Stallion determining foals sex....?????

[Rusel]

It was a long ride from Mo to FLorida after dropping off Dancer at Bernices.... So I let my mind wander.... passing over large heart research for endurance info which I've mashed into tiny pieces.... when my mind wondered over the notion that maybe,,,, just maybe..... stallions do not determine the sex of foals...

MAYBE.. stallions only determine the possibility of the sex of the foal..!!!

Okay... hear me out... (understand I had 22 driving hours to work this idea through)

I understand that stallions carry the X and Y while the mares carry only the Y Y... So without the X contributed by the male there would be NO COLTS...... BUT

Fact 1: for the first few (10) days of development the embryo is considered to be female.

WHAT IF::: at the time of the starting of the development of the sexual organs there is an X factor available for development BUT because of the hormonal output of the mare at this critical time the X factor is

1) overridden and what developes is a filly with more masculine attributes and a little more aggressive by nature....

2) not quite overridden and you have a colt that is slighter built in comparison and may develop only 1 normal teste or small testes.

REASONS TO WONDER:

1) Since labs have been able to spin sperm and guarantee the sex of the foal there have been recorded incidents that the foal came out not as guaranteed.... NOW... did the lab do a poor job... or did the mare decide the sex....

2) Since embryo transfers to host mares there have been some recorded color patterning on foals produced that more resembles the dam that was carrying the foal... such as blazes or high socks... bodies like the parents, chrome like the host...

So if a HOST MARE can influence color is it not also possible that a mare has the ability to influence the determination of sex by her chemical input...

Just something to occupy my mind while driving..... and a few other ideas also,,,, but later...

[Pasofinoguy]

I used a trick when i bred my old stallion to my old mares. And in the two tries i got 2 fillies. So I know i needed to try it more but I got the fillies i wanted by using this trick. They said its like 85% affective.

[Carol Nelson]

Gee...all I can think about while driving 22 hours is what I'm gonna get for a snack when I get to the next gas/restroom stop...and if I'll be able to make it there by the time I need to... :rofl

[Pinto Paso]

We have two "tricks" that we started using about 15 years ago... previous years had resulted in about 72% colts. At the time fillies were much more valuable and easier to sell plus we wanted fillies to hold back for our own breeding.

We talked to some old time horse people, a couple of vets and read books on fertility... Finally we decided to use one method that worked on the life cycle of the semen and another old wives tale which also is partially related to how the sperm travels etc.

after using these methods (together at time and individually) we came up with a success rate of 96.4% fillies. ONE foal in all of our tries came out a colt - funny thing was, the mare carried like it was a filly and it was early like a filly...

We have only used these methods for live cover and without using shots to bring the mare in or to drop the egg after breeding so can not say how the methods would work with the AI scenario. We have used it with 5 stallions and use it for breeding for fillies, not colts.. Colts are harder to breed for because of the timing and life cycle of sperm..

Cant say we have backed it up with science but it works for us :D

[Abejita]

2) Since embryo transfers to host mares there have been some recorded color patterning on foals produced that more resembles the dam that was carrying the foal... such as blazes or high socks... bodies like the parents, chrome like the host

Well unless you are getting a raging colorful pinto when you were breeding a STB(although I remember seeing an article in one of my hoofbeats mags years ago about some pintos and other 'odd' colored stb's..before ET)..I sure think that is a big jump without scientific evidence.
I have seen more than one loudly patterned foal from two parents that had a lot less color. In one case the same breeding had been done many times..and ONE of those came out with a lot of white on her face and high stockings etc.All the other full siblings might have had one or two low white pasterns and a spot on the forehead.So it can happen.

[Rusel]

So you tease with "tricks" but don't supply the details....

What GOOD is THAT..!!!! Fill us in....

[motorgypsy]

There are a lot of variables. The stallion's contribution does determine the but he must provide healthy sperm to be able to produce both genders. If the Y sperm are faulty there will be no colts which can happen. The same is true of the X form the sire but this is less common. The mare in this case has no role in the fact that all foals from this stallion will be female. This would be the fault of the stallion. I know a human male with this condition and he did indeed have all female offspring.

If the mare is bred early in the cycle so all the male sperm are dead before the egg is ready to be fertilized, getting a filly is the "fault" of the breeder or the mare if she won't stand at any other time. Female sperm are larger, swim more slowly, are tougher and live longer.

The acidity of the birth canal also plays a role in gender selection. If I remember correctly more acid is more likely to be female and more basic, male and in fact humans have been known use dilute vinegar or baking soda to improve the odds of a particular gender offspring.

Multiple breedings are supposed to favor I think the male and a single early breeding, a female offspring. Breeding right on the ovulation date at the time the egg can be fertilized etc., will favor a male offspring because the male sperm swim faster.

And there probably are other things that influence the gender of the offspring.

Now to get to Rusel's speculation of the "in betweeners". There are genetic flaws that can produce things like genetic males who look in all aspects like a female but have no uterus.

There are some that have three rather than two sex chromosomes like XXY and XYY and there are some really strange ones that will produce a baby that is born looking a like a female but when this individual reaches puberty it will develop male sex characteristics and become a normal adult male. In the case of the genetic male that is a phenotypic female even though she has XY, her body does not respond to testosterone so by default she becomes a real female but cannot reproduce. In the class we took they said a number of female models have this syndrome.

In some cases the mother produces a lot of testosterone during pregnancy and the baby is born with males characteristics but is really a female. It's been a long time since I took the course in human genetics so I can't remember of the individual becomes a sterile male or later changes to a female.

So as she said - gender is not cut and dried. You have male, female and sortof male and sortof female and some with both characteristics who get to choose which gender they want to be. Pretty interesting.

[Pinto Paso]

So you tease with "tricks" Fill us in....

I'd tell ya, but then I'd have to kill you. :lmao

I wont post in a public forum, because it is not scientific, and in fact is part of our maketing - why we can offer, guaranteed color, guaranteed filly or free rebreeding and you keep the 1st foal on some of our studs and guaranteed filly on others...

[Rusel]

And there probably are other things that influence the gender of the offspring.

Now to get to Rusel's speculation of the "in betweeners". There are genetic flaws that can produce things like genetic males who look in all aspects like a female but have no uterus.

There are some that have three rather than two sex chromosomes like XXY and XYY and there are some really strange ones that will produce a baby that is born looking a like a female but when this individual reaches puberty it will develop male sex characteristics and become a normal adult male. In the case of the genetic male that is a phenotypic female even though she has XY, her body does not respond to testosterone so by default she becomes a real female but cannot reproduce. In the class we took they said a number of female models have this syndrome.

In some cases the mother produces a lot of testosterone during pregnancy and the baby is born with males characteristics but is really a female. It's been a long time since I took the course in human genetics so I can't remember of the individual becomes a sterile male or later changes to a female.



GREAT.... So first I had to learn color genetics, :smile: then along comes X factor for large heart, :-? now testosterone having an influence on the gender of the foal.... :shock: I'll have to ask for a life extension so I can learn it all.....!!!! Guess when I can no longer ride I'll research...!

PS by the way.... THANKS FOR THE INFO ....very interesting....

[LynnG]

I understand that stallions carry the X and Y while the mares carry only the Y Y... So without the X contributed by the male there would be NO COLTS...... BUT

Mares have the XX chromosomes. Stallions are XY, so the male contribute either a X (female) or Y (male) to one of the female's X.

I love my fillies, but if its meant to be a male, so be it... as long as its born alive and healthy.

[Rusel]

Gee...all I can think about while driving 22 hours is what I'm gonna get for a snack when I get to the next gas/restroom stop...and if I'll be able to make it there by the time I need to... :rofl

That's funny Carol.... I ususally eat my way across the US when hauling horses also... but for some reason, this trip, I had no appetite.... maybe because it was the first time I would be leaving Dancer with anyone... He did great... I'm the one who got homesick for my horse...

[PattiB]

I know how long that trip gets, I've made it a few times myself. I usually listen to book tapes to keep me awake, I'm not sure thinking about filly/colt would do it for me.

We had a mare that had 13 offspring, 10 of those fillies to various stallions. Someone told me she must have an acidic uterus that gave us all those fillies! Debbie once told me to flush a mare with vinegar before breeding her to get fillies but I never tried it.

[Serendipity]

I'm with LynnG here Alive and healthy. I tryied breeding or color and still never got it I have 2 of the worst marked pintos around 8-) but god love'em.breeding has been Russian Roulette :shock: with me the past few years but we're trying again so I don't care what it is just alive and Healthy ;-)

[motorgypsy]

Alive and healthy is good!!! - 4 legs, one head, one butt and a good brain would be nice also!!