Abstract

PIP: In view of the impairment of transport and survival of spermatozoa i n the genital tract of progestagen-treated spayed ewes compared with tha t observed in normal animals and the possible relationship with the prod uction of cervical mucus, 2 experiments were conducted to study the pattern of response to exogenous progesterone and estrogen. The production of cervical mucus was measured at intervals of 6 hours about the onset of estrus in ewes treated with exogenous progestagen administered intramuscularly or intervaginally. There was a quadratic pattern of production with peak values early in the estrous period. Although there were no differences between groups in the total amount of mucus produced, levels recorded in untreated ewes were lower in the preestrous period. Within the intravaginal progestagen group, those ewes which exhibited estrus within 42 hours of sponge withdrawal produced greater quantities of cervical mucus than did animals which came into heat after this time. This relationship was not evident within the intramuscular progesterone group. It was concluded that the variable cervical mucus response observed after the cessation of treatment may contribute to the lowered fertility commonly observed following the synchronization of estrus. The cervical mucus response to injected steroids was recorded in spayed ewes. This was a specific line ar response to exogenous estrogen. Progesterone priming resulted in higer levels of cervical secretions from 24 to 42 hours after the admini stration of estradiol benzoate (ODB). Intravenous administration of OBD caused an earlier but short-lived response.