Post-estrus bleeding (metestrus bleeding) in cattle occurs due to withdrawal of which hormone?

Correct Answer: Estrogen

Metestrus (post-estrus) bleeding in cattle occurs 1–2 days after the end of estrus due to the sudden withdrawal of estrogen. During estrus, high estrogen levels cause vasodilation and increased capillary permeability in the uterine endometrium. When estrogen levels drop sharply after ovulation, these capillaries rupture and blood passes through the cervix as a small amount of blood-tinged mucus.

Clinical Significance

• Metestrus bleeding in cows appears as a small amount of blood on the tail/perineum approximately 1–2 days after standing heat ends.
• It confirms that the cow was in heat 24–48 hours earlier — useful for retrospective heat detection.
• It does NOT indicate that the cow is in heat at the time of observation.

Comparison

• Proestrus bleeding (Bitch): Due to high estrogen causing diapedesis — before heat.
• Metestrus bleeding (Cattle): Due to estrogen withdrawal — after heat. ✔