Teasing for Successful Breeding

A good teasing program is essential for insuring success in an equine breeding program. Without it, breeding can become a hit-and-miss proposition, despite the sophisticated tools that are available to veterinarians and breeding technicians.



There is a basic reason for its importance. It is one of Nature's tools to insure that there will be propagation of the species. All one need do to realize this is to observe horses in the wild.

Each band of mares is presided over by a dominant stallion which, when the time is right, will breed all mares in the band except his own daughters. The lead stallion's daughters are bred, when the time is right, often by a subservient stallion trailing along with the band. Or, in some cases, they are spirited away by another stallion seeking to establish his own band.

The behavior of the wild stallion in relation to his mares is significant and far different from a stallion in domestic circumstances. The domestic stallion, generally speaking, becomes excited at the approach of a mare, even if she isn't in estrus. He normally is kept in a box stall or paddock, and when a mare approaches or he is led in the vicinity of one, the message he receives is one dimensional--it is time to breed.

Not so for the stallion in the wild. When the mares are not in estrus, the wild stallion ignores them, sexually speaking. Actually, this attitude prevails for much of the year. It only changes in the spring, when longer days and green grass signal a change in the mare's reproductive system.

At that time, the wild stallion will tease the mares in the band on a regular basis. However, he will not attempt to breed them until they are in full estrus. Sometimes, he will breed a mare only once, having an uncanny ability to detect when she is going to ovulate. Often, however, he will cover her a number of times in a short period.

Once she has conceived, he will make no more sexual advances unless she absorbs or aborts the embryo or fetus and returns to estrus.

The procedure in a domestic situation is not nearly so simple or straightforward. For one thing, we don't wait for long days and green grass to begin the breeding season. Instead, it often begins in February, when a mare is not normally cycling.

Merely teasing a mare in February will not bring her into estrus. About the only thing that can awaken her reproductive system from its sleeping state is light. Light activates the pituitary gland and causes it to release follicle stimulating hormone (FSH), which stimulates ovarian function. Once the ovaries are up and working reproductively, the mare begins her estrous cycle. (See this month's Back to Basics, "The Essential Elements of Equine Reproduction," article #277.)

The use of artificial light can launch the estrous cycle about six weeks earlier than normally would be the case. The procedure involves utilizing a 200-watt light bulb in a box stall to extend the hours of light to 16 per day. Using a box stall generally is more effective than simply turning on lights in a large shed or paddock because one can be certain about the quantity of light received by the mare in the stall. In a large shed, a timid mare might hang back in a corner with insufficient light.

The rule of thumb is that if there is enough light by which to read a newspaper in any corner of the stall or shed, there is enough light to stimulate reproductive function.

Once the lighting system is begun in the late fall or early winter, it should be continued into the spring months. If the lighting is discontinued midway through the season, the result could be a severe upset to the estrous cycle. When you turn the reproductive season on with lighting programs, there will be a corresponding reduction in the breeding season at the other end. So if you start the lights in October or even November, mares may stop cycling in May or June.

Immediate response should not be expected. Normally, it takes between 45 and 60 days for a mare to show signs of estrus. The use of light has no bearing on fertility; it merely brings about earlier estrous cycles. Once the mare shows the first signs of estrus, a teasing program should begin.

Although the matter of lights and their effect on the estrous cycle was discussed in the article on regulating estrus in the December issue of The Horse, we would like to pass on a suggested approach to an artificial lighting schedule as presented by Dr. M. E. Ensminger in his book, Horses and Horsemanship. The lighting guide that follows is for the northern United States. Slight adjustments would be required for various geographic locations.

November 1--Lights on at 7 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6 p.m.

November 8--Lights on at 6:45 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6 p.m.

November 15--Lights on at 6:45 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:15 p.m.

November 22--Lights on at 6:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:15 p.m.

November 29--Lights on at 6:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:30 p.m.

December 6--Lights on at 6:15 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:30 p.m.

December 13--Lights on at 6:15 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:45 p.m.

December 20--Lights on at 6 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 6:45 p.m.

December 27--Lights on at 6 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at
7 p.m.

January 3--Lights on at 5:45 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 7 p.m.

January 10--Lights on at 5:45 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 7:15 p.m.

January 17--Lights on at 5:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 7:15 p.m.

January 24--Lights on at 5:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 7:30 p.m.

January 31--Lights on at 5:30 a.m. and off at 8:30 a.m. On at 3:30 a.m. and off at 7:45 p.m.

February 7--Lights on at 5:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at
8 p.m.

February 14--Lights on at 5:30 a.m. and off at 8:30 a.m. On at 3:30 p.m. and off at 8:15 p.m.

February 21--Lights on at 5:30 a.m. and off 8:30 a.m. On at 3:30 p.m. and off at 8:30 p.m.

A simpler solution is to add enough hours of light at the end of the day to provide 16 hours, combined from daylight and artificial light. The key time in this scheme is the additional evening light.

There is another concern that must be addressed before we delve further into the subject of teasing--nutrition. Emaciated mares or obese mares might come into estrus, but might not become pregnant, thus negating any efforts to get them to early estrus.

A mare also should be kept as free of stress as possible as she approaches the breeding season, and she should be involved in a good worming and vaccination program. Many veterinarians recommend that mares be wormed every three months. Consult with your veterinarian before the breeding season to see what he/she recommends for your area.

The Program

Now that we have the mare under lights, in the proper physical condition, and she is showing signs of behavioral response, it is time to begin the teasing program.

Just how important is a good teasing program? We turn to Edward L. Squires, PhD, of Colorado State University, where a good deal of research involving all facets of reproduction has been carried out:

"Inadequate or improper teasing constitutes a major cause of poor reproduction performance in mares. Normally, cycling mares should be teased daily with at least one stallion. Mares that have not achieved normal cycles and mares exhibiting the first day of diestrus should be teased with two stallions. The mare should be teased by the stallion head to head, and at the buttocks and external genitalia."

He is advocating a one-on-one teasing program. At some breeding farms, mares are housed in pens and are teased by having an attendant lead a stallion along the fence. The reasoning is that mares in heat will come to the fence and make contact with the stallion.

That approach is fine for the bold, aggressive mare, but poses problems when mares are timid or shy. Sometimes mares of this type will hang back and not show any outward signs of heat even though they are in estrus.

In any group of horses there is a ranked pecking order that starts with the most dominant mare and works its way on down the line through whatever number is present, be it two or 20. It takes little imagination to see what effect this will have at teasing time on a mare which holds pecking order number 20 in a group of 20. She is going to stay out of harm's way, no matter what is going on within her body reproductively.

Just how the teasing is done can be influenced by the size and shape of facilities at hand. At some farms and research centers, the facilities might be highly sophisticated. Some operations put a stallion in a pen in the center of the mare field and let the mares choose their contact, with the handler observing from outside the field. By contrast, the backyard breeder might have nothing better than a wooden fence to put between stallion and mare when he is teasing. Whatever the facility, the first thought should be for safety of mare and stallion and for the handlers involved.

Highly important to a good teasing program is the temperament of the teaser. A stallion which is overly vocal and aggressive might frighten timid mares. Needed is a stallion which will "talk" to the mares, but will make no attempt to bite or strike. Yet, he must be aggressive enough to elicit a positive response from a mare which is in estrus, but is slow in manifesting the classic signs.

"In any teasing schedule," advises Martha M. Vogelsang, PhD, Texas A&M University, "mares should be given adequate time to react to the stallion and the surroundings. In group teasing, using a stallion cage, mares need 15 to 20 minutes opportunity to demonstrate their behavior. In hand-teasing, several minutes should be spent with each mare. Mares in intense estrus or those in diestrus or early pregnancy will normally display the expected behavioral characteristics quickly. Mares that are just coming into estrus may take slightly longer to exhibit any signs when exposed to the teaser stallion."

Vogelsang is a strong advocate for keeping records of behavioral estrus of each mare during each teasing session and applying a numerical score for what is observed. Following is her scoring system:

0--Rejection of stallion's presence (ears pinned, kicking, biting, or pawing at stallion) or complete lack of interest in stallion.

1--Not aggressive toward stallion, but looks away or is not interested.

2--Shows interest by facial expression and might approach stallion; slow to show interest. Mares might raise tail or exhibit some winking (eversion of the labia of the vulva). Mares might show these signs at a distance, or in close proximity to the stallion.

3--More interest in stallion is demonstrated through facial expression, tail raising, flexion of pelvis (posturing), winking, and urination.

4--Intense interest in stallion as demonstrated by turning hindquarters to him, leaning toward him and exhibiting continuous winking and urination.

Keeping records as advocated by Vogelsang is highly important because each mare is an individual and will have an individual response to the stallion. Only by knowing what is normal for her and how her reaction is evolving can we be sure just what her reactions mean as the teasing sessions continue.

At one point in my equine career, we stood five stallions at our facility. Not only did we note vast differences in mare reactions, but each of the stallions also reacted as an individual whether being used for teasing or for breeding.

The reactions ranged from the eager youngster who, if allowed to, would have come out of his stall on his rear legs when a mare in estrus was in the vicinity, to the 20-year-old veteran who seemed able to tell in a heartbeat when a mare was ready to be bred. When she was ready, he did the job with no hassle and no fuss. When she wasn't, he merely turned away.

At the moment we are standing only a young cutting horse stallion to a very limited book of mares. Fortunately, he is a very polite, but aggressive teaser and is easily handled when breeding.

It is better if one doesn't have to use the stallion which is doing the breeding as the teaser. However, this is not an option at many small operations and the stallion must do double duty.

Although we only bred a few mares to our young stallion this spring, each reacted differently to teasing. It seems to me that environment could play a factor in how quickly a mare in estrus responds to teasing. The mares which live on the ranch had no distractions when being teased. They were used to all of the sights and sounds. That wasn't so for visiting mares.

Our own three mares, which have been on the place for some time, responded immediately to teasing when in estrus. They squatted, urinated, and winked and were very receptive.

The mare my partner shipped in from Minnesota was on the shy side and seemed uncertain about her new surroundings. Every new sound and movement seemed to distract her. We found that the most effective way to tease her was to lead the stallion to her paddock and wait. When in estrus, she would, at first, stand back and stare at him, then slowly approach. As mentioned, he is a mannerly young stud and after nickers and nuzzling, she would demonstrate the classic signs of estrus and become receptive, forgetting for the moment at least to be concerned with what was going on around her.

Another mare was brought over by a neighbor. She was a bit ill at ease in the beginning and she, too, seemed more interested in her new surroundings than in the stallion. After an extended teasing session, however, she began to show the classic signs.

The final mare was different from all the rest. We did the teasing with a wooden barrier between the two, and that turned out to be a good idea. She struck, squealed, and showed no interest, although the man declared she had demonstrated estrus to his stallion just before he brought her over.

Suddenly, just as we were about to call a halt to the teasing, the mare squatted and urinated. She appeared to forget about the strange surroundings and focused on the young stallion. Just that quickly she changed from totally non-receptive to receptive.

I report on these experiences to underline the need to know and understand each mare involved and to keep records of each teasing session. Vogelsang's scoring approach is a wonderful way to do this, in my opinion.


Back to the matter of safety that was alluded to above. There are several approaches that can be taken to minimize danger to all concerned.

Stall Door
Perhaps the simplest approach to teasing involves use of the half-door of a box stall. One of two approaches can be taken--the teaser can be presented to the mares or the mares can be presented to the teaser. The less time-consuming of the two is to present the stallion to the mares. With the bottom stall door firmly latched, the teaser is led to the stall and allowed to come nose to nose with the mare on the other side of the latched lower door. If she is receptive, she will allow him to nuzzle her. If not, she will likely retreat to the rear of the stall and stand there with ears pinned or even squeal and kick the door or wall of the stall.

Teasing Wall
Basically, this is the same approach as that involved with stall door teasing, but with some additional safeguards. The wall should be of solid planks and, if one is to maximize safety for both teaser and mares, both sides of the wall should be heavily padded to avoid injury if one or the other strikes or lunges. The use of a teasing wall allows a little more flexibility in handling the mare than does the stall door. With this approach, the person handling the mare can position the mare's body in relation to the wall so that the stallion can better nuzzle her.

Teasing Chute
This is another variation that sometimes is used on larger farms where a number of mares must be teased each day. The side of the chute on which the stallion approaches would be constructed much as the teasing wall--solid planks. Several mares can be put into such a chute at one time and the teaser led along it.

Teasing Cage
This method involves construction of a teasing cage in one corner of the pasture where the stallion can be released. In order for this to be effective, dominant mares would have to be removed or the result could be the same as when the stallion is led along a fence line--the dominant mares which are in estrus will come forward while the timid mares will hang back even though they might be in estrus.

Perhaps the approach with the most problems and, to the best of my knowledge, is not utilized frequently in the equine industry, involves teasing with a stallion that has had a vasectomy. A vasectomized teaser would tease, mount, and make entry, but would not impregnate. The potential problems are obvious. First, one would worry about transmitting disease and second, there would be the concern about the chance of injury to both mares and teaser.

(This approach has been perfected by the beef industry. At large breeding establishments, "gomer" bulls are used. Surgery has made it impossible for them to penetrate a cow, but all of the reproductive desires are there. When a cow stands for the "gomer" bull to mount her, she is immediately shunted off to the breeding shed and is artificially inseminated.)

When the mare has a foal at her side, the business of teasing becomes a little more touchy. Again, more than one factor is involved. Some mares are so possessive that if their foals are removed from sight during teasing or attempted breeding, they will not respond to the stallion even when in estrus.

On the other hand, if the foal is allowed too close to the mare or the stallion during teasing and breeding, there is danger of injury. The best method I have found when a mare is that possessive is to have someone hold the youngster where the mare can see it, but also where it is out of danger of being kicked or struck.

At a number of Thoroughbred farms in Kentucky's Bluegrass country, where mares often are transported short distances to the breeding farm and returned in a short period of time, the foal simply is left behind. Sometimes, the foal's being out of sight and out of hearing translates into being out of mind when the possessive mare is presented to the teaser.


Once the teaser has done his job and the mare demonstrates that she is in estrus, it is decision-making time for breeding farm personnel as to just when to breed her, whether it be through artificial insemination or natural cover. The breeding is timed as close as possible to ovulation to reduce the number of covers required to achieve a pregnancy.

The time-honored approach is to have a veterinarian rectally palpate the mare and feel the size of the developing follicle. Added to the veterinarian's arsenal in recent years, and used with regularity by many practitioners, is ultrasound. Its use adds another dimension in determining optimal breeding time. (It also is an excellent device for detecting early pregnancy.)

Also in the practitioner's arsenal are several pharmaceutical products that can suppress estrus and/or assist in "short cycling" mares, or, in the case of human chorionic gonadotropin (HCG), stimulate follicles to ovulate.

No matter how sophisticated the techniques or the hormonal treatments, however, there is no replacement for a good teasing program. Male-female contact is necessary before the true mating process begins. It is nature's way. (See "Regulating Estrus" in The Horse of December 1998, article #588.)

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.

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