This study aims to contribute towards the genetic improvement of Nigerian local chicken ecotype through selection. Genetic parameters for body weight at first egg (BWFE), egg number (EN) and egg weight (EW) till first 90 days of lay were estimated for both selected and control lines. Selection was based on an index using BWFE, EN and EW as the selection criterion traits. After three generations of index selection, BWFE, EN and EW all improved significantly (P<0.05) in the selected line. The heritability estimates for all traits in the three generations for both lines were moderate to high (BWFE, EN, EW,). Low to high positive genetic and phenotypic correlation was observed between BWFE and EW. The genetic and phenotypic correlation between BWFE and EN, and EW and EN were generally moderate to highly negative in both lines for all generations. However, in the second generation of the selected line a positive genetic correlation (0.33) was observed between EW and EN.
An experiment was conducted using 400 pullets each of H and N brown Nick (Strain I) and Black Olympia (Strain 2) to determine the influence of weight grouping on short term egg production traits. The two strains of layer type chickens were separated on the basis of plumage pattern and body weight at three weeks of age. The result indicates that the high bodyweight (HBW) groups were signi icantly (P < 0 05) heavier than the l ght bodyweight (LBW) categories up to the time o first egg in both strains. The HBW and LBW groups were s milar in total feed to first egg in both strains. The HBW lines in strain 2 produced significantly (P < 0 05) heavier eggs at first egg, at 30 and 40 weeks compared to the LBW class. There was no significant (P > 0.05) difference between the HBW and LBW lines in strain I for weight o first egg, egg weight at 30 and 40 weeks respectively. Henday rate of lay and total egg mass did not vary according to bodyweight groups in both strains 1 and 2 However, the light brown pullet groups (LBHBW and LBLBW) in strain I were significantly (P < 0 05) superior to the dark brown counterparts (DBHBW and DBLBW) in henday rate of lay and total egg mass. The results further showed that the HBW groups in strain 1 were significantly (P < 0 05) more efficient in converting feed to eggs than the LBW counterparts. In strain 2, there was no significant (P > 0.05) difference between the HBW and LBW groups in feed per dozen eggs. The comparative performance between the two strains of chicken showed that strain I was sign ficant y (P < 0.01) superior to strain 2 in weight of first egg, egg weight at 30 and 40 weeks and henday rate of lay respectively. The two strains of chicken were similar in body weight at first egg and feed per dozen eggs. Based on these results, the only apparent advantage of rearing the HBW and LBW pullet groups separately was in the efficiency of converting feed to eggs in s rain I and in weight of first eggs, egg weight at 30 and 40 weeks in strain 2 Between the two strains of chicken, farmers may opt for s rain I pullets because of its superior performance in egg number and egg weight traits.
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