Production of cervical mucus in ewes treated with exogenous progestagen and oestrogen

Abstract

The production of cervical mucus was measured at intervals of 6 hr about the onset of oestrus in ewes treated with exogenous progestagen administered by the intramuscular or intravaginal route. There was a quadratic pattern of production with peak values early in the oestrous period. Although there were no differences between groups in the total amount of mucus produced, levels recorded in untreated ewes were lower in the pre-oestrous period. Within the intravaginal progestagen group, those ewes which exhibited oestrus within 42 hr 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 oestrus. The cervical mucus response to injected steroids was recorded in spayed ewes. This was a specific linear response to exogenous oestrogen. Progesterone priming resulted in higher levels of cervical secretions from 24 to 42 hr after the administration of oestradiol benzoate (ODB). Intravenous administration of ODB caused an earlier but short-lived response.