Birthweights on ET bulls

[cpubarn]

I think we have discussed this before, but a search didn't give me what I wanted, looking for advice from those with ET experience...

I had a DJ Salute (Simmental) x Stockman (angus) embryo put in.  I knew that neither bull was "calving ease".  I put the the embryo on an older moderate cow that always has 100lb calves out of our easy calving herd bull, and got a 120lb bull calf.  She had him herself, he is a VERY nice calf as far as I can tell at 6 hours of age.  


The question is how much of that 120lbs do I attribute to the genetics, and how much to the recip? For those of you familiar with the genetics, would you expect 120lb calves from this mating?

and no I'm not going to write down 85lbs and sell him as a heifer bull, I would be very disapointed if I bought a suprise like that, he will be steered.

Mark

 

[JTM]

In my mind 120 lbs is 120lbs. Until the breed associations come up with some kind of way to adjust birthweights on ET calves that they believe is ethical, I will continue to record the actual weight.

 

[cahiltang]

all had to do with the breeding... the recip has nothing to do with it

 

[showsteerdlux]

all had to do with the breeding... the recip has nothing to do with it

That might be the most inaccurate statement I have seen on here in awhile. I would say the recip is half of it and the genetics half.

 

[shortdawg]

Birthweight is very much affected by the environment the cow lives in ! If she's in knee deep grass all fall or summer and can eat all she wants that calf is going to be bigger than in the opposite environment .

 

[GoWyo]

Cold winter and having to push more feed seems to increase birth weights.

 

[aj]

Enviroment makes some difference but in my opinion not as much as people always say.Its the biggest out I have heard and you always hear it. jmo

 

[OH Breeder]

One theory behind increased birth weights of offspring from cold-exposed dams relates to blood flow. It is well established that when exposed to extremely cold temperatures, mammals shift blood flow from extremities and skin to major internal organs. This survival mechanism ensures that essential organs (brain, heart, liver) continue to function normally even in cold weather. As a result of this shift in blood flow, there may be greater blood flow and nutrients reaching the fetus. However, short-term cold exposure in women has actually been shown to decrease blood flow to the fetus.


here is a good brief article on cold and bw's


http://www.cattletoday.com/forum/viewtopic.php?f=5&t=32161&p=351393

 

[shortdawg]

At the front of the No Bull Sale catalog there are traits listed and their heritability - BW is listed as 40 percent heritable. Maybe John can chime in and tell us where he got that info.

 

[cpubarn]

Thanks for the info so far,  I finally checked back in, and edited the original question a liitle to hopefully clarify it.
  My spelling always goes from bad to worse when I'm excited.

 

[Cattledog]

Interesting topic.  three years ago one of my ET bulls had a birth weight of 108.  I was going to steer him but decided to take a chance on him as his Sire was calving ease and so was his dam.  I currently have around 20 show oriented cows and my grandfather has about 80 commercial cows.  I used him as clean up on my cows and my grandfather used him on 20 other cows.  We weren't brave enough to use him on heifers.  When his calves came not one weighed over 83 lbs.  So far this year my grandfather has had 8 calves from this bull out of his heifers.  All unnasisted and under 80 lbs.

I don't think BW is very relavent out of recips.  This would also include low birth weights out of recips.  I always tell my customer what they weigh when they're born...you have to if you want to stay in business!

 

[KYsteer]

Our ET calves will weigh on average 10-20 lbs heavier than the AI group.  I have heard of some huge weights when IVF is used and these are all with small BW angus genetics.  The AAA does not use the actual BW and WW of ET calves to adjust the EPD's of the individual.  It is just the predicted index EPD average of the sire and dam.

 

[justintime]

I have not seen any major differences in BWs of ET calves, at least none that I can attribute to only being caused by being born from a recip dam. So far, I have 6 ET calves born this year and they have have been between 90 -98 lbs. I find it interesting that the heaviest so far was a bull calf at 98 lbs and a flushmate brother was born 6 days later and weighed 90 lbs. I do believe there are many factors that affect BW and gestation length in particular. On two occasions I have had 18 days between the first born of a flush and the last one ( all from the same flush and implanted the same day). In both cases, the last calf born was a heifer, which also goes against the theory that some people have that male calves will go longer term than female calves.In one of these cases, there were  6 calves born from the same flush and all were heifers. All our ET calves are parentage verified by DNA, so there is no question that they were all flushmates.  I am certain that gestation length is very heritable, but I also think that the recip can have a considerable influence. I have one recip who has now had 6 ET calves and she is always the last one to calve from a set of embryos implanted the same day.I have another recip that has had 3 ET calves now, and she has consistently calved ealrier than the other recips with embryos from the same flush. This recip calved 6 days ago and had a heifer calf that weighed 88 lbs. I am still waiting on two other recips to calve that were implanted with embryos from the same flush and at the same time. All three of these recips were ultrasounded with heifer calves last summer.

I do believe that environment does have a considerable affect on birth weights. We have had a very cold nasty winter, and most of the cattlemen I see are saying their BWs are higher this year. Ours may be a little higher as well, but we are just getting into calving and only have 15 calves in so far and I will know a lot more in a few days.So far, all have been unassisted except for a backwards calf. It looks like the bulls got their work done early as there are probably 50 cows close to calving, and I have breeding dates on many of them, yet really have no idea which one will calve next. One thing I do know, is that they certainly do not calve in the order they were bred.  As I said, our birth weights may be slightly higher this year, over last year. Last year our heavkiest Touchdown calf was 85 lbs and this year there has been two at 92 lbs, which may be significant or may be completely by chance.

 

[Cattledog]

Our ET calves will weigh on average 10-20 lbs heavier than the AI group.  I have heard of some huge weights when IVF is used and these are all with small BW angus genetics.  The AAA does not use the actual BW and WW of ET calves to adjust the EPD's of the individual.  It is just the predicted index EPD average of the sire and dam.

I thought that I read somewhere that if the angus embryo calf is born to a registered Angus recip you can get numbers on them.  They take the numbers of the recip to calculate difference.  Not sure how the calculations would go.  I could be completely wrong on this too!  ;D

In all honesty, I don't think BW is how calving ease should be measured.  I believe the shape of the calf is a better tell.  I've seen some 80lb. club calves that are shaped like a bowling ball.  All the bone and butt just isn't meant to come out easy!  I think there is an epd CED.  I look at that before I pay too much attention to the BW EPD. 

 

[texas111]

I agree cattledog the ced is more relevent than the bw.  Of course the bw is important, but the ced is the real deal.  As you stated an 80 lbs calf can come hard while a 92lbs calf can come easily.  IMO ced is a very important epd to know when breeding.  Also the recip will alter the bw of a calf.  It is not a suprise that the calf was 120lbs bw.  You could try the calf as a bull and he might suprise you and have low bw like his parrents.  Its a crap shoot.  Good luck to ya!

 

[cpubarn]

Thanks for the input,

Next refinement to the idea.  I bought these embryos hoping for a nice stout cow or bull, bit of an old school mating, could live with birthweights up to 100 lbs.  Since this first one out of a recip tips 120, even if the next one is 100lbs, do you exclude the entire mating, or just cut the heavy calf?

How much influence to full sibs do you give to the next calves?

Thanks again...

Mark

 

[Cattledog]

I don't know if I would cut the first bull.  If you're gonna keep the bull for yourself try him out on some bigger cows.  Also, did the person you bought these embryos off of have any calves from the flush?  Did he keep any for bulls?