A study was conducted in Nasarawa State, North Central Nigeria to determine the productivity and egg quality traits of free range naked neck and full-feathered chickens. A total of one hundred and two smallholder farmers were randomly selected. Information was obtained on average eggs per clutch, hatchability and mortality, while hen`s body weight was measured directly on the day of egg collection. One hundred and two freshly laid eggs (51 eggs from each genotype) were used to evaluate external and internal egg qualities. Body weight and average eggs per clutch were significantly (p< 0.05) higher in naked neck genotype compared to the normal feathered birds (1.30 vs. 1.16kg; 11.63 vs. 9.71 respectively). Normal feathered genotype recorded higher mortality (36.85%) than naked neck birds (28.60%). No significant (p> 0.05) difference was found between the two genotypes in hatchability. Mean values for egg weight, egg length, egg width, egg shape index, shell thickness, albumen weight, albumen height, yolk weight, yolk height, yolk width and haugh unit were significantly (p< 0.05) higher in naked neck hens than their normal feathered counterparts. There was no superiority in shell weight and yolk index. The association between egg weight and other egg biometrical traits were found to be positive and significant (r = 0.22-0.79; p< 0.05). Other egg parameters were either positively or inversely correlated with each other. Egg weight was better predicted (R2 = 34.44%) using a combination of egg length and egg width. The estimation of shell weight from egg length, egg width and egg weight gave lower values (R2 = 2.86-3.91%). The incorporation of allometry improved the prediction accuracy of shell thickness, albumen weight and yolk weight from egg weight (R2 = 44.16,43.89 and 49.89%). It is concluded that the introgression of the naked neck gene into poultry could play a pivotal role in the genetic improvement of traditionally managed flocks.

Sheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation. Morphological traits of Uda and Balami were significantly (P < 0.05) higher than Yankasa, which were both higher than West African Dwarf (WAD) sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content (PIC) of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci (0.783 to 0.93). Mean heterozygote deficiency across all populations (0.171 to 0.534) possibly indicate significant inbreeding (P < 0.05). Mean values for F ST , F IT and F IS statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds (D_A = 0.184) while WAD and Balami are the farthest apart breeds (D_A = 0.665), which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE. These results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The higher genetic variability in Yankasa suggests the presence of unique ancestral alleles reflecting the presence of certain functional genes which may result in better adaptability in more agro-ecological zones of Nigeria. These genetic characteristics are potentially useful in planning improvement and conservation strategies in Nigerian indigenous sheep.

Multivariate analysis of morphostructural characteristics in Nigerian indigenous sheep

An experiment was designed to study the effects of genotype and housing system on the performance of two commercial layers, Bovans Brown and Lohmann Brown in the hot-dry and wet seasons in Lafia, Nasarawa State, Nigeria. Six hundred, 27 week-old layers were used. One hundred and fifty birds of each strain were randomly assigned to the battery cage system, while another one hundred and fifty birds of each strain were managed on deep litter. The observation for the hot-dry and wet seasons lasted 2 months each respectively in the year 2004. Body weight, hen-housed egg production, egg weight and mortality rate were significantly better in Lohmann Brown than Bovans Brown (1.75±0.01kg vs. 1.69±0.01kg, 74.50±0.84% vs. 68.72±0.86%, 53.70±0.24g vs. 52.43±0.26g, 0.58±0.09% vs. 1.20±0.15%; p<0.05). Birds in cages were superior to those on deep litter in terms of hen-housed egg production, egg weight and mortality (74.06±0.75% vs. 69.16±1.02%, 53.40±0.24g vs. 52.73±0.29g, 0.68±0.10% vs. 1.10±0.15%; p<0.05). Generally, birds performed better in the wet than hot-dry season in body weight, hen-housed egg production, feed intake, egg weight, egg cracks and mortality (1.76±0.01kg vs. 1.68±0.01kg, 74.92±0.74% vs. 68.30±0.86%, 98.51±0.50g vs. 90.90±0.23g, 53.92±0.18g vs. 52.22±0.27g, 1.99±0.23% vs.5.12±0.39%, 0.55±0.08% vs. 1.22±0.15%; p<0.05). The interactions between genotype×housing system, genotype×season and housing system×season produced significant results. Proper housing design, provision of quality and adequate feeds and proper timing of the laying period were recommended.