Linda_d wrote:I think the biggest reason for low conception/live foal rates is that domesticated horses are bred primarily for performance rather than primarily for producing off-spring. A dairy farmer isn't going to make any money if his cows don't get pregnant so that they can freshen (produce a calf and provide milk) next year, but a TB breeder isn't going to make money if his horses don't actually win on the race track (either for him or for somebody else). So, the dairy farmer culls cows that don't produce calves every year while the horse breeder culls mares that don't produce winners regularly, and will keep a stakes winning mare that only produces a live foal every other year if her foals win stakes when they do get to the track. Moreover, it's likely he'll keep a filly or two from that stakes winning mare for his broodmare band, especially if they're stakes winners themselves, and the stakes winning colts from this mare may go on to become sires, passing on many of her poor reproductive traits to their daughters.
For feral horses, as for dairy cattle, breeding "success" is producing a foal every year, so getting in foal and being able to carry and birth that foal is selected for first. For domestic horses, getting in foal and being able to carry and birth the foal are much less important than producing a foal that goes on to eventually be a great performer.
Bingo!
