The effect of different extenders on the motility and morphology of ram sperm frozen or stored at 4 °C


Abstract: This study was conducted to evaluate the effects on sperm motility and abnormality in ram semen extended with skimmed milk (M), sodium citrate (SC), Tris (T), and Bioxcell® (B) after storage in liquid form at 4 °C and in frozen form. Ejaculates were collected from 3 Akkaraman rams by artificial vagina twice a week during the non-breeding season. After pooling, each pooled ejaculate was split into 4 equal aliquots and diluted with skimmed milk (M), sodium citrate (SC), Tris (T), and Bioxcell® (B) extenders. Sperm motility was significantly higher (P < 0.05) in M compared with B, SC, and T on the first and second days (48 h) of storage. With regard to the percentage of total abnormal spermatozoa, the results in M were different from (P < 0.05) from those of SC and T on the first day (24 h) of storage but no different from B. Differences among extenders were found to be significant post-thawing for spermatozoa motility and the percentage of total abnormal spermatozoa. The total abnormality of semen diluted with M was significantly lower than that observed in the other extenders. Consequently, it was found that skimmed milk was better than the other extenders in terms of the sperm parameters evaluated during liquid storage and post-thaw.

Keywords: Ram semen, extenders, liquid storage, cryopreservation, sperm parameters

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