Opposite variations of two epididymal components and blood plasma testosterone in two breeds of rams

Abstract

1. Testicular volume (T Vol), blood plasma testosterone (T) concentration, seminal plasma α-glucosidase (α-G) specific activity, l-carnitine ( l-C) concentration as well as semen characteristics were compared in eight Finnish Landrace (F) and eight Suffolk (S) rams throughout 21 months. 2. Only T Vol and T exhibited a typical seasonal variation in both breeds, whereas l-C, α-G and live sperm output presented a seasonal profile only in S rams. 3. l-C and α-G variations were opposite to those of T in S rams, while they fluctuated in F rams throughout the entire experiment, as did live sperm output. 4. Only the number of ejaculates and T were significantly higher in F rams (3.50 ± 0.08 in 5 min and 7.62 ± 0.40 ng/ml) than in S rams (2.30 ± 0.05 in 5 min and 5.5$¯0.30 ng/ml); these two characteristics might therefore be considered as two indexes of sexual activity in rams. 5. By contrast, among all characteristics measured, only α-G was significantly higher in S rams than in F rams (1.33 ± 0.04 vs 0.77 ± 0.03 mU/mg proteins); this result, as well as seasonal α-G profile present in only S rams, allowed us to conclude that α-G might be considered as an additional index of seasonal reproduction in rams.