Genetic evaluation of growth performance of kashmir merino sheep

Abstract

A study was conducted to evaluate the growth performance of Kashmir Merino sheep at two Government Sheep Breeding Farms (Kralapathri and Goabal) in Kashmir using 6299 birth records spread over 21 years (1997 to 2017). Mixed linear model with sire as a random effect and year, sex, birth type, parity and farm as fixed effects were used for analysis. The overall least squares means for birth weight (BW), six months body weight (W6), average daily gain from birth to six months (ADG1), metabolic weight at six months (W6 0.75), Kleiber ratio from birth to six months (KR1), yearling bodyweight (W12), metabolic weight at yearling age (W12 0.75), average daily gain from six month toyearling age (ADG2) and Kleiber ratio from six months to yearling age (KR2) were 3.26±0.06 kg, 18.74±0.47 kg, 84.60±2.63 g, 8.96±0.17kg, 9.27±0.12, 21.75±0.66 kg, 10.03±0.23kg, 22.21±3.01 g and 2.11±0.25, respectively. The effects of year and sex of animal were significant (P<0.01) whereas, effect of birth type (except BW) and farm was non-significant for all the traits. The effect of parity was significant on the BW, W6, W6 0.75, KR1 and W12. The estimates of heritability for BW, W6, ADG1, W60.75, KR1, W12, W120.75, ADG2 and KR2 were 0.64±0.07, 0.54±0.07, 0.54±0.06, 0.55±0.06, 0.54±0.07, 0.60±0.09, 0.69±0.09, 0.50±0.08 and 0.59±0.08, respectively. The genetic, phenotypic and environmental correlations ranged from low to high. The high heritability estimates of traits under study indicated existence of genetic variance which can be utilised to improve growth performance and feed efficiency conversion of Kashmir Merino sheep. To reduce the generation interval, 6 month body weight (high heritability and high genetic correlations with other traits including 12 month weight) canbechosenas aselection criterion.