pro-oestrus

例句：

1. 1. The female deer is in the pro-oestrus stage, which means she is ready to mate.
   这只雌性鹿处于发情期，意味着她准备交配。
2. 2. During the pro-oestrus period, the female deer will be more likely to mate with a male deer.
   在发情期，雌性鹿更有可能与雄性鹿交配。
3. 3. Pro-oestrus is a critical period for breeding in many animal species.
   对于许多动物种类来说，发情期是繁殖的关键时期。