Mrs Mom commented on seeing a horse with a severe parrot mouth a couple of posts back and it got me to thinking...
I did own a parrot mouthed horse one time. He was a tiny dynamo of a speed event horse and was so darn cowy that when he locked onto a calf or steer, you could just throw the reins away and focus on roping. Since he was a gelding...the question of reproducing that fault never came up.
I'm sure that everyone else was raised with the understanding that the parrot mouth condition was entirely genetic and was the result of one or both of the parents having the same condition. In the case of my little gelding, neither of his parents were parrot mouthed and he really didn't get noticeable until he was a 4y/o. I think he was 5 or 6 before I got his teeth worked on by a really good veterinarian who enlightened me a whole bunch about this horse's mouth. Not only was he significantly parrot-mouthed, he apparently had very soft teeth. He was missing a few already and the vet found another broken one still in his jaw. The only indication that this horse had any dental issues was that he carried his head slightly tipped while loping to the right.
The vet explained that the primary reason a parrot jaw is undesirable is because of how the teeth line up in the mandible. Any misalignment in the jaw bones leaves a horse with the propencity to "grow" hooks both on the upper and lower teeth.
Now, based on talking to my equine dentist, I started doing a little reading. According to the dentist, parrot jaw is not necessarily genetic! And it can be fixed to a certain extent with proper dental work. Now, I certainly am not knowledgeable enough to discuss this in detail, but I did find this really good article on the subject...Equine Dental/Parrot Mouth. There are good pictures included of both mild and severe cases.
Now in the article, they talk about the over grinding of teeth during dental work, which is something that CdnCowgirl brought up in previous comments. With modern power tools, this is a valid concern. I'm very comfortable with the expertise of the dentist I use, but he came highly recommended. Actually, anyone I talked to about getting horse's teeth worked on, they either recommended this guy or an equine specialist veterinarian who is nearly 200 miles away. I wouldn't recommend that anyone just hire the first name they came across and let them go to grinding on your horse's teeth. In that case, manual floats sure would be the way to go, lot less chance of creating more of a problem than they are fixing. As far as the sedation? Every horse I've ever had worked on, even with manual floats were sedated. I do remember hearing about an equine dentist in AZ, who used homeopathic remedies to relax horses so they could be worked on. I kind of poo-pooed the idea, but still wanted to see it in person(not enough to pay for his services though). A couple of people I talked to about him said they didn't think he got much accomplished with that method. So I stuck with what I knew, which was still manual floating at the time and regular sedation.
So back on topic, I asked our dentist what exactly creates a parrot mouth, if it is not entirely genetic? He said most often it is caused by feeding horses out of mangers, rather than on the ground and foals that are weaned late. Gulp!! So, to the top of the list for him to check out in May will be little Shooter. I think Shooter has a mouth that resembles Moon's anyway, it sure would suck if I've caused further damage by leaving him on his momma that extra time.