Teasing and Insemination Methods for Breeding Mares

Oklahoma Cooperative Extension Service • Division of Agricultural Sciences and Natural Resources
Gregor Morgan, Asso. Professor Veterinary Medicine
David Freeman Extension Equine Specialist
Stacy Lee, OSU Equine Center Manager

Teasing Systems for Detecting Estrus in Mares

In the wild, a mare in estrus and the stallion will actively seek one another to ensure that breeding occurs. While this method may he used with a band of domesticated mares in which the desired stallion is turned with the group, the risks of injury to stallion, mare and foals can be quite high. Consequently, stallion owners are not willing to risk injury to their stall ion or to client mares and foals, so alternate methods of detecting estrus have been developed.

Accurate estrus detection will assist in efficient use of labor, stallion semen use, and ultimately, overall conception rates on breeding farms. Conception rates are highest in mares when they are inseminated between the time period of 36 hours before and up to the time of ovulation. Ovulation occurs most frequently 24 to 48 hours prior to the end of estrus, and estrus duration is usually three to seven days in length. During estrus. the majority of mares will show signs of sexual receptivity. Careful monitoring of this receptivity combined with the use of rectal palpation and ultrasound to verify the follicular status of the mare enables breeding managers to minimize the number of necessary inseminationsto obtain conception. Many commercial breeding farms have been able to have a large percent of conception on one time breeding when employing accurate use of these methods.

Several key items must be considered when planning a teasing system. Teasing systems require a person with expertise ofestrus behavior of mares. The individual responsible for teasing must fully understand estrus behavior, factors that can affect it, and possess a well developed power of observation to detect subtle behavioral differences in mares.

Special facilities for teasing may need constructed. Design of the facilities should include both horse and human safety factors. Also, location of the facilities should provide easy access of mares and farm personnel.

Usually, a teaser stallion is maintained on farms with a large number of mares. Overuse of the breeding stallion as a teaser should be avoided to reduce the potential of breeding stallion injury. Also, stallions used heavily for teasing may develop "frustration-induced behavior changes. If breeding stallions are to be used as teasers, they should be rotated and never physically abused for their sexual advances toward the mares.

Teasing Score

Some type of a scoring system should be utilized so that progressive changes in a mare's behavior can be followed as she enters and cycles through estrus, and so breeding histories of individual mares can be recorded for future evaluation of estrus. The majority of mares are very consistent from year to year in their behavior however, mares are extremely individual in their response and many factors can influence the observed estrus behavior.

A normal expected response of a mare showing signs of estrus to a teaser stallion includes obvious interest in the stallion, urination, vulva] winking and squatting. However, a significant number do not respond appropriately and estrus behavior is suppressed. The mare may appear disinterested to the stallion and lack other visible signs of estrus even though she is ovulating. There are many circumstances that estrus behavior suppression has been known to occur:

Some wet mares in the presence or absence of their foals.
Very hot, cold, wet or windy weather, or abrupt changes in the weather pattern.
Before feeding.
Old mares/maiden mares.
Presence of many biting insects, or other distractions moving mare attention away from the stallion.
Early or late in the breeding season.

Dates, teasing scores, palpation and ultrasound records (if done), breeding dates and many other pieces of information must be recorded accurately. Should a poor breeding season result, records are essential to identify the possible reasons so corrective measures can be facilitated. One commonly used system to record estrus behavior is given below.


1.Diestrus-obvious hostility to the stallion; ears back, striking, biting and squealing
2.Indifference, passive behavior
3.Slight interest in teaser, may urinate with vulval eversion (winking)
4.Obvious interest in teaser, urination, vulval eversion
5.Strong interest in teaser, frequent urination, vulval eversion and squatting

On many breeding farms, mares are teased every other day of the breeding season until they are confirmed pregnant. Those mares exhibiting behavior relative to a tease score of 3 or larger are checked further by palpation or ultrasound to identify the follicular status of the ovaries and other conditions of the reproductive tract. These pieces of information assist the breeding manager in the decision to breed a mare on that day.

Teasing Methods

Exposing the mare to the teaser is done routinely every other day to every day depending on individual farm programs. The method in which it is done varies widely depending on such factors as pasture and alleyway layout, available facilities, types of mares (wet or dry), quantity and quality of available labor and the type of teaser stallion used. The main consideration of choosing a teasing method should be the safety of horses and humans involved.

Stall teasing. This method can be very destructive and injurious to all concerned. If a mare has a foal at side, she may not show estrus well in a confined space and in the presence of her foal. This method is practiced more so on Thoroughbred farms.

Teasing bar/rail. In this method, mares are led individually to the teaser and allowed to make head to head contact over a well constructed partition physically separating the two animals. Foals can be left in the stalls to allow the mare to pay full attention to the teaser. This method is labor intensive requiring handlers for the mare and teaser.

Teasing over the paddock fence. A specifically constructed area offence enclosing the mares in their paddock is a quick and relatively safe way of teasing the mare group. Most mares will move towards the teaser, some will show obvious estrus and others hostility. However, a number will remain neutral which requires them to be haltered and teased individually. This method is best suited forsmaller groups of mares (15 to 20) and is most suited to barren mares. Foals are at risk of injury.

Teasing chute. In this method, eligible mares are run down an alleyway and the teaser is led alongside each mare. This is a rapid teasing method but has the potential for injury. Mares and foals should not be in the chute together. This method is best suited for barren mares.

Teaser led through the paddock. This method has the potential to be dangerous for the safety of horses and handler. However, with proper handling and training of the teaser and with small groups of barren mares (6 to 8), this is a quick method of teasing.

Confinement of the teaser in a stout pen in the mare paddock. Comparatively, this is a natural method that requires minimal handling of animals. However, it is essential that the mare herd be watched closely by someone knowledgeable of differences of estrus behavior in mares, and how herd behavior can affect estrus.

Under most circumstances, mares are teased in the morning. This timing has its disadvantages, particularly in the case of stalled mares. Usually they have finished feeding and are anxious to get out with their foals and exercise. When accustomed to this routine, they may have little patience for the teaser. However, after a days grazing, their attitude towards the teaser is very different and more amenable to accurate teasing response. If afternoon teasing can be facilitated for stalled mares, the outcome may be more rewarding.

Additional Aids to Teasing

1. Instruct all farm personnel on the signs of estrus so they can inform the person in charge of teasing, should they notice a mare "showing to her foal or other mares in the stall or pasture.
2. Assign one reliable person the responsibility of teasing, and check that they are recording information on all mares teased.
3. Construct a "foal holding pen close to the teasing rail! chute (if using) as some mares will not show unless she knows her foal is close by her side.
4. Regardless of which method used, twitching mares to tease is both unnecessary and often misleading. Many times, a twitched mare will show estrus when in fact she is not.

The results of teasing cannot be conclusive in every case due to individual variations in response and the limited time available in many cases to expose mares. Therefore, rectal palpation of characteristic changes in the mares reproductive tract by a qualified veterinarian should be utilized in the overall management program to confirm the diagnosis of sexual state.

Natural and Artificial Insemination Methods for Breeding Mares

There are basically two methods of breeding a mare: natural cover by the stallion or collection of the ejaculate from the stallion by artificial means, followed by processing of the semen and artificial insemination (A.T.) of the mare.

Regardless of the method, proper management and handling of the stallion through the breeding process is critical to a successful breeding program. A person who is knowledgeable of horse behavior must be in charge of stallion handling as these animals can be very dangerous during breeding to both humans and the mare. At the same time. the stallion himself can be at risk of injury by the mare unless she is properly handled.

Many young stallions can be very hesitant to breed when beginning service as a breeding animal because of discipline measures he might have received under a previous training or showing program. It is not unusual for the stallion to have been punished for displaying normal sexual behavior prior to becoming a breeding animal, and retraining these animals can be very difficult and occasionally impossible. One needs to be careful not to severely punish young stallions for displaying normal sexual activity if he is potentially to be used later at stud.

Normal stallion behavior at the time of breeding consists of a courtship pattern. Usually the stallion fixes his eyes on the mare and arches his neck, followed by pawing and restlessness. He then usually shows a marked curling of the upper lip (Flehmen response). The stallion then usually approaches the mare at her head or neck, nickering to her. He may nip. nudge or smell her neck and body along her flank, and her external genital organs. By that time, most stallions are ready to mount and breed the mare.

Breeding Shed

Most farms utilize enclosed breeding sheds that assist in providing a closed, clean environment with limited distractions. The area should he relatively level, free from sharp objects or miscellaneous equipment lying on the ground, and have a non-slip surface for footing. Sand. crushed limestone, pea gravel, clay and rubber matting are examples of floor coverings used effectively in breeding sheds. Maintaining a well] ii~hted. dust free, clean breeding area will assist in safety and horse health. The area should be large enough (minimum of 30 feet by 30 feet) so handlers or horses can move safely out of a dangerous situation should one arise. Entrance and exit ways of stallions, mares and breeding personnel must be preplanned to insure safety and ease of use.

Natural Breeding

Natural cover breeding is required by some breed associations ~ the Jockey Club for Thoroughbreds is the most notable. In addition, several producers utilize natural cover because it requires less knowledge and abilities in semen handling, and it does not require an A.I. technician. It is. however, not without disadvantage. Apart from the risk of injury to the stallion associated with natural breeding, there is danger of spread of venereal disease to mares through

breeding and the stallion himself becoming infected. There is even a possibility of the stallion spreading it from mare to mare during teasing or courtship. Disposable materials should be used whenever possible to minimize the chances of spread from stallion to mares and possibly other stallions. Non-disposable equipment that might come into contact with disease organisms should be restricted for use on a specific stallion.

While in the wild, stallions may breed several mares several times a day. Under most stud farm management policies, stallions are allowed to cover mares one to three times every other day. Prior to breeding, the mare's tail should be wrapped and the external genital organs and the surrounding body area should be washed, preferably with water alone. Many soaps may adversely affect semen and are unnecessary to get the mare clean for service. Mares with caslicks will need them removed prior to covering.

It is usual practice to provide some type of restraint to the mare being bred naturally to protect the handler and stallion. Farms have used breeding hobbles, twitching the lip or ear (not recommended), quick release knee-strap (can cause the mare to be too unstable), or putting felt boots on the rear hooves of the mare. Maiden mares may need additional restraint until they become more acquainted with the breeding act. All these are intended to prevent injury to the stallion as many mares, even in strong estrus, may strike at the stallion. Mares will particularly strike at the stallion after ejaculation is completed and he is dismounting.

When the stallion has gone through the preliminary courtship and has a full erection, the penis is usually washed with warm water only to remove obvious debris. Paper towels or non-lint surgical wrap should be used to dry off excess water. The stallion is then lead to the hind quarters of the mare from one side (usually the left) with the stallion handler on his near side. For safety reasons, the mare handler must also be on the near side. Upon mounting, the front legs of the stallion may be held forward and against the mare's chest. He then usually does a stamping dance with the back feet, and ejaculation itself is indicated by a flagging of the tail and cessation of the back-feet dancing. Following ejaculation, the stallion usually pauses before slowly dismounting. The penis is usually washed off with warm water immediately following dismounting. Stallions are prone to kicking at this time so caution is advised.

Artificial Breeding

Artificial breeding requires more labor and greater expertise in semen collection, handling and insemination. Also, more equipment is necessary to ensure semen viability between collection and insemination. However, artificial breeding has several advantages that make it the method of choice for breeds allowing it to be used to produce registerable foals. It greatly reduces the transfer of disease because of the lack of contact between stallions and mares. In addition, A.I. allows breeding of physically impaired mares, management of unruly stallions and it reduces the stallion ejaculates for the season by allowing multiple mares to be bred from single ejaculates. Also, because semen is usually evaluated upon each collection, problems with semen quality are readily noted. The chances of stallion and mare injury are reduced notably when using a collection dummy instead of a jump mare.

The semen is collected using an artificial vagina (A.V.). The A.V. is constructed to simulate the temperature and pressure of the mare's vagina to induce the ejaculatory reflex. Several models of A.V. s have been used successfully, but the Colorado model and Missouri model are the two most frequently used in Oklahoma. The A.V. is composed of an insulating jacket which surrounds a water filled rubber boot. Temperature and pressure is important to elicit the ejaculatory response. The internal temperature of the A.V. should be between 110 and 1160 Fahrenheit at time of collection. Temperatures greater than 120 Fahrenheit may damage sperm. Pressure in the A.V. can be controlled by the amount of water in the boot or by pumping in air. The pressure should be set such that the penis fits "snugly in the A.V. Stallions will require small differences in both pressure and temperature for proper collection. Therefore, individual requirements should be recorded and used each time the stallion is collected. The rubber boot is lubricated with an appropriate non-spermicidal lubricant. A collection bottle is attached for semen deposition on the end of the boot. An in-line filter placed in the A.V. collection bottle is normally used to separate the sperm rich fraction of semen from the nonsperm fraction, or gel.

Basically, the stallion is stimulated (teased) as for natural breeding and prepared similarly. A mare in estrus is normally used to tease the stallion, and used for the stallion to mount if not using a collection dummy. When trained, many stallions will need little stimulation before mounting, reducing the need for an estrus mare to be present.

A collection dummy, also called a mare phantom, is used on most breeding farms using A.l. Dummies vary in size, elevation and angle due to individual breeding manager's or stallion preference. Simple designs use large water heater casings or two 50 gallon oil drums welded together for the center core. These objects are covered with several layers of foam padding surrounded by a durable. nonabrasive covering made from material such as canvas or leather. The mounting dummy is constructed on top of two pipe legs. The legs are securely anchored in the ground and are made to be adjustable so the dummy can vary in height and angle. A common mistake is to set the dummy to high for the stallion to comfortably mount.

Upon mounting a jump mare or breeding dummy, the stallion's penis is directed into the A.V. by the A.I. technician. As with natural mating. it is important that the stallion handler, mare handler (if using a jump mare), and the A.L. technician be on the same side during the collection process. The A.V. is held at a height and angle to simulate the position of the mare's vagina. The stallion's reaction time should be the same as if breeding a mare.

Once collected, the semen is usually evaluated for concentration, motility and normal morphology. These evaluations are used to calculate the necessary amount of semen. Semen is highly susceptible to cold shock, so maintenance (in a warm environment by incubation) of semen and all evaluation and insemination equipment is necessary.

Once collected, the semen may then be used in one of three ways:

Insemination without dilution into one or more mares.
Diluted with appropriate semen extenders containing antibiotics and energy source for insemination into one or more mares.
Centrifuged and re-suspended in semen extenderto reduce bacterial content and inseminated into one or more mares.

Raw semen should be inseminated within one hour, while extended semen may be stored under special conditions for two to three days before losing all motility. At room temperature, it should maintain excellent fertility for at least four to six hours. Good fertility has been achieved with insemination of as little as 100 million live, motile sperm. A single ejaculate may have 60 to 120 times this number. Normally, however, a minimum of 300 to 500 million live spermatozoa are recommended to be inseminated.

Routinely, insemination of the mares immediately follows semen collection, evaluation and calculation of insemination dose. The mare is restrained in a set of stocks constructed with a solid hind gate that serves to protect the A.I. technician from being kicked when inseminating. The mare is prepared by wrapping the tail, and washing and drying the vulva and perineum. The necessary dosage of semen is drawn into a previously incubated syringe and insemination pipette. A sterile obstetrical sleeve is used to cover the palpating arm. A suitable non-spermicidal lubricant is applied to the sleeve. The insemination pipette is guided through the cervix into the mares uterus by vaginal palpation. A finger is used to guide the pipette tip through the cervix into the uterus, where the semen is deposited.

Overall conception rates can be affected by numerous factors, stallion semen quality, mare body condition, herd health programs and nutrition to mention a few. Acceptable rates of conception, greater than 90 percent of the mares bred having live foals, have been achieved successfully by natural and artificial insemination methods. Regardless of themethod of choice, it is imperative that highly skilled, trained, knowledgeable people are in charge of a farm's breeding program.

Oklahoma Cooperative Extension Service • Division of Agricultural Sciences and Natural Resources
Gregor Morgan, Asso. Professor Veterinary Medicine
David Freeman Extension Equine Specialist
Stacy Lee, OSU Equine Center Manager
Visit: Oklahoma State University for more information on the health of your horse.