Luprostiol is indicated for 1) estrus control and 2) termination of pregnancy in mares under the following conditions: Estrus Control: Luprostiol is effective as a luteolysin and may be used to regress a functional, progesterone producing corpus luteum, subsequently inducing estrus, ovulation and normal conception in breeding mares under the following conditions: Estrus Control in Normal Cycling and Transitional Phase Mares: Normal cycling mares that demonstrate estrus activity may be treated to shorten the estrous cycle. Treatment should be given during the diestrus period when functional corpora lutea are present. Mares displaying estrous cycles, albeit erratic, may be treated if mature corpora lutea are present to shorten and/or reinitiate the estrous cycle. Estrus Control in Postpartum Mares: Postpartum mares that exhibit an overt foal heat but are not bred at this heat, in order to avoid reduced fertility, may be treated six to 12 days after the foal heat ovulation to attempt an early return to estrus ("second" foal heat) and subsequent breeding opportunity. Lactating mares that do not exhibit a foal heat and that are considered to be in lactational anestrus may be treated approximately 21 days postpartum in order to initiate estrus cyclicity. Estrus Control in Mares With Persistent Corpora Lutea: Mares not cycling due to a persistent corpus luteum (CL) may be treated to terminate functional luteal tissue. This would include: mares considered pseudopregnant (i.e., bred and determined not to be pregnant but displaying signs of pregnancy as a result of persistent CL activity). mares in clinical anestrus (i.e., not cycling during the breeding season due to persistent CL activity). mares that have lost a conceptus during early gestation and that have not recycled due to persistent CL activity. maiden and barren mares in extended periods of diestrus due to persistent CL activity. Termination of Pregnancy The luteolytic activity of luprostiol is also effective for the induction of abortion in mares pregnant for 36 days or less.

1990