A study on the effect of age, breed and season on sexual behaviour, testosterone concentrations and scrotal circumference in Egyptian rams

The objective of this study was to detect the influence of age, breed and season on sexual behaviour, testosterone concentrations and scrotal circumference in Egyptian rams. The study was carried out at agricultural research center belonging to Minia University, Shosha village, Samalut city, El-Minia. Ten crossbred and five adult Ossimi rams were used during this study. Every ram was allowed to breed two ewes to evaluate its sexual behaviour for a twenty minutes test. Blood samples were collected three times per season at two weeks interval from each ram during the period of experiment to measure testosterone concentrations. Also, scrotal circumference was measured at the same frequency and time interval as blood samples. Sexual behaviour was better in old rams than young ones (p<0.01), but it was not affected by breed or season (p>0.05). Serum testosterone level was higher at autumn (7.13±02.9 ng/ml) than at winter (5.54±0.29 ng/ml) in crossbred rams (p<0.01), while in Ossimi rams, higher level was obtained in spring (8.24±.39 ng/ml) than in summer (3.99±0.40 ng/ml). Mean scrotal circumference was higher in older rams (30.20±1.20 cm) than younger rams (22.53±1.27 cm). There was no significant difference for measures of scrotal circumference between crossbred rams (30.86±1.09 cm) and Ossimi rams (30.93±1.06 cm). Season had no significant effect on scrotal circumference in crossbred rams, whereas in Ossimi rams the effect of season was significantly obvious with the highest and lowest values were recorded in spring (31.0±1.05 cm) and winter (30.60±1.17 cm) respectively. It could be concluded from this study that the age of rams had a great influence on their sexual behaviour and scrotal circumference, while the effect of breed and season on sexual behaviour and scrotal circumference was not clear.