Do cows produce blood during menstruation?

Answer 1

Cows DO NOT menstruate. This is solely a human reproductive physiology characteristic, not a bovine reproductive physiology characteristic. Cows have an Estrous cycling period, NOT Menstrual period. During the Metestrus period, a cow (both cows AND heifers) will show a bit of postestrual bleeding caused by the withdrawal of estrogen 2 to 3 days after the cow or heifer goes out of heat. A portion of the lining over the caruncles in the female bovine's uterus become engorged with blood and bleeding from the smaller capillaries may occur. If you didn't see the female in heat, this (the slight bloody discharge) is evidence that she was in heat a few days earlier.

By definition, menstruation is the sloughing of the endometrium in the uterus to the exterior. There is no defined period of sexual receptivity during menstruation, and the timeline for the description of the cycle begins and ends with menses, not ovulation nor estrus. The estrous cycle begins and ends with estrus and/or ovulation; the follicular phase is short and the luteal phase long. The Menstrual cycle begins and ends with the start of menses (sloughing of endometrium). Ovulation occurs in the middle of the cycle. The follicular and luteal phase are the same length.