Would you breed to a stallion?

[runamuk]

which beg's another question ...if you could "fix" a dwarf with medication...would you?

runamuk,

JMHO…I personally don’t believe it would be possible to fix a dwarf with medication. Because of the deformities involved.

But how ever maybe the parents having medication, sure couldn’t hurt, but here we go again….Testing is needed! Hum…

But I did think it was a good article…..

Joyce

533866[/snapback]

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pituitary dwarfism in humans can now be reversed by using growth hormones...so yes some types of dwarfism do have the potential to be "fixed"

and that was why I asked.

 

[Southern_Heart]

runamuk,

In a human then.... yes I would fix... but leaves the question can or could it be done in a horse or has it ever been tried???

 

[Minimor]

congenital hypothyroidism caused by nitrate poisoning. Yes, it does cause things such as an underbite, longer gestation, foaling difficulties, silky haircoat and leg problems. However, those leg problems consist of weak extensor tendons, swellings on the knees, and immature bones in knees &/or hocks. I have personal experience back when we were raising Morgans.

We also had foaling problems in 2004; those problems were due to an iodine deficiency and nitrate poisoning. Our foals appeared normal, but because they never stood we had no indication of how affected their legs were--had they been strong enough to stand we may have found that their extensor tendons were severely affected.

Regardless, back in 1991 when we had our problem with our Morgans I talked to a research vet at WCVM Saskatoon--he was specializing in congenital hypothyroidism, though at that time his studies were fairly new & there were many unanswered questions. I talked to him again in 2004, and he had many more answers for me this time around. Because some on here had talked of the deformities their foals had from nitrate poisoning, I asked him about the leg deformities. He said there are no deformities as such, though he thought it possible that when people mentioned deformities they were referring to the weak extensor tendons, the immature bones in the joints (which can lead to tarsal crushing syndrome) & the swollen knees--all of which I was familiar with. Otherwise, he said, congenital hypothyroidism does not cause true deformities. Obviously his research has been mainly on big horse breeds where dwarfism isn't an issue in the first place. I have no idea how many Miniatures he has studied.

Since in big horses congenital hypothyroidism/nitrate poisoning does not cause dwarfism symptoms other than the underbite & silky haircoat, if in Miniatures it is causing "typical" dwarf characteristics such as the domed forehead, disproportionately short legs, twisted, deformed legs, etc. etc., then I would venture a guess that in these Minis there is more going on than "typical" nitrate poisoning/congenital hypothyroidism. My theory--and obviously it is just a theory--is that with dwarfism existing in Miniatures, the nitrate poisoning may trigger the dwarfism gene to be more apparent. I shall have to call the university one day and discuss this theory with the research vet, but so far I haven't gotten around to doing that.

Minor deformities caused by congenital hypothyroidism are reversible in some cases; our Morgan filly that was born with an underbite and weak legs did grow out of it--as her own thyroid gland began functioning, her jaw grew out so that she had a perfect bite, and her weak tendons did heal--in time her extensor tendons became normal, her knee swellings went away, and she never had a problem with tarsal crushing. But, in other horses that are more severely affected, the condition does not correct itself completely, regardless of diet. so, I have to think that if a Mini is quite badly affected by dwarfism caused by nitrates...it would not be treatable/correctable.

 

[Margaret]

You can not, in my opinion, categorically make the statement, "my herd is free of the dwarf gene" in the following sense. Lets say your stallion IS a carrier but the mares he is bred to are not. This could be the case unless you have many many mares you are breeding to that stallion and you happen on a mare who has the gene. You may never know that indeed your stallion is a carrier and the same goes for a mare who is but is not paired up with a stallion who isn't. Now is it a "fact" that we know unconditionally that it takes the mare and the stallion to be carriers to pass this on? Or are we just assuming that this is the case in humans so hence it's the way it is in horses????? Are there any conclusive studies that have been done with regards to this in minis?

Well , in my case with only 2 mares stemming from a solid line of non-dwarf breeding, I can narrow down who I would, and would not reasonably suspect, as I believe it takes two gene carriers to produce a dwarf, and to think otherwise would mean dwarfism is a dominate gene,and dominate genes are expressed like the color gene, pinto markings etc... so two must carry the gene to produce one. I am not one to get into semantics over things- but my case is fairly simple to deduct, with a total of 3 horses.LOL ....But it does help to know some history of dwarf producers..., to enable one to do this. - I am fortunate to have a friend who specializes in the study of this. In any event, until a test is available, "pedigree" is all we have to go off of,..to see who we have, that may be a carrier, as the genetic dwarf gene is passed on from the prior generations, and they can be traced. This is just one way to deal with it, that I find reasonable, until a more conclusive test can be implimented. (rather than do nothing until a test can be developed)

 

[Danielle_E.]

Margaret, yes with 3 you are pretty safe to assume as long as you are able to go to the very very very beginning of your horses pedigrees. What I should of said is NOBODY is immune to having a dwarf foal. It may not happen genetically but it could happen because of environmental issues or hormonal issues. All I am saying is people who think "oh it will never happen to me" well don't be so sure about that, YOU NEVER KNOW is what I am saying and it's best that we learn as much as we can instead of finger pointing. It is a problem in minis period and the sooner we all open our eyes and get a study funded the better it will be for the breed. I may not get liked here after I say this and no I haven't had any dwarves born here, not yet anyway, but the attitude that seems to be prevalent on the foum HAS chased away some extremely knowledgeable people because of past discussion on this topic and some of the things that were said. These individuals have alot to offer in educating us with regards to dwarfism and other issues and what do we do, we silence them. Not a good thing.