By B. W. Pickett, Ph.D.
Professor Emeritus, Colorado State University

Part 1:
During the past thirty-five (35) years there have been numerous changes in the art and science of breeding horses.  However, the object has always been the same, get the highest percentage of mares pregnant as possible, on the first-service (or cover),with minimum labor and other expenses. Until the 1960's it was assumed by many breeders that the reproductive capacity of horses was lower than that of other species of livestock. However, since then it has been shown that horses are just as fertile as other species when the same criteria and management skills are applied.

Prior to the advent of ultrasonography, breeding mares at the appropriate time in relation to ovulation, was the single most common reason for reduced pregnancy rates on the first-service.  Since ultrasound, breeding at the appropriate time in relation to ovulation has become a secondary problem.  It is the sincere belief of this writer that the single most prevalent reason for reduced fertility today is lack of cleanliness or sanitation .  This is due in many cases to poorly designed facilities, lack of knowledge and managerial
skills of the people doing the breeding, and insufficient appropriate equipment.

Equine semen contains a wide variety of bacteria.  Fortunately, the majority of these bacteria's are normal inhabitants of stallion genital tracts and external genitalia, while others are capable of causing infection, particularly in susceptible mares. In general, stallions do not exhibit clinical signs of disease, and in fact may not become infected, although they may transmit the bacteria resulting in disease in the mare. In addition, some bacteria and/or their metabolic by-products, detrimentally affect semen quality and fertility, while others do not appear to be detrimental. Consequently, every effort should be expended on the breeding farm to decrease the number of bacteria in semen.

At the time of natural mating, some bacteria is deposited into the female reproductive tract.  Also, when semen is collected in an artificial vagina (AV), some bacteria will be introduced with the semen into the female reproductive tract, although the number of bacteria introduced will be greatly reduced when (AI) is used, since the ejaculate is divided among numerous mares.  Further, the semen can, and should be extended with an extender containing antibiotics, which will further reduce the number of bacteria placed in the mare.  When normal, reproductively healthy mares are exposed to bacteria normally found in semen they rarely become infected. In contrast, when these same bacteria are introduced into the reproductive tract of sub-fertile, for example, aged mares, these same bacteria may persist, and establish a bacterial endometritis.  Subfertility due to bacterial infection of the uterus of mares results in a very significant economic loss to the equine industry every year.  Consequently, if significant progress is to be made in reproductive efficiency and capacity, control of bacteria in the entire breeding process is essential. Therefore, the purpose of this series is to increase the awareness of the breeder to some of the various sources of bacterial and chemical contamination of semen, and some methods of reduction and/or control.

Cleaning the collection Mare and/or Phantom
When semen is collected with an AV it is customary to use a live mare or phantom (dummy) for the stallion to mount. When a stallion mounts a mare or phantom for collection of semen, it is not uncommon for a considerable amount of clear fluid to be emitted from his penis. Generally, there is considerable movement of the mare and stallion with the result that this fluid is spread over the mare's buttocks, flanks, tail, etc. and/or over the phantom. This fluid may be nature's way of cleansing the stallion's reproductive tract prior to sexual contact. If so, this fluid may be heavily laden with bacteria. Therefore, the mare or phantom must be cleansed before each stallion is collected, (Figures 1 and 2), because the next stallion's penis may touch areas on the mare where this pre-ejaculatory fluid from the previous stallion was sprayed, and "pick up" whatever organisms were shed by the previous stallion.  The mare's tail-wrap should also be changed between stallions.

The mare or phantom should be cleansed with a tamed iodine solution wherever the stallion's penis is likely to come into contact with hair, skin, or phantom. The individual doing the washing should wear disposable gloves (Figure 1).  Further, when paper toweling or cotton pledgets are used for cleaning the mare, they should not be put back into the bucket, since this contaminates the washing fluid.

Figure 1.  Cleansing the tease mare before collecting another
stallion.  Please note that the person washing the mare is
wearing disposable, plastic gloves (arrows).

Figure 2.  Phantom or "dummy" mare used
as a mount for collection of stallion semen.

Washing the Stallion's Penis
Warm water (42ºC) (~108ºF) is placed into a bucket containing a plastic liner secured with a stout rubber band.  Again, measure the temperature, do not estimate.  A container for rinsing the stallion's penis is placed into the bucket (Figure 3).  The container used to rinse the stallion's penis should be easily cleaned, such as stainless steel, be or completely disposable. In general, use of disposable material reduces the chances of spreading disease and/or reuse of unclean equipment.  The stallion is then brought from his stall and presented to an estrous mare, if necessary, for him to attain an erection.

He should be allowed to tease the mare with as much freedom and enthusiasm as possible without endangering himself, the mare or personnel. When a full erection is attained,  the handler puts some restraint on the stallion to permit quick, effective washing (Figure 4).

Figure 3.  Bucket with water at (42ºC) (~108ºF), and cup for
use in washing and rinsing the stallions penis.

Figure 4.  Appropriate position and procedure for washing a
stallion's penis.

The individual who washes the stallion should wear plastic, disposable gloves . It is generally somewhat easier and quicker if someone holds the bucket while the stallion is being washed.  The stallion's erect penis should be deflected, not grasped, and moistened with water, and massaged gently, but thoroughly, more water is added as necessary.  The penis should be observed closely during the washing procedure for lesions, inflamed urethral orifice, etc.  When it is suitably cleaned, the penis is thoroughly rinsed (Figure 5), drying is not necessary. If the stallion's penis becomes contaminated after washing, but before collection, the rinsing procedure should be repeated.

When a stallion's penis has not been washed for an extended period,  many times excessive smegma accumulates on the penis and prepuce and adheres to the skin. If this is removed without some special precautions, a sore penis may result. The stallion should be presented to an estrous mare until he attains an erection, at which time the penis can be massaged gently with generous quantities of a warmed water-soluble lubricant, such as K-Y jelly® The stallion is then returned to his stall for 1 to 2 hr to permit the lubricant to penetrate and soften the smegma so that it becomes easy to remove by thoroughly washing the stallion's penis with Ivory® soap and warm water.  After a stallion's penis has been thoroughly cleansed, which may require several washings with soap and water, he should be washed only with clean, warm water for the remainder of the breeding season, provided, of course, that he is being collected approximately every other day. In natural service, the stallion should be washed with warm water before and after breeding.

Figure 5.  Rinsing a stallion's penis.

Collection of Semen
When the AV is ready for semen collection and lubrication has been done, the sleeve used for spreading the lubricant should be left in the artificial vagina .  Thus, when it is taken into the semen collection area, the amount of foreign material that gets in the AV will be minimized.  Do not remove the sleeve until just prior to semen collection. Unless the breeding shed, which generally serves as a semen collection area, is covered with a material, such as rubber bricks, that can be easily washed, the area can be a significant source of bacteria due to dust, etc. Assuming the floor is covered with wood shavings, tan bark, sand, etc. The material on the floor should be sufficiently dampened with water to prevent any dust from rising during the semen collection process.  In the event that the stallion has not ejaculated after three intromissions, the AV should be taken back into the laboratory and the liner changed. It has been shown that as the number of intromissions increase so does the number of bacteria in the semen.

Preparing a mare for Insemination
1.) Place mare in stocks.
2.) Place a shoulder-length plastic sleeve over one hand and arm, and a wrist -length glove over the other hand (Figure 6).

Figure 6.  Shoulder-length sleeve on one arm and
wrist-length glove on opposite hand in preparation
for wrapping a mare's tail.

3.) Make a ball of the mare's tail hair (Figure 7).

Figure 7. Making a "ball" of a mare's tail.

4.) Pull the plastic sleeve over the ball of hair and up the entire length of the tail (Figure 8).

Figure 8.  Placing a plastic sleeve over a mare's tail.

5.) When the tail is completely covered, secure the sleeve at the base of the tail with 1' porous, white, medical tape (Figure 9).

Figure 9. Securing a plastic sleeve at the base of
a mare's tail with tape.

6.) Lift the mares tail and secure it in an elevated position (Figure 10), or have an assistant manually hold the tail.

Figure 10. Tying a mare's tail in an elevated position.

7.) Apply liberal amount of warm water to the mare's perineal area (Figure 11).

Figure 11. Wetting a mare's perineal area with warm

8.) Gently scrub the mare's perineal area thoroughly with Ivory? soap. Start scrubbing
directly on the vulvar lips, then move to the anus, then to each side (Figure 12).

Figure 12. Washing a mare's perineal area with soap.

9.) Rinse the area free of soap (Figure 13), and repeat the procedure two more times ( or more if necessary).

Figure 13. Rinsing a mare's perineal area with warm water.

10.) After the final rinse, wipe the area dry with paper towels (Figure 14). Like the scrubbing procedure, start the drying procedure directly on the vulvar lips, then move to the anus, then to either side.  Be sure to carefully dry the area at the base of the tail, so if water is trapped in that area it does not run down onto the clean, dry perineum.

Figure 14. Drying a mare's perineal area with clean
paper towels.
This concludes Part 1.

Note: Many will think that some of these recommendations are trifles, but remember trifles result in excellent fertility and excellent fertility is no trifle.

Go to part 2 of this article
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