Determination of Gender by Placement in Uterus
 

This is information that will be important to breeders.
I had wondered for years how to determine, if there even was a way it could be done, the sex of the puppies my ladies were carrying. This information would certainly assist me with waiting lists for specific litters. So, after MUCH research and reading and study, and keeping track of my own litters and the sex of the puppies born in each litter, it has been MY concuring experience, that puppies carried in the right horn are most often males, and in the left horn are most often females. When I say "most often", that means probably close to 85% of the time (or more!), this holds true! Of course, there is ALWAYS exceptions to the rule, that will keep you from say this is a failproof way of always determining the sex of the puppies your momma is carrying!

I would LOVE to challenge all serious breeders, where it can really benefit you knowing the sex of the babies you may end up with, to do your OWN research with your own litters, and see how often your results with your own litters, fall in line with the academia! This last litter of mine was, once again, spot on.....on xray, we had 3 in the right horn and 2 in the left horn. As expected, we have 2 females and 3 males! After doing this with all my litters over the last 5 years, the results are accurate enough for me to share what I experienced. This may be old news for many of you, but I had never read any information from breeders regarding "sexing" their litters prior to birth.

Gald to see we continue to study the important stuff.:eek:

Absolutely!! Knowledge is a wonderful thing! It would be super if breeders could/would share with other breeders, information that has evidenced based outcomes that could be utilized in breeding programs!

I think that would be great to share. I will pose this question with my Blackie breeders and the Cdn Yorkie breeders I am friends with.


I will also ask them to try to notate the right left hand horn Xray results = sex / gender


It is great to know as some diseases are sex linked - and would be nice to know how many genetic tests I am likely planning on. Also in large breeds where males are significantly bigger/stronger etc than females, it would be good to know. Although many of us wee females tend to own the *big males*:D:D

It is really very useful and exciting information for some breeders, for a variety of reasons! Kind of takes the "crap shoot" down just a notch, of expectations in a pregnant female. Thanks Gail!

Hmmmm...I'll make a note of that. I can "sex" mine by heart rate. Eight litters and only "guessed" the sexes wrong once. My vet even notes it now just to see if I'm correct.

Great!! Please share your parameters for heart rate = sex of pup! Is there any published data verifying this method?!

Sorry, I'm still not "getting" it. I've used several vets and nobody ever showed me on x-ray how you can sort out the whelps by which horn they're in. Sometimes I can feel which horn they're in, but not always. Often I feel they're moving all over the place. Once the birthing starts I'm totally consumed with getting everyone out alive.

If you have an xray done, it is clear on xray which horn they are in, left or right. Your vet should be able to tell you which horn the puppies are in by looking at the xray! It is easily visable on the shot taken with the female positioned on her back!

No just my vet's notes in my chart. lol.

I started it rather jokingly because I remember the OBN/GYN office telling me they could predict the sex by heart rate (this was long before the 20 week date of the only US you would have back then)....any way there is a noticeable difference in heart rates and honestly I've never timed it.

My x rays are taken from the side...so it's impossible to determine which horn. I never saw one taken with a bitch on her back either...I have see from above which usually makes for a not so good x ray.

My vet always does two views, one is lateral, the other is with her on her back, an anterior abdominal shot. This enables us to determine and measure head/pelvic ring ratios and presentations of the babies at that point in time....this last litter xray had everyone lined up head to tail, with all heads presenting, and while they CAN rotate, this whelp presented exactly as shown on x-ray, all came head first. As anticipated, the two little girls in the left horn came first, and the males from the right horn followed. The two females were the smallest of the babies on x-ray, so after all babies were born and weighed, it was affirmed the girls were the babies that were indeed occupying the left horn.

for a lateral xray wouldn't the ones less visible be on the side the bitch is laying on for the xrays

OK, well, I have no medical training other than what breeding Yokies has exposed me to, so asking for x-ray with bitch on her back so I can predict gender isn't something I would have thought of. When I get a prenatal x-ray it's mainly to calm my own nerves. When they say it's only one big whelp I get very scared and line up help for a c-section. When they say it looks like 5 or more I recruit extra hands-on help to clean them up. get them breathing, and keep me breathing. My vet is a very smart man and I will discuss this with him at some point. :)

Yes.....basically done to determine if there are any "hidden" that may be missed from just one top view. The anterior abdominal shot is the one that gives me the most valuable information, actually seeing how far the babies are before entering the birth canal......
My vet just got a new xray system and what a digital deal this thing is! No more old timey xray films up on the box light! It is displayed on a large computer screen and the images are so sharp and clear, "high definition" and the program on the xray system will perform all kinds of measurements. We just enter what information we want to know and it calculates it and gives it to us!...I used to have to measure heads with calipers on the old xray films, and then measure pelvic ring....with her new digital system, the program will measure each puppy, wherever you click on that puppy image, and then measure the pelvic ring to determine if there is going to be a problem with the birth! Totally removes the question of "weonder if the head/puppy rotates a little, will it still pass"....it is all done digitally and is a beautiful tool for us! I am actually enthusiastic about "paying" for this new equipment she has brought into her practice! She told me she is asking Santa for a brand new, high tech ultra sound machine for Christmas!

See if he will keep score on c-sections he does, to see what percentages he gets with first hand experience, as it correlates to published data......majority of males are from the right horn, majority of females are from the left horn. My vet is going to do this in her practice, for 2015! Evidenced based outcomes!

[QUOTE=Yorkiemom1;4514719]See if he will keep score on c-sections he does, to see what percentages he gets with first hand experience, as it correlates to published data......majority of males are from the right horn, majority of females are from the left horn. My vet is going to do this in her practice, for 2015! Evidenced based outcomes![/QUOTE

First, I'll ask him how to use prenatal sexing of my whelps to improve my breeding. If there is a good health related reason to determine sex ahead of birth, I'll certainly take the extra trouble of getting a fancier pre-natal x-ray. Dr. K has a very busy practice. I somehow doubt he'll be enthusiastic about tracking sex of his c-section deliveries, but I'll mention it. I do know he'll do it if there's a valid reason to.

[quote=magicgenie;4514798]Prenatal sexing of a litter may not be helpful with your breeding program. I wouldnt bother with it if it did not assist me in my program. Fortunately, my vet does become actively involved with research and statistics in reproduction and breeding programs, and anything she can do easily, that will provide information for her breeders, she is more than happy to help. She indicated it would not slow down her c-sections at all to make a quick, simple note about left and right horn sexing.....she also uses dictation during her surgeries, so it is actually just part of her procedure to say "male from right" or "female from left". While she has 6 other vets in her large practice, she is the only one that will be following this with me. If knowing your sexes for, say waiting lists for your babies, then it is probably not anything you would be interested in. I can move people around on waiting lists and give my people a very good idea when they can expect their baby to be born and from what litter, so it benefits my program.

I find it hard to believe that is nothing but coincidental if male pups are coming from just the right horn. It is an interesting subject though.

It is the male that determines the sex so I would figure it is just a matter of which sperm gets there first, male or female. It is my understanding that after the bitch is bred the female sperm live longer than the male sperm do. I have noticed that if I breed a bitch early in her heat cycle that she tends to have more female pups. I thought perhaps because by the time the bitches eggs have dropped that only the female sperm are still alive. Of course that is just my theory and it does not always work. It could be just coincidental also. I have had litters of all males and litters of all females and many mixed sex litters.

Most of the time when I breed a female I try to breed her around the 9th day of her heat cycle if she will accept a male. Then I will skip two or three days before breeding her again. It just seems like I get more female pups by doing it that way.

I had first heard this theory years ago at a reproduction seminar...so I started reading literature on the idea, and it does work out to be reasonably accurate! There was alot of material I couldnt get to because it was for vets....and while not completely absolutely a fail safe way of predicting male/female pups, it seems to work out that way majority of the time. I fully intend to try your system of breeding early in cycle to see if I get more females.....I NEVER have enough females.....everyone wants females!

Hello yorkiemom1. Its been a while.

My girl had 2 litters of 2 pups......all pups were girls. Both times, the x-rays showed one pup in each uterine horn. Although, I didnt read all posts in this thread and not certain if this has been discussed, could it be not the left or right horn, but rather the placement in the horn?? (did that make sense?)

I did find that the dash-dash vs. dot-dot on auscultating the heartbeats was accurate in predicting they were all females.

Very very cool observation!
Thanks for sharing it 😉
Xoxo