Progesterone plus PMSG Priming in seasonally anovulatory lactating Sarda ewes exposed to the ram effect.

The aim of this trial was to evaluate the effectiveness (fertility and lambing) of priming with a single injection of progesterone plus PMSG in anovulatory lactating Sarda ewes subjected to the ram effect (RE) in spring. Thirty ewes (P4 group) were i.m. injected with 30 mg progesterone and 500 IU PMSG 36 h before ram introduction (d 0). This treatment was compared to a 12-day treatment with fluorogestone acetate intravaginal sponges that was followed by injections of 350 IU PMSG upon sponge withdrawal (FGA group, n=30). All ewes responded to RE, showing plasma progestrone concentrations >1 ng/mL between d 6 and 12 (FGA) or 6 and 9 (P4). Eighty-nine percent of the P4 ewes conceived at first ovulation, and 11% conceived following a short estrus cycle. Lambings occurred on d 150.4 +/- 3.9, and the lambing rate was 100%. The fertility of the FGA ewes was 83% for the induced ovulation and was 7% for the second ovulation after a normal cycle. The FGA ewes lambed on d 149.8 +/- 4.4, and the lambing rate was 83%. Two abortions were recorded for the FGA ewes, which had higher prolificacy than the P4 group (2.2 +/- 0.8 vs. 1.8 +/- 0.4, respectively; P<0.05). Both fertility and the lambing rate were high in both groups, with a high degree of estrus synchronization, and there were no significant differences between the groups. We concluded that priming of lactating Sarda ewes in spring with P4+PMSG before RE is an effective and competitive method (cheaper and more practical than FGA+PMSG) of inducing fertile ovulations in these ewes.

Seasonality of plasma testosterone in males of four Mediterranean goat breeds and in three different climatic conditions.

The aims of the present work were to evaluate if a seasonality of plasma testosterone concentrations exists in Mediterranean male goats and it may be affected by climatic conditions. Testosterone concentrations were determined throughout 1 year in blood samples collected weekly from 24 males of 4 Mediterranean goat breeds (Ionica, Garganica, Maltese and Red Syrian), fed a constant diet, maintained without interactions with does and reared in 3 farms with different climates, in Italy. Plasma testosterone concentrations were affected by season (P<0.0001), being higher during summer (8.33+/-0.35 ng/mL) than during autumn (6.81+/-0.26 ng/mL), which were in turn higher than in winter (1.55+/-0.08 ng/mL) and spring (2.04+/-0.15 ng/mL). An effect of breed was recorded (P<0.001), Ionica bucks having the highest plasma testosterone means, Red Syrian and Maltese the lowest. The onset of the reproductive season was similar among the breeds. Ionica bucks had a later offset than Red Syrian and Maltese and a longer reproductive season than Maltese bucks (P<0.05). No effect of farm nor interaction breed x farm was recorded. Single sporadic peaks of plasma testosterone were recorded in many bucks, outside the main reproductive season, especially during spring. In conclusion the bucks of all the four breeds displayed a clear seasonality of plasma testosterone, with very low levels from January to May and high levels from July to November; hormone levels and pattern of seasonality were affected by breed and not by climate.