Genetic variability in juvenile growth traits of Ugandan indigenous chicken populations raised under an intensive deep litter system

Uganda’s indigenous chickens (IC) display significant phenotypic diversity in body weight (BW) and growth performance. However, there has been no study on the genetic diversity related to juvenile BW and growth performance in indigenous chicken populations (ICP), to support early selection of improved growth performance. The objective of this study was to assess the genetic variation in chicken juvenile BW and growth among selected ICP in Uganda. Three populations of IC were sourced from Apac, Lira and the National Semi-Arid Resources Research Institute (NaSARRI), as founder populations. Chicks were hatched from founder eggs, wing-banded and reared under identical conditions, in a deep litter system. Body weight was recorded weekly from hatch to four weeks of age. Hatch weight was higher (P<0.01) for Apac and Lira birds compared to NaSARRI. Mean Daily gain (ADG) was greatest for Lira and lowest for NaSARRI birds. The mean relative Growth Rate (RG) of chicks from Lira and Apac was comparable, but both were greater (P<0.05) than for NaSARRI. Broad-sense heritability estimates for BW0, BW1, BW2, BW3, and BW4 were 0.35, 0.50, 0.54, 0.47, and 0.56, respectively. Genotypic variances for BW measurements varied (P<0.05) among the ICP. The heritability estimates for ADG and RG were 0.41 and 0.49, respectively, with genotype variances differing significantly (P<0.01) across the ICP for both ADG and RG. These results demonstrate both phenotypic and genotypic variability in juvenile BW and growth performance. Moderate heritability and positive phenotypic correlations suggest that these traits can be effectively improved through selective breeding.