Effect of eCG and progestagen on ovarian follicle population in goats

Communication publiée dans l'article "Abstracts" (p. 43-108)

International audience

Inglés. The aim of present study was to evaluate the response of ovarian follicle population to eCG/progestagen treatment in goats. In second half of February, seven Serrana goats (G-eCG) received 250 UI of eCG (Intergonan®, Intervet, Holland) at the removal of intravaginal sponges impregnated with 20 mg of flugestone acetate (Chronogest® CR 20 mg, Intervet, Holland) and kept in place during 6 days. Six other Serrana goats (G-C) remained untreated as controls. Ovarian transrectal ultrasonographic examinations were performed in both groups at 0 h, 20 h, 42 h, 72 h and 92 h after eCG administration in G-eCG. Follicles were counted and classified according to the following classes: total follicles, <3, ≥3, 3-5 and ≥5 mm in diameter. At 0 h no differences (P > 0.05) between groups were found in any class of follicles. However, an increase of total follicles between 0 h (7.1 ± 0.4) and 72 h (9.9 ± 0.4) or 92 h (10.3 ± 0.6; P < 0.001) was observed in G-eCG, but not in G-C (P > 0.05). Also, in G-eCG, the number of 3-5 follicles class increased from 0 h (1.7 ± 0.3) to 42 h (3.8 ± 0.2; P < 0.001) followed by a decrease at 72 h and remained constant at 92 h (2.3±0.3), variations not observed in G-C. In >5 class, the number of follicles remained constant (1.2 ± 0.2) in all examinations, without differences between groups. The number of follicles <3 mm was constant in both groups until 42 h (4.7 ± 0.3) but increased at 92 h (7.1 ±0.5; P < 0.001) in G-eCG. These results suggest that low dose of eCG stimulate the number of 3-5 mm follicles present in ovaries but not the small (<3 class) follicles, in order to ovulate.