what affects the ratio of females/males in calf crops?

[Running Arrow Bill]

heard of an a.i. bull having a 80% heifer crop which was confirmed by several breeders having experience with him...



have a bull that is throwing 75% heifer crop, the last two years for us, and checked his overall, still the same... 75% heifers....



?1. what factors will affect the ratio of heifers over bulls???????

my late father had a theory: whichever of the breeding pair was in the 'better' condition was the one that had the 'say' in what sex the offspring would be


?2. have any of you noticed something like this in your herds?


p.s.

don't blame bill for this post...
his other half is the one who posted this... grins

 

[jnowack]

There was a simalar thread on here recently.
The bull determines the sex. Sperm carry one sex chromosome either x or y. Unfertilized eggs can only carry x because the cow has 2 x chromosomes.

I have heard that the male sperm survives freezing and thawing better which is the reason for more bulls when AI'ing.

I suppose it could be possible for a bull to have a genetic defect that would affect the survivability of one sex or the other but I don't know if that has ever been documented.

I do remember a story about one of the King's (don't remember which one) that had only daughters and tried to have a son with several different women. Supposedly only his female sperm were viable.

 

[randiliana]

I have also seen information that says the environment inside the cow can affect what she has. For example (and I don't know if this is correct) if her uterus etc. are more acidic the female sperm will survive longer, which would mean that the cow would be more likely to have a heifer calf.

But, we have seen the same thing as you, one bull that consistently threw 2/3 heifers. You wouldn't think that that many cows would have the "correct" environment year in and year out, especially if they weren't always the same cows with the same bull.

 

[Beefy]

i thought that your best cows always have bull calves? is that not right?

 

[bigbull338]

ive heard a semiler tale about bull/heifer semen.if i remember correctlythe heifer semen floats to the bottom.where as the bull semen floats to the top.but its been yrs since ive heard itan my mind could be somewhat dull on the subject.

 

[Ryan]

i thought that your best cows always have bull calves? is that not right?

Yes. Absolutely right Beefy. Especially if really really want a heifer this year from here... you better believe it'll be a bull.

 

[mgman]

While I agree it's the bull who carries the x/y chromosone, I also believe that the cow has alot to do with the sex of the calf. I've had a number of cows over the years that will consistently have heifer calves year after year, regardless of what bull they're bred to, and others who will always have bull calves regardless of the bull they're bred to.

 

[TheBullLady]

I've had the same.. a handful of cows that always have heifer calves.. no matter what bull. Conversely, I can't remember ever having a cow that just had bull calves.. :roll:

 

[Diehard40]

50 : 50

 

[MikeC]

Used the very same bull two years in a row. 1st year 65% bulls. This year 70% heifers.
I guess it all evens out in the end. ;-)

 

[Bluestem]

Interesting subject. Was Just talking about this this evening with a neighbor. We're dropping nothing but bull calfs. We wondered if stress could determine the sex of a calf?

 

[3MR]

No No No , The only way to ensure a Heifer calf is to bury a half eaten turnip in the middle of your calving pasture in the light of the full moon exactly 56.3 hours prior to the first cow calving. If you dont get all heifers in that crop you must have timed it wrong.


Works for wart removal and gout as well :lol: :lol: :lol:

 

[redfornow]

No No No , The only way to ensure a Heifer calf is to bury a half eaten turnip in the middle of your calving pasture in the light of the full moon exactly 56.3 hours prior to the first cow calving. If you dont get all heifers in that crop you must have timed it wrong.


Works for wart removal and gout as well :lol: :lol: :lol:

Now that is good science there, this is what cattle business needs is more people thinking like this one.
Thanks for the post I will use it...

MD

 

[TxStateCowboy]

if her uterus etc. are more acidic the female sperm will survive longer

So its proven,
females survive in acid=> female=acid

acids are found in poison=> acid=poison

so one would have to conclude... women=poison

;-)

 

[Beefy]

not at all TxState.
Women are the fruit of life. they are to be worshipped and adored. like a truely rare flower that must be pampered to ever behold its magnificence.

 

[cfpinz]

not at all TxState.
Women are the fruit of life. they are to be worshipped and adored. like a truely rare flower that must be pampered to ever behold its magnificence.

Brown-noser!!! :lol:

 

[Texas Gal]

We have one old cow that has had 2 heifers and 9 bulls; another, 5 heifers and 1 bull and one that has had all heifers(4 so far). All others are just about 50/50. We let the bulls take care of the ladies so I don't have any explanation for this phenomena.

 

[VanC]

not at all TxState.
Women are the fruit of life. they are to be worshipped and adored. like a truely rare flower that must be pampered to ever behold its magnificence.

Wife been reading your posts again, Beefy? ;-)

 

[msscamp]

No No No , The only way to ensure a Heifer calf is to bury a half eaten turnip in the middle of your calving pasture in the light of the full moon exactly 56.3 hours prior to the first cow calving. If you dont get all heifers in that crop you must have timed it wrong.


Works for wart removal and gout as well :lol: :lol: :lol:

Well, thanks for sharing that. No wonder we keep getting bull calves - I was told to bury a 1/4 eaten Red Delicious apple, stem side down! :roll: :lol: :lol: :lol:

 

[Jeanne - Simme Valley]

not at all TxState.
Women are the fruit of life. they are to be worshipped and adored. like a truely rare flower that must be pampered to ever behold its magnificence.

AND DON'T YOU FORGET IT!!!!
All kidding aside - that was VERY nice - did you mean it???

Agreed - bulls sperm is EITHER X or Y - and yes, some bulls produce more of one sex than the other - and yes, some COLLECTIONS will have more X's than Y's or visa versa.
BUT, the cows uterine environment also affects the life/viability of the sperm. So they BOTH affect the sex.