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gem@oakmeister
Silver Member
421 Posts |
 Posted - 04 Nov 2010 : 3:31:31 PM
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A friend and i were discussing foal gender recently and pondered the subject of stallion or mare determining the sex of the foal. She tells me her vet say's a stallion is not responsible for the foals sex but i know from human biology lessons (we wont discuss how long ago) that the male does determine the sex. female xx so can only contribute x. male xy so can provide either. therefore if he provides x child will be girl, if he provides y it will be a boy. Now i'm not suggesting for a moment that the man in question has any control over the chromozone (spelling)that he forwards at time of conception, but it occured to me that if this was the case in humans it was most likely the case in all species.
I have heard many tales of AI giving more fillies and natural covering more colts, but i think this is based on the opinion that female sperm are stronger and male sperm quicker.
What i would love to know is does the xx and xy explanation really only apply to humans or is it the case in horses cattle dogs etc etc. Any genetics experts reading, please clarify.
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LYNDILOU
Platinum Member
United Kingdom
13976 Posts |
Posted - 04 Nov 2010 : 5:12:24 PM
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It is the same in all mammals , the female only carries the female side xx, it is the male who determines the sex, but we have a resident vet Lisa on here I am sure she can help explain for you  |
   
www.dreamfield-arabians.com |
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Jamana
Gold Member
England
682 Posts |
Posted - 04 Nov 2010 : 5:20:23 PM
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As far as I know the X Y situation is the same in horses as people. However I am no genetics professor so I am willing to be corrected.
There are cases however of mares that have 'only' colts or 'only' fillies regardless of sire (methods of covering determining sex I am not sure of as I only deal with TB's so only natural covering) In these situations I can only assume that the mares's body positively selects for sex by only continuing with the pregnancy of the sex that is favoured.
On a slightly different tack re genetics I can remember trying to explain the genetic inheritance of tobiano coat pattern to a gypsy man we bought a cob mare from. He listened and nodded and agreed about why the mare had produced solid foals to one sire and coloured to another but then said " I know all that, but Chloe always throws black and white/black/black and white/black no matter what 'orse she covers with" Thing was, he was right and she duly had a black foal and then a black and white!! So that is why genetics to me is not the answer to everything that it seems to be |
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Kharidian
Platinum Member
England
4297 Posts |
Posted - 04 Nov 2010 : 5:39:33 PM
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I agree with those who say the stallion determines the sex in as much as he provides either X sperm therefore XX is female or Y sperm therefore XY is male.....however the mare will contribute either by the acidity or otherwise of her reproductive tract (favouring either X or Y sperm). I believe the timing of covering from ovulation will also have a bearing as one or other of the sperm will live longer.
There was some talk a while ago (related to humans) that diet can affect reproductive tract acidity and therefore the chances of conceiving a desired sex; I think (in simplistic terms) it was dairy for female i.e. more alkaline and more fruit & veg i.e. more acidic for males but this is all off the top of my head and not researched.
Caryn |
Kharidian (Prince Sadik x Khiri)........ Alkara Cassino (H Tobago x Rose Aboud)
aka "Roger".................................... aka "Chips"
     
The first image is from an original painting by Pat Shorto.
South-East Essex |
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Dark Angel
Silver Member
England
285 Posts |
Posted - 04 Nov 2010 : 6:00:17 PM
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| DNA is an acid in itself and gender is determined in the female reproductive system at methylation. I do not believe it is determined by any kind of acidity within the reproductive tract. |
Hereford |
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Kharidian
Platinum Member
England
4297 Posts |
Posted - 04 Nov 2010 : 10:45:46 PM
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There's actually quite a lot of information about gender selection and timing of intercourse, diet, acidity etc if you google it; however, not being a statistician I don't know how valid the research is.
Caryn |
Kharidian (Prince Sadik x Khiri)........ Alkara Cassino (H Tobago x Rose Aboud)
aka "Roger".................................... aka "Chips"
The first image is from an original painting by Pat Shorto.
South-East Essex |
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Valentine Arabians
Gold Member
United Kingdom
586 Posts |
Posted - 05 Nov 2010 : 11:51:36 AM
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Yes, it is very complicated and confusing and I don't care whether a colt or a filly appears as long as both mum and baby are healthy.
Going on to AI, we have had the one mare AI'd four times, and have had 3 fillies and 1 colt, so the tales seem to be right. |
Liz & Walter Downes
www.ValentineArabians.com
Lincolnshire |
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foal gender
