Effects of quantitative feed restriction on the semen quality of Nigerian local cocks

Abstract

Twenty (20) mature local cocks were randomly assigned to five feeding treatments with four cocks in each treatment. Group I cocks (full-fed control) received 90g of a 16% CP commercial growers ration per cock per day. Cocks in Groups II, III, IV and V received 63g, 45g, 27g and 18g of the same ration per cock per day, representing 70%, 50%, 30% and 20% of Group I intake, respectively. The feeding trials lasted for 8 weeks during which two ejaculates per week were collected from each cock using the massage technique. Ejaculated semen samples were subjected to both physical and biochemical evaluations. Results showed that cocks that were severely underfed (i.e. Groups IV and V) took significantly longer time (P<0.01) to ejaculate. Also ejaculation failures were encountered more frequently with the severely underfed cocks than in cocks that were moderately underfed (i.e. Groups II & III). There were no significant differences in most of the biochemical parameters between cocks in all the treatment groups. However, ejaculate volume, progressive sperm motility and sperm concentration were significantly depressed (P<0.01) in the severely underfed cocks than in the moderately underfed cocks. It was thus concluded that providing breeding local cocks with one half to three quarters (i.e. 50-70%) of their normal daily ration would neither undermine their semen producing ability nor affect their semen quality adversely.
Key Words: Local cock, feed restriction, semen quality