Effects of underfeeding on semen quality of Rhode Island cocks.

Fifty Rhode Island chickens were randomly assigned to five treatments with ten cocks in each treatment. Group I cocks (full fed control) received 140 g of a 16% CP growers ration per cock per day. Cocks in Group II, III, IV and V received 98, 70, 42 and 28 g 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 one ejaculate per day was collected from each cock using the massage technique. The 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. In addition, ejaculation failures were encountered more frequently with the severely underfed cocks than in cocks that were moderately underfed (i.e., Groups II and III). There were however, no significant differences in most of the biochemical parameters between cocks I all the treatment groups. 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. Thus, this study revealed that providing Rhode Island red and white cocks with one-halfto three-quarter (i.e., 50-70%) of their normal daily ration would neither undermine their semen producing ability nor affect their semen quality adversely.