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Animal Breeding and Genetics
Asian-Australasian Journal of Animal Sciences 2002;15(1): 7-10.
https://doi.org/10.5713/ajas.2002.7    Published online January 1, 2002.
Estimation of Genetic, Phenotypic and Environmental Trends in Hariana Cattle
K. Singh, M. L. Sangwan, D. S. Dalal
The breeding data relating to Hariana herd spread over 18 years (1979-96) were analysed to estimate genetic, phenotypic and environmental changes in characters of economic importance which might have taken place during the several years of selective breeding practiced in the herd. The average genetic changes in a given character were estimated by four methods. The phenotypic trends observed for different economic traits were not significant. On changing the method of estimation, magnitude and direction of genetic trends changed. Comparison of estimates of genetic trends by different methods showed that adjustments for biases due to non-random allotment of dams with respect to their age and merit suggested by Powell and Freeman (1974) were useful for increasing the precision of the estimates. Hence, this method was found to be the best method for estimation of genetic trends. The estimate of genetic trends by this method were 4.03 6.21 days, 3.24 5.33 kg, 0.15 0.43 days, 0.09 0.59 days, 0.01 0.02 kg and 0.01 0.01 kg for age at first calving, first lactation milk yield, first lactation length, first calving interval, first lactation milk yield per day lactation length and first lactation milk yield per day of calving interval, respectively.
Keywords: Genetic Trends; First Lactation Milk Yield; Age at First Calving

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