Section: Breeding Management of the Mare
Breeding management can be done with or without the help of a veterinarian. Degrees of intervention vary from turning horses out in pasture for natural cover to breeding a mare by artificial insemination with frozen-thawed semen. In most breeding farms there is veterinary intervention at some level. The veterinarian can perform one or several of the following tasks depending on the particular breeding situation:
Pre-season mare examination
Mare follow-up with palpation/ultrasonography (heat detection)
Semen collection and evaluation
Artificial insemination
Pregnancy diagnosis and follow-up
Twin management
Vaccinations during pregnancy
Diagnosis of embryonic loss or abortion
Diagnosis and treatment of infertility problems
Heat Detection
Mares can only be bred at the appropriate time of their cycle through good heat detection. The most common way to detect heat in mares is to tease them consistently, that is three or four times per week, by presenting a stallion in-hand. When a stallion is not available, teasing may be attempted with a gelding, but it is often inaccurate and should not be trusted as the sole means of heat detection. Alternatively, in small farms where the individual mare is being bred by artificial insemination with cooled or frozen semen and a stallion is not available, the veterinarian must rely on accurate palpation and ultrasonography of the reproductive tract to ascertain when the mare is ready to be bred. This requires expertise and accurate knowledge of the anatomy and physiology of the mare's reproductive tract.
Nevertheless, teasing with a stallion in-hand remains as the most accurate way to detect heat in mares. There are several teasing methods to perform this procedure safely and accurately:
If mares are turned out to pasture, the stallion can be walked along the fence line and mares in heat may show interest and approach the stallion. The main drawback to this technique is that some subordinate or shy mares may stay away even when in heat. Alternatively, mares in pasture can be herded into a long teasing rail or chute and this will allow individual attention to each mare by the stallion in-hand, and therefore better heat detection.
If mares are in stalls, the most practical method of teasing is to walk the stallion along the barn aisles and tease the mares individually through the stall rails. However, a few mares may stand at the opposite wall of the stall making heat detection tricky. Mares can also be walked individually into the breeding shed and placed behind teasing stocks with the stallion held in-hand and allowed to sniff and contact the mare through the rail. This system is quite accurate for heat detection purposes but is very time consuming and impractical in large breeding operations.
Mares in heat will show one or several of the following signs:
Interest towards the stallion
Allowing contact and advances from the stallion
Winking (opening and closure of the vulvar lips)
Urinating
Tail raising
Squatting or standing in the breeding position
Mares in diestrus (not in heat) will not tolerate the stallion's advances and may:
Pin their ears
Squeal
Strike
Kick
Try to get away or rear
When teasing mares for estrus detection it is important to realize that each mare is an individual and the array of signs of heat in each mare should be recognized through routine teasing and accurate record keeping. Furthermore, maiden mares never exposed to teasing may feel threatened by the advances of a stallion at first and may need some acclimation period before they feel comfortable displaying signs of heat. Most mares readily tolerate teasing and display clear signs of estrus or diestrus once acclimated to the routine.
