Which sign is typical of the Pro-Oestrus phase in the bitch?

• A. Vulva becomes enlarged
• B. Bloodstained discharge
• C. Will become flirtatious and excitable with the male but refrain from mating
• D. Will not willingly allow male to mate

Answer: (B)

In pro-oestrus, estrogen rise causes changes in the reproductive tract, most notably a vulvar swelling with vaginal discharge that is blood-tinged. The bitch often attracts males during this phase but will not allow mating yet, which changes once estrus begins and she becomes receptive. The most characteristic sign listed here is the bloodstained discharge, which clearly indicates pro-oestrus. While vulvar swelling also occurs, the discharge is a distinctive, time-linked sign of this phase. The behavior described in the other option aligns more with estrus, when the bitch is receptive to mating.