on 90-day milk yield. Least squares analysis of data showed that beta-LG AA animals had higher milk yield than the beta-LG AB genotype in both breeds (P < 0.01).
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