Assertion: estrus's estrus | /r/HasProperty | regarded
Facets:
value: as lasting 10 to 18 hours
type: TEMPORAL
value: usually
type: DEGREE
Source sentences:
text: Estrus is usually regarded as lasting 10 to 18 hours, but there is evidence that estrus in modern high-yielding dairy cows is much shorter, probably about 8 hours.