在发情期，公山羊会激烈争斗以确立统治地位。

During the ___rutting period, male goats fight fiercely to establish dominance.

春天，我们经常能看到鹿在森林里发情。

In spring, we often see deer ___rutting in the forest.

连续几天的拖拉机车队在这条土路上留下了深深的车辙。

The tractor convoy ___rutted the dirt road deeply after several days of use.