Comparison of sperm characteristics, antioxidant and oxidant levels of frozen semen produced in bulls'0.5 and 0.25 ml straws

The aim of this study was to compare the quality of bull sperm produced in 0.5 and 0.25 ml semen straws before and after freezing.

In this experimental study, semen samples were collected from 12 dual purpose Simmental (Fleckvieh) bull kept at Iran Simmental Cattle Breeding Center during a two-month period. Each ejaculate was divided into two equal portions. Then, the formulation and freezing processes were performed separately for each type of straw. Sperm qualitative characteristics, antioxidant and oxidant levels of frozen semen produced in bulls' 0.5 and 0.25 were compared.

The results showed that all sperm quality parameters in 0.25 ml straws were better than 0.5 ml before and after freezing. Catalase (CAT) activity was higher in 0.5 ml straws than 0.25 one, but it was not statistically significant. Malondialdehyde (MDA) levels were lower in 0.5 ml straws than 0.25 ml straws, but the differences were not statically significant. Moreover, no remarkable difference was observed in the activity of superoxide dismutase (SOD) activity enzyme.

Based on the findings of the present study and with the aim of reducing the production costs, it is recommended that bull sperm production centers and herdsman inseminators use 0.25 ml straws for semen freezing and cattle artificial insemination.