Genetic and phenotypic trends for economic traits in large white yorkshire pigs
2000
Singh, G. | Khanna, A.S.(Chaudhary Charan Singh Haryan Agricultural University, Hisar (India)).
Study was undertaken to estimate genetic and pheotypic trends for economic traits in Large White Yorkshire pigs. Data on 10 580 piglets in 1 331 litters from 53 sires and 195 dams at the Government Pig farms, Hisar and Ambala, over the period 1982-96, were utilized. The phenotypic trend in Hisar herd were in favourable direction for all the traits except litter size at birth, while those from Ambala were in contrary direction. Genetic trends at Hisar farm were favourable for age at first farrowing and inter-farrowing interval, while unfavourable for other traits. Genetic and environment trends were in opposite direction for all the traits except inter-farrowing interval. The estimates of genetic trends at Ambala farm were favourable but associated with environmental trends in opposite direction for age at first farrowing and sex-ratio. While, for other traits these trends were reversed. The adjustments for biases due to non-random allotment of dams with respect to age and merit and for environmental fluctuations were useful for increasing the precision of the estimates. Second method of Powell and Freeman was most reliable for estimation of genetic trends.
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