Resumen

AVENDANO, Leonel; ALVAREZ, Daniel  y  CORREA, Abelardo. Induction of estrus and fertility using subcutaneous implants in anestrous dairy goats. INCI [online]. 2003, vol.28, n.4, pp.225-228. ISSN 0378-1844.

Forty-four multiparous dairy goats, purebreed and crossbreed of Nubian, Toggenburg, Saanen, La Mancha and French Alpine breeds were used to determine the effect of Norgestomet (3 and 6mg) when used in conjunction with eCG during the anestrous season on the time to onset of estrus, induced estrous, fertility, gestation duration, number of kids per doe and kids birth weights. The animals were assigned randomly to 3 groups; a control group (n=15) without hormonal treatment, another group (n=14) treated with 3mg of Norgestomet (half implant) placed subcutaneously in the ear for 11d; and a third group (n=15) treated with a 6mg Norgestomet implant placed in the same location for 11d. Both treated groups received 500IU eCG i.m. 24h prior to progestagen removal. The group treated with 6mg Norgestomet had a shorter (P<0.05) interval from progestagen removal to estrus than the group treated with 3mg (16.8 ±0.76h vs 24.6 ±0.8h). Nevertheless, the induced estrus (100 vs 93%) were similar (P>0.05) in both groups. Fertility was higher (P<0.10) in the 6mg group (87 vs 57%). No estrous activity was observed in the control group. Gestation length, mean number of kids per doe and mean weight at birth were also similar (P>0.05) in the 3 and 6mg groups. Dairy goats implanted with 3mg Norgestomet exhibited similar estrous induction, but had lower fertility rate than the group implanted with 6mg.

Palabras clave : Goats; Anestrous Season; Progestagen.