I have been reading all over the internet about this, but only its been reversed. Breeding the smaller mares to the bigger studs. But say you breed a 16.2 hand mare to a 12.1 hand stud. Does the foal tend to take the size of the dam or the sire?
How big do the foals tend to get?
This is a topic I am interested in, as well. I am barely over 5’, and would at some point I would love to breed my 16.1h mare to a pony to get a smaller horse for me to ride.
Honestly, I’ve never noticed a difference. I’ve seen short foals and tall foals from either combination, it just seems to depend on the genetics inherited and the way the foal is fed.
However many people will swear by one combination over the other. 
I have a 15.3 hand TB mare I have bred to Roc USA twice and Ralando.
Right now the 6 year old is 16.3 and 2 year old brother is almost 16.2! The Ralando colt is very tall and will probably be 17 hands.
So while my mare is small, she produces the stallion size and some.
So I bred her to a small section A welsh pony stallion. The foal is a year old and he is about 13.3 right now. He will probably end up around 14 hands. Foal looks like a welsh pony and is very well proportioned. Good mover and good conformation.
I wasn’t sure what size foal she would have but it looks like my caution in only breeding to an 11 hand stallion was right because he will barely make a large pony!!!
I would do it again because this welsh foal is adorable, super smart and such a character!!!
Here is a picture of my 2 year old and the pony foal. Same mom and they are a year apart. 
I have a small Thoroughbred who was used as a broodmare by her previous owner and bred exclusively to a Welsh pony stallion. The babies which I have been able to find and follow on the internet are medium and large ponies. One of them has a photo in which he looks like he might have grown out of pony size into a small horse, but I’m not sure because the woman who is holding him in the photo might be very short. But all of the babies are smaller than the mom.
I think its a crap shoot - some times they come out tall, sometimes small, sometimes in between. Knowing if a particular horse tends to “throw big” etc may give you a better idea (like my appy mare was by a 15.3 hand stallion from a line known for “throwing big” and has matured to 16.3 - taller than her 16.1 1/2 dam).
Heck, its the same with people. I know a couple, she is short, 5’1", he is tall 6’2", one of their sons is short 5’2" and looks more like “mom”, the other son is tall 6’1" or so and looks like “dad”.
I would say an “in the middle” out come is less likely than tall or short when mixing two unlike kinds.
A word of caution, when you breed big to little, not everything comes out medium size. I bred a WB mare to a Morgan stallion, and the offspring has a lovely refined Morgan head, and big WB teeth and tongue. We cannot find a bit that is comfy for him.
At the quarter horse farm next door, they regularly breed regularly breed their stud to draft and draft cross mares so they have nurse mares. The babies often have bigish draft frames and small upright pasterns and feet.
OMG they both are GORGEOUS! They both look like each other in a lot of ways too!
It doesn’t have to be a crap shoot if you know your bloodlines and do your homework. That being said, a lot depends on breeding what to what!
For example, if you are going to breed a warmblood mare to a crossbred pony stallion (combination of various breeds, i.e. Welsh/TB stallion), it may be a lot harder to predict height, as you don’t know if that crossbred stallion might pull in some height from the Thoroughbred parent.
The cross that will give you the best indicator of height is breeding with one purebred parent. i.e. crossing your warmblood mare with a purebred Section A or Section B Welsh Pony stallion. Welsh ponies, in particular, are bred with height in mind, so there is often less chance of suddenly getting an “unknown” height getting thrown into the mix. Section A Welsh Mountain Ponies, for example, are bred to be a maximum of 12.2 HH in North America. A maximum of 12.0 HH in the UK.
If you are wanting the foal to stay under 14.2 HH and remain a pony, I personally would not breed a mare taller than 16.0 HH or 16.1 HH…and that would be crossed with a purebred Section A Welsh Mountain Pony stallion or a smaller purebred Section B Welsh Pony stallion with no height in their pedigree. Now, people have done that cross with a taller mare and a taller pony stallion, but it then becomes a bit of a crap shoot. There are never any guarantees, but sticking with a Welsh stallion under 12.3 HH and a warmblood or TB mare 16.0 HH or under will give you the best chance at producing a foal that remains under 14.2 HH.
Below are a few photos of foals by our purebred Welsh stallions and out of warmblood and Thoroughbred mares. All have stayed pony height.
14.2 HH Grey over fences - 12.2 HH Section B Welsh x 14.2 HH Thoroughbred mare
14.1 HH Bay head shot - 12.2 HH Section B Welsh x 16.0 HH Hungarian Warmblood mare
14.2 HH Bay over fences - 11.1 HH Section A Welsh x Thoroughbred mare
13.3 HH Chestnut head shot - 11.1 HH Section A Welsh x 15.2 HH Thoroughbred mare
It is fairly common to breed Tb x Connemara and Tb x WB (I prefer Trakehner). I have gotten more size when the mare is the Trak or TB.
Examples:
Mare (17 hands) x Sire (14.2) has equaled one who is 15.3 at Five, one is 15.2 at only Two years (full siblings, string tests to 16 hands) and the colt from this year is the same size as a same age filly who’s parents are both good sized horses.
Mare (14.1) x Sire (16.3) equals a 14.3 as a Two year old, who might go 15.1 at maturity.
Mare (15.2) x Sire (15) got 15.1 (expected).
Will be interesting to see what the Mare (13.3) x Sire (16.3) produces, size wise.
We have just bred our new 16.0 1/2 HH Dutch Warmblood/TB mare to our new Section B Welsh Pony stallion, Daventry’s Power Play. He currently measures 12.3 1/2 HH and we hope to get a nice large pony out of the cross!
[QUOTE=csaper58;7659752]
At the quarter horse farm next door, they regularly breed regularly breed their stud to draft and draft cross mares so they have nurse mares. The babies often have bigish draft frames and small upright pasterns and feet.[/QUOTE]
(sorry to derail)
Uggg - so what do they do with these franken foals? I understand that “nurse mares” are a necessary evil at times - but it seems that often very little thought is put into the other life that is a product of it 
I read a study where they compared the size of horse foals from the same breeding in ET ponies and ET horses, and also the size of pony foals of the same breeding in ET ponies and ET horses. In all cases, the size of the foals in ET horses were larger than the foals in ET ponies and the size differences remained through adulthood.
So, this suggests that a horse mare in general is expected to have a larger than a pony mare regardless of genetics.
In our case, we purchased a 16.3H hanoverian/TB that was bred to a 14.3H connemara stallion. The resultant filly is now 6yo, between 15.2 and 15.3 and a wide ride . Really lovely mare. I’m now a big fan of the connemara crosses.
I’m siding with Daventry on this one. I know what my stud’s sire has produced over the years bred to a variety of mares of sizes ranging from 13 hands to well over 16 hands. At this point I think it makes predicting size of the foal even if the mare is maiden much less of a crap shoot. Same with my stallion though he hasn’t been bred to a lot of mares. He has been bred to a range of sizes that has given me a far better idea of what he’s likely to produce height wise. It’s easier to do that with a stallion for obvious reasons as opposed to a mare which is likely to have produced fewer offspring over time. As far as will you produce more size if the mare is larger than the stallion…?..I’ve seen it go all over the map even within the same breed. Know your bloodlines and make sure you know them more than a few generations back
I bred my 16.1h Hanoverian mare to a Section A Welsh pony (he was about 12.1h). I did A LOT of research on picking a stallion that really produced his type, movement and height, even when bred to pony mares. It took me abut 6 months to pick a stallion as I was really aiming to get a true pony out of the breeding, essentially a type consistent with a GRP.
Resulting pony just got his permanent pony card and doing Third Level dressage. He routinely wins against his WB competitors at good sized rated shows. He is also often Pony HIgh Score and Year End High Score Pony.
[QUOTE=Daventry;7659890]
Below are a few photos of foals by our purebred Welsh stallions and out of warmblood and Thoroughbred mares. All have stayed pony height.
14.2 HH Grey over fences - 12.2 HH Section B Welsh x 14.2 HH Thoroughbred mare
14.1 HH Bay head shot - 12.2 HH Section B Welsh x 16.0 HH Hungarian Warmblood mare
14.2 HH Bay over fences - 11.1 HH Section A Welsh x Thoroughbred mare
13.3 HH Chestnut head shot - 11.1 HH Section A Welsh x 15.2 HH Thoroughbred mare[/QUOTE]
After reading your post, my virtual trailer is now full of ponies. lol.
[QUOTE=smith_sporthorses;7659593]
But say you breed a 16.2 hand mare to a 12.1 hand stud. Does the foal tend to take the size of the dam or the sire?
How big do the foals tend to get?[/QUOTE]
You will have a small horse. It will look typically like an overgrown pony. Everything will be where is “should” be, with the exception of height which will be shorter. Historically, you don’t want to exceed 15.3 with your mare if you intend to breed for ponies.
My boy Empire’s Power can be a great downsize for the bigger mares as well as an upsize for pony mares. He’s 14.3. the folks that have bred their big mares to him have been very happy with their babies. this for epowers above
www.empirespower.com
We have a mare here that is out of a 17 hand WB mare by a section A pony stallion. She is 3 1/2 and looks like she will stay a LG pony unless she has some crazy growth spurt. Her breed and I both were shocked. She is bred to a WB stallion this year and we are hoping that some of her taller genes will kick in. Time will tell.
We also bred our sport pony mare to a Wb stallion. The resulting foal at 4 months old is just as tall as mom. He was born normal size but has grown leaps and bounds since he hit the ground. We have done several of the “predict foal mature height” and all have him in the 15.2+ range. Based on his size compared to the other foals, I would say that could be very likely and exactly what we were aiming for when we did the cross.
Here he is at 3 months
https://www.facebook.com/WorthAShotFarm/photos/a.1407780046146536.1073741827.1407586846165856/1458727864385087/?type=3&theater
Perhaps not an issue but my concern would be what happens if the foal takes on more pony characteristics and is too small to nurse. Is that a possible risk factor?
