GENETIC AND PHENOTYPIC PARAMETER ESTIMATES FOR GROWTH AND CONFORMATION TRAITS IN GUINEA-FOWL

Multitrait maximum likelihood procedure was used to estimate heritabil ities for body weight and conformation traits, genetic and phenotypic correlations among these traits. Data taken from 6309 guineafowls (pro geny of 116 sires) produced in 18 hatches during 1987 through 1989 at Central Avian Research Institute, Izatnagar, were used. Analysis was c arried out by a mixed model containing hatch and year as fixed effects and sites within year as random effect. Paternal halfsib heritability estimates for body weight at various ages unadjusted for fullsib rela tionship ranged from 0.2 +/- 0.11 to 0.58 +/- 10. The heritability of shank length at 8, 12 and 16 weeks were 0.25 +/- 0.14, 0.34 +/- 0.19 a nd 0.24 +/- 0.13 respectively. Corresponding estimates for keel length were 0.27 +/- 0.16, 0.12 +/- 0.20 and 0.03 +/- 0.12, respectively. Es timates of heritability of breast angle at 12 and 16 weeks were 0.23 /- 0.16 and 0.30 +/- 0.18 respectively. Heritability estimates of the traits adjusted for fullsib relationship were 13 to 28% lower than the unadjusted heritability. These results suggest that heritability obta ined from halfsib correlation method ignoring dam effect into the mode l need to be adjusted for fullsib relationship. Genetic and phenotypic correaltions among body weights at various ages were high and positiv e. Similarly, genetic and phenotypic correlations between body weights and conformation traits were positive and high. Moderate to high heri tability of 4-and 12-week body weight and high genetic association bet ween these two traits suggested that selection to breed guinea fowl fo r heavy market weight can effectively be made in two stages, first on the basis of 4-week body weight and secondly on the basis of 12-week b ody weight.