The bull achieves intromission of the penis and ejaculates. Pelvic thrusting is observed during this process with one or both hindlimbs momentarily off the ground.
The bull dismounts quickly after the ejaculation. Retraction of the penis back into the prepuce is observed as the bull is dismounting the cow or shortly thereafter.
A female in estrus is mounted by a bull wearing a chinball marking harness. A safe non-slippery surface is important. Standing to be mounted is a cardinal sign of estrus.
Chin resting is an early test by the bull to determine whether the female will stand to be mounted or will move away. The animal on the left is a teaser animal wearing a chin-ball marking harness.