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NZ Appaloosas February 20, 2011 February 22, 2011

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At what embryonic development stage does coat colour show in a foal? Diane

NZ Appaloosas Sun, 02/20/2011 - 23:26

(presuming you can see thru' to the embryo).

Diane

accphotography Sun, 02/20/2011 - 23:33

Do you mean when the hair comes in?

NZ Appaloosas Sun, 02/20/2011 - 23:36

well, yes and no... I guess what I'm asking is at what stage do melanocytes migrate out into skin and hair? How many months into development?

accphotography Mon, 02/21/2011 - 01:21

Threnody should be able to answer that question (if not MP). I hope she sees this. I used to know. :S

Dogrose Mon, 02/21/2011 - 03:05

I'm pretty sure its very early in the development of the embryo when the neural crest is still forming. Nothing would actually be visible to the eye until the melanocytes were active- albino animals, for example, have a full compliment of melanocytes (unless they also have white markings) but as they aren't activated you can't tell they are there.

critterkeeper Mon, 02/21/2011 - 09:22

I know when Maya miscarried her foal (5 months gestation), you could see that it would have been a pali foal...it also looked like it would have had splash or sabino as the bottom of the legs were pinkish and the head had a pinkish bottom-heavy stripe.

Maigray Mon, 02/21/2011 - 09:25

I think it's very early on as well - I want to guesstimate within the first week, depending on the species? When the neural crest cells start their migration.

NZ Appaloosas Fri, 02/25/2011 - 19:22

The reason I asked is that Misty aborted the day I asked this, and the foal was all white. She would have been about 2 or 3 months along. "All white" shouldn't be possible unless Bubba has Lp or it was too early for any colour or pattern to be seen in the embryo.

Diane

rabbitsfizz Sat, 02/26/2011 - 02:35

Just to throw this into the ring, but Dalmatian pups are born white and develop the spots pretty quickly but not immediately. Same for Siamese kittens, born off white.
So, the foal could have been Leopard.................

critterkeeper Sat, 02/26/2011 - 09:04

There are lots of incidents of babies born white and then developing spots later: Not just white with spots, but look at heelers, Aussie's and bluetick hounds, born with just the white and basic spots and then develop their ticking. Based on that, it would not have been a huge stretch to believe the foal could have been a leopard or few spot foal.

Threnody Sat, 02/26/2011 - 10:31

At 2-3 months of fetal development there is often no visible color. So the foal appearing white or pink is normal. The foal was more than likely a genetically normal color, but it never developed to the point where it would be visible.

We don't really know exactly when the melanocyte migration starts in horses because it all occurs under the skin. This is sadly why there isn't more info on equine color development in the womb because it all happens out of sight from the human eye. It does appear to happen early, but by the time we see signs of color, the process that got it there is long over.

It seems on average around 5-6 months into fetal development that you can visibly see at least some pigment in the foal's skin. Chestnuts and dilutes take longer than black bases to be visible to the human eye.

Adurna Sat, 02/26/2011 - 13:51

I don't know if I understand all things right, but for the question when melanocytes stay place on their final position this could be interesting:

"Work in W/W mice has shown that this mutation impairing the function of KIT results in the disappearance of developing melanocytes by the time embryos reach the age of eleven days."
from: http://hdl.handle.net/10225/564 (Brooks, Samantha Ann: STUDIES OF GENETIC VARIATION AT THE KIT LOCUS AND WHITE SPOTTING PATTERNS IN THE HORSE. University of Kentucky, Dissertation 2007)

NZ Appaloosas Sun, 02/27/2011 - 01:01

[quote=rabbitsfizz]Just to throw this into the ring, but Dalmatian pups are born white and develop the spots pretty quickly but not immediately. Same for Siamese kittens, born off white.
So, the foal could have been Leopard.................[/quote]

Nah...unless maybe the spots are developed later in the embryonic stage????

Diane

NZ Appaloosas Sun, 02/27/2011 - 01:02

[quote=rodeoratdogs]NZ, did it even have it's hair yet?[/quote]

Don't know, as I was in the office, and hubby disposed of the fetus before I got home. Digging that sort of thing up just isn't my cuppa, if you know what I mean.

NZ Appaloosas Sun, 02/27/2011 - 01:05

[quote=Threnody]At 2-3 months of fetal development there is often no visible color. So the foal appearing white or pink is normal. The foal was more than likely a genetically normal color, but it never developed to the point where it would be visible.

We don't really know exactly when the melanocyte migration starts in horses because it all occurs under the skin. This is sadly why there isn't more info on equine color development in the womb because it all happens out of sight from the human eye. It does appear to happen early, but by the time we see signs of color, the process that got it there is long over.

It seems on average around 5-6 months into fetal development that you can visibly see at least some pigment in the foal's skin. Chestnuts and dilutes take longer than black bases to be visible to the human eye.[/quote]

Thanks, that's the answer I was *afraid* I was gonna get, LOL. So the issue of Bubba maybe having PATN-1 can't be solved until we do another test breeding and get a nose-to-toes pattern foal.

Diane

AppyLady Sun, 02/27/2011 - 08:12

Sorry your mare aborted. I had a mare abort a few years back, but I can't remember what stage of development it was at. The fetus was all white -- or more likely it [i]appeared[/i] all white because it didn't really have much hair yet. It had mottled skin on its muzzle and the mane & tail were mixed with red & white hairs. I don't remember exactly (and I didn't take pictures) but there were clues that it was going to be a red leopard (sire was palomino leopard).

I have heard that paint patterns develop earlier than Appaloosa patterns, which is why Appaloosa spotting won't express on Paint white.

Threnody Sun, 02/27/2011 - 10:28

I'm sorry about the foal too NZ. :( Never a wanted experience.

As far as appy vs paint patterns they both have the ability to cancel each other out equally. Pinto white just [i]appears [/i]more bold with its patches devoid of pigment versus LP's blankets roaning and speckled skin under the white.

AppyLady Sun, 02/27/2011 - 15:47

I actually like the combination of tobiano + leopard. The paint white will still be white, but the patches that would ordinarily have base color will be white with leopard spots. You can imagine a line around the spots, and see where the dark patches would be. Looks really cool!

NZ Appaloosas Mon, 02/28/2011 - 01:29

Thanks guys. Just puts a back a year, if we don't decide to just go ahead and geld Bubba.

NZ Appaloosas Tue, 03/01/2011 - 04:29

It's not Lp that I'm trying to find out if he has, it's Patn-1. He's out of a leopard mare, so there's a chance he got it. As far as Lp is concerned, he's got no characteristics, but if he produced a nose-to-toes pattern with Misty, who is HZ for Lp, then keeping him intact makes more sense.

Diane

rodeoratdogs Tue, 03/01/2011 - 09:32

[quote=NZ Appaloosas][quote=rodeoratdogs]NZ, did it even have it's hair yet?[/quote]

Don't know, as I was in the office, and hubby disposed of the fetus before I got home. Digging that sort of thing up just isn't my cuppa, if you know what I mean.[/quote]

I Most definitely know what you mean, sorry for your loss. :((