Effects of genetic and environmental factors on productive performances of Hilly Brown Bengal goat at Naikhongchari

Abstract

The present experiment was studied to investigate the effect of genetic and non-genetic factors on productive performances of Hilly Brown Bengal (HBB) goats at the research farm. For this purpose, initially, a total of 69 does of different generations and 20 bucks and finally, a total of 76 does and 09 bucks were used to study productive parameters of HBB goat. The studied Animals were reared in a semi-intensive management system with natural breeding facilities. Goats were allowed to browse for 6-8 hours and mounting in hills with two times concentrates supplementation @ 1% of their body weight. Here three seasons, three generations were considered and parity was counted up to fifth. The data were statistically analyzed by using least-squares analyses of variance of the general linear model (GLM) procedure of the SPSS, 20.00. Sex of kids was significantly (p<0.05) affect the birth weight of kids, where male kids had higher birth weight (1.24 kg) than female kids (1.15 kg). Kids born in summer season had higher birth weight, litter weight, liter size, placental weight, kidding frequency, fortnightly body weight gain up to 6 months, pre and post-weaning gain with reduced mortality rate. Statistically, in summer season, approximately 11.22% and 3.45% heavier kids born, 9-10 g higher daily gain occurs in pre and post-weaning periods and 900-1100 g higher body weight at 3 months of age were found when compared with rainy and winter season respectively, where rainy season had highest body weight at 6 and 9 months of age. Highest percentage of total kidding (41.61%) was also found in summer season with reduced mortality rate (14%), while the highest mortality (64%) occurred in rainy season. Dams parity had significant (p<0.01) impact on production performances and kids mortality rate, where kids litter weight (1.60 to 2.35 kg), litter size (1.38 to 2.08) and placental weight (246.85 to 263.77 g) were increased linearly with the increment of parity up to four, while kids mortality were reduced from 36.57 to 8.44% with the increment of parity up to 5th. Results suggested that the trends of multiple births (twin and triplet) were increased with the advancement of parity, where twin and triplet kid composition increased linearly from 21 to 68% and 0 to 18% among the total kids born, respectively, while single kid percentage reduced from 79 to 14%. Best productive performances of goats were attained in 1st generation with its highest value of kids’ birth weight, weaning weight, litter weight and litter size. There had significant effect (p<0.01) of birth type on kids birth weight, body weight changes and placental weight, where single kid had 30.85% heavier birth weight than the quadruplet with highest placental weight (219.77 to 257.45 g), while highest dams post-partum weight losses (4.8 kg) occurred in triple kidded does. Reduced kid mortality from 36.56 to 1.76% and 51 to 18% can be obtained with the increment of kids’ birth weight and age, respectively.