THE EFFECT OF RESTING ROOSTERS FROM EJACULATION ON THE QUALITY OF SPERMATOZOA IN SEMEN

During an investigation of the chemical composition of fowl semen it was felt necessary to study the effect of varying the length of rest periods between ejaculations on the quality of fowl spermatozoa. Such information could be useful for future work on the storage ofsemen in vitro for long periods, since there might be an optimum ejaculation rate for obtaining spermatozoa of the best quality and thus likely to survive best in vitro. Twenty related males of the Breeding Line of Brown Leghorns at the Poultry Research Centre, Edinburgh (Blyth, 1954) were selected randomly from roosters trained for the artificial collection of semen. Semen had been collected and examined at least once weekly from all the males for a month before the start of the experiment. The males were subdivided randomly into five groups; one group was kept as a control and the other four were rested for 2, 4, 6 and 8 weeks respectively, between ejaculations. Semen was collected consistently from the males in the control group throughout a 10-week experimental period at intervals of 2, 3 or 7 days; eac