Horse Racing Forum - USA Thoroughbred Races

As a long time race fan, I was reading some of the posts on Zenyatta’s FBook page and just couldn’t believe some of the comments (well, actually I could). However, it did make me start wondering (actually have thought about it before) about how breeders decide – time wise – whether or not to breed the current year or wait until the following year if it's a late foal.
I know that after giving birth, most mares will have their first ovulation about half way through their “foal heat”, which appears to be 5 to 16 days (so about the 9th or 10th day post foaling). If the mare is bred and catches, then normal gestation is 11 months (usually 320 – 360 days).
So, as an example, if a mare foals on 4/20 and all goes well, then her foal heat ovulation would be around the 30th. If so, and she was bred and caught, then the resulting foal estimated due date would be late March or early April.
But, if all does not go as planned, my questions are:
1. Do breeders usually try to breed during foal heat?
2. How does a breeder decide when it’s too late to breed for the current year? I know that a lot of sheds are open through June, but that means a May foal, which I’ve read is considered a late foal.

Thanks...

ETA: If I've gotten anything incorrect please let me know...

I don't know any TB breeders, but the Gypsy breeder I know prefers to let a mare recover completely from foaling, and NOT breed on the foal heat. Yes, I know Gypsies are way different than TBs, but I think the animal husbandry is much the same.

I asked once at a farm that no longer stand stallions this question about breeding on a foal heat and was told that they prefer not to do that. This was in PA, not sure how it is in KY or elsewhere.

We've never bred on a foal heat. Generally speaking, it's just safer for the mare to give them more time to recover. A foal heat pregnancy is also a lot more likely to abort which is why many KY farms don't breed their popular stallions to cover mares on their foal heats. If you let the foal heat go by, a mare is usually ready to be bred back at around 30 days post foaling.

As for how late is too late, that's an individual decision. The latest foal we've ever had was born May 22nd. I don't mind May foals but I wouldn't breed for a June foal. The notion of a foal being "too late" really only matters for the sales. There have been many successful racehorses who were born later in the year like Northern Dancer and Lookin at Lucky (both born May 27th) and Mucho Macho Man (born June 15th.)

This year, after the long hard winter we've had it seems as though many mares are foaling late--as much as several week late. So there will be a lot of late foals this year (and next year too as mares are being bred back later than they usually would be.)

TBird wrote:We've never bred on a foal heat. Generally speaking, it's just safer for the mare to give them more time to recover. A foal heat pregnancy is also a lot more likely to abort which is why many KY farms don't breed their popular stallions to cover mares on their foal heats. If you let the foal heat go by, a mare is usually ready to be bred back at around 30 days post foaling.

As for how late is too late, that's an individual decision. The latest foal we've ever had was born May 22nd. I don't mind May foals but I wouldn't breed for a June foal. The notion of a foal being "too late" really only matters for the sales. There have been many successful racehorses who were born later in the year like Northern Dancer and Lookin at Lucky (both born May 27th) and Mucho Macho Man (born June 15th.)

This year, after the long hard winter we've had it seems as though many mares are foaling late--as much as several week late. So there will be a lot of late foals this year (and next year too as mares are being bred back later than they usually would be.)

Thanks so much TBird - especially glad to hear that many don't breed during foal heat...

So, just supposition:

If Zenyatta foals by the 20th, all goes well, and if they decide to breed her it would probably be about May 20th (if it works out to 30 days). If she catches, then her expected due date would be April 27, 2015 (using 342 days). If that were the case, I'd be surprised if they didn't breed her...

ETA: Found a great site for calculating breeding dates:
http://www.marestare.com/foalingchart.php