Is the stallion or the mare responsible 4 determining sex of baby? And...

[Wits_End_Eventing]

A few more additions from a bit of research…

1. About bias in observation:

My vet made the comment that he’s seen mares who typically have mostly fillies and some mares have mostly colts.

I am SURE your vet is excellent. Please know this is NOT a comment on his/her opinion or practice style just a general comment about practice, expertise, and statistics.

Even as a practitioner where you see lots of animals (or kids if you are a pediatrician like I am), you can draw false conclusions from what you see because you really need a HUGE sample for statistical validity. For example, many physicians still treat yellow or green mucous as a “sinus infection” yet we know that this is not correct (from studies where needles were used to aspirate samples from sinuses). You can have colored mucus with a viral infection which is untreatable and only 0.5% to 2% of URIs develop into a sinus infection - MANY fewer than prescriptions written. Yet, good physicians will tell their patients to look for a change in the color of their mucous…

2. About change in the mare’s body condition:
   Here is a good article on the question of whether or not change in a mares body condition affects foal outcome:
   http://www.horsetalk.co.nz/breeding/foalsex-126.shtml.
   Note, however, that the initial statement “A study by a New Zealand-educated scientist at the University of Nevada has helped to disprove critics of the theory, which was developed in 1973” is NOT supported by the rest of the article. I think it basically says we still don’t know but research is ongoing.

3. About using flow cytometry to determine gender:
   Good New York Times article on sperm sorting and the ethical dilemas for people:
   http://www.nytimes.com/2007/02/06/health/06seco.html

Here’s a good article on a company that offers pre-fertilization sex sorting for animals: http://colotech.wordpress.com/2007/03/26/gender-selection/. Again, I love the fact that they consider a success, a dog litter where they tried to select for females and got 3 females and 2 males…Hope the owners didn’t pay too much money for that one…I don’t think I would be using them if I were breeding dogs, but…

This article states: “By using a flow cytometer…the semen is sorted according to the gender it would produce. The first filly was produced using this technique of predetermining the sex of a foal in 1998. Her name was Call Me Madam.”

According to this article, “in 1998, the world’s first sex-selected horse, “Call Me Madam” was produced by XY Inc. of Fort Collins, Colo. While XY Inc. continued their research and production of sex-selected foals, the service was not commercially available to breeders”… “The use of sex-selected semen in conjunction with intracytoplasmic sperm injection will be offered to horse breeders for the 2010 breeding season.” Evidently, “Chilled or frozen semen can be sent to the facility for sorting the sperm cells. The sample is sorted and the semen is frozen into straws with a small number of sperm cells per straw. Each straw is considered a one-use straw. Once the egg has been recovered from the mare, the straw is thawed and the best sperm cell selected for use in the intracytoplasmic sperm injection (ICSI) procedure.” “The process is quite specific and the assurance rate currently for getting the correct sex foal is over 95%.” Of course, there is not literature noted to back that claim up, but the technique definitely has scientific merit.

XY Inc. has liscenced the technology to the company Sexing Technologies. They do not mention horses, and I could not find any prices, but IT AIN’T SOUNDING CHEAP… Don’t think we will be going with this technique anytime soon, but I can sure see how a breeder with some cash and a good program who had perhaps the last dose of a certain stallion’s frozen semen in existence and wanted to produce a foal with a certain gender could be tempted… If anyone finds out more or tries this, please let me know!!! I am SURE I can’t afford it but am fascinated by the technology…

Wow WEE, thank you you little braniac!
I wish it was that I am particularly smart, but really I am just a good researcher, persistent and OCD. Anyone can do it with google. Here are my tips:

• check your facts, just because the internet says so doesn’t mean it is true
• go with accredited organizations whenever possible or well known news sources like The New York Times, etc. It is a little frustrating to me that you cannot easily access articles from the American Academy of Equine Practitioners.
• Never trust information from anyone selling what you are researching without independent verification…:eek:

[Bravestrom]

[QUOTE=CDE Driver;5723782]
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![/QUOTE]

I love this one - almost spewed my coffee - and i could do this as our forest is very private but we had a full moon last night. In any event -since I am not breeding anyone this year I will have to remember this one.

[Waterwitch]

http://www.horsetalk.co.nz/breeding/foalsex-121.shtml

Can’t find my copy of the original research at the moment but the above is a summary of the application of Trivers-Willard hypothesis to feral equines.

[back_in_the_saddle]

you can draw false conclusions from what you see because you really need a HUGE sample for statistical validity.

Yea… no kidding. How do you explain, based on the research you’ve read, “a” mare who’s had nothing but fillies (5 or more) or “a” mare who’s had nothing but colts (5 or more)?

True when you do the averages of a few hundred pregnant mares, the genders will end up 50/50 or close to it. What we’re talking about here is THE individual who has only one gender or the other (or a large % in one direction). Is that luck or is there something more to it with THOSE individuals? Not all mares fall under this category but a select few do.

[Jos]

[QUOTE=Bats79;5723773]
Actually - the dairy cow industry has a high percentage of success[/QUOTE]

Unfortunately, the success rate is not that high even in the bovine, with rates in one research project being between about 40% and 50% depending upon deposition location (Kurykin J., Jaakmaa Ü., Jalakasa M., Aidnika M., Waldmanna A. and Majasa L.; (2007) Pregnancy percentage following deposition of sex-sorted sperm at different sites within the uterus in estrus-synchronized heifers. Theriogenology 67:4, 754-759). I do remember seeing another research article in the bovine which suggested that pregnancy rates with frozen-thawed sex-sorted semen were considerably lower than that (I believe they were in the same range as in the equine, as presented below), but I do not recall the research document.

For the equine research results have been presented as follows:

• Pregnancy rates for sex-sorted sperm in the equine are reported to be low.[list]
• For fresh semen pregnancy rates are reported as 37.5% (Lindsey AC, Bruemmer JE, Squires EL, 2001. Low dose insemination of mares using non-sorted and sex-sorted sperm. Anim. Reprod. Sci. 68. 278-289)

• For frozen semen pregnancy rates are reported as low as 13% ([i]Lindsey AC, Schenk JL, Graham JK, Bruemmer JE, Squires EL, 2002 Hysteroscopic insemination of low numbers of flow sorted fresh and frozen/thawed stallion spermatozoa. Equine Vet J. 34 (2), 121-127[/i])

[/list] The cost of sex-sorting equine semen is quite significant - the last I heard was $5,000 for 3 breeding cycles, but I do not know if that is still the current price.

I would like also to strongly support the observations made by Wit’s End Eventing in regard to the need for large numbers for healthy statistical analysis. When lecturing, we often hear that someone has had x number of fillies in a row (or colts) and that they are convinced that their method of facing the mare uphill when being bred (or adding a copper penny to the water bowl; or feeding cider vinegar; or breeding only on a waxing/waning - I forget which - moon) is the reason for their success. Heck! Based upon the “one-farm research group” I could produce an “accurate research statistic” that indicates that breeding horses between the 34th and 41st parallels in the USA will result in 94% colts (if bred by Kathy and I!). Sadly, I have found that remonstration is often useless, so I now sagely nod my head and say how happy I am for them - but to the widespread audience here, I will say what I am really thinking again: you don’t have statistically valid numbers to prove the point, nor is there a suitably “controlled” situation to consider it “research”! Indeed, even properly conducted research in the equine is often hampered by a lack of numbers in many parts of the world. The reason that a goodly amount of research is performed in Brazil is that they usually have access to a larger number of horses for the research group.

So the sad fact is that the only way that has scientifically demonstrated a bias towards a higher rate of one sex or the other pre-breeding is the use of sex-sorted sperm, with about a 90-95% bias (again, depending upon which research is cited). The downside is that there is a significant reduction in single-cycle pregnancy rates, and the cost overall is much higher.

So feel free to dance naked in the woods or only breed your mare facing uphill - indeed, with the former, you may be able to offset some of the breeding costs by charging admission - but don’t bet the farm on a greater than 50% statistical odds for the outcome!!

[Kyzteke]

@Jos;5724049

So feel free to dance naked in the woods or only breed your mare facing uphill -

OMG, if I danced naked in the woods, my mares might be so mentally scarred (not to mention my neighbors) that they would be unable to conceive ever again!:eek:

[whbar158]

[QUOTE=back in the saddle;5723994]
Yea… no kidding. How do you explain, based on the research you’ve read, “a” mare who’s had nothing but fillies (5 or more) or “a” mare who’s had nothing but colts (5 or more)?

True when you do the averages of a few hundred pregnant mares, the genders will end up 50/50 or close to it. What we’re talking about here is THE individual who has only one gender or the other (or a large % in one direction). Is that luck or is there something more to it with THOSE individuals? Not all mares fall under this category but a select few do.[/QUOTE]

This is much like flipping a coin there is a 50% chance of getting heads and a 50% chance of getting tails each time you flip it. You could flip it 10 times and get 10 heads, just because you get heads the first time doesn’t increase the odds of getting tails, it is 50/50 each time. So yes a mare could have 5 fillies but if she could have 50 foals I am sure the % would be much closer to 50/50.

[Equine_Reproduction]

[QUOTE=Jos;5724049]
Heck! Based upon the “one-farm research group” I could produce an “accurate research statistic” that indicates that breeding horses between the 34th and 41st parallels in the USA will result in 94% colts (if bred by Kathy and I!). [/QUOTE]

Your statistics would be flawed 'cause every other mare we breed for everyone else gets a 50/50 representation of colts vs. fillies <ROTFL>. They MUST be owned by us!!

FWIW, I absolutely will not do the naked fertility dance ‘cause Jos would be charging admission. Granted, it would be for a horror show, but just sayin’ ;). So that’s probably the only thing we’ve tried that I have no idea whether or not it will work!

[MyssMyst]

[QUOTE=CDE Driver;5723782]
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![/QUOTE]

gigglesnort

[back_in_the_saddle]

[QUOTE=whbar158;5724114]
This is much like flipping a coin there is a 50% chance of getting heads and a 50% chance of getting tails each time you flip it. You could flip it 10 times and get 10 heads, just because you get heads the first time doesn’t increase the odds of getting tails, it is 50/50 each time. So yes a mare could have 5 fillies but if she could have 50 foals I am sure the % would be much closer to 50/50.[/QUOTE]

Well, I’ll take a mare who starts off producing more fillies while on her way to making everything average.

[Wits_End_Eventing]

He he he…

Sadly, I have found that remonstration is often useless, so I now sagely nod my head and say how happy I am for them - but to the widespread audience here, I will say what I am really thinking again: you don’t have statistically valid numbers to prove the point, nor is there a suitably “controlled” situation to consider it “research”!

My favorite is the Mom who told me that I would not believe her BUT the reason her child had not been in to the office for a sick visit yet was due to this piece of Wilkes County lore: Take a stick and cut it to exactly the length of your newborn child. No one can see you do it. Put the stick somewhere were it is in the dark, will stay dry, and no one will find it. You child will be healthy.

There is also a Wilkes County belief that your child will have something bad happen to them if they do NOT fall off the bed in the first year of life. One of my Moms told me she was so nervous that, when her child had gotten to 9 months without falling off the bed, she put pillows next to the bed and pushed her off. Mother and child were fine AND so far, nothing terrible has happened to them.

Of course, when I worked in California, I had 2 Dads who attempted breast feeding. Way to long a story for this forum…

From my dealings with the human race, it is SO tempting to believe all these things because it gives us a false belief that we have some type of control over this crazy world.

Here are my observational factoids from 35 years with horses:

1. Everything kills or maims them. Like toddlers, if you turn them loose on a football field with one small but very dangerous object, they will immediately turn and canter towards it.
2. There is a gene for horse addiction. In my family, it is passed from aunt to niece. If it is turned on, you are screwed. My husband has threatened multiple times over the years to start horses anonymous for people like me…
3. Like taking your car to the mechanic, the minute you say to a clinician, my horse always does X, he/she will immediately stop doing it for precisely the length of the clinic. If you say to said clinician, my horse will never do Y no matter what, said horse will immediately turn around and execute whatever it is perfectly…
4. Horses LOVE entropy and Murphy’s law! (And, my husband adds, to make you a liar…)

“A” :winkgrin:

[DownYonder]

go with accredited organizations whenever possible or well known news sources like The New York Times

I’m sorry, but I found this to be the funniest comment in this entire thread. :lol:

[Jos]

[QUOTE=Wits End Eventing;5724304]
One of my Moms told me she was so nervous that, when her child had gotten to 9 months without falling off the bed, she put pillows next to the bed and pushed her off. Mother and child were fine AND so far, nothing terrible has happened to them.[/QUOTE]

See? It’s scientifically proven!! No boubt adout it!!! :winkgrin:

[Equine_Reproduction]

[QUOTE=Wits End Eventing;5724304]

Of course, when I worked in California, I had 2 Dads who attempted breast feeding. Way to long a story for this forum…[/QUOTE]

Okay…this one made me snort. I’m ASSUMING you mean they were trying to FEED the CHILD! Otherwise, I have to ask…No, no…struggling NOT to type…I’m not going to ask. Forget it. Jos! You get to address that one <ROTFL>…

Edited to say that I’m truly astounded that Jos DIDN’T touch this one in the first place

[TrinitySporthorses]

2. About change in the mare’s body condition:
   Here is a good article on the question of whether or not change in a mares body condition affects foal outcome:
   http://www.horsetalk.co.nz/breeding/foalsex-126.shtml.
   Note, however, that the initial statement “A study by a New Zealand-educated scientist at the University of Nevada has helped to disprove critics of the theory, which was developed in 1973” is NOT supported by the rest of the article. I think it basically says we still don’t know but research is ongoing.

Very interesting, thank you.
The article I read that said that change in weight around conception influenced sex was from Equus Magazine, which I usually consider to be a very reliable source of scientific information. This article states that only 30% of studies seem to back that up, so I guess we’ll wait and see what future research can come up with…

[Jos]

[QUOTE=Equine Reproduction;5724679]
I’m ASSUMING you mean they were trying to FEED the CHILD!..
Edited to say that I’m truly astounded that Jos DIDN’T touch this one in the first place :D[/QUOTE]

A little Domperidone here, a little Sulpiride there, the odd hallucination from the Sulpiride, the insane belief that nursing will stimulate milk production no matter the sex of the breast-owner…

Nope, nothing there to touch really… all pretty straightforward! :lol:

[sportnhorse]

I am not a big breeder, but to date my stallion has produced all fillies and only one colt. The colt was o/o a mare whose only previous foal was also a colt. Her second foal by my stallion was a filly too. When I truly have nothing to do, I ponder the relevance of this:lol: Do some stallions consistently produce more of one sex than others? Could this mare have had any influence on the fact that she had 2 colts in a row - from completely unrelated sires? Intriguing:)

[back_in_the_saddle]

[QUOTE=sportnhorse;5725177]
I am not a big breeder, but to date my stallion has produced all fillies and only one colt. The colt was o/o a mare whose only previous foal was also a colt. Her second foal by my stallion was a filly too. When I truly have nothing to do, I ponder the relevance of this:lol: Do some stallions consistently produce more of one sex than others? Could this mare have had any influence on the fact that she had 2 colts in a row - from completely unrelated sires? Intriguing:)[/QUOTE]

In chickens, there ARE some lines that produce more hens than roosters. The typical hatch ratio of my plymouth rocks is 5 hens to 2 roos.

[sportnhorse]

[QUOTE=back in the saddle;5725215]
In chickens, there ARE some lines that produce more hens than roosters. The typical hatch ratio of my plymouth rocks is 5 hens to 2 roos.[/QUOTE]

Slightly OT, but funny you should mention chickens, I have OEG for insect control (1 rooster & 3 hens) and they breed way more hens than roosters. The last clutch has only 1 rooster in it. I used to breed Leopard Geckos and you can manipulate the sexes of hatchlings with temperature control during incubation. Pity horses aren’t quite so simple!

[Graymaresrule]

@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.

True but I think there are a few more factors involved. My repro vet stands a stallion and breeds his own mares monitoring the mares and collecting and inseminating as needed. He, like Jos and Kathy, gets mostly colts from his own mares but when he ships semen there is a closer to 50-50 ratio.

IIRC in human repro it was once thought that the XY sperm being slightly smaller were faster but the XX sperm had longer lives so that if humans had intercourse around the time of ovulation or slightly later the chances of a boy were higher. If intercourse took place well beforeovulation some of the XY’s had died off and the XX’s had the advantage.
Also vaginal pH (forget which like vinegar and which liked baking soda) matters