Effect of Ambient Temperature on Reproductive and Physiological Traits of Nigerian Indigenous Chickens

Genetic adaptation and response to selection depend on genetic variation within and between populations, whereas characterization of the population is a first step towards its improvement. This study demonstrates that variation in genotypes observed in reproductive performance observed among the Nigeria indigenous chicken under the tropical ambient temperature could be explained by the difference observed in the seminal plasma biochemical parameters evaluation. A total of Sixty (60) adult local breeding cocks comprising of 20 normal, 20 frizzle and 20 naked neck cocks were selected randomly from the poultry breeding unit of Teaching and Research farm Ambrose Alli University Ekpoma. Semen was collected from them using abdominal massage technique and analyzed for semen characteristics. The normal feathered cocks had the highest values of rectal temperature (RT), respiratory rate (RR), pulse rate (PR) and heat stress index (HSI) while the least was observed among the naked neck cocks. The semen pH for all the strains was slightly alkaline and ranged from 8.30±0.62 for normal-feathered to 7.49±0.05 for naked neck of the Nigerian local cocks. On Semen motility, normal feather cocks had the highest (P < 0.05) value with a mean value of 97.55±1.16%, while the frizzled cocks had the least value of 60.99±0.05% respectively. Normal feathered cocks had the highest value of calcium (Ca++) and albumin (Alb), naked neck with the highest level of total protein (TP), phosphorus (P) and total cholesterol (TC) while the frizzled feathered chicken performed better in terms of sodium (Na+ ) and glucose (Glu). However both naked and frizzled feathered cocks had higher values of seminal plasma potassium (K+) and chlorine (Cl-). Pairwise correlations of the semen characteristics ranged from low to high values. From factor analysis with varimax rotation of the intercorrelated traits, two principal components (PC) which accounted for 84.13% of the variation in motility chicken semen were extracted. The difference observed could be exploited in management, conservation and selection decision under tropical decisions.