Scientific Proof if there is any

[Frankie]

I usually ignore most talk. I have heard a lot lately though on the deafness of horses depending on how they are bred, especially in Overo's.

Kind of curious as to how a color gene can cause deafness. (rumor told)

Has anyone else heard of this? Is there some type of scientific proof? What is the actual cause if it is true? I would prefer information with something to back it up with.

Or, do you have a place you can send me to gather information.

thanks

 

[Frankie]

Info Page, Deafness

Deafness info page

I would like to see a study.

 

[rabbitsfizz]

Carolyn the latest thinking is that deafness could be associated with Homozygosity in Splash but obviously a horse can be h/z and still be a Tovero or what ever- have more than one pattern, anyway. There is also a line of Paint's in Oz called the Miller line, exclusively Splash and exclusively deaf. The only deaf Mini I have dealt with was represented to us as Frame but when I looked into it was combination Frame/ Splash.

 

[Sue_C.]

Kind of curious as to how a color gene can cause deafness. (rumor told)

It is a fact that colour is directly related to deafness in some breeds of dogs and cats as well. All white cats, with blue eyes, are almost certain to be deaf, and Australian shepherds which are mostly, if not all white; are commonly, if not always, deaf as well. Not sure just exactly why...but it is sadly true. There are several Australian Shepherd rescue organizations, which specialize in finding these deaf dogs loving homes. I myself, have been owned by a pure white, blue-eyed-deaf cat.

I have read here, that some forum members suspect deafness in their horses/foals, because of them being white, as well.

 

[rabbitsfizz]

Yes, deafness is linked to white- hence deaf Boxers, Dalmatians, Collies etc. But the mare I worked with had only the pattern She was not white, in fact she was mostly brown and looked like a Frame.

 

[Hosscrazy]

Here's an article published by UC Davis.

According to this article, a Dr. Gary Magdesian of UC Davis is currently conducting research on the heredity of deafness in Paints.

UC Davis Link

 

[Frankie]

Thanks so much to all.

LSU has done some studying on this if you would like more info.

Just not much out there.

thanks again

 

[Dona]

Here's an article published by UC Davis.
According to this article, a Dr. Gary Magdesian of UC Davis is currently conducting research on the heredity of deafness in Paints.

UC Davis Link

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Hmmmm....this article doesn't give the whole story. Judging from her picture, this colt's dam is obviously a Sabino (probably combined with Frame) The sire also has the characteristic white legs of a Sabino. Frame alone would have dark legs. I highly suspect the subject colt is actually a Maximum White Sabino...but the article doesn't even mention Sabino at all.

 

[Ojai Minis]

Here's my thinking (watch out

). Could it be that it's bloodlines and the animals just happen to be white because of the genetic bloodline? Why are some people born deaf. Are only "white" people deaf? Or is it a genetic defect, like hip dysplasia or PRA, etc?

Okay, back to my thinking to see what I can come up with next.

Liz V.

 

[Hosscrazy]

Very interesting point, Dona!!!

 

[Lewella]

Blame it all on Jeanette Gower's color book.......... Because of the Miller line of deaf Splash White Paint horses in Austrailia she jumped to the conclusion that all Splash White horses are deaf. Well, they aren't. Gambling Man, one of the most famous homozygous Splash White Paint horses in history was not deaf. Barlink Macho Man was not deaf - another very well known Splash Paint here in the US. Interestingly, they both produced deaf offspring.

A researcher friend has a theory that I think is quite valid. She theorizes that deafness associated with Splash White is connected to the "newness" of the mutation in the breed. In breeds like the Icelandic where Splash has been around forever deafness is unheard of. In Arabs and Saddlebreds, where just a few Splash individuals are know and some of the individuals known are suspected to be new mutations, deafness in Splash Whites is common.

One of the major research hurdles in any type of pattern/deafness connection in equine is the lack of pattern knowledge of most researchers. The UC Davis article posted is an excellent example of this. Not a single one of those horses is just one pattern. Whiskey Topsy is a Frame + Splash. Peppers Promise is Sabino + Frame at the very least (could certainly be Splash too) and Heathen's Shooter is Splash + Sabino also (he looks primarily Splash but given the max white sabino foal we can deduce he's likely also Sabino - a photo of his belly spot would probably confirm it).

 

[HGFarm]

I dont know about horses, but I know in cats it goes with the white gene. And not all white cats are deaf. I have some white cats that have 'odd eyed' -one blue and one green, but some are deaf, some not. I was told that ALL white cats with two blue eyes are deaf for sure, but I have a beautiful white Manx, with two blue eyes and she is not deaf.

I cannot find a particular pattern in the cats, so would assume it is similar in the horses??

 

[Sue_C.]

HGFarm, does your blue-eyed white cat have even just a few dark hairs on it's head or anywhere else on it's body? That is usually all it takes, for some reason, to prevent deafness.

 

[rabbitsfizz]

The black hairs, usually on the head, only have to be present at birth. It was about 88% correct with my Mother's Persians. We did get blue eyed hearing cats, and we got yellow eyed deaf cats, but we never had an odd eyed deaf cat. Dalmatians have a lot more deafness than ANYONE is ever going to admit- our Dalmatian club was going to include mandatory hearing tests for showing pups (The Kennel Club will register ANYTHING) but everyone breeding to show has their pups tested anyway, so it was not necessary. People breeding for money are not going to take any notice of a little thing like deafness, so no way to police it. When you have a 16.2hh deaf horse, you sort of can't ignore the problem