R3,
Your articles that you have provided with your questions and your stance on this subject early on was aimed at explaining the reasons for the malformations seen in Miniatures is due to environmental causes not an inherited gene or genes.
Your recent questions below and my quoted answers I have already provided in multiple different threads to you and others.
"Both of my posts have been asking whether or not environmental factors can disrupt fetal development and cause birth defects that to the untrained eye LOOK LIKE , but ARE NOT caused by the dwarf gene."
"Do you acknowledge that ENVIRONMENT CAN CAUSE BIRTH DEFECTS (not dwarfism)? And, do you acknowledge that some of those defects are traits that may LOOK SIMILAR TO SOME DWARFISM TRAITS?"
My answers are:
Of course I do, I have always stated those things happen, and they happen all over the world. It is a very well known scientific fact that the environment and its problems can cause developmental (or congenital) defects in all life forms including plants. And these defects can have SOME characterisitcs of other genetically inherited diseases, namely dwarfisms.
Quote from one of my answers to you on Nov 19
"I cant tell you how many things or various degrees of exposure can cause congenital malformations in only one animal in only one species, there are probably millions of examples.. In other words there are billions of things randomly that can happen all over the world, and there are things that can happen that look like an inherited disease that occurs by chance and not due to a dwarf gene, this foal looks like one of those examples."
Some of my other answers from your Nov 11 questions. With regards to my stance on environment causing birth defects.
"I want to again try to explain my opinion, I strongly feel these types of dwarfisms I am working on are genetic in nature and NOT environmentally induced. The chances of a specific toxin in the environment, be at toxic levels ALL OVER THE WORLD, to produce this high number of dwarfisms is very scientifically unrealistic. If nitrates were that toxic all over the world you would see MASSIVE congenital malformations and deaths from numerous other animals including humans, not just our little Miniature horses. "
"BTW nitrate toxicity is relatively a low level toxin to horses when compared to sheep and cattle, due to the different digestive tracts, ruminants vs monogastrics, meaning it takes a higher level to affect horses than it does cattle or sheep. However, horses are more susceptible to nitrate poisoning than other monogastric animals due to the cecum. Below is a website about pollutants and ground water, where this info above came from."
"I have done quite extensive searches for anything reported or documented, describing any type of birth defects from Nitrate poisoning that mimic DISPROPORTIONATE dwarfism. I have yet to find any. If you have any information describing any credible documentation with pictures or physical descriptions of horses being born with disporportionate dwarf characteristics from nitrate poisoning, I would really appreciate you sending it to me. "
My answer to Minimor's question on Nov 12th, it contains some of my opinion as well about the separation of genetics and environment and its interactions.
"That said, your question IS very valid. Yes there is a DEFINITE chance that Miniature horses born or raised in the affected areas and are carriers of the dwarf genes can have a dwarf affected by hypothyroidism from Nitrate toxicity and show characteristics of both diseases, one due to environment and one due to genetic inheritance. OF COURSE THAT CAN HAPPEN. I APPLAUD you for having the resourcefulness to look into those things on your own, and critically examining the situation."
"I have been adamant about my position because not a single person has yet to ask your intelligent question, every one of the questions posed so far have been to blanketly blame nitrates for the dwarfism irregardless of the fact that the vast majority of the nitrate toxicity characteristics look nothing like the dwarfisms seen in this breed. One characterisitc of one disease does not make it the same disease for something else with the same one characteristic."
"I guess all people with club feet are dwarfs since that is a characterisitic of some dwarfisms in humans. That doesnt sound rational to me."
"Dwarfism inheritance and expression is indepedent of Nitrate toxicity, one can have both and one can have either or. What you would see are the characterisitcs of both expressed if you have a dwarf with nitrate toxicity and some things will be compounded in severity, BUT Nitrate toxicity in no way will make the dwarf gene show up more often in homozygous form to cause a dwarf. Apples and oranges, recessive diseased gene and environmental toxin. "
"For someone to not have a dwarf since fixing the nitrate problem, they either no longer have the carriers or they are having a great session of Russian Roulette so far, and their number isnt up yet again. The percentages are still there with the same horses to have a dwarf again irregardless of Nitrate toxicity."
Part of my answer to Zacharyfarms's question on "Nitrates Again" that I answered on Nov 12.
"It is starting to sound as if some of you are taking a known toxin and its effects on fetal growth and blanket applying it to any abnormality you see in the Miniatures, genetic or not. I dont get it. I am not saying there are no cases of hypothyroidism in the minis, on the contrary I know it exists, as it does in other horse breeds. And I am not saying that there arent any cases of Nitrate toxicity in Miniatures, on the contrary I am sure it has and will happen, but to blame everything wrong conformationally, congenitally or genetically in the minis on Nitrates is really not thinking things with a rational, critical mind. Are we going to blame all of the dystocias and foaling problems in the Miniatures all over the world on Nitrates too, and ignore their size as probably THE major factor??"
"I know of other toxins, drugs, etc., that can cause similar physical characteristics that are shown on that pdf. I just dont see how you CANNOT distinguish between characteristics of different diseases whether genetic, congenital or environmetally induced. There are differences in their etiology I will not go into here about all three. I would be literally writing a book. "
"I am not belittling this toxin, I just do not see a single glaring similarity other than a slight under bite in one photo,the head is even normal in shape, and it is a large horse foal, not a mini. Dwarfs have numerous other characteristics that do not coincide with nitrate toxicity."
I hope you can read my opinion better with it all in one answer in one thread, and that you read it entirely.
Your articles provided you with some good answers to your own questions as well, below is an article you read and provided.
http://www.vet-med.wsu.edu/depts-vth/EquineNews
here is a quote from it.
"In the past, the thyroid gland has been blamed for more than its fair share of problems. But the latest technology and improved blood tests indicate that true thyroid disease in horses is quite rare, and ensuring the right levels of iodine in your horse's diet can prevent most problems."
So from that alone, if you have a foal born on your farm and it looks suspicious, dwarf or toxin, or thyroid level, there are tests you can have done on your horses and feed and ground, hay, etc. to rule out environment, thyroid, etc. Or if those tests do reveal something, then you might want to re-evaluate your management of your horses. Especially if you have more than one foal born in a year that might or might not be a dwarf. This is not to rule out, like I already wrote above, that you could have both environment and genetics involved at the same time. Those are issues you have to figure out with a knowledgeable vet.
your questions
"The second part is HOW TO TELL THE DIFFERENCE between dwarf foals and foals with environmentally caused (not genetically caused by dwarfism) birth defects. That is ALL I have been asking. I don't know how I can ask this any more plainly."
"I don't know the numbers, but I would suppose that it is entirely possible that environmental defects account for less than 1% of deformed miniature foals, and that dwarfism is the cause of the other 99+%. However, the percentages are immaterial to my question (although it would be interesting if that number is known), as what I want to know about is my potential foal that isn't 'normal' when it is born. "
"If I have a foal that is born with a domed head, bent legs, and a protruding lower jaw, how can I tell if the foal is a dwarf (genetic condition, unrelated to environment) OR if it has developmental deformities due to environment (not cause by dwarfism)? Please point out the differences so I can understand them.
THAT IS ALL I WANT TO KNOW."
My answers:
I cannot try to explain every variance in expression of genetics and its interaction with the environment by an internet forum. I am not here to diagnose a problem via the internet. That would be blatantly ignoring scientific information pertinant to each individual case seen. Therefore I cannot give you a list of characterisitcs that are definitely dwarfism, and a list that are definitely environment, or definitely thyroid. That is not being scientifically sound at all to any of the cases. That is why I am very clear in giving my opinion about a horse that I think is a dwarf. I answer it as my opinion and that IF the horse shows characterisitcs identical to other dwarf horses I say that it is showing characteristics like the dwarfs I have seen of a certain type. Meaning that a horse I comment on shows characteristics consistent with the very possible inherited genetic disease I am researching. If that is not satisfactory to you, not a problem, you can have your own opinion as well.
There are so many influences in the environment, genes that have not been discovered, and their interactions that are expressed in an individual, etc. Until more is known, I cannot tell you that "such and such horse has a type of congenital dwarfism due to hypothyroid," without having lots of tests done; genetic, blood and environment. Versus that same horse is "100% a dwarf of such and such type and here is the test to prove it". I dont have those answers, you would have to do those things to rule out certain possible causes of your horse's problem with your vet's help and hope someday there is a genetic test for some of these diseases.
You also cant rule out that a foal born is just a badly conformed horse and not a specific type of dwarfism or congenital malformation from a toxin or an out of balance hormone, it is basically undesired genes that are being expressed.
I hope this clears up your questions about my opinions and that I answered you as fully as I could.
John
As a side note;
Why do so many people want to blame something or someone else for their foal with bad conformation and not the quality (or lack of) of their own stock??
Why is it that so many people in the Miniatures dont want to learn BASIC correct horse conformation, and be able to critically examine their own stock and its quality?
Remember this is not a true "breed" that breeds "true". We have a whole lot of undesired genes floating around in our gene pool.
Sorry, My little rant with food for thought.
