Reference for Bekhorot 33:27

ניחזי אנן הכא במאי עסקינן ברחל שילדה מין עז ואביו תייש

One authority maintains that the sheep goes back to its former status<span class="x" onmousemove="('comment',' R. Meir holds that it must be given to the priest and that it is not a nidmeh. The ewe from a goat referred to here does not actually mean a ewe, for a female animal is not consecrated as a firstling, but it means an animal looking like a ewe.');">¹⁶</span>

Jastrow