Embryo yield and quality are associated with progestogen treatment during superovulation protocol in lactating Lacaune ewes.

This study assessed the effect of progestogen treatment length on ovarian parameters and embryo yield in superovulated Lacaune ewes collected by nonsurgical embryo recovery. Twenty-three lactating ewes were superovulated 30 d apart using a cross-over design. All ewes received 60 mg of MAP intravaginal sponges for 6 (G-6 group) or 9 (G-9 group) d. A total dose of 133 mg pFSH was given in six decreasing doses (twice a day) starting at 60 h before device removal. Ultrasound examination of the ovaries was performed at the first pFSH injection and one day before embryo recovery, which was performed 6-7 d after the onset of estrus. Embryo recovery was conducted only in ewes that expressed estrus and were mated. There was no difference (P > 0.05) in the total number of follicles between G-6 (15.7 ± 1.0) and G-9 (15.6 ± 0.8) at the time of the first pFSH treatment. The percentage of responding donors with ≥3 corpora lutea (CL; 78.2% [18/23] vs 69.5% [16/23]), mean (±SEM) CL number (7.0 ± 1.2 vs 8.1 ± 1.6), transcervical passage rate (94.4% [17/18] vs 83.3% [15/18], and ova/embryo recovery rate (54.5% [60/110] vs 68.0% [83/122]) were not different (P > 0.05) between the G-6 and G-9 groups. However, the mean number of viable embryos was lower (P < 0.05) in the G-6 group (1.8 ± 0.7) than in the G-9 group. (3.5 ± 1.1). In conclusion, treatment with an intravaginal MAP sponge for 9 d during a superovulation protocol is beneficial for viable embryo yield in Lacaune ewes out of the breeding season.

Effect of different concentrations of l-carnitine in extender for semen cryopreservation in sheep.

This study assessed the effect of l-carnitine (LC) in sheep semen extenders containing or not egg yolk for cryopreservation in sheep. Two extenders (TRIS-egg yolk or the commercial optiXcell™ IMV medium) were used, totaling six groups: IMV - (0, 5 and 10 mM LC) and TRIS - (0, 5 and 10 mM LC). After the freezing-thawing process and throughout incubation at 38 °C for up to 3 h, several parameters were evaluated: sperm kinetics, hypoosmotic, plasma membrane integrity, capacitation status and lipid peroxidation level. The supplementation of either 5 or 10 mM LC randomly affected some parameters and, overall, TRIS was superior (P < 0.05) than IMV extender. In the LC-groups, IMV had greater (P < 0.05) oxidative stress than TRIS. In conclusion, although LC affected isolated parameters, its supplementation in semen extender had no consistently beneficial effect on freezing-thawing ram sperm.