Semen Collection from Stallions

Semen is collected from stallions as part of breeding soundness exams, as well as for artificial insemination. Semen collected for insemination can be used fresh, cooled and shipped to another location, or stored frozen for use in the future.

Use of an artificial vagina is far and away the most common method for collecting semen from stallions. The AV used with stallions is similar to that used for species such as bulls, except larger. The image below shows a popular design of a stallion AV (disassembled). Due to the large ejaculate volume, a collection bottle is used instead of a tube. The blue cone next to the AV is not a special hat worn by the semen colletor; rather it is an insulating cone that is placed over the end of the AV to shield the semen collection bottle from thermal shock.

Stallion semen often contains a large volume of "gel", a gelatinous secretion from the seminal vesicles. Gel is ejaculated after the sperm rich fraction. To minimize contamination of the semen with this gel, a nylon filter can be inserted into the collection bottle when the AV is assembled (shown above); the gel is trapped in the filter and discarded.

Certain combinations of tranquilizers have been used to induce ejaculation from stallions. This technique is useful for collecting semen from stallions that cannot mount a mare or phantom due to musculoskeletal disease. Electroejaculation should not be attempted with stallions.

>Semen Collection

Semen is often collected from stallions using an estrous or ovariectomized teaser mare. The disadvantages of this practice are that it can be dangerous for the collection team, the mare and the stallion, and there is a good possibility that sometimes the mare will be bred by the stallion. To protect the stallion, the mare should be hobbled to prevent kicking. An alternative to use teaser mare is to use a "phantom" mount - an inanimate mare look-a-like. Roughly 2 of 3 stallions can be trained to mount and be collected using a phantom. This method is outlined below.

When a phantom is used for semen collection it is still useful to have a live, estrous mare to tease and arose the stallion. Such a teaser mare can be seen in the picture at right standing in a stock next to the phantom.

The images below show a typical series of events in collecting semen from a stallion. Note that all the involved people are wearing helmets. Stallions are large, aggressive, unpredictable and dangerous. They frequently strike, kick and bite. Hence, personnel safety should be given constant attention.

Semen Evaluation

As for any species, semen should be evaluated immediately following collection for gross abnormalities such as blood. Normal values and ranges for stallion semen are presented below.