Effect of Season and Age on Semen Characteristics and Physiological Changes in the Testis of Jonobi Bull Breed in Iraq.

Abstract

The study was conducted in the physiological laboratory - Department of Animal Production of the Agriculture college- Basra University, from 11/2/2017 to 2/1/2018, to investigate the relationship between two factors (age and seasons) and the characteristics of semen (pH, sperms concentration, mass and individual motility, live and dead sperm, testosterone level, AST, ALT and ALP enzymes concentration) of Jonobi bull breed in southern of Iraq. A total of 12 samples of Jonobi bulls were used, aged 2-4 years old. The results showed that there was a significant (P<0.05) increase in the pH values, AST, ALT and ALP enzymes concentration in the semen of younger bulls (2 years old) in comparison with the older ones (4 years old). Whereas, the mass and individual motility, live sperm, sperms concentration and testosterone level increased significantly (P<0.05) in the semen of older bull (3 and 4 years old) in comparison with younger animals (2 years old). The pH values, AST, ALT and ALP enzymes concentration were increased significantly (P<0.05) in spring season as compared with the other season, while, the mass and individual motility, live sperm, sperms concentration and testosterone level increased significantly (P<0.05) in the summer and autumn seasons compared to other seasons.