Rushing a Mare During Breeding

Q: I'm a veterinarian asking this question on behalf of clients who are standing a stallion at stud.  The stallion isn't new to breeding or to this farm; he's in his third or fourth breeding season. He normally breeds eagerly, without hesitation. Recently, he's been doing something unusual just with one particular mare. He seems interested in this mare but rushes right up and mounts her before he's ready (gets an erection).  They pull him off, and he does the same thing again. If they take him to another mare, he proceeds as usual--teases, gets an erection, and waits for the handler to signal him to mount.  They asked me what might be causing his rushing of this one mare and what they should do about it.

A: What great questions! Mounting without erection happens more frequently with novice breeding stallions and is more often a general response rather than specific to one mare. But I have seen exactly what you describe in experienced breeders --mostly in stallions with the wisdom of pasture breeding experience. Yours just happens to be the third similar question on this topic in a couple of weeks, so we'll answer this one here in the column.

My first recommendation would be to convey the information that mounting without erection is a very normal part of the natural breeding behavior of equids--zebra, wild asses and donkeys, wild horses, and pasture breeding horses. In fact, observations of all these species indicate that under natural field breeding conditions, stallions mount twice on average without an erection to every mount with an erection. Under natural breeding conditions, mounting without an erection is the rule rather than the exception, most likely because as estrus progresses, most mares go through stages where we would interpret their behavior as "Yes, yes, yes, yes, please, oh please, NO WAY!"A plausible explanation is that a mount without an erection is a test of true receptivity of the mare --will she stand, or at the critical moment of vulnerability, will she let fly? This is just like the chin-resting response and "false mounts"in bulls; mounting without an erection is likely highly adaptive.  We wonder whether it is instinctive or learned.  As with almost everything else, it probably is a combination of the two.

Source: TheHorse