Evaluation of semen characteristics in Corriedale rams under controlled and natural photoperiod and temperature conditions

Abstract

Semen production was evaluated during one year in two groups of four Corriedale rams each: Group A (treated), submitted to 8 hr light: 16 hr darkness per day, at temperature of 18,3 ± 4,2°C; Group T (control), kept under natural conditions. The two groups were fed with the same nutritional regime: native pasture, hay alfalfa (1 kg/animal/day) and oat grains (0,8 kg/animal/ day). The treated group showed superior semen production in relation to the control group, with statistical difference (P < 0,05) for the following characteristics: volume, spermatic concentration, motility, vitality and spermatic abnormalities. The seminal fructose concentration did not show difference between the groups, but a higher concentration of citric acid in the seminal plasma was found in the group T (P < 0,05). The majority of seminal characteristics analyzed showed statistical difference among seasons of the year (P < 0,05), being the seasonal effects more striking over the control group.