BW corelation to WW

[randiliana]

I know this has been hashed over many times, but since we weighed a bunch of calves yesterday, and it is raining out I have time to play around with my records. Here is how BW and WW relate to each other in our herd.

I divided the calves into groups by BW, Under 75 lbs, 75-90 lbs 90-105 lbs and Over 105 lbs. I did this for the calves from each of the last 3 years.

2005
<75 lbs, avg BW 66, Avg adg 2.09 (10 head)
75-90 lbs, avg BW 82, Avg adg 2.28 (19 head)
90-105 lbs, avg BW 96, Avg adg 2.51 (44 head)
>105 lbs, avg BW 110, Avg adg 2.58 (21 head)

2006
<75 lbs, avg BW 67, Avg adg 1.99 (13 head)
75-90 lbs, avg BW 83, Avg adg 2.30 (46 head)
90-105 lbs, avg BW 96, Avg adg 2.37 (47 head)
>105 lbs, avg BW 111, Avg adg 2.51 (14 head)

2007 (and this is only preliminary as not all calves are weighed yet)
<75 lbs, avg BW 66, Avg adg 2.22 (9 head)
75-90 lbs, avg BW 83, Avg adg 2.43 (23 head)
90-105 lbs, avg BW 96, Avg adg 2.57 (27 head)
>105 lbs, avg BW 111, Avg adg 2.76 (14 head)

The average difference in ADG from the big BW to the smalll BW calves is 0.517 lbs/day. The average difference in BW is 44 lbs. On 205 days that = 150 more lbs on the big BW calves than the small BW calves.

Now, I am not saying I (or anyone else) should be trying for 110 lb calves. Just stating what the differences in this herd were. Keep in mind also that generally the 2 year old's calves had smaller BW's and the cow's calves had the larger BW's. Although there will be 2 year olds in the 90-105 lb group and cows in the <75 lb group.

 

[salemhigh]

I also found the heavier births have a higher ww on avg. but i also have more open cows that have the 100 plus birth weights,on a 60 day breeding season .all in all ive found just as many pounds weaned total on 85 pounders as any weight, year in year out, by the time opens are included in the total pounds weaned.

 

[DiamondSCattleCo]

Thanks for posting those numbers Randi. I'd always meant to post my own numbers, but never had enough ambition to do so

Salemhigh, as someone who shoots for the 100lb BWs, I can honestly say your open percentage will decline drastically as you cull out the cows who can't handle the big calves. My own calving percentage is high 90s in 60 days. The only open cows that I end up with around here are old timers whose days are done and probably should have been culled earlier.

Rod

 

[MikeC]

I also found the heavier births have a higher ww on avg. but i also have more open cows that have the 100 plus birth weights,on a 60 day breeding season .all in all ive found just as many pounds weaned total on 85 pounders as any weight, year in year out, by the time opens are included in the total pounds weaned.

Do you mean that cows that have 100+ lb 'calves' are open, or do you mean cows whose actual BW was 100+ lb had more opens?

I have never seen a correlation between BW and breed backs unless there were difficulties during parturition.

These old crossbred cows spit out 100 pounders like spitting watermelon seeds.

 

[DiamondSCattleCo]

These old crossbred cows spit out 100 pounders like spitting watermelon seeds.

Never heard it put quite like that before :lol:

Rod

 

[randiliana]

I also found the heavier births have a higher ww on avg. but i also have more open cows that have the 100 plus birth weights,on a 60 day breeding season .all in all ive found just as many pounds weaned total on 85 pounders as any weight, year in year out, by the time opens are included in the total pounds weaned.

We run about a 7%-8% open rate. I have not seen any connection between higher 100+ lb BW and open cows. Even twins here don't usually cause open cows.

Our average BW is usually in the 92-94 lb range, year in and year out. I certainly have no intention of pushing it up to 100 lbs, but if a cow has a 100+ lb calf I don't have a problem with it. I won't deny that we pull the occaisonal calf, but it is not a common occurance either. We have the odd cow that will consistantly pop out 115+ lb calves, and then breed back on time every year. As long as she is calving on her own, and having healthy calves I won't cull her.

 

[salemhigh]

in my cows avg age is 5 years old,i have noticed when one has the 100 plus pound calves, 90% of my open cows is one of those cows ,so in my herd the 80 to 90 weights work best here on a total income basis.

 

[ALACOWMAN]

in my cows avg age is 5 years old,i have noticed when one has the 100 plus pound calves, 90% of my open cows is one of those cows ,so in my herd the 80 to 90 weights work best here on a total income basis.

could be more nutritional than difficulty in calving

 

[ArrowHBrand]

A BW/WW post has once again been transformed into low BW calvers vs high BW calvers. Ol' Rod at Diamond S Cattle Co. and I have gone around this issue before and when it's all said and done, what works for him is great and what works for me is great. Any way I find that as our cows age they tend to have heavier calves, topping out at 85-90 lbs with one or two going higher than that. I could believe that a higher BW would lead to a higher WW because the calf may have a 20-30 lb jumpstart plus a heavy calf may suck the cow down so far it's forced to depend more on graze or creep feed than a lighter calf.

 

[DiamondSCattleCo]

Hmmmm, I didn't see any kind of real debate between the high BW guys and low BW guys. But we could get into another one if you wanted, since its been a few months ;-) I will disagree with your idea that the high BW guys pull down their cows more. My cows are all on dry pasture yet and all are fat and sassy. As Randi alluded to and as I've mentioned before, its all in the breeding stock you choose.

 

[Jeanne - Simme Valley]

randiliana's figures shouldn't be surprising. BW is HIGHLY correlated to WW. That's a given! But, the trick is to find those "outlying" bulls that give you lower BW & higher WW.
As far as the correlation between 100# calves & opens - I would think they were dystocia cases and you were unaware of it. Cows can end up having a live calf after struggling for many hours. Dystocia definately can affect breed-back. Also, your cows may not be able to handle the demand on her nutritionally. I would say it was more a management issue than a # of pounds.
If you don't have cows that can handle 100# calves, you can see many problems.

 

[KNERSIE]

randiliana's figures shouldn't be surprising. BW is HIGHLY correlated to WW. That's a given! But, the trick is to find those "outlying" bulls that give you lower BW & higher WW.
As far as the correlation between 100# calves & opens - I would think they were dystocia cases and you were unaware of it. Cows can end up having a live calf after struggling for many hours. Dystocia definately can affect breed-back. Also, your cows may not be able to handle the demand on her nutritionally. I would say it was more a management issue than a # of pounds.
If you don't have cows that can handle 100# calves, you can see many problems.

Jeanne is spot on as usual.

The middle of the road don't neccesarily have to mean exactly the middle, you can drive closer to either side without hitting the barrier.

 

[Jeanne - Simme Valley]

randiliana's figures shouldn't be surprising. BW is HIGHLY correlated to WW. That's a given! But, the trick is to find those "outlying" bulls that give you lower BW & higher WW.
As far as the correlation between 100# calves & opens - I would think they were dystocia cases and you were unaware of it. Cows can end up having a live calf after struggling for many hours. Dystocia definately can affect breed-back. Also, your cows may not be able to handle the demand on her nutritionally. I would say it was more a management issue than a # of pounds.
If you don't have cows that can handle 100# calves, you can see many problems.

Jeanne is spot on as usual.

The middle of the road don't neccesarily have to mean exactly the middle, you can drive closer to either side without hitting the barrier.

 

[ALACOWMAN]

A BW/WW post has once again been transformed into low BW calvers vs high BW calvers. Ol' Rod at Diamond S Cattle Co. and I have gone around this issue before and when it's all said and done, what works for him is great and what works for me is great. Any way I find that as our cows age they tend to have heavier calves, topping out at 85-90 lbs with one or two going higher than that. I could believe that a higher BW would lead to a higher WW

• because the calf may have a 20-30 lb

jumpstart plus a heavy calf may suck the cow down so far it's forced to depend more on graze or creep feed than a lighter calf.

there may be some truth to that but the bigger calve's also had more adg than the others. they got to have a moma that can keep em going.

 

[randiliana]

A BW/WW post has once again been transformed into low BW calvers vs high BW calvers. Ol' Rod at Diamond S Cattle Co. and I have gone around this issue before and when it's all said and done, what works for him is great and what works for me is great. Any way I find that as our cows age they tend to have heavier calves, topping out at 85-90 lbs with one or two going higher than that. I could believe that a higher BW would lead to a higher WW

• because the calf may have a 20-30 lb

jumpstart plus a heavy calf may suck the cow down so far it's forced to depend more on graze or creep feed than a lighter calf.

there may be some truth to that but the bigger calve's also had more adg than the others. they got to have a moma that can keep em going.

That is exactly what I was trying to point out. It wasn't the 20-30 lb advantage of BW alone, but the .5 lb/ day extra growth. Some of that you can contribute to mama and some to the calf's growing ability. Some animals seem to be able to put more weight on, on the same feed ration. That I think is more what you are seeing.

 

[Chris H]

Good data to look at. I do admit to going back to the post where you posted the picture of that big heifer with a 109 lb bw and doing the calculations myself just to make sure you subtracted the bw from the ww when calculating the adg.

How long have you been analyzing the data like this? Have you seen any frame size increase through keeping the larger, faster growing heifers? Is your birthweight creeping up?
Is your calving in a pretty tight window or is it strung out over several months? If it's strung out, have you seen any bw trend that might correspond with the temperature? Reason I ask that is several studies have shown the same cows, bred the same way, will have smaller calves in warmer climates.

 

[randiliana]

Good data to look at. I do admit to going back to the post where you posted the picture of that big heifer with a 109 lb bw and doing the calculations myself just to make sure you subtracted the bw from the ww when calculating the adg.

How long have you been analyzing the data like this? Have you seen any frame size increase through keeping the larger, faster growing heifers? Is your birthweight creeping up?
Is your calving in a pretty tight window or is it strung out over several months? If it's strung out, have you seen any bw trend that might correspond with the temperature? Reason I ask that is several studies have shown the same cows, bred the same way, will have smaller calves in warmer climates.

Hope I did my math right ;-) 8) .

I have been keeping records like this for about 10 years. The last 5 have been fairly detailed.

So far we have been unable to keep enough heifers to really notice if there would have been a big change. But the ones we are keeping tend to be about the same size as the majority of our cow herd. Even the 'top' heifers that we have kept seem to level out to the same size as the rest of the herd. BW has been pretty consistent over the years, we usually average 92-95 lbs. We calve for approx 60 days, from about Mar 5 to April 28ish. Always seem to have a few stragglers. With the last few years and BSE we have had a few summer/fall calvers, and contrary to what the studies have shown those calves are usually as big or bigger than anything we have in the normal season. But it has only been a few head, and not enough to really compare.

 

[Chris H]

Of course you did the math right, haha.

Using the data as you have can make a case for not shying away from larger calves. We have never been worried about 100 lb calves ourselves but we'd prefer calves in the 80's that grow well.
The Hereford Ass'n provides us with breakdowns by sire groups to check performance, so that's how we analyze our data.

Do you have anything broken down for survivability by birthweight?

 

[ArrowHBrand]

A BW/WW post has once again been transformed into low BW calvers vs high BW calvers. Ol' Rod at Diamond S Cattle Co. and I have gone around this issue before and when it's all said and done, what works for him is great and what works for me is great. Any way I find that as our cows age they tend to have heavier calves, topping out at 85-90 lbs with one or two going higher than that. I could believe that a higher BW would lead to a higher WW

• because the calf may have a 20-30 lb

jumpstart plus a heavy calf may suck the cow down so far it's forced to depend more on graze or creep feed than a lighter calf.

there may be some truth to that but the bigger calve's also had more adg than the others. they got to have a moma that can keep em going.

That is exactly right!

 

[randiliana]

Of course you did the math right, haha.

Using the data as you have can make a case for not shying away from larger calves. We have never been worried about 100 lb calves ourselves but we'd prefer calves in the 80's that grow well.
The Hereford Ass'n provides us with breakdowns by sire groups to check performance, so that's how we analyze our data.

Do you have anything broken down for survivability by birthweight?

I want our calves to average in that 95 lb range. A bit higher wouldn't bother me too much, but I do know that not every cow can handle a 100+ lb calf, and for now I don't want to have to cull that deeply into the herd. As long as she can have it on her own, and raise it respectably that is all I concern myself with. So the low BW/Low producing cows will end up on the cull list. Here we have a 2 chance rule, I will forgive one poor calf (especially out of a heifer), but not 2.

I don't have anything broken down that much at the moment, but usually the dead/weak calves we have are on the small end of the spectrum.