Article on thehorse.com about genetics of height

[Gayle_in_Oregon]

[QUOTE=arlosmine;7330786]
It’s much less predictable to breed extremes in type and size to one another. Rather than a blend of the two, you can get “Frankenpony”: horses head, pony legs, horse body, pony feet.

I have three warmblood X Pony crosses:

One is a Haflinger X Hanovarian. Han sire was about 16.2, Haffy mom was around 13.3. My guy is 14.2 and weighs 1000lb. His head is the same size as my 16.2 hand cob cross. (thank god it’s a cute head!) he has a longish, stout body on short legs. He is rather oddly proportioned, but correct work has muscled him in the right places, and he no longer looks like he is going to tip over and land on his nose. He has lovely big bone and big hard feet. BEST BRAIN EVER. He moves like a pony until you get him through his back, then he is much improved. He is the best school horse in the world since I can put tiny children and larger adults on him. He is fantastically trainable: not a world beater athlete, but I have made a personal project out of him because he is tries so hard. I will show him second level this year.

I also have a coming three year old Wesser Ems gelding. Fancy! His dam is a 12.2 hand section B welsh pony. Dad is DSF Farscape, a 16.2 hand Westfalen. yesterday I measured “Fig” and he is 14.1/2" at the wither. Right now he is level and looks almost ready to back. The string test says 14.2…but we will see. I may have a hony on my hands in a few years, but since my sport of choice is dressage, I opted to risk getting a little oversize, rather than under. If he goes “over” my back-up plan as marketing him as a hunter pony goes up in smoke. I have to wait until he’s six and gets a permanent card before I could ask real money for him in the hunter market, since he’s an F-1 cross and could well have a late growth spurt.
He is a more harmonious blend of horse and pony parts. He looks and moves like a small horse, with really good horse gaits. His walk, in particular is very nice…an 8 at least (let’s hope it stays that way with a rider on him!) His temperament is fantastic.

Finally, I have a Cob X TB cross. Mom was a 16 hand TB, dad a 14 hand Cob. This guy’s hocks, head, knees and feet were all so big when he was a yearling that he looked like a great Dane puppy. He was down hill forever. When he finally leveled out at five I thought he was done growing at 16 hands. Then he grew another 2 inches between his fifth and seventh years. I researched both parent’s ancestors, and found that the mare had two full brothers over 17 hands. The sire had some of the very tall Cobs a few generations back in his pedigree. All the latent “tall genes” in mom and dad got together for my guy. He has been a wonderful horse. We evented, showed in open dressage, went horse camping…you name it. Another stellar temperament.

So: it is a crap shoot! If you are needing a specific size, you are not likely to get exactly what you want. If you would breed your mare regardless of size, go ahead. I would look at the size behind the mare, and for sure breed her to a stallion with lots of babies on the ground to get an idea of what he throws.

Then there is the possibility of a frankenhorse… I love my Haffy cross, but if I was trying to breed for a horse for myself, I would have failed.

Good luck! Pony crosses are delightful :)[/QUOTE]

As the breeder of Fig…here are some thoughts…my pony mare, his mom LOOKS like a small horse…she has the pony ears and ‘bunny’ tail of a Welsh B but otherwise, she looks like a very good small horse. Her neck is long, he hip is longish and she is refined like a small T/B or Anglo Arab. So, she is phenotypically “Typey” like a horse. The stallion we bred her too is also “Typey” and not a big warmblood horse but just proportionatly like the pony mother. I do think height is a multi-gene characteristic. Some of height is in the lower legs, some in the upper leg and a lot in the body and wither…so a low withered horse/pony may be shorter than the exact same horse/pony with tall withers which are just fingerlike projections of the spine…A soft pasterned equine will be shorter than the same one with straight pasterns. So, the article is correct but way over simplified in my mind on all the variables that affect genetically affect height. Breeding a T/B to a really ‘cobby’ or draft pony type pony is not only a height difference it is also a huge type difference. Is the horse being bred tall because it has long upright pasterns, a long cannon, straight shoulder and very high wither…??? If this horse was bred to a shorter one that has a short and sloping pastern, short cannons, laid back shoulder and low wither…well you can see where I am going here. I think height is created by many variables. If you breedy a horse looking but shorter pony to a horse that is typey…you probably wont get ‘fankenpony’. All breeding is a bit of a crap shoot. But, those who are dedicated to doing it well have fewer big ‘ooopsies’. The mare I bred for Fig has had 3 foals, 2 by horses and one by a typey cob and all look like small horses, large ponies and all so far are maturing at around half way between the parents…so go “Fig” ure…

[Appsolute]

[QUOTE=wyeoakequine;7331926]
Wow, Appsolute- getting a 16.3 baby from a 13.3 mom musta been a shock! That’s pretty wild… but totally in line with the article from The Horse.[/QUOTE]

It was!! He just kept growing and growing and growing. Big head big body - ended up selling him to a 6’2" tall man - they fit perfectly!

[grayarabpony]

[QUOTE=stoicfish;7332778]
No where in the article does it say that height is only based on one gene. It does however, try to give the average person an understanding of how genetics works and why the height of the parents is not necessarily the deciding factor.
It is correct information, it just does not have all the details that would probably not be helpful to most of the readers.
I bet there are a many genes that are responsible for the finished height, including the ones responsible for skeletal proportions, metabolic traits and a host of others.
On that level it is really complicated, yet on a practical level you can look to the pedigree and see what is present. Horses that are around 15 hands for the last 5 generations should hold no surprises. They are homogeneous for those traits.
However, Wb’s, like people pointed out, are not always recorded accurately and have a huge variation in size and type. I think Contendro is known for throwing some smaller and larger horses. His pedigree on the dam line has some smaller horses and the sire line has some very tall horses, apparently, he carries both traits that he can throw. http://www.sporthorse-data.com/d?i=10005018[/QUOTE]

Then what the heck was this?

“All of this brings us back to our earlier scenario involving the breeding of a short mare to a tall stallion. Genetics will dictate that we won’t get the in-between horse we have been seeking. The offspring would have inherited one or the other of the parent’s genes for growth. If it received the mare’s gene for growth, the offspring will likely wind up being short.”

Plus, there is no mention of codominance or modifers or other factors.

“There are two types of genes-dominant and recessive. The genetic rule of thumb is that the dominant gene will always have its way when paired with a recessive gene. Sometimes, however, both parents pass on a recessive gene for a particular trait, and it is that recessive gene that is expressed.”

and

"At that time, one of the prevailing theories was that if plants with opposing colors were crossed, the result would be a plant that was intermediate in color. In the case of the white-flowered plant being crossed with the purple-flowered, the result might have been expected to be a light lavender.

Mendel proved that theory to be groundless. He did not get any plants with intermediate coloration with a crossbreeding program."

Statements like these are my beef with the article. It’s so simplistic as to be practically useless.

[Hippolyta]

[QUOTE=grayarabpony;7333277]
Then what the heck was this?

“All of this brings us back to our earlier scenario involving the breeding of a short mare to a tall stallion. Genetics will dictate that we won’t get the in-between horse we have been seeking. The offspring would have inherited one or the other of the parent’s genes for growth. If it received the mare’s gene for growth, the offspring will likely wind up being short.”

Plus, there is no mention of codominance or modifers or other factors.

“There are two types of genes-dominant and recessive. The genetic rule of thumb is that the dominant gene will always have its way when paired with a recessive gene. Sometimes, however, both parents pass on a recessive gene for a particular trait, and it is that recessive gene that is expressed.”

and

"At that time, one of the prevailing theories was that if plants with opposing colors were crossed, the result would be a plant that was intermediate in color. In the case of the white-flowered plant being crossed with the purple-flowered, the result might have been expected to be a light lavender.

Mendel proved that theory to be groundless. He did not get any plants with intermediate coloration with a crossbreeding program."

Statements like these are my beef with the article. It’s so simplistic as to be practically useless.[/QUOTE]

Agreed. In addition the language is odd (the genetic rule of thumb?). The traits that follow simple Mendelian rules are few & far between, anyway.

[RockstarPony]

We have a strange height situation with one of the babies at the barn that I’d love an explanation for… there’s a two-year-old purebred Connemara colt who’s just been sticked at 15.2hh and looks quite awkward, like he’s still got a few good inches to go. His dam is 14.1hh and his sire is 15.1hh, which makes me wonder if there’s some sort of gene in his sire’s line that would suddenly add height? (Can’t find the paternal grandsire’s height, but I know his sire was only about 14.2hh.) We’ve all been scratching our heads trying to figure out how this kid could’ve gotten so tall!

[exvet]

there’s a two-year-old purebred Connemara colt who’s just been sticked at 15.2hh and looks quite awkward, like he’s still got a few good inches to go. His dam is 14.1hh and his sire is 15.1hh, which makes me wonder if there’s some sort of gene in his sire’s line that would suddenly add height?

I’m going to guess if you go back 2-3 generations you will find the height. I have a Welsh cob stallion who is 15.1 hands. He is 7 years old. His sire is 14 hands and his dam is 14.2 hands. I happen to know where he got his height because I use to own his grand dam who was between 15 and 15.1 hands. It really is necessary imo to know the height through at least 3 if not 4 generations back. In some breeds there is still quite the variation/range you can see.

Virginiabred speaks of breeding purebred Welsh but there is the issue of which section, which brings us to Welsh cobs. You can have a Welsh cob which is basically anything bred from the 4 sections and only one individual in the family tree has to have been a Welsh cob to deem anything after a Welsh cob forever more (at least since the time that there has been 4 sections). I have two section Cs. Both are the result of a section C (does not exceed 13.2 hands) bred to a section D (over 13.2 hands with no upper limit). If you go a few generations back, however, both have section A’s (do not exceed 12.2 hands if US bred, do not exceed 12 hands if UK bred) showing up in their pedigree. Both of mine happen to be around 13 hands. I bred the section C mare, 13 hands to my stallion who is 15.1 hands and have ended up with a filly who at 18 months is already 13.3 hands at the croup. In all seriousness The height ranges I have in my herd/breedings are no wider nor surprising than what I’ve been reading/hearing/seeing among warmbloods.

Now getting back to speaking about Welsh PONIES, both the section As (again height limit is 12.2 hands US and 12 hands UK) and Bs (height limit is 14.2 hands US and 13.2 hands UK) the height is tighter especially if you speak of UK bred; however, it behooves one to still know the height in the pedigree especially if you have a mixture of imported and US stock.

I use to be better versed in connemaras many years ago when I took a couple of years to look closely into both breeds, flying around the country looking at the stock of many breeders in the process of deciding which direction I wanted to go. I remember quite a bit of size range (saw 13 to 15 hands within much of what I looked at), challenges with US vs Irish/UK bred and the like. My guess still is that the connemara in question has height hidden in the background or like a few in my breed, rumors of someone else jumping the fence back in the day before DNA typing became a matter of practice :winkgrin:

[VirginiaBred]

@exvet

Virginiabred speaks of breeding purebred Welsh but there is the issue of which section, which brings us to Welsh cobs. You can have a Welsh cob which is basically anything bred from the 4 sections and only one individual in the family tree has to have been a Welsh cob to deem anything after a Welsh cob forever more (at least since the time that there has been 4 sections). I have two section Cs. Both are the result of a section C (does not exceed 13.2 hands) bred to a section D (over 13.2 hands with no upper limit). If you go a few generations back, however, both have section A’s (do not exceed 12.2 hands if US bred, do not exceed 12 hands if UK bred) showing up in their pedigree. Both of mine happen to be around 13 hands. I bred the section C mare, 13 hands to my stallion who is 15.1 hands and have ended up with a filly who at 18 months is already 13.3 hands at the croup. In all seriousness The height ranges I have in my herd/breedings are no wider nor surprising than what I’ve been reading/hearing/seeing among warmbloods.

Now getting back to speaking about Welsh PONIES, both the section As (again height limit is 12.2 hands US and 12 hands UK) and Bs (height limit is 14.2 hands US and 13.2 hands UK) the height is tighter especially if you speak of UK bred; however, it behooves one to still know the height in the pedigree especially if you have a mixture of imported and US stock.

exvet is correct. Otteridge Farm only breeds to the Section B, and the occasional Section A Welsh stallion (depending on the movement) for the desired cross. And another thing that makes a difference is we always have one side of the equation be a purebred.

[FLIPPED_HER_HALO]

I find it all kind of interesting and confusing as well, just like the whole color genetics thing.

A friend has a gelding and mare that are full siblings…gelding was the first foal out of the maiden mare, and he topped out around 15.2 and the 2nd foal is over 17 hands.

Just like with the color thing. My mare has 2 full siblings, one is gray and the other two are bay…

[Samotis]

This is all interesting!

I have a 15.3 hand TB mare I have bred to the same 17 hand stallion twice.

Her first foal is now 5 and he is 16.3 but leggy and very TB IN TYPE.

Her second foal and full brother is coming 2 in April. He is much more substantial in bone and is already 16 hands. He will be at least 17 hands.

I then decided my niece needed a pony and bred the same mare to a Section A welsh pony who is 11 hands. No size in his family, I made sure of that!

Pony foal is now 9 months old and about 12.3. Looks every bit of a pony and seems proportionate. Luckily mom looks like a big pony so I was confident with the risk.

It will be interesting to see how big the pony ends up!!!

[Samotis]

This is the pony foal. Other colt is the 2 year old that is close to 16 hands already.

They are best buds and it is so funny to watch them play!

[VirginiaBred]

CUTE!!!

[Blacktree]

I would love to know if there are inaccuracies in the recordings of heights in our black mare’s (Weltstern x Viking Song) or our stallion’s (Mascarpone x Memelruf) pedigrees. This cross has produced: foal one - 17.1, foal two: 18, foal three: 18.3 + and could grow more, foal four: 17.2 and still definitely growing, despite not seeing any freakishly tall horses on either side! There is one horse that I found that is 17.3 a few generations back, but nothing else is super tall on either side, and nothing compares to foal three!

[wyeoakequine]

I love hearing about everyone’s different experiences! I will probably go ahead with the pony cross to my mare when the time comes, and now I know better what kind of homework I need to do to maximize my chances of getting what I’m hoping for.

FLIPPED HER HALO - I wish I could find this web app I happened across one time which allowed you to choose the horse’s genotype for color and changed the illustrated horse to match. It was the coolest presentation of color genetics I’ve ever seen. In the case with your mare and her siblings, it’s not so complicated. One parent was heterozygous for grey and only passed the grey modifier onto one of the three offspring.

Samotis - CUTE baby!!! Love him!

[fire_911medic]

[QUOTE=Dr. Doolittle;7330764]
fire_911medic–did your stallion inherit the phenotype of HIS sire, rather than his dam? According to the above article, it would seem that foals will tend towards the height of the parent whose phenotype they inherit.

I would love to hear anecdotal evidence to this effect (or that refutes this theory–obviously “nothing is 100% predictable” when it comes to horses–or breeding); this is an interesting topic![/QUOTE]

He is almost a complete duplicate of his sire except for color. He is black where both his sire and dam were bright bays. There is no black in the dam line, but there was in the sire’s line. He was a throwback color wise similar to a red head that may pop up in humans from several generations back. Everyone that sees him though identifies immediately that he is out of the unbridled line as he looks so much like him. His sire looked identical to unbridled.
As far as what he throws, he throws his height, leg length, and generally refines build a bit. He also throws his trademark blaze which comes from the dam’s side, though unbridleds tend to carry alot of white. However, the blaze from Go Man Go in the dam line is pretty much a trademark of that line and they are about identical. My stallion’s foals carry that same blaze. Color wise, they tend to favor the mare’s color, and if she has color (ie paint), he will throw that. I always joke with mare owners if you don’t like the color of your mare, he probably isn’t the stallion to breed to (because high probability you will get that color or a variation of it). So far no complaints. His one unique stamp that he puts on foals is a gold rimmed ears (similar to black points on a bay) that clarifies the dark ones as a seal bay. Kinda cute !