发情中的

例句：

1. 1. The dog is in the estrus stage and needs to be mated.
   这只狗处于发情期，需要交配。
2. 2. The cow is in the heat and can't be milked for a few days.
   这头奶牛正在发情期，几天内不能挤奶。
3. 3. The male deer is in the receptivity phase and ready to mate.
   雄性鹿处于可受精阶段，准备交配。