Is roan to roan breeding lethal???

[MindyLee]

I seen on another fourm where this question was being discussed amoung many folks and figured I would ask it hear myself because Im wondering now. I read that 2 roan horses can not produce a foal because it is lethal and the mare will absorb the foal. Now I dont know if this is true but I have 2 roans bred togather and expecting a foal in April that more than likely be a roan for sure. The dam is a bay roan and the sire is a buckskin roan. As of now the baby is kicking like crazy, wants out, and dose'nt feel like it has been absorbed to me. I guess when he or she is born I'll find out for sure but for now I'm going with this is a false statement.

What do you think and do you believe this to be true or false???

 

[End Level Farms]

This is completely false.

Roans can be homozygous and we know what that means. One R gene needs to come from both parents in order to create a HOMOZYGOUS anything.

Now roans with overo LWO is a different matter. And two roans who are LWO positive can produce a lethal but it has nothing to do with the roan and everything to do with the LWO.

According to Animal Genetics Coat Calculator the following are the chances you have of each color foal from the mating of a Buckskin Roan and a Bay Roan.

Offspring Color Probability

32.96% -

Buckskin Roan

32.96% -

Bay Roan

10.99% -

Buckskin

10.99% -

Bay

2.34% -

Palomino Roan

2.34% -

Chestnut Roan

2.20% -

Smoky Blue Roan

2.20% -

Blue Roan

0.78% -

Palomino

0.78% -

Chestnut

0.73% -

Smoky Black

0.73% -

Black

 

[Jill]

We do not have any roans now, but did used to have a true bay roan stallion (never bred him though). If I remember right, roan x roan has a 25% chance of being lethal and if so, foal is absorbed early on (vs. the really heartbreaking situation you can get with LWO x LWO).

 

[kaykay]

The jury is really out on this one. There are big horse breeders that say they breed roan to roan all the time with no losses or absorptions. But I wonder how you could really know. Past theory was they aborted or absorbed very early so that you didnt know.

Also though I think the color roan in miniatures is used so much when its not a true roan. Many times its a sabino horse and mistaken for roan. Kinda like all those Palomino minis that are actually silver bay

 

[Jill]

Kay has a point. Many mini owners do not know the difference between true roan and sabino roan. As someone who's owned / owns both, once you are educated as to the difference, it's easy to recognize.

Primarily, a true roan will have roan hairs on the body, upper legs and neck, but the head will not have roan hairs. On a sabino roan, you will find the roan hairs distributed all over the horse, including head and lower legs.

Neither true roan nor sabino roan is "uncommon" in minis, however, sabino is probably more often seen (and in varying degrees). To add to the possible confusion, it's not unusual to see greying horses inaccurately called roans (most often "blue roan").

 

[kaykay]

To add to the possible confusion, it's not unusual to see greying horses inaccurately called roans (most often "blue roan").

Yep I forgot about that one. When people come out they always refer to Promise as blue roan and I keep telling them shes a true grey LOL It is hard because a slow going grey like Promise has the darker head and dark leg points like a roan but we know shes a slow going grey

 

[MindyLee]

Well... all I can say is that neither one of my horses that are roans have any paint genes behind them as far as I can tell. All are buckskins, bays, and roans that I have seen with a few other solid colors in there as well. But no paint genes to give those sabino/homo mix-ups that I am aware of. ( not saying absolute for sure) but not seeing them. I could'nt post a photo of my mare or stud, but the mare can be seen under my name and there is no doubt about it that she is a bay roan. White/gray body with black mane/tail/legs and bright red head with no white hairs through the head and legs. This is the same for the stud just buckskin instead of bay in color. And they both have white hairs through-out their bodies too. All I can say is that neither horse is gray and that they both are true roans with no doubt.

 

[Songcatcher]

From your description, both your horses are true Roans. As kaykay mentioned, the jury is still out on the issue of "lethal Roan." If it is lethal (and I do believe it is from my studying), it is 25% lethal, not lethal in every case. Also, it is inutero (sp) lethal, not producing a foal that will die. Evidence indicates that Roan X Roan crosses result in a lower conception rate and simply come back into season on schedule.

There has been a study done that claims there are Homozygous Roans. However, people who have examined the results say that many of the foals produced are NOT true Roans, but Sabinos.

MY conclusion (from reading, not from personal practice) is that breeding Roan X Roan will produce a 25% lower conception rate (mare returning into season) 25% Solid color, and 50% heterozygous Roan. Of course, the mare returning into season and being rebred will alter the percentages.

 

[sdmini]

We have bred roans almost exclusively in QH for years. While yes we do pasture bred our foaling conception and foaling data does not support the lethal foal theory. We have enjoyed 90% first cover conception and CARRY on all our mares for the past 20 years or better. Of those that did come around the second time or run open we have not seen an increase in roan mares bred roan verses non-roan mares.

While I have yet to actually find a real homozygous roan I also have to say that regardless of what the book says my data supports the fact that my horses can't read.

 

[MiLo Minis]

What you have to remember about percentages in breeding is that it is not 25% of the breedings BUT 25% EACH and every time you breed, so you are not going to end up with 1 in 4 mares losing their foal because of a 25% change of the foal being lethal.

 

[rabbitsfizz]

Good point, Lori, statistics, basically, can be made to support anything at all, which is why we cannot rely on them for accuracy!

IME Roan X Roan lowered the conception rate to zero!

The mare bred to a non- Roan conceived immediately, as she had done in previous years, but bred to the Roan stallion she returned in season like clockwork, in fact he got fed up with her!

As said the jury is still out on this, especially as a lot of the "roans" in QHs are not actually true Roans, but Sabino Roan (one of the reasons behind all those "crop out" Pintos, I think

)

The main issue here, though, is that Roan X Roan does not, ever = dying foal, you will only ever just not get a foal, so if the mare in question is safely in foal you have nothing at all to worry about.

 

[sdmini]

What you have to remember about percentages in breeding is that it is not 25% of the breedings BUT 25% EACH and every time you breed, so you are not going to end up with 1 in 4 mares losing their foal because of a 25% change of the foal being lethal.

Exactly HOWEVER if I was to believe that roan to roan did cause absorption we should still see more roan mares bred roan coming back in season later on in the year and that was not the case. By this "rule" we should have more roan mares breeding a second time during the course of a breeding season verses non-roan mares and again that was not the case. We disbanded most of our mares a couple years ago when we were hit with a prolonged drought but there were 10-12 roan mares bred roan every year for 20 yrs+.

Personally I've never seen a sabino "roan" that looks like a true roan although I do acknowledge that many sabinos were labeled as roan in years past. Also, perhaps it's because we were sticklers about the roan coloring but I've seen FEW sabino "roan" QH's period.

 

[StarRidgeAcres]

I also have to say that regardless of what the book says my data supports the fact that my horses can't read.

 

[Minimor]

I read that 2 roan horses can not produce a foal because it is lethal and the mare will absorb the foal.

Mindy Lee--What no one has really been specific so far--it isn't that roan x roan cannot produce a foall--the theory is that if the resulting foal is homozygous roan it will not be a viable embryo and will die early in the pregnancy--resulting in the mare coming back into heat. There is only a 25% chance of roan x roan producing homozygous roan, so if we assume the theory is true, there is still a 75% chance that any foal from this cross will be heterozygous or non-roan and therefore a 75% chance that the cross will result in a live foal. Therefore, the fact that your roan mare is now safely in foal to a roan stallion doesn't really disprove the theory.

We aren't going to know if the theory is true or false until someone comes up with a test for roan.

 

[MindyLee]

Thank you Minimor! That sums it up and is less confussing to me in your statement. Now I get what everyone is talking about. I just was'nt sure because like I said before. My mare is pregnet 1st time 1st bred and took with no problems. I only heard of the lethal white in paint horses, not roans. THANKS EVERYONE!!!

 

[Amy]

We have a blue roan stallion -- have bred him to blue roan mares, bay roan mares & red roan mares -- always have had a very healthy foal each spring from each breeding. Love the roans & have several of them.

 

[rabbitsfizz]

Amy, it is more than possible to breed Roan X Roan and get a foal.

The only issue thought to happen is with H/Z Roan, as stated.