Abstract

EVANGELISTA V., Shirley et al. Equine chorionic gonadotrophin (ECG) stimulation during the luteal and non-luteal phases on ovarian response and embryo quality in llamas. Rev. investig. vet. Perú [online]. 2009, vol.20, n.1, pp.33-40. ISSN 1609-9117.

The effect of superovulatory treatment during the two phases of the ovarian cycle on follicular growth and embryo quality was evaluated in 45 sexually adult llamas. Animals bearing a >7 mm follicle, observed by ultrasonography, were selected and allocated into 3 groups: T0 (non-stimulated), T1 (superovulatory treatment during the non luteal phase), and T2 (superovulatory treatment during the luteal phase). Animals in groups T1 and T2 received 1 ml of LH (day 0) for synchronization of the follicular wave and 1000 IU of eCG (day 3) as superovulatory treatment. Vaginal sponges impregnated with progesterone were used on days 3 to 7 in T2 to simulate the luteal phase. The induction of the ovulation (day 8) was done through natural mating and the application of GnRH (1 ml). Embryo recovery was done 7 days after natural mating (day 15) on T1 and T2. Similarly, embryo recovery was done 7 days after natural mating and application of GnRH in T0. The number of preovulatory follicles was larger in T1 (11.07 ± 7.53) and T2 (6.13 ± 7.11) than in T0 (1.07 ± 0.26) (p<0.05). The number of corpora lutea was larger in T1 (9.27 ± 3.37) than in T0 (1.07 ± 0.26) and T2 (6.47 ± 4.29) (p<0.05). The number of recovered embryos was larger in T1 (3.47 ± 4.26) than in T0 (0.33 ± 0.48) and T2 (1.33 ± 2.53). The results showed that superovulatory treatment during the non luteal phase had a better response than superovulatory treatment during the luteal phase.

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