What determines the sex of a fawn?

[ikoff]

Last year we had 5 fawns...4 does and 1 buck. So far this year, we have had 7 fawns...5 does and 2 bucks. We have used the same breeder buck both years. So my question is...is it the buck or is it bad luck?

[ddwhitetails]

I would assume it is just like humans......we the men determine the sex.......well our swimmers do.........it's all in which swimmers get to the egg first!!!!

[virgil]

Your pretty smart Dennis i learned that from the movie look who's talking . Were did you learn that from.

[ddwhitetails]

oh my buddy Virgil is back on........I learned it in my sex ed class.....see i did pay attention in school ....at least in that class!!!!

[Neeby]

Hey Ike, Depending on what you bred too, having more doe fawns could be considered good luck!

[Wooden acres]

Hey Dennis , your sort of right . It's not always that fastest swimmer that gets to the egg first that gets the job done . Several sperm may enter the fallopian tube and reach the egg at the same time. It's the sperm with the strongest emzymes and can sort of eats it's way through the outer coating of the egg that fuses and makes the pregnancy and that's not always the first one there ! At least that's what I was thought and it's just my opinon I could be wrong .

[ddwhitetails]

Ok I will agree but in a sense it is still the first one.......I guess it should be worded the first one IN rather than the first one there:D

[ikoff]

I thought maybe it was the lenght of the buck's unit...giving the slower boy swimmers a fighting chance. Could you tell that by the size of the bucks feet?:D

[CurtisLloyd]

Why do people have to make a competition out of everything, the only way to increase odds is to spin the semen in a larger amount in a centrefuge and remove the semen from a certain level ( can't remember top,bottom or middle) this will greatly increase the ratio of one sex over another. I don't want to here about someone who is live beeding and spinning their buck!

[Mitch P]

Big feet. units, and spinning. Boy you guys have this Pollock in a daze. :eek:

[Mitch P]

The question was,What determines the sex of a fawn. Don`t know but if I lift the tail I can tell ya what it is. :D If I have my glasses on. :p

[Rustyblaster]

Forget the picture of the buck's feet. I want to see the picture of an okie or pollock spinning a livebreeder.:p

Seriously though, I have never heard of the spinning the semen on a cetrafuge to increase odds of specific sex. I would be curious to hear more of that science. Or just more crazy ideas of sex determination factors!;)

I have to agree with Mitch. What determines the sex is the eyes or hands of the one checking.:D

I heard a theory once that the more stress the does experience prior to conception the better the chances for buck fawns. Just a theory that doesn't have much scientific backing but it was hard to dismiss when the guy telling me had 75% buck ratio two years running!:rolleyes:

[WICKED WHITETAILS]

My fiance's family have a big dairy farm and AI everyone of their cows. I have talked to her mom to just get the whole process figured out, (but see is a little shy when you start to talk about her breeding cows.) But she has told me that there is actually sexed semen that you can buy for cows where in her case she would want all heifers for future milking stock, where a beef farmer would want all bulls. That would be something to see if the deer semen could head in the same direction.

[ddwhitetails]

Wicked we a long wats from Heck I'm just trying to get good quality semen in the industry...:cool:

[IndependenceRanch]

Jared, the industry has already been working on that.

[ikoff]

OK, I ask a simple question since my breeder buck the last two years is spitting out 75% doe fawns and I am wondering if he is going to keep doing that or if maybe the odds will be changing. If not I think my breeder will transform into a shooter!:eek: And then Curtis wants to turn this into a unit contest!!!:D Please..... only pictures of feet.

[Scott Heinrich]

Sex of the offspring is determined by moon-phase and a ouija board.

[wvdeerman]

I have wandered this myself. My wife tells me I am CRAZY, but I still don't think just the male decides the sex of the fawn. I have a 7 year old doe from J-44 genetics. She bred as an 8 month old fawn, and gave us a single buck fawn. In the past 6 years, she has given us twins every year. We have bred her with three different bucks during those 6 years. Of those 12 fawns, only 1 has been a buck. Odds are that it would be 50% bucks...but only 8% being bucks is really hard for me to understand.

Coincidentally, this doe comes from a doe that in 6 years of breeding, with 2 different bucks, only ever gave 2 doe fawns out of 12 total fawns. They were twin does from her first breeding. (Whick I kept the one that we are discussing) She then gave us twin bucks 5 years in a row. The thing that makes this even stranger, is that two years in a row, both mother and daughter were bred to the same buck. Both does gave the normal fawns, twin bucks from the mother and twin does from the daughter.

I am not totally convinced that the father is the only deciding factor on the sex of the fawns.

My one explananation is that some does may contain a chemical in their uterus that is counterproductive to certain sperm cells. Working almost like a spermicide, but chemically deactivating either male or female sperm cells and allowing the other to remain to reach reproduction. If this can be possible, this removes the fact that the father chooses the sex of the fawn. It is the sperm that does decide, but the doe does have an influence.

Does anyone out here have enough scientific backing to confirm or deny my theory?

[Wooden acres]

Deerman your very correct ! There are certain females within all mammal animals as well as humans that do not except either Y or X sperms. Not sure why but I know there are . Man I would have thought you AI experts would have jumped all over this thread. When they sex sperm they do it using somesort of dye that sticks to the chromesome makeup of each individual sperm . The X sperm contains more chromesome make up of which the dye sticks to than the Y sperms and thats how they seperate the X and Y sperm when they make sexed semen for sale . The sexed semen in the cattle industry comes in red 1/4 cc straws. The big draw back is in conception, it's like 20 to 40 percent lower in cattle than when using regular unsexed semen . So Ya I think we should head in that direction then we can drop our conseption down to about 55 percent or so and pay more for the sexing proccess to boot ! . Just kidding .That wouldn't be to good now would it ? Now if we'd use sexed semen and we're trying to make a buck and our doe just happens to be one of those mammals that really only excepts or settles to make females our concetion is pretty much zero to 15 percent at best !! I've been through the zero conception and that's not good !! I think even using sexed semen it's about 85 percent accurate in getting the sex your wanting and breeding for ! Just a thought and I could be way wrong .... :)

[Renee]

Female DNA has 2 copies of the X chromosome so all female gametes (eggs) have only X chromosomes. Males have one copy of the X chromosome and one copy of the Y chromosome so their gametes (sperm) will either have an X chromosome or a Y chromosome in a ratio of 1:1. When the sperm mixes with the egg you either get offspring that have 2 X chromosomes (a female) or 1 X and 1 Y chromosome (a male). This is why they say the male 'decides' the sex, whatever chromosome the sperm is carrying determines what sex the offspring is. Under normal circumstances the chance of conceiving a male vs a female is 50/50, keep in mind this is for each mating. Every time an animal breeds the chance of having a female is 50%, it doesn't matter if the mother has given birth to 10 females in a row the probability is still 50% for each mating.
As far as I know the sperm attempting to fertilize the egg have an identical chance. I have never heard of any kind of sex selection in Cervids though it does occur in other species, most notably reptiles. I did a quick online search and couldn't find any data to support the theory that Cervids have any control over the sex of their offspring.
That being said it is possible to perform sex selection on the sperm cells before insemination by either centrifugation or flow cytometry though I don't know if anyone is doing this in deer. Hope this helps:)

[John Swank]

I have somewhat always been fascinated by this phenomenon and read several research articles from A&M, as well as a few other biologists on the subject.

Research indicates that it is possible to manipulate the fetal sex ratio through herd density and nutrition, as the explanation claims it is mother natures way of balance. I don't have enough active brain cells to completely understand the reasoning behind it, but that's what they claim.

I did do a little experimenting last fall of my own and so far (it just may be dumb luck) with eleven fawns born - only three were doe. I still have one doe that has not had fawns yet. She could easily give me three doe fawns and make it eight buck and six doe. I hope she gives me doe fawns as I have two of them sold from her. The way it looks thought, one lucky fellow might end up with two buck fawns in place of doe... :eek:

I will be trying the same methods this fall in order to see if we can get majority buck fawns again - before I will be convinced it works.

I honestly think it was just dumb luck is all....



.

[Rustyblaster]

Take a coin and flip it heads or tails.:confused: Do this ten times. Let this represent what a particular doe may throw say.. over a period of five years. Now let's say you do this combination another ten times to represent the other ten does you breed over the next five years. If you chart the info I would bet there were does that were buck heavy and some that were doe heavy.
I think it is hard not to consider sex-influencing behaviors because of the possible benefits of mastering or unlocking the code but because many of us breed say less than 20 does per year it is hard to get 50% metrics on a consistant basis. you don't see much chatter from larger farms about lopsided sexes so that is my hillbilly evidence to support my claim!:rolleyes::D

That being said, maybe post you ratio or number of buck fawns to the number of doe fawns. So far I am three buck fawns to one doe fawn or 3:1. Others share your numbers so far.

[John Swank]

Rusty,
So far out of 6 doe live bred, 5 of them had a total of 11 fawns - 8 bucks fawns & 3 doe fawns.

I still have one doe left that didn't fawn. The way it looks, she will be having triplets again this year. I try to shoot for 15-20 fawns a year, with a group of 10 or more buck fawns as the goal.


I think it was just dumb luck, this year....


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[virgil]

Renee ithink you hit the nail on the head thats how i've always under stood it to be. Its all just a matter of who gets in first. Scientific studies show this to be a fact however scientific studies could be wrong as they often are.

[gcw matt]

DC
IF putting the does in a confined space with limited buck activity gives you more buck fawns, then wouldn't breeding them on the second cycle do the same thing? I know this is theory, but When I put CIDRS in last year I had two does in heat (out of 5). 1 has fawned and given me 2 buck fawns. Now I had trouble with 2 of the 5 and I pulled the CIDRS early and put them in with the breeder buck. They both had twins 1 boy 1 girl each. This would mean that my theory is wrong, but the one doe has thrown twin girls the past 2 years. Next week when I get the rest of my AI done I will see what my ratio is. Has anyone else had a higher ration of boys to girls out of their second cycle breedings?

[Wooden acres]

I believe under normal conditions the does ovum or egg can and will recieve either an X or Y sperm but I still think there are some ,maybe few in numbers but some that adapt to only recieve one or the other . I know when I was talking to a few old dairy buddies they said conception was lower in using sexed semen because some cows just wouldn't except some semen that was sexed . I do believe there are some females who's ovum or eggs adapt to recieve one or the other in a Y or X sperm and these cows if bred to the wrong sexed semen will not concieve . I'll see if I can't get some literature from the company Genex .. Now keep in mind this is in cattle not deer but I'm thinking it could also hold true in Cervids too ! Just a thought !!

[John Swank]

I got to thinking about the discussion on this topic and thought of those who might like to read a little further on the subject.

With this, I am not implying anyone is right or wrong, just offering some further information for consideration.

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Sex Ratio Variation in Odocoileus: A Critical Review, by Louis J. Verme © 1983.


Abstract

Literature on deer (Odocoileus) reproduction was reviewed to elucidate the relationship between a doe's nutritional state when bred and sex of progeny conceived. Available data revealed a correlation (P < 0.01) between progeny sex ratio and fecundity rate of does older than 1 year. Percentage of male fawns progressively declined with increasing maternal age and litter size. These findings support the hypothesis that undernourished does tend to produce a surplus of males, whereas more females are born to mothers in good vigor at estrus. Population characteristics and biosocial factors also influence sex ratio outcome, however. The theoretical aspects of sex ratio variation and its herd management implications are discussed.

You can view the abstract and introduction by clicking this link (http://www.jstor.org/pss/3808595)

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Sex Ratio of White-Tailed Deer and the Estrus Cycle, by Louis J. Verme and John J. Ozoga © 1981

You can view the abstract and introduction by clicking this link (http://www.jstor.org/pss/3808704)

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Both of these articles are copyright protected and will require a purchase, or a visit to a participating Library or University, in order to read the full versions.



Interesting stuff for sure... ;)



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[PaintedMeadowsBJs]

I was under the same belief ...My reasoning behind it was...When there is lack of food the doe's produce bucks to disperse the young bucks further out from the herd...for less competion for food.

[ikoff]

This question isn't as simple as it first seemed. I feed all of my deer the same feed...corn and cracked corn along with alfalfa hay in the fall and winter and custom-made pellets in the spring and summer. Maybe I should be feeding them different? The problem with that would be darting my breeder buck twice a year. What does everyone else do as far as feeding is concerned?

[Droptine]

I was under the same belief ...My reasoning behind it was...When there is lack of food the doe's produce bucks to disperse the young bucks further out from the herd...for less competion for food.

I believe the same thing. It seems crazy if you just think about it on the surface with little thought, but I have a rancher friend of mine who swears that when their is a drought year more buck fawns are born.

[skip]

Interesting observations.Here is my scenario last year first fawn apr 28. Bred on first cycle .This year when no fawns came till may 30 and 3 fawned on jun 2. I know they didn't get bred till second cycle.Buck to do ratio on fawns:9 buck fawns 2 doe fawns.
Kinda confirms theory on second cycle.

[Spiderman]

A few years ago I got 14 fawns and only 2 were bucks. This year , I have 12 fawns so far and only 2 are bucks. Last year it was near 50/50 but I haven't had a "buck" year for a long time. This is with many different bucks over the years . I have the book "Whitetail Deer of North America" and it states lean times for the does says to them , don't expand the population.... while times of lots of food says" extend the population with more females born. This is nature and deer are wild animals with years of evolution without human interference so I guess I feed mine too good. I tried to cut back a little last year on feed before the rut but they still looked the same and gave me an over abundance of girls. Jim

[John Swank]

I got dibs on who will be the first feed company to offer a flush ration to produce more bucks fawns? :D

Seriously though, there seems to be a lot of variables in what determines the sex ratio of fawns. It's not as simple as changing the nutritional plain of the does diet, from my understanding. Some of it has to do with exactly when the doe is breed as far as timing after or during the onset of estrus.

Low buck populations with a heavy doe population would lead to doe being bred later in estrus than with a heavy population of buck - more buck can breed more doe closer to the onset of estrus. A low buck population results in a higher buck fawn ratio due to doe being bred later in estrus, statistically speaking.

Also family structure of the herd would play a role as to prevent high levels of inbreeding as bucks tend to leave the family group at around puberty or close to one year of age, unlike a doe that will spend up to three or more years in a family group. I agree some buck fawns can breed before one year of age...

Stress during estrus can also be a big factor as it causes the adrenal gland to produce higher levels of adrenaline, which suppress luteinizing hormone and other reproductive hormones including estrogen that can change the PH level and temperature of the uterus.

I do agree, most of these aspects are based on wild deer but as herd managers we could/can manipulate the scenario to our benefits, I would think.

[brianjames]

Most people have no bucks in pen when they AI, and usually only one when backing up or live breeding. So I'm curious to how this applies to sex ratio?

[Wooden acres]

Guys I agree we can somewhat regulate what we get . I can tell you back in the 90's when we were selling lots of cattle embryo's and we wanted heifers we'd breed our flush cows after 9 PM and one year useing the embryo's we couldn't sell we got 105 heifers and 7 bull calves. Now these were holstein dairy cattle and not deer but there has to be something to it. My flushing vet was Richard Schulte and it was his idea to breed several times at night but never befor 9PM and it really worked . We'd breed several times as we were trying to fertilize anywhere from 0 (bad flush) to 55 eggs(great flush) at a time . I my self would really like to see more embryo work done with deer then I would using sexed semen . Why not just put in a quick thaw embryo then mess around with sexed semen and lower conception ? If you do a search on how they sex bull semen you'll see that one draw back was the females that will adapt to only a Y or X sperm keeping conception low . Just google sexing bull semen , I tried it this morning .. Pretty interesting .. Just my opinion nothing more !!

[kydeer]

Rusty
I had 2 does live bred.Each of them had 1 buck fawn and 1 doe fawn.Which in my opion,I think that is about the best anybody can hope for.Now I have one to carry on the gene's and one to breed with.The one doe I bred to Draxxin.He scored 151@1,he has a real good look to him,he is a Maxin son.The farmer that own's him,run's a ad in Whitetail Heartbeat mag.I only say that in case you want to see a picture of him.The other doe I bred to Evergreen,he scored 290@3.I am a very happy camper with this fawning season.Liven the dream.

[Edgemoor]

so far this year my ai'd does produced 11 does and 7 bucks, pretty good considering i want to keep most of these fawns. my 1st live cover pen has produced 8 bucks and only 1 doe, also pretty good. my only problem is i sold too many live cover doe fawns and now i only have 1 pen left. i've tried several things in the past, but it seems like the buck makes the most difference.