Assertion: estrus's estrus | /r/HasProperty | see section
Facets:
Source sentences:
text: Certain sex hormone levels (e.g. high blood estrogen levels) and reproductive tract structural changes (e.g. increased follicle growth on the ovaries, greater thickening of the uterine walls) all give the vet and cat owner important clues as to just how close a female cat is to reaching the state of "estrus", but regardless of these changes, a female cat can not be termed to be "in heat" or "in estrus" until she shows the behavioral signs and symptoms appropriate to feline estrus (see section 3) and until she stands to allow a male cat to mount and mate with her.