Efecto de laaplicaciÓn de estradioly progesterona sobre lasupervivencia embrionariaen llamas

The effect of exogenous oestradiol and progesterone on embryonic survival around the period of maternal recognition of pregnancy was evaluated in 80 adult llamas with ≥15 days after parturition. An ultrasound evaluation was conducted to detect a preovulatoryfollicle (≥7mm), and then, animals were mated with a male for ≥15 minutes of copulation time. Animals were allocated into 4 groups: G0, placebo; G1, 0.2 mg/llama/day of estradiol; G2, 15 mg/llama/dayof proligestone, and G3, 0.2 mg/llama/day of estradiol and 15 mg/llama/day of proligestone. Injection of hormones and placebo was done at days 8 and 9 after copula. Mating day was considered as day 0. Ultrasound evaluations were done on day 2 to determine ovulation, on day 9 to measure the size of the corpus luteum, and on days 20, 25, 30 and 35 to observe the presence of the embryonic vesicle and the embryo. Sexual behaviour was evaluated to verify female receptivity on day 0 and to diagnose earlypregnancy on day15. Embryonic survival was higher in G1 (75%) as compared to other groups: G0 (57.9%), G2 (52.6%), and G3 (55.0%) until day 35, but without significant differences. The size of corpus luteum on day9 was larger in pregnant (12.8 mm) than in non pregnant llamas (10.8 mm). In conclusion, the results suggested that the application ofestradiol between days 8 and 9 after mating mayimprove embryonic survival rate in llamas.