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Abstract
A nucleus-breeding flock of selected Black Bengal goat was established in the Bangladesh Livestock Research
Institute (BLRI) with the objective of conservation and improvement of the breed. A total of 120 does of different
generations (70=foundation stock, 45=First generation and 5=Second generation) and 20 bucks (15=Foundation
stock and 5=First generation) were used to study the genetic parameters of Black Bengal goat on productive and
reproductive traits. Animals were bred naturally. Goats were reared under intensive and semi-intensive management
to compare performance. Birth weights of kids were 1.49±0.13 and 1.28±0.11 kg, respectively for intensive and semiintensive
rearing system. Number of services required for each successful conception was 1.16±0.019 with an
average gestation length of 143.33±0.68 days. Litter size increased (P<0.001) linearly with parity. Average litter size
of Black Bengal goat was 1.94±0.06. Rearing system, season, parity, generation and generation × parity interaction
did not affect (P>0.05) the post partum estrous interval. Young females attained puberty at an age and weight of
186.02±10.52 days and 9.4±0.52 kg, respectively. In case of intensive rearing system it took 139 days to show 1st
heat compared to 198 days in semi-intensive rearing system. Intensive system reduced the age at 1st kidding to
284±31.2 days from 370±25.5 days in semi-intensive system. The effects of parity, generation, and generation ×
parity interaction on kidding interval were not significant (P>0.05). The average daily milk yield and lactation length
was 1.088 kg (750g suckled milk + 338g from hand milking) and 68.07±2.83 days respectively. The effect of parity
and generation on doe weight after kidding was significant (P<0.01) but the effect of generation × parity interaction
was not significant (P>0.05). Heritability estimates from sire and dam component for birth weight, weight at 3, 6, 9, 12
months of age and litter size were 0.92, 0.48, 0.34, 0.45, 0.88 and 0.17, respectively. Heritability estimates only from
sire component for birth weight, weight at 3, 6, 9, 12 months of age and litter size were 0.05, 0.28, 0.77, 0.29, 0.18
and 0.15, respectively. Repeatability estimates for birth weight, litter size, kidding interval and daily milk yield were
0.47, 0.15, 0.02 and 0.49, respectively.