Genetic parameters for body weights, egg traits and antibody response against Newcastle Disease Virus (NDV) vaccine among two Tanzania chicken ecotypes.

Genetic parameters were estimated for production traits and primary antibody response (Ab) against Newcastle diseases virus (NDV) vaccine among two Tanzania chicken ecotypes viz. Kuchi and Tanzania Medium (Medium). Production traits studied were body weights at 8 (Bwt8), 12(Bwt12), 16(Bwt16), and 20 (Bwt20) weeks of age, age at first egg (AFE), egg number in the first 90 days after sexual maturity (EN-90), egg weight (EW), egg shell thickness (STH), and egg shape index (ESI). Heritability estimates for Bwt8, Bwt12, Bwt16, Bwt20, AFE, EN-90, EW, STH, ESI and Ab for Kuchi chicken were 0.38 +/- 0.10, 0.41 +/- 0.07, 0.44 +/- 0.08, 0.45 +/- 0.09, 0.42 +/- 0.10, 0.31 +/- 0.05, 0.43 +/- 0.08, 0.53 +/- 0.11, 0.48 +/- 0.13 and 0.27 +/- 0.06, respectively. Corresponding estimates for Medium ecotype were 0.39 +/- 0.09, 0.43 +/- 0.10, 0.42 +/- 0.08, 0.43 +/- 0.07, 0.52 +/- 0.11, 0.32 +/- 0.06, 0.50 +/- 0.07, 0.61 +/- 0.13, 0.52 +/- 0.10 and 0.29 +/- 0.05, respectively. Genetic (r (g)) and phenotypic (r(p)) correlations in both ecotypes were highest among body weights (i.e. r(g) = 0.60 to 0.93 and r(p) = 0.54 to 0.78), and were lowest (around 0.10 and below, ranging from positive to negative) among primary antibody response against NDV vaccine and production traits, and among eggshell thickness, egg shape index and other production traits. The magnitudes of heritability estimates obtained in this study indicate good prospects of improving these traits in both ecotypes through selection.