In cows and many other animals, the female is in estrus just before ovulation. 母牛和许多其他的雌性动物都正好是在排卵前发情。
Conclusion The effect of estrus induction used gradually increased diethylstilbestrol was better than that used constant dose. 结论隔天给药，逐渐加量乙烯雌酚组诱导发情的效果明显好于隔天给药，恒定剂量组乙烯雌酚组诱导发情的效果。
During estrus, the female is fertile and will accept a male. 在发情期，母犬可以接受交配并且具有生育能力。
Progesterone levels remain elevated for8 to10 weeks following estrus in order to thicken the lining of the uterus in preparation for pregnancy. 黄体酮的水平会在发情期之后的八到十周内持续增高，以加厚子宫内膜，从而为怀孕做准备。
