And…are there ways to up the chances of it being a colt or filly? For instance…a certain mare or stallion tends to always throw colts?
I know the first question probably has a simple, proven answer but not so sure about the second one. I’m sure there are a lot of “old wives tales” that get thrown around but I just wasn’t sure if there were any new scientific findings when it comes to gender predictability.
The stallion is responsible…the dam carries two x’s and the sire carries an x and a y…so a 50/50 chance of getting an xx (filly) or an xy (colt)
Just like in people it is the male, or stallion in this case, that decides the sex of the baby. I believe there is research that explains which one, the “boy” sperm or “girl” sperm is faster when first inseminated and the other one lasts longer, so you can try to up your odds on getting the sex you want with when in your mare’s cycle you breed her. It just slipped my mind which one is which though!! I’m sure someone will chime in who knows. In any case, you’ll really get what you get! Of course your best chance will be to get what you want the least as Mother Nature so loves to play tricks!
ahh, so when you see a stallion that MOSTLY throws colts, its simply just coinsidence?
:lol: yeah, so true! I would love to know where that information came from and to know more about it!
Actually, a very interesting study in the last few years showed that when mares are gaining weight, they will produce colts 80% of the time, while if they are losing weight, they conceive fillies 80% of the time.
Of course, I am referring to a weight trend, not just a single day or week. The prevailing thought to why this occurs is that if food is abundant, then it is a good time to make males, which in turn produce lots of babies every year. Whereas a lack of forage would indicate the population is struggling and mares should produce fillies, which will only be making (at most) one foal per year.
So far this has worked for me, but it has only been 3 foals- so not statistically significant. Keep in mind, however, that mares are most likely to conceive when their body condition score is a 6 (slightly fat), so do not starve your mare away to nothing to try for a filly!
As for your first question, biologically speaking- the stallion determines whether the baby will be an XX (female) or XY (male) since the mare always contributes an “X” while the sperm will contain either an “X” or a “Y”
Just like in people, it is the male who determines the sex of the offspring. Only the stallion has both x and y chromes to pass along. If you see a mare that seems to have just fillies, or a stallion that seems to throw lots of colts for example, that’s just by chance.
Ask Equine Rep, she is fairly consistent. :lol::lol::lol::lol::lol::lol:
I am not so sure it is just by chance. There is many cases of species being able to sex their young depending on environmental circumstances or group needs. It may be more subtle in horses but in a herd setting, it would make sense if they could. The study looks like it could be indicative of this.
Even though the stallion provides the x or y it would be in the mares body that the selection process would take place, so if there is selective factors, it would be the mare.
I do not think it has been revealed that stallions release more of x or y in certain cases.
To add: even if there is no selection process, the stallion is not determining the sex. He is providing the possibilities of two outcomes. It would be a random event if there is not selective factors. It is an old fashioned way to view it that the stallion determines the sex. As much as a craps player determines what the dice will be.
I think how close to ovulation the mare is inseminated can also be a factor in determining the gender of the foal (same is true in humans). The male sperm don’t typically live as long as the female sperm, so if you breed your mare very close to the time of ovulation you would increase your chances of a colt.
You hush yo mouth!!! 
I’m on a filly run…I’ve now had TWO in row now. Hrmph!! 
Stallion determines the sex. Lots of speculation on other things that might influence whether or not there is a way to insure getting one sex or the other. Breeding close to or considerably earlier than ovulation with the idea that “male” sperm are faster but die off quicker and the female sperm are slower but last longer living. Influencing the PH of the uterus is theorized as having an influence. Some stallions producing predominantly one sex or the other. With that said, other than the research with the wild horses, there has been nothing to prove one way or the other that any other method, short of sperm sex sorting, works.
My experience? EVERYTHING causes males with the occasional female thrown in to just mix it up <rolling eyes>. Our last mare is at 346 days and it’s 104 degrees here today. I’m guessing we have another colt coming up and our run on fillies is over and back to our regularly programmed station - COLTS!
I think it is all 50/50 - I bred my stallion twice before gelding - one filly and one colt - which is perfect for me.
[QUOTE=stoicfish;5723022]
Ask Equine Rep, she is fairly consistent. :lol::lol::lol::lol::lol::lol:
I am not so sure it is just by chance. There is many cases of species being able to sex their young depending on environmental circumstances or group needs. It may be more subtle in horses but in a herd setting, it would make sense if they could. The study looks like it could be indicative of this.
Even though the stallion provides the x or y it would be in the mares body that the selection process would take place, so if there is selective factors, it would be the mare.
I do not think it has been revealed that stallions release more of x or y in certain cases.
To add: even if there is no selection process, the stallion is not determining the sex. He is providing the possibilities of two outcomes. It would be a random event if there is not selective factors. It is an old fashioned way to view it that the stallion determines the sex. As much as a craps player determines what the dice will be.[/QUOTE]
Why I would say it is up to the stallion is because the stallion is providing the x or the y genetically. So the genetic material that makes a horse male or female is coming from the male genes.
gender determination
OK. Hope this helps…
The sex chromosomes are the X chromosome and the Y chromosome. Sperm are the male gametes in humans and other mammals, and they contain either an X or a Y chromosome. Eggs are the female gametes and contain only the X sex chromosome thus the sperm cell determines the sex of an individual. If a sperm cell containing an X chromosome fertilizes an egg, the resulting offspring will be XX or female. If a sperm cell containing a Y chromosome fertilizes an egg, the resulting offspring will be XY or male.
The “male sperm die sooner and swim faster than female sperm because the Y chromosome is smaller” theory (i.e. the “Shettles method” which says the closer to ovulation you have sex, the more likely you are to have a boy.) has little to no scientific evidence to support it.
There is a theory that a woman can change her vaginal pH through diet to increase the chance of the female sperm surviving on the theory that female sperm are more hearty. Again, little to no supporting data.
No form of prefertilization (i.e. before egg meets sperm) gender selection has been shown to be reliable although the recent technique of using flow cytometry to sort sperm prior to IVF to allow couples to increase the chance of having a baby of a certain gender (they use the fact that the X chromosome is slightly heavier than the Y chromosome) is felt to be promising but not yet adequately verified and also ethically problematic in humans.
The only reliable techniques for gender selection are post-fertilization (i.e. after egg and sperm meet) like fluorescence in situ hybridization or embryo cell biopsy, etc. Post-fertilization, preimplantation genetic diagnosis can determine gender 100% but can require multiple IVFs and has obvious ethical issues making it controversial for use in humans… ACOG (American Academy of Ob/Gyn) supports gender selection techniques only when a couple has known or suspected risk of having a child with a severe sex-linked genetic condition. Here is a link to the ACOG discussion on gender selection: http://www.acog.org/from_home/publications/ethics/co360.pdf
I asked our repro vet recently if gender selection was something you can do in horses, and she said she has heard of research done using flow cytometry prefertilization to determine equine gender but that it was, obviously, very expensive.
Again, using any breeders individual experience does not have statistical validity. You would have to have a LARGE blinded and controlled study to determine it any technique really worked. Like so many things in equine medicine, much of what we think is “truth” is really more hearsay… We had 5 colts and 1 filly last year and have had 5 fillies to date this year. I have a family in my practice with 6 girls (kept trying for a boy) and a family with 5 boys for the same reason. Statistics are tricky things and only make sense if you look at the REALLY big picture. :winkgrin:
Wow WEE, thank you you little braniac! And actually written in a way I can understand. Thank you!
If there was a simple way to breed for colts or fillies, I am absolutely sure Kathy would have done that already! LOL!
Terri
I remember reading about this study; it was not really controlled, in that it was an observational study done with mustangs (I believe in Australia).
Their theory was simply that female embryos are tougher than males…which we all know <g>. So they are more likely to survive in years when forage is scarce.
Last time I bred one of my mares I REALLY wanted a filly, so I fed her very well for 4 mos prior to breeding…probably quite abit more then what she really needed. Then, a week prior to breeding her, I cut her down to just afew flakes of hay a day…in other words, her caloric intake went from 2x what she needed to (probably) about 30-50% of what she needed. I kept her on the “starvation” diet till she was 30 days in foal…at that point she was actually right at her “normal” weight, so she really wasn’t being starved, but her body thought so.
Got a filly! Again, this certainly doesn’t prove anything, but it was nice.
Now that I know everything I’m going to breed is going to be sold, I don’t really care that much, so I’ve never tried it again, but…
My vet made the comment that he’s seen mares who typically have mostly fillies and some mares have mostly colts. My mare seems to be a mostly filly mare. 6 different stallions were used out of 7 pregnancies and 5 fillies/2 colts as a result. All but the first was frozen semen.
Has anyone else noticed traits like this with individual mares? Is something in their biology only allowing the female sperm to penetrate the egg? Deep horn insemination was used the last time so you’d think the male and female sperm would have equal opportunity. ???
Actually - the dairy cow industry has a high percentage of success (I’m sorry I don’t have access to the data at the moment) with sex sorted semen. This is the sorting of the semen prior to insemination.
It is not unusual for dairy farmers to use sex sorted semen in their top cows to produce daughters rather than sons.
[QUOTE=Equilibrium;5723662]
If there was a simple way to breed for colts or fillies, I am absolutely sure Kathy would have done that already! LOL!
Terri[/QUOTE]
Yup. I’ve tried just about everything including standing on my head and spitting nickels. I get…colts. <lol>.
[QUOTE=everafterfarm;5723013]
Just like in people, it is the male who determines the sex of the offspring. Only the stallion has both x and y chromes to pass along. If you see a mare that seems to have just fillies, or a stallion that seems to throw lots of colts for example, that’s just by chance.[/QUOTE]
There was an international study showing that single mothers-to-be are statistically more likely to have a daughter than their patnered counterparts - so the hypothesis is that their seems to be a yet undetermined way that the mother-to-be’s body preferentially selects the X chromosomes. >51% of human babies are female and the number is rising.
I don’t really think this is relevent to all those mares - but it really interests me.
I really think it mostly has to do with which way you twirl when you run out in to the forest, naked, during a full moon to do your mare fertility dance!
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