Equine Reproductive Procedures. Группа авторов

Чтение книги онлайн.

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).

      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