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Embryo transfer in anoestrous recipient mares: attempts to reduce altrenogest administration period by treatment with pituitary extract
Author(s) -
LAGNEAUX D.,
PALMER E.
Publication year - 1993
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1993.tb04840.x
Subject(s) - ovulation , medicine , embryo transfer , follicular phase , pregnancy , endocrinology , embryo , estrous cycle , andrology , biology , hormone , genetics , microbiology and biotechnology
Summary Groups of ovariectomised and anoestrous mares were treated with altrenogest and used as recipients for embryo transfer. Progesterone concentrations in all ovariectomised, pregnant mares increased only after 85 days of pregnancy, but in 2 out of 4 anoestrous pregnant mares progesterone increased between Days 40 and 50 of pregnancy. Follicular growth and luteinised follicles suggested that altrenogest could be withdrawn earlier. To test whether exogenous LH treatment could stimulate earlier onset of ovarian progesterone secretion, anoestrous, recipient pregnant mares treated with altrenogest were treated with LH (25 mg CEG (crude equine gonadotrophin) im daily (N=5). Two of the 4 control mares ovulated at Days 58–60 and plasma progesterone increased. The other 2 mares did not ovulate. In the mares treated with CEG, altrenogest treatment was withdrawn in 3 on Days 45, 50 and 55 respectively. One mare aborted on Day 54 when endogenous progesterone was still very low and there was no indication of ovulation and/or luteinisation in the 5th mare. There was no significant difference in increasing progesterone concentrations between CEG‐treated mares and untreated mares, suggesting that such treatment in anoestrous recipient mares is relatively inefficient.