Effect of improved diet on semen quality and scrotal circumference in the ram

The aim of this investigation was to assess the effect of improved diet above maintenance requirement on reproductive parameters, including testicular size, semen volume, sperm concentration and viability. Twelve Bakhtiary rams were allocated to two groups of six animals and were fed during a 12-week experiment period with different diets which were designed to supply maintenance and above maintenance requirements (dry matter, energy and protein). Dry matter (DM), barley and soybean meal for control and treatment groups were 1.5 kg, 8%, 0% and 2.1 kg, 25%, 17%, respectively. Semen was collected by artificial vagina every other week. Scrotal circumference, sperm concentration and total number of spermatozoa per ejaculate significantly increased in treatment group (P<0.05). However, neither semen volume nor proportion of live and dead spermatozoa was affected (P>0.05). Likewise, there was a significant correlation between scrotal circumference and sperm production in treatment group (P<0.01, r = 0.96). It was concluded that improved dietary intake with higher energy and protein supplementation in Bakhtiary rams can improve their reproductive performance during the breeding season.