May I point out that there is nothing at all in that rule proposal about grandfathering in the OFFSPRING of the currently registered horses. The only grandfathering clause I see is in regard to those horses already registered prior to the date the rule change takes effect. So, if the rule goes into effect 1-1-1011 then the 2011 foals will be eligible for registration only if they do not finish up over the 38" at the top of the withers. They may very well finish up at 38" or less at the last mane hair, but not at the top of the withers….so that is why it makes a difference to have the rule start 1-1-2012 or 1-1-2013…to let the 2011 foals be registered the old way.
Will people purposefully breed for low withers? I can't say for sure--but I do think that there are a good many Mini owners and breeders who don't have a clue that well defined withers are a good thing, and so simply don't pay any attention to what kind of withers their horses have. And there must be some out there that don't care for high withers, because they don't seem to care for the improved action/way of moving that comes along with the kind of conformation that has good withers, a laid back shoulder, etc etc. If they don't want the bigger moving horses then they are likely to be breeding for lower withered horses....and I suspect there are plenty that, if they had to choose between two horses that were much the same size at the top of the wither, would choose the lower withered horse over the horse with the well defined withers.
Now, I am not saying that is any reason to not change the measurement spot to the top of the wither. The reason I say not to change to the top of the wither is that this proposal does not include any increase in height to allow for a good wither. And IMO passing this rule as it is would be taking a step back in overall quality. Why? Because those people breeding taller horses will be in luck if their taller foals finish up at 38" at the top of the wither, out of luck if the foal finishes up over 38" at the top of the wither. A horse with low withers will be more likely to have little difference between the last mane hair and the top of the wither. The horses with higher withers will likely have more difference between those two points. So....this means that if you raise taller horses, all of which finish up at 37-38" at the last mane hair....those foals that have high withers are likely to be 39" or a little more at the top of the wither. They will be out. Those with lower withers will be in. Since better withers as a rule go along with the shoulder that has a better angle--and of course not always, I've seen some butt-ugly high withered horses too!!--and better withers are associated with better movement....by eliminating one you are quite possibly eliminating the other. The hidden agenda....that really isn't so well hidden at all....is eliminate some of the taller and/or better moving horses.
I also maintain that delaying this rule to 2012 or 2013 is of little benefit otherwise. Overall it is not going to help those breeders that have the taller horses in their program. Sure, they can register their 2011 foals, but what are they supposed to do with that taller breeding stock then. Chances are slim that 10 or 12 year old broodmares are going to go back out into the showring…certainly they won't be marketable as show horses! There will be no market for them as breeding animals. How many people are going to buy 37" or 38" mares or stallions for breeding? I would guess not very many. I have gotten 37.5 and 38" foals off 36" mares bred to 30.5 & 32" stallions…and yes, those same mares have given me 36" foals when bred to a 37" stallion, so you just don't know—but I can say for sure that if I were wanting to breed AMHR Minis and the height limit is 38" at the top of the wither, I sure wouldn't be buying broodmares that are 37.5 or 38" at the last mane hair! I suspect that there are many that would agree with me on that choice. Perhaps a few would take the chance, but "a few" doesn't make much of a market for all the taller horses in AMHR.
I know those in favor of this rule change don't want to see that, and those people will say that it's not really true that this rule change would ruin a number of breeding programs the moment it is passed, but it is true. It's easy to say just make a few adjustments & all is good, but that is easier said than done in many cases. It's easy enough to do if you have plenty of money and can afford to keep those taller horses that are undesirable for breeding or if you really don't care what becomes of them & can just dump them somewhere for next to nothing and then go out and buy new breeding stock. Many people, though, don't have that kind of money—unless they can sell some horses they cannot afford to buy new ones and unless they sell some horses they don't have room for new ones and if the horses they have to sell are not marketable they don't want to just dump them for whatever they can get at some sale.