Their bull gendereth, and faileth not; their cow calveth, and casteth not her calf. Their bull gendereth - עבר ibbar, passes over, i.e., on the cow, referring to the actions of the bull when coupling with the female. Their flocks multiply greatly, they bring forth in time, and none of them is barren.
Related Commentaries of Job 21:10
Job 21:10
10 Their bull gendereth, and faileth not; their cow calveth, and casteth not her calf.