Genetic trend for growth in a closed indian herd of Landrace x Desi crossbreds

Gaur, G. K.; Ahlawat, S. P. S.; Chhabra, A. K.; Paul, S.

doi:1998.11.4.363

Article

Animal Breeding and Genetics

Asian-Australasian Journal of Animal Sciences 1998;11(4): 363-367.
https://doi.org/10.5713/ajas.1998.363 Published online August 1, 1998.

Genetic trend for growth in a closed indian herd of Landrace x Desi crossbreds

G. K. Gaur, S. P. S. Ahlawat, A. K. Chhabra, S. Paul

Abstract

This study has objectives of to estimate the genetic and phenotypic trend for growth in a closed herd of Landrace 횞 desi crossbreds. The possibility of early selection of boars was also investigated in order to reduce generation interval and thus, to enhance response per year in selection programmes. The data originated from Livestock Production Research (Pigs), Indian Veterinary Research Institute (IVRI), Izatnagar (UP), India-a unit of All India Coordinated research Project on Pigs (AICRP on Pigs). Data consisted of 891 crossbred piglets, progeny of 29 boars. The piglets were born in 132 parities of 72 sows between 8 years from 1987 to 1994. Records on weight at birth, at 2 weeks interval upto 8 weeks of age (W1, W2, ~ W8) and at 16th week (W16) were used in this investigation. BLUP estimates of the sires were computed. Breeding value of each sire was estimated as twice of sire and sire group solutions. Phenotypic trend was estimated as regression of weight performance on year. Genetic trend was computed by estimating regression of breeding value of sires on time. Average body weights ranged from 0.92 kg (W1) to 18.95 kg (W16) and showed a continuous increase over age. Heritabilities of the weight at 4th and 6th week were medium (0.29 and 0.14). Rest of the weights were highly heritable. The product moment and rank, both correlations were high between breeding value for W6 and W16 (0.68 and 0.70). This shows that sire selection for W6 can be successfully implemented in order to achieve sufficient genetic improvement in growth. Phenotypic trend was positive at all ages. The phenotypic regression coefficient raged from 0.02 kg at birth to 0.40 kg at 16 weeks. Genetic trend was also positive. The regression coefficients of average breeding value of sires on time showed a range of 1.471 kg (0.021 to 1.492 kg) for different weights. These coefficients were significant and higher than their corresponding phenotypic regression coefficient.

Keywords: Pigs; Crossbreds; Growth; Genetic Trend