Genetic Parameters of Growth Traits in Crossbred Sheep

Abstract

Data spread over 11 years (1986Data spread over 11 years ( -1996 pertaining to a synthetic population developed by inter se mating of half-breds of Corriedale and Russian Merino with Nali maintained at CCS Haryana Agricultural University, Hisar were utilized for the estimation of genetic parameters for growth traits. The means for birth weight (BWT), weaning weight (WWT), six month body weight (SWT), yearling weight (YWT), preweaning daily gain (PRW) and post weaning daily gain (POW) were 3.35 kg, 10.79 kg, 13.28 kg, 18.96 kg, 82.6 gm and 27.6 gm, respectively. The effects of year and season of birth and sex of lamb were significant for all the traits under study except the effect of season of birth for WWT, SWT and PRW. No definite trend was observed over the years for the averages of body weight and gain. Lambs born during the spring season performed better for BWT, WWT and PRW while the performance of lambs born during autumn was better for the other traits included in the study. The male lambs were heavier than the females for body weight at all stages and gain in weight. The heritability estimates for WWT and PRW were low; for BWT and SWT were moderate and for YWT and POW were high. Birth weight had high heritability and high genetic correlations with subsequent body weights and gains but due to the presence of a maternal effect on BWT and WWT, a sequential selection procedure is recommended for the improvement of growth rate in sheep.

Growth and carcass trait association with variation in the somatostatin receptor 1 (SSTR1) gene in New Zealand Romney sheep

“…The phenotypic correlations observed between the various growth and carcass traits are similar to those observed in other studies (Singh et al 2006;Brito et al 2015), but with some exceptions. The correlations between loin, shoulder, leg and total yield were moderate or strong and positive in this study, but were negligible in the study of Shrestha et al (1986).…”

“…The correlations between loin, shoulder, leg and total yield were moderate or strong and positive in this study, but were negligible in the study of Shrestha et al (1986). The correlation between birth weight and pre-weaning growth rate was 0.562, but Singh et al (2006) reported a value of 0.18. The correlation between V-GR, and loin yield and shoulder yield were −0.159 and 0.07, respectively, but Einarsson et al (2015) reported the correlation between GR, and loin and shoulder yields were 0.37 and −0.43, respectively.…”

Genetic analysis of growth traits in Harnali sheep

“…This is in close agreement with earlier findings in the same breed [ 13 ]. The averages were, however, higher than those reported as 1.82±0.03 kg in Garole × Malpura crossbred [ 14 ], 3.25±0.17 kg in synthetic sheep [ 15 ] for BW; in Nali crosses for WW, SMW and YBW [ 3 , 13 , 15 ]. Higher WW in lamb reflects better mothering ability of the dam's as compared to other breeds.…”

“…The growth rate is an economic trait of interest in domestic animals as growth of the lambs is a reflection of the adaptability and economic viability of the animal and hence may be used as criteria for the selection among breeds and the individual within breeds [ 3 ]. Fast growth rate ultimately determines their meat producing capability up to marketing age.…”

“…At present about 300 animals of Harnali sheep are maintained at university farm besides several animals have been disseminated to farmers around Hisar. The literature is dotted with conflicting and sporadic reports regarding genetic parameters of growth traits in sheep [ 3 - 6 ].…”