Premium
Recent attempts to improve synchronisation of ovulation and to induce superovulation in the mare
Author(s) -
PALMER E.
Publication year - 1985
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.2042-3306.1985.tb04584.x
Subject(s) - ovulation , follicular phase , medicine , progestogen , endocrinology , buserelin , estrous cycle , luteinizing hormone , biology , stimulation , follicle stimulating hormone , seasonal breeder , testosterone (patch) , follicle , hormone , ecology , receptor , agonist
Summary Recent experiments designed to improve synchronisation and stimulation of ovulation in mares are described. The addition of daily injections of oestradiol benzoate to a routine synchronisation protocol, that utilised intravaginal sponge administration of a progestogen, ally I trenbolone, for seven days followed by an injection of prostaglandin at the time of sponge removal, reduced pituitary follicle stimulation hormone (FSH) secretion during treatment, increased the interval from sponge removal to ovulation but did not improve synchronisation of ovulation. Addition of daily injections of testosterone to the protocol reduced the secretion of pituitary luteinising hormone (LH), but not FSH, during treatment and it did improve synchronisation of ovulation. Attempts to stimulate follicular growth with an anti‐oestrogen, tamoxifen, during late anoestrus or after synchronisation treatment during the breeding season were unsuccessful; FSH and LH secretion rates and follicular growth were not stimulated. Treatment of mares with an extract of horse pituitary glands during successive oestrous cycles to give a total of six treatments per mare during the breeding season induced the growth of a mean of 3.3 mature follicles but only a mean of 1.8 ovulations in each treated cycle. This treatment regime did not seem to exhaust the pool of follicles that can be stimulated in subsequent cycles.