Dwarfs (Registries and our responsibilities)

[Molly's Run Minis]

honestly, i think the responsibility lies with the breeder, NOT the registration. the horses dont decide who breeds with who, who is quality enough to breed, etc. as far as i know the registration doesnt dictate that either as long as the horse meets the height requirement. thats the breeders job. while a dwarf may just pop up out of 2 seemingly normal parents, its the breeders decision on what to do in this situation, a. keep breeding them together. b. give the stud and mare a second chance, but never breed the pair to each other again. or c. cut the stud and sell the mare as a non breeding animal. the choices a breeder makes in a time like this will show whether the person cares about the welfare of the horses or just about money. situations like this also show how responsible a breeder is. imo, it takes more courage to admit something failed than to admit something went right.

 

[rabbitsfizz]

Molly is absolutely right.

As to the incidence of Dwarfism in Minis, No, there is no possibility of all Minis carrying it and I have never heard that suggested before.

We thought the same thing, btw, in Dobes, when Von Willebrands (a sort of haemophilia) was discovered, but, in fact, with careful testing and even more careful breeding the sensible people are eradicating it. Not gone yet, but the incidence of carriers being used is getting less and less.

Only wish the QH people were as sensible.

 

[R Whiteman]

If the registries have a rule against allowing dwarf or animals with dwarf characteristics and they allow animals with those characteristics to be registered contrary to their rules then are they not liable? Isn't there some implied quality control expected when they have such a rule? I would think the liability would increase if they had a report and failed to take any action. We live in a land where people get rich doing stupid things and then suing someone because someone failed to protect them from their stupid actions. Maybe this isn't so far fetched.

Some say there is no rule in place to deal with the problem. I say it is not any different than an animal going over height. The papers belong to the registries and can be revoked for cause at any time. Dwarfism is not allowed. The problem will continue because it is just like those mares and stallions that are over and still producing registered babies. Yes, it is all about the integrity of the people involved.

As I see it,

Ron

 

[Charlotte]

As others have said here, until there are tests for the genetic forms of dwarfism there really isn’t anything the registries can do other than what AMHA does which is require photos and refuse registration to obviously dwarf horses. Not the best solution, but the best we have so far.

Interestingly, a few years ago when Frank asked one of the genetics experts studying dwarfism in miniatures if the incidence of dwarfism in the breed is staying about level or going up or down the answer indicated it was dropping off noticeably. That must tell us that we breeders are breeding away from these genetic abnormalities…..they are becoming less common in the breed as a whole.

And again, I have to mention the abnormalities that appear like genetic dwarfs, but are not genetic but caused by other factors. This first came to my attention some years ago when I heard of a farm having a very high percentage of ‘dwarf’ foals from one sire. The percentages were too high (something around 60% dwarf foals per year over a 2 year period) to be statistically correct so I was suspicious as to what the heck was going on. The first year the vets said geld the stallion! The breeder used a totally unrelated stallion the second year on some of the same mares and some different mares. The same thing happened. The vets said Whoa! This isn’t right. You have something environmental going on. So the testing began of water and feeds and hays and pastures. The vets were very concerned that this could be something toxic to humans also.

It turned out to be high nitrates. Very common in certain types of grasses under certain environmental conditions. Once the nitrate issue was removed all of those horses went on breeding for many years and never produced another deformed foal. Because I was aware and interested in this subject I later heard of other farms…4 total in Ok, MO, AR, and KS…where the same things happened….stallions sired a high percentage of dwarfs….stallions went to other farms and never sired another dwarf.

At this same time I first read the report about deformed Standardbred foals in Canada. It wasn’t this report, but this is reporting the same occurrence.

Standardbred Report

If you read about the abnormal foals they are described with the same visual defects we miniature breeders would call ‘dwarf’ defects. Domed heads, underbites, very crooked legs. So these reports and farm histories have to be telling us that all ‘dwarfs’ aren’t genetic which means until we have tests for the genetic dwarfs we are just stuck with being very careful breeders and with doing our research on foal abnormalities and what may cause them. The bottom line is….a mare or stallion that produces an abnormal foal may not carry a genetic abnormality…..the abnormality may be caused by something in the horse’s environment! Personally, I have come to the conclusion that miniature horses are the ‘canary in the coal mine’. They are much more sensitive to various toxins at much lower doses than their big relatives are.

Quotes from this article:

several abnormalities were observed, including congenital deviation in the sagittal plane of both carpal joints, and severe, non-reducible, bilateral flexural deformities of the forelimbs. Bilateral hind limb weakness was observed when the filly was assisted in standing up, and flexural deformity of the hocks was also noted. There was pronounced mandibular prognathism, with a 1.5-cm deviation from normal jaw alignment. The head was slightly domed.
In this case, the mare was fed a diet of moderate quality hay and oats throughout gestation, with no mineral supplementation or access to pasture. The mare may have been iodine deficient due to the lack of mineral supplementation, the hay may have contained nitrate, or both. Nitrate is more likely to be present in greenfeed (immature cereal crops). Forage grown under stressed conditions, such as dry weather, has an increased probability of containing nitrate (10). The summer of 2001 was very dry in southwestern Ontario, which may have resulted in an increased nitrate level in some Ontario forages. The forage grown during the summer of 2001 would have been fed during the latter two-thirds of gestation to mares that were bred late in the season (May and June 2001). The equine fetal thyroid gland becomes active by the 4th or 5th mo of gestation (2) and may be most susceptible to insult from poor nutritional conditions in the early to middle part of gestation.

The dry summer of 2001, combined with lack of mineral supplementation, may have predisposed some late-bred mares in Ontario to produce hypothyroid offspring in the spring and summer of 2002. However, it is important to note that there are other potential sources of nitrate, including contaminated drinking water and irrigated pastures. Further investigations should be conducted regarding the prevalence and etiology of TH-MSD in foals in Ontario to increase awareness of this disease.

 

[rabbitsfizz]

Wow....that is SO interesting!!! Thanks for posting that Charlotte.

 

[ohmt]

But what are considered "dwarf characteristics"? I hear it all the time, but it is just speculation and perspective at least as far as i'm considered. There are probably a lot of horses with what some consider dwarf characteristics that don't have any dwarf genes and some without any that do. It takes 2 genes to make a dwarf according to research available as of now. I agree with others that say that the registries should not have any obligations until there are tests available. Susan O's post was perfect. I DO think that registries should continue to educate as much as they can with the information that is available at this time. Other than that, I do not see how they could fairly go further without tests. I hope there are tests available soon.

 

[ohmt]

Thanks for posting that Charlotte! Very interesting!

 

[lil hoofbeats]

So if there was a test developed for dwarfism and that test was available, and i had a horse that looked like a dwarf, because it lacked nutrician at some point in gestation, but tested negative, it would be ok to breed it?

Just wondering what everyone was kinda thinking on that issue.

 

[Riverrose28]

I would have to say NO! Do you want reasons?

 

[bluerogue]

Charlotte brings up a very interesting point. As someone who has training, has worked, and is very interested in the environmental fields, I can say without any doubt in my mind that some dwarfs produced every year are not "true" genetic dwarfs. There are so many things that can affect fetuses in utero. Granted her examples are on the more extreme side regarding the numbers, but it just makes it that much more believable (to me anyway, as I've seen such reactions in my work). I remember discussing this issue with Becky at one point, as there was a thread here about it. We got bashed on the thread, but it's been proven (even more since then) that environment DOES affect fetuses, sometimes in very adverse ways. Fetuses are sensitive to certain stimuli, and the reactions to that stimuli can be very unfortunate.

Generally speaking, it *should* be somewhat easy to tell if there were environmental impacts in the production of a dwarf (especially if there were multiple dwarfs born on a farm in one year, and it is not normal for that farm). However, knowing what to look for to identify what caused the issue is sometimes not easy at all. There are so many things that can cause adverse reactions in fetuses. And sometimes it's not something the farm owner has done... it's something someone else has done (and possibly not even close to the farm), that has somehow found it's way into the pasture or barn. Just like neighbors having oleander, and a few leaves blowing into a horse's paddock, allowing the horse access to the leaves, thus resulting in possible death of the horse. Did they mean to let the leaves get in with the horse? Probably not. But the result is the same, if the horse ate one of the leaves. Totally unintentional (or not, depending on the neighbor). The neighbor doesn't even have to be particularly close by... just close enough that wind can carry those leaves. In some places, that can cover a pretty darn big distance!

However, because you aren't going to be able to prove (until there are accurate tests for dwarfism) if a particular horse is a "true" dwarf, or an environmentally produced dwarf, the result should be the same. The dwarf horse shouldn't be bred (in my opinion). Even if a horse is an environmentally produced dwarf, *I* still wouldn't chance it. If that horse's genetic material was messed up enough that it became a dwarf, who knows what else has been changed in its genetic code. There hasn't been enough research regarding environmental dwarfs to say that they won't pass on their undesirable genes (and in my opinion, that they have undesirable genes is enough to remove them from my breeding herd).

As far as breeding dwarf producers, it's much easier for a stallion to produce many more offspring. I'd be more likely to geld the stallion and test breed the mare. Mares produce a max of maybe 20 foals in their lifetime? And that's if their owner exposes them every year, and they are very prolific. More often the count is closer to 15 or less. Stallions can produce thousands of foals in their lifetime. The damage of a stallion producing dwarves *can* be much more extensive. That said, I think I'd have a very hard time even test breeding a dwarf producing mare. She'd at least get a good number of years off while I thought about it. This is assuming there wasn't an outside factor causing issues.

The question of the subsequent offspring (or prior produced offspring) of a dwarf producing horse is a completely different can of worms. They might all be clear, but that one dwarf foal throws them all into suspect. Until there is a way to prove conclusively that a horse is a carrier (or not) we just kind of have to muddle along as we have been. Thankfully we are making progress. That we are able to discuss this in a calm and thoughtful manner is itself an improvement. It used to be that this topic caused people to start flying off the handle.

 

[lil hoofbeats]

I would have to say NO! Do you want reasons?

Sure, if you are willing to share your thoughts i would love to hear them

 

[Minimor]

The only thing is…those standardbred foals in the article Charlotte posted did not have legs that were similar to the legs of a dwarf. The description of the leg deformities those standardbred foals had is not the description of the twisted legs of a dwarf foal. I know this because 1—I had a Morgan foal affected by this in 1991 (she was mildly affected—her issues are described in the nitrate thread from a few days ago. I doubt anyone bothered to read it. 2—In 2004 I specifically asked Dr. Andy Allen of WCVM about the leg deformities seen in foals affected by nitrates/mineral deficiency. He confirmed that the leg deformities of these foals are as I had learned in 1991 (again—I gave details in that nitrate thread of a few days ago)—extensor tendon weaknesses, knee and/or hock joints that are not properly formed—and the leg deformities are a result of those immature or soft bones in the knee and hock. Some foals are unable to stand; others do manage to stand and move around but as they mature the knee and/or hock joints are not strong enough to support the added weight and the small bones in those joints are literally crushed. I have never heard or read anything that indicates this is the issue with dwarf foals. Dwarfism seems to cause a completely different sort of leg deformity. The monkey mouth (underbite) of an affected foal does appear very similar to the monkey mouth (underbite) of a dwarf foal, but that is the only real similarity. An affected foal does not, except for the underbite, have the head of a dwarf. It does not have the disproportionately short legs, nor the long body of a dwarf, nor does it have the overly large intestines that give some dwarfs the extremely potbellied appearance.

 

[bluerogue]

The only thing is…those standardbred foals in the article Charlotte posted did not have legs that were similar to the legs of a dwarf.

I wasn't referencing the article, I was adding my opinions and knowledge of the subject. There are many types of dwarfism, and different compounds can affect fetuses differently. Just as different people can look at the same foal and say yes or no that it is a dwarf, different people can have differing opinions about environmental dwarfism (or other deformity).

 

[Riverrose28]

Sure, if you are willing to share your thoughts i would love to hear them

For all the deformities that you see on the outside, there are usally more on the inside, it would stress the animal in question to be bred.

Also how would I know it was environmental factors and not genectic?

There are too many conformationaly correct horses to bred I wouldn't take a chance.

 

[susanne]

If/when genetic testing for dwarfism is available, environmental deformities would be no less tragic, but hopefully no longer confused with true dwarfism, and therefore a genetic moot point. Same with individual traits that are merely poor conformation -- these animals would still be undesirable for breeding, but not because of their genetic makeup.

 

[susanne]

Double post

 

[CS Classic Acres]

So the only way to tell for sure it the animal is a dwarf is to test for it??

Several years back a had a beautiful palomino pinto filly that looked 100% normal at birth , had a good bite, straight legs, tiny head. After her yearling year she developed a slight underbite, and never was able to get weight over her back and stopped growing at about 27 inches. She was on a regular worming rotation and a balanced feed program that all my young horses do well on.

I felt she might be showing dwarf charatristics , can they develop them later?

I pulled her papers and she went to a home for therapy work. I was amazed at the number of people who even after I said she was a probably dwarf asked if she came with papers. Even if she wasn't I felt conformationally she shouldn't be bred.

 

[Riverrose28]

So the only way to tell for sure it the animal is a dwarf is to test for it??

Several years back a had a beautiful palomino pinto filly that looked 100% normal at birth , had a good bite, straight legs, tiny head. After her yearling year she developed a slight underbite, and never was able to get weight over her back and stopped growing at about 27 inches. She was on a regular worming rotation and a balanced feed program that all my young horses do well on.

I felt she might be showing dwarf charatristics , can they develop them later?

I pulled her papers and she went to a home for therapy work. I was amazed at the number of people who even after I said she was a probably dwarf asked if she came with papers. Even if she wasn't I felt conformationally she shouldn't be bred.

I'm not sure if these characteristics are dwarf or just bad conformation, but I have had one do this too.

She was born from a dam that produced an AMHA Chmapion by a different stallion, she too was perfect at birth, just very tiny. We showed her as a weanling AMHR in produce of dam at our area show and took the class, she was just weaned. Then the next year as a yearling we showed her 4-H and she took the division of 2 & under beating out all the quarter horses, walkers, thourobred, arabs, etc. and ended up earning more points then any of the other conformation classes and won high point halter horse of the year. After the last 4-h show she was in her yearling year and started to develope a bad bite. I had the vet come and check her teeth, she floated them and her bite still continued to go off, plus it seemed as though her neck stopped growing and her head started to look large compared to the rest of her. In the spring of her second year the vet checked her mouth again and said she didn't need to be floated and there was nothing she could do about the bite. At age three she measured in at 27"s and was sold as a pet.