HGG Community Forums

While a horse's own PT has nothing to do with breeding, their AFPT (average foal performance testing) does have to do with breeding because the PT a horse can produce in their foals is reflective of their breeding ability. To calculate AFPT, average all the performance scores (PT) of the foals. Mares with a higher AFPT have greater breeding ability than those with lower AFPT.

PT doesn't have much to do with breeding. However, some people like a high PT on their high star stallions to show that they have progressed a certain amount to be able to throw high stars. However, I've had B papered 13PT stallions before....

AFPT is the the PT average of all of the foals which can be a good indicator of the parent's breeding ability. Because good parent breeding ability can mean good foal breeding ability or good foal showing ability.

My problem with AFPT in mares is sometimes, for example I have a 2G closed gene mare. So sometimes she will get a 2G B papered closed gene stallion. Other times she gets a 2G A papered stallion if I have one for that gene. Even other times she'll get a star stallion so I can get that gene on some show ponies. So the AFPT on MY horses gets messed up. The other problem I have is I don't PT test my 3G foals in this example.

The older a mare is, the more reliable her AFPT is. The first year she can have a crazy high PT foal, or a really low PT foal. From the edges of her range. But when they are older its more reliable. Which is why its amazing that that 19YO mare you have has such a high AFPT.

The other thing to consider is if you cull lower PT foals then that will also mess with your scores. So if you have a 15YO mare with no foals that's a good indicator she needs to be culled....

Most people only cull by AFPT with mares that are at least a certain age. So that way they know that outliers aren't going to hurt it as much.

Pasture bonus will also affect AFPT. If your favorite mares get pasture bonuses, then they will not produce foals from the complete bottom of their range. The other mares without as much pasture bonus will still have foals from all of their range. So their foals will have a greater "standard of deviation" and a slightly lower AFPT.


So....if you have a group of mares, from a similar age group, paired with similar quality stallions, with consistent similar pasture bonuses, and you either keep track of the culled foals PT, or look at how many foals a mare has (assuming you've bred her every season), then sort by AFPT like you have, and you can start selling the mares that are near the end of the list.

I'm super impressed by people who can cull mares by AFPT. Although unfortunately due to how my barns are run, I just can't. Sometimes I breed just for auction fodder, and SBA everything with no pasture bonus. Other times I want some flashy show horses/broodmares, so I let foundations or 2G's hang with my star stallions. Some horses have 30 days pasture bonus. Other horses have none.... Sometimes I have a PF stallion, other times an expro. On breeding horses I don't PT at all, so there will be no AFPT on their parents. ETC. So although it doesn't work for me, I do encourage and applaud that you are trying, and I hope someone that does cull mares by AFPT will be able to help you.

So... way too long story short... The mares at the top of your search there, are going to have a tendency to be better than the mares near the end of your search.