fence or tease rail should still be observed for estrus behavior.
Behavioral Responses
Common behavioral responses of mares in estrus and diestrus are listed in Boxes 2.1 and 2.2 and shown in Figures 2.1 and 2.2.
Box 2.1 Common Behavioral Characteristics of Mares in Estrus
Tail raised and arched or deviated to one side
Rhythmic eversion of the labia and exposure of clitoris (“winking”)
Passive urination
Ears relaxed and either held forward or in a neutral position
Rear limbs slightly abducted (i.e., wide‐based stance)
Stifles and hocks flexed
Lowering of the pelvis (i.e., “squatting”)
Leaning into fence or gate
Vocalization (squealing)
Calm behavior; does not try to bite or strike stallion
Box 2.2 Common Behavioral Characteristics of Mares in Diestrus
Tail held down or aggressively switched from side to side
Ears pinned back
Aggressive toward advances of the stallion
Biting at the stallion
Attempt to move away from the stallion
Squealing or vocalization
Calm behavior; does not try to bite or strike stallion
Figure 2.1 Mare in estrus (i.e., teasing in heat). Note the base‐wide stance, raised tail, and urination.
Figure 2.2 Mare in diestrus (i.e., out of heat) on far side of teasing wall. Note the ears and aggressive stance.
It should be noted that expression of estrus does not always indicate that a mare is in the follicular phase of the estrous cycle. Seasonally anovulatory mares, ovariectomized mares, and pregnant mares have all been reported to occasionally show signs of estrus when teased with a stallion. This may be due to submissive behavior or a lack of progesterone.
Records
Maintaining an accurate record of teasing behavior will be helpful when monitoring the estrous cycle of a mare. Notations can be made as to whether or not the mare exhibits overt, subtle, or no signs of estrus throughout a cycle (Table 2.1).
Table 2.1 Abbreviations for responses of a mare to a stallion (i.e., teasing behavior).
| Abbreviation | Levels: Option 1 | Levels: Option 2 | Behavior |
|---|---|---|---|
| H | + | +++ | In heat |
| O | – | – | Out of heat |
| H/O | +/– | ++ | Coming into or going out of heat |
| I | + | Indifferent |
Silent Estrus
Maiden mares may not show heat well and foaling mares may not show heat at all unless the foal is restrained and/or safely away from the stallion. Subordinate mares may be inhibited from expressing estrus in the presence of a dominant mare. In addition, a mare may have a preference for, or an aversion toward, an individual stallion. Mares with “silent estrus” may have lower concentrations of estradiol 17 β than mares expressing normal estrus.
Additional Comments
There are many systems used for teasing mares, including chutes, rails, fences, pens, and paddocks. Keys to successful teasing are patience, persistence, and knowing the behavioral characteristics of each mare. Consequently, it is advantageous for the same individual(s) to tease mares each day, so that slight variations in individual responses can be recognized.
Further Reading
1 Ginther OJ. 1979. Reproductive Biology of the Mare: Basic and Applied Aspects. Ann Arbor, MI: McNaughton and Bunn, pp. 59–68.
2 McCue PM, Scoggin CF, Lindholm ARG. 2011. Estrus. In: McKinnon AO, Squires EL, Vaala WE, Varner DD (eds). Equine Reproduction, 2nd edn. Ames, IA: Wiley Blackwell, pp. 1716–27.
3 Tail Wrap and Preparation/Washing of the Perineum
John J. Dascanio
School of Veterinary Medicine, Texas Tech University, USA
Introduction
The mare’s perineum should be washed prior to internal reproductive procedures and in preparation for foaling, to remove gross debris and to reduce bacterial numbers. In addition, the perineum is washed prior to perineal surgery such as the placement of a Caslick suture (vulvoplasty). The perineum is also washed as part of the minimum contamination breeding technique to reduce contamination of the uterus during natural cover or artificial insemination.
Equipment and Supplies
Tail wrap, tail rope, non‐irritant soap, roll cotton, stainless steel bucket, plastic bag/bucket
