VGO-0029
QUESTION
Which one is the longest phase or period of the estrous cycle?
OPTIONS
(A) Proestrous
(B) Estrous
(C) Metestrous
(D) Diestrous
ANSWER
(D) Diestrous
EXPLANATION
Diestrus is the longest phase of the typical bovine estrous cycle because the functional corpus luteum maintains progesterone secretion for most of the cycle. Proestrus is the shorter preparatory period before heat, estrus is the brief period of sexual receptivity, and metestrus covers early postovulatory luteal development. Their individual durations are shorter than the established luteal phase represented by diestrus.
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Veterinary Gynaecology and Obstetrics · 240 Questions
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