Genetic evaluation of performance traits in harnali sheep using different models
Abstract
The 20 years (1997-2016) data of growth, reproduction and wool traits of a synthetic population of Harnali sheep developed by inter-se mating of half-breds of Corriedale and Russian Merino with Nali maintained at Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar were utilized for the present study. The overall least squares mean for birth weight (BW), weaning weight (WW), six month body weight (SMW), one year body weight (YBW), age at first lambing (AFL), weight at lambing (WL), average lambing interval (ALI), grease fleece weight (GFW), staple length (SL), fibre diameter (FD) and medullation percentage (MP) were 3.26 kg, 12.85 kg, 16.96 kg, 24.13 kg, 736.42 days, 29.37 kg, 373.42 days, 1746.89 gm, 5.64 cm, 25.22 μ and 26.68 %, respectively. The effect of period of birth, sex of lamb and dam‟s weight at lambing were significant for all the growth traits under study. The effect of period of birth, dam‟s weight at lambing were significant for all the reproduction and wool traits The heritability estimates for growth traits were moderate to high, low for reproduction traits and moderate to high for wool traits. The average breeding values of Harnali sire using dfferent univariate, bivarate and multivariate animal models (Wombat, 2005) were estimated as 3.28 kg, 12.91 kg, 17.02 kg , 24.14 kg, 736.24 days, 28.43 kg, 1759.81 gm. 5.09 cm, 25.34 μ and 26.67 % for BW, WW, SMW, YBW, AFL, WFL, ALI GFW, SL, FD and MP respectively. Criteria of comparison of different models showed that multivariate model have higher value of coefficient of determination (R2value) and lowest Sum of squares due to error (MSSE), Akaike information criterion (AIC), Bayesian information criterion (BIC) and Log L value which indicated that multivariate animal model is more accurate than other models. Keeping in view the high heritability of SMW and its favourable correlations with body weights at later ages and grease fleece weight, it is concluded that selection on the basis of SMW would be the best approach to improve growth and wool production in Harnali sheep.