Effects of location and season on productivity and productive adaptability of two parent stock exotic layer chicken strains in a warm-wet environment

Tropical commercial poultry industry is anchored on exotic strains which suffer varying degrees of productivity and adaptability problems. Adaptability is the ability to produce better or demonstrate least variation in productivity under multiple environments. The study was undertaken to examine the productivity and adaptability of Bevan Nera (IB) and Isa Brown (IB) parent stock strains under two locations and seasons. Data on weekly feed intake (FI g), cock weight (Cockwt, g), hen weight (Henwt, g), hen house production (HHP, %) and egg weight (Ewt, g) were collected from a commercial parent stock breeding farm in Ibadan, Nigeria, on the two strains. Data were subjected to general linear model analysis (GLM) procedures using SAS (1999), while mean separation was by bonferoni t-test (P=0.05). The statistical model was randomized complete block design (RCBD) in factorial. Factors of importance were Genotype (S), Location (L) as Fixed, and Season (S) as random. The effects of location on seasonal productivity and season on locational productivity for strains were 7.38, 4.96; and 4.99, 8.11 (%) for BN, IB respectively. GxL and GxLxS interactions were significant (P<0.043 and <0.013) for adaptability of strains. Locational adaptability indices were 48.59 and 51.41 while Seasonal adaptability indices were 63.32 and 36.68 (%) respectively for BN and IB strains