Vaginal smears at this stage often showed nucleated cells characteristic of oestrus.
It is, however, less prominent than in oestrus, and does not gape.
Females which had borne and suckled young were first found to be in oestrus 65 to 104 days after birth of the young.
An apparent instance of hostility between rival males competing for an oestrus female was observed on September 2, 1950.
Females examined in February mostly were perforate and many of them appeared to be in oestrus.
oestrus oes·trus (ěs'trəs)
Variant of estrus.