Canine heat or estrous cycle varies in length .

犬热或发情周期不同的长度。

Estrous cycle and pregnancy length of domestic animals .

家畜的发情周期和妊娠期。

Gene expression profile of the mouse oviduct during the estrous cycle .

小鼠输卵管生殖周期间基因表现图谱的分析。

Having one estrous cycle per year .

每年只有一个发情周期。

And if I knew what estrous was .

要是我了解什么叫发情就好了。