GENETIC PARAMETERS OF GROWTH AND REPRODUCTION IN THE WEST AFRICAN DWARF GOATS REARED IN THE HUMID TROPICS
ABSTRACT
Twenty-five intensively managed mature West African Dwarf goats were used for the experiment comprising 20 Does (dams) and 5 bucks (sires). The goats were classified into 5 mating pens of 4 Does (dams) and one buck (sire) randomly assigned per pen. Fresh water and forage were provided ad libitum in addition to 1kg concentrates Cajanus cajan to each animal per day. Data were collected on weights at birth and weaning; litter size and linear body measurements. Body weight gain was calculated. The data were subjected to analysis of variance in completely randomized design using the statistical package of social science (SPSS) computer package. The Paternal Half-sib Analysis model was used to estimate sire component of variance from which the additive genetic variance and heritability were calculated. The descriptive statistics (mean ±S.E) and Coefficient of Variation for birth weight, litter size, body weight gain and body weight showed that birth weight of the offspring were significantly different (P<0.05) between sires. The weaning weight of offspring of different sire groups indicated non-significant differences (P>0.05). Body weight gain of sires group recorded significant differences (P<0.05). The effect of sex of the animal body weight, body weight gain, body length, arm length and height at wither showed that male progenies were higher than females; while the effect of season of birth indicated that kids born in dry season had higher daily weight gain (44.16±3.11g) than those born in wet season (42.32±3.74g). The heritability estimates for birth weight, litter size and weaning weight were low, moderate and high (0.15, 0.22 and 0.88), respectively. The estimates of heritability for body length at birth were moderate, while at 6 months of age the heritability was high (0.95) and this indicates high potence for genetic improvement. Linear body measurement traits (body length, arm length, and height at wither) recorded high heritability values. Phenotypic, genotypic and environmental correlations between pairs of parameters in West African Dwarf goat traits ranged from -0.01 to 0.99.