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Objective: To test the effects of extenders and packaging methods on morphological and functional characteristics of frozen thawed Ossimi ram semen. Methods: Ram semen was pooled, diluted in 3 different extenders: Tris-egg yolk (TEY), Tris-soybean lecithin (TSBL), and Tris- butylatedhydroxytoluene (TBHT), equilibrated at 5 °C for 4 h, and packaged in straws or pellets for freezing. Semen was evaluated for sperm progressive motility, viability, abnormality, and membrane integrity after dilution, equilibration and thawing. The percentages of viable, early apoptotic, apoptotic, and necrotic spermatozoa as well as comet assay parameters were determined in post-thawed semen. Total antioxidants capacity, malondialdehyde and lactic dehydrogenase were assayed in thawed seminal plasma. Results: After equilibration, only sperm membrane integrity was significantly higher (P < 0.05) in TEY and TSBL than in TBHT. After thawing, TEY or TSBL in straws significantly improved sperm progressive motility and vitality (P < 0.05). In thawed seminal plasma, TBHT or TSBL in straws and TBHT in pellets significantly reduced malondialdehyde, and TBHT in pellets significantly increased lactic dehydrogenase (P < 0.05). TEY in straws increased viable sperm, while significantly decreased early apoptotic and apoptotic sperm (P < 0.05). DNA damage was significantly decreased (P < 0.05) in straws with TEY and TSBL, and tail moment decreased in straws with all extenders (P < 0.05). Conclusions: Despite the disadvantages of dilution of cryopreserved semen with egg yolk, ram semen cryopreserved with TEY gives the best physical, morphological and functional characteristics in straws compared with pellets, followed by semen diluted with TSBL. However, semen diluted with TBHT or TSBL, regardless of packaging method, showed the highest impact on antioxidant status of cyopreserved ram semen.

Estrous synchronization is a promising management device to get better reproductive proficiency, particularly in ruminants. However, limited information is available about the influence of long and short-term progesterone administration on estrous synchronization and reproductive performance in ewes during May season, particularly in Egypt. In this study, a total of 144 ewes have been utilized for estrous synchronization and reproductive performance in ewes during May season. Ewes were separated into six groups with different treatments as follows: G1, control (natural mating), G2, ewes were treated with 20 mg Cronolone vaginal impregnated sponges (Flurgestone acetate, FGA). The sponge was remained intravaginal for 11 days. Each ewe was intramuscularly (i.m.) injected with 500 international unit (IU) Pregnant mare serum gonadotrophin (PMSG) on the day of sponge withdrawal (day 11), G3, ewes were treated with intra-vaginal sponges. The sponge was remained intra-vaginal for 11 days, on day 10, each ewe was injected with 25 mg ultra-short progesterone (P4) (1 ml Lutone). Each ewe was injected i.m. with PMSG (500 IU) on day 11. G4 ewes were treated with intra-vaginal sponges. The sponge was remained for 11 days. Teaser ram was introduced to treated ewes after sponge withdrawal. The 5th group (G5), ewes were treated with intra-vaginal sponges. The sponge was remained intravaginal for 11 days. On day 10, each ewe was injected with 25 mg P4 (1 ml Lutone). Teaser ram was introduced to treated ewes after sponge withdrawal. The 6th group (G6), the same treatment of G2, but the sponge was inserted intra-vaginal only for 6 days. Each ewe was i.m. injected with 500 IU pregnant mare's serum gonadotropin (PMSG) on day 6. Synchronization was better in G2, G3 and G6, respectively and all short-term group animals came into estrus. In addition, onset of estrus and its duration differs significantly among groups. Reproductive performance also showed a significant difference among groups and the shortterm group has the highest fertility rate. Given the above information, our data concluded that progestagens synchronized estrus (long term or short term) and administration of PMSG (500 IU) at sponge withdrawal improves the reproductive efficiency of artificially inseminated crossbred ewes. [ABSTRACT FROM AUTHOR]