Sex of calves

[justintime]

I am not sure if it is the luck of the draw or if there is a reason for this happening. For the past three years we have had a much higher percentage of heifers than we do bull calves born. In 2006 we had 72% heifers, in 2007 we had 80% heifers, and so far in 2008 we have 3 bull calves and 28 heifers out of 31 calves born so far. Some of these calves are ET, some AI and they are also from 5 herdsires. Maybe it will turn around but, if past history means anything, we may have another bumper crop of heifers again. These calves are from an array of sires, some are purebred Shorthorn, some are Shorthorn X Angus/Maine cross.
Don't take me wrong, as the heifers are easy to sell, but I really would like some more bull calves as we are trying to get a bull sale off the ground... and it is hard to have a bull sale with a bunch of heifers.

Anyone have any ideas? Is this random chance? Looking back over my records, I see a trend to more heifers born, but nothing like we have seen in the past 3 years.
I have heard old timers say that a high percentage of heifers in a calf crop means a dry year ahead. I have always thought of this being an " old wives tale" but then we have certainly been on the dry side for the last 3 years. If this is the case, this year sounds like fun!

 

[knabe]

what's the ratio breakdown by technique?
some discussions about this have focused on ai'g at different points in the heat cycle.
break it down by breeding at what time of day if it's easy to do by am or pm

 

[itk]

You sound like Bill Gates complaining about to much money.  ;D In the case of shorthorn heifers there is no such thing as to much of a good thing. If you figure out what you are doing wrong (or right in this case) let me know because I would like that percentage of heifer calves. How are things going for the sale? If you get a chance send me some data and pics.

 

[red]

Cowboy said once that by breeding late in the cycle you tend to have more heifers than bulls. I know we finally had a bull after 2 years of all heifers. Still have a higher heifer ratio to bulls this year, 2:1.



Red

 

[justme]

If that is true...were breeding to early in the cycle (lol)  Last year 3 or 4 heifers to 27 bulls.  Now were 1 for 1 on bulls.  You know when you finally have kids that want to show heifers, you get bulls lol. 

 

[rtnok]

I was always told if the tempature is high you stand a better chance of heifers because heat weakens the sperm. This just may be an old wives tale. roni

 

[JSchroeder]

For what it's worth the most basic algorithm I run on my simulations is the code that determines the sex of offspring.  It's an absolute 50/50 split by completely random chance.  There are no outside factors and over the course of 6,000,000 animals born on the various sites is as close to a 50/50 split as any statistician could possibly hope for.

However, every few months people come up with wild brained theories on various things that impact the sex of these virtual animals and have 'proof' for their false theories.  Through the same methods used as real life, they've come up with most of the theories in real life regarding sex allocation and proven them via the simulation.  However, at least on the simulations, none of them hold the slightest bit of truth.

 

[shortdawg]

We've sexed 10 so far and have 5 bulls and 5 heifers on the way.

 

[xxcc]

are your calves sired by AI or natural service?  (I thought natural service by the 5 herdsire comment).  How old are your bulls?  Male sperm swim faster than female sperm.  Older bulls tend to place the bundle of sperm in there farther giving the female sperm a higher probability to make the trip.  If your bulls are mature (like age 5 or older) that may explain a little bit of your issue. :-\

 

[justintime]

xxcc....some calves are AI, some are ET calves, some are from natural service. Our walking bulls are : 2 four year old, 1 eight year old, 2 two year old. All ETs are heifers so far. I have two pregnancies that were sexed as being bulls, but the way things are going, they may have changed their minds and decided to be females... haha ... just joking. Today we had 1 bull born so I thought we may turn a corner, but the bull calf was followed by 3 more heifers. So that makes the count... 4 bulls and 31 heifers from 35 calves so far. We may get a dozen bulls in a row next, and then it wouldn't look so goofy, but I am doubting it.

ITK, believe me, I am not really complaining, but this trend does seem to be a little strange.

 

[aj]

I never say never..but I'm with JShroeder on this one.I'm 7 and 7 right now with natural breeding.

 

[Cowboy]

Hello all -- haven't meant to be hard to find, just been busy of late and haven't gotten to post  much!

This hfr/bull ratio thing has been interesting the last few years -- more than usual. It seems to me that the more we use a syncronization program, the ealier it leads the cows to be bred, especially ona timed AI basis.

Female cells swim SLOWER, but will live a few hours longer than males, so -- if you tend to be breeding more cows in the PM, by simple math, ther cows are getting bred a few hours earlier than if they had came into heat in the after noon, and then were held to be bred the next morning. Every one following that comment??

JIT -- there have been years where I prayed for hfrs, and by me tending to breed late all the time on purpose, I couldn't get a songle one n my own herd. The last couple of years, we have been closer to average, but still I get more bulls than hfrs.

Only one year did we get all hfrs, (I only had 4 cows that year so go figure!! hehe) I do not sync my cows, and I breed them on all natural heats -- we do not use a bull -- I told myself along time ago tht if the time ever came when I couldn't get my cows bred by arm service, it was time to quit!!! It hasn't evolved to that point yet -- thank goodness!!! hehehe

The bottom line in my experience is -- even though the differences may be slight at times, there is a difference from early to late breeding. You have to pay very close attention to the details of your years services to see it, but it is there! I have also seen the fact that in natural bred herds, the older herd sires do produce a percentage of more hfrs for some reason, xxcc may be correct with his thinkiing!

All in all, most years in larger herds are pretty close to that 51-49 ration to bulls hfrs. If you watch your cows in heat with herd bulls present -- that cows  will let each other ride them all the way thru the heat -- but the bull is rejected until quite late in the heat -- nature has the timing all figured out -- she knows that if she is bred too soon, and the bull leaves, then she may not ovulate in time to fertilize the egg. It just makes sense.

Oh well, I love the hfrs but also we need those bull calves to make steers -- never fails to amaze me when I really want to bull form a certain maiting -- I always get a hfr and vis-versa. The last couple of years I intentionaly bred every cow to make a replacement hfr, so that the ones I did get were correct -- the bulls were not as good for show steers but it is a good tradeoff, now I have fantastic females to make steers later!!! It at least works good on paper right??

Hope every one is doing well calving, we are getting the first one right now as we speak, so I am out the door to see how she is doing -- a Lady's Man bred to Dream ON -- it better be a female -- the cow is clean for TH -- and is 6 days early! YEAH

Terry

 

[justintime]

Ok... the mystery deepens around here. I just had another calf, another heifer..... this time an ET calf from an embryo that was sexed to be a male. I bought these embryos cheap because they were sexed male. The embryos sexed female from this flush sold for 4xs as much as my male embryos. Does this mean I have to send the seller more money?
I was talking today to a guy who sexed over 200 embryos last year. He said he wondered what the ratio would be when they decided to do this, but when they were done it worked out to almost exactly 50:50.

 

[red]

now that is bizzare!!!!

Red 

 

[simtal]

I think that part of the phenomenon is uterine environment.  We all have those cows that always have heifers or bulls, regardless of natural service or AI.  I know in people that some uterine environments are more conducive for males or females.

 

[knabe]

Ok... the mystery deepens around here. I just had another calf, another heifer..... this time an ET calf from an embryo that was sexed to be a male. I bought these embryos cheap because they were sexed male. The embryos sexed female from this flush sold for 4xs as much as my male embryos. Does this mean I have to send the seller more money?
I was talking today to a guy who sexed over 200 embryos last year. He said he wondered what the ratio would be when they decided to do this, but when they were done it worked out to almost exactly 50:50.

just for grins, you could send some tissue to make sure you don't have a calf with xxy or other scenario.  how were they sexed?  by sight or under the microscope and they looked at the chromosomes.  could have been mislabeling, though that's never been known to happen in science or the government.

 

[kanshow]

Very interesting... 

Natural service:  Our commercial herd is splitin the fall and calves in two locations in the spring.      Last spring - the herd to the north ran almost 75% bulls to 25% heifers.  The south herd had very close to 50/50.  I should mention that fall sort is random.

AI:  pretty close to 50/50 last spring.  Although a few years ago a friend of mine helped us out with heifers - we synch, heat detect, and AI all of the heifers within a short time, and we usually use one bull.  Anyway, for the heck of it, we kept track of who AI'd who..  Her success rate was good - 80% and she ran almost 85% heifers.  My percentage that year was a little lower - but in my defense I did more of the stragglers - and I had pretty close to 50/50.  The other guys were 50/50. 

ET:  Last year's figures.  Put in 20 total - had 10 ET calves.    Fresh embryos were all heifers and frozen were all bulls. 

 

[Rocky Hill Simmental]

I posted this before but... My current commerical bull has mainly heifers. We've used him for 3 years and he's only had one bull calf. He's 5 years old now.

I bred my registered heifers to a registered bull who has calves of both gender.. this could be interesting.

 

[cowz]

It has been a HEIFER-PALOOSA this year......yikes!  But it always seems to even out by the time you finish calving the whole bunch out.

 

[justintime]

Three more calves today... all heifers of course. That makes it 4 bulls and 36 heifers. Another 120 to come, so the sexes still have a chance to even out, but after 3 years of high numbers of heifers, I am beginning to wonder if Mother Nature is getting a little confused.