Question about EPDs and performance data

[ArmyDoc]

On the Red Angus site, they list a lot of information about Bulls. In the perfomance data for example, they list the Birth Weight, 205 day weight and weaning weights. Underneath this, they list a ratio. What does this ratio mean, or refer to?

For example:
..... BW WW YW
Data 66 570 1055
Ratio 89 107 106

What does the ratio of 89 mean when referring to the birth weight of 66#, or the ratio of 107 to WW of 570#?

 

[Frankie]

On the Red Angus site, they list a lot of information about Bulls. In the perfomance data for example, they list the Birth Weight, 205 day weight and weaning weights. Underneath this, they list a ratio. What does this ratio mean, or refer to?

For example:
..... BW WW YW
Data 66 570 1055
Ratio 89 107 106

What does the ratio of 89 mean when referring to the birth weight of 66#, or the ratio of 107 to WW of 570#?

Ratios are in-herd measurments. Ratio of 100 is average.This animal was born smaller than his contemporary group if he had a birthweight ratio of 89. Yet he was heavier at weaning (ratio 107) and yearling (106) than his contemporary group. Ratios may tell you more than actual performance because they reflect performance of a group of calves managed the same way. One breeder could creep feed his calves and get higher weaning weights, but his calves' ratios will still be 100 for average performance in his herd. You couldn't compare ratios between herds.

 

[MO_cows]

It would make it even more useful to know how many were in the contemporary group. If he was 107% of the average weaning weight of a group of 50 it's more impressive than a group of 3.

 

[ArmyDoc]

Thanks! That explains a lot. Where would I find out the size of his contemporary group?

 

[Frankie]

Thanks! That explains a lot. Where would I find out the size of his contemporary group?

You'll probably have to ask the bull's owner? I think some breeds put that information, along with the pedigree, on their reg certificate, but my breed association (AAA) doesn't. The owner is the only person who has access to ratios, contemporary groups, etc.

 

[ArmyDoc]

Bummer.
Well, it lists more information on the progeny data, it lists:

.... BW WW YW
Data 72 561 924
Ratio 99 103 103
Groups 17 19 15
Progeny 41 44 33

I take it that means the mean BW is 72#, which is 99/100 or just under average for the breed?
Projeny 41 means he has 41 offspring in 17 groups used to determine that number?

 

[ArmyDoc]

I decided to search on the top bulls based on BW, WW and YW. Their performance data and progeny averages are all over the place. For example

http://search.redangus.org/animal/1187338
His numbers are:
....CED BW WW YW
EPD -3 4.5 64 108
Acc 32 63 54 44
. % 97% 98% 1% 1%
Performance Data
.....BW WW YW
Data 80 780 1303
Ratio 97 111 111
Progeny averages
......BW WW YW
Data 89 746 1332
Ratio 109 107 108
Groups 4 9 7
Progeny 27 27 16

OK, so far so good - top 1% so WW and YW are very high, BW and CE as expected are low. But what about this one:
http://search.redangus.org/animal/953895
His numbers are:
...CED BW WW YW
EPD 8 1.2 65 111
Acc 36 66 58 49
% 27% 70% 1% 1%
Performance Data:
BW 60 WW 559 (no YW listed)
Progeny Averages
.....BW WW YW
Data 72 503 890
Ratio 100 105 114
Groups 16 20 4
Progeny 60 59 5

How can this Bull be listed as being in the top 1% for WW and YW, but have progeny Averages that are #250 lower for WW and #400 lower for YW?

 

[dun]

It's pretty simple. Look at the percentiles and what those weights are at the link:
http://redangus.org/genetics/epd-percentiles

 

[ArmyDoc]

Not sure I understand your answer. Both of the sellected bulls are in the top 1% for WW and YW EPDs. As I understand it, the EPDs are supposed to give and indication of what the expected diffence in progeny would be... - in other words, two bulls with the same EPD for WW should produce calves that have a similar WW. But these two bulls EPDs are the almost the same, but their progeny averages are several hundred pounds apart. I don't understand how they can have similar EPDs when their offspring are so different. Shouldn't the second bulls EPDs be lower for WW and YW if his offspring are 250# lighter at weaning and 400# lighter at a year?

 

[dun]

I don;t know how EPDs are calculated but there may be a correction type of deal for animals that are such outliers for WW and YW Anything above 55 for WW is in the upper 1% and over 100 for YW is in the upper 1%. Neither bull has much in the line of accuracys and that also plays into the calculations some way I would think. Also, being sired by a black Angus may contribute to the difference sine black and Red Angus have different bases sothe correction for the different bases probably also enter in

 

[Frankie]

Not sure I understand your answer. Both of the sellected bulls are in the top 1% for WW and YW EPDs. As I understand it, the EPDs are supposed to give and indication of what to expect from the bulls progeny... but these two bulls progeny averages are several hundred pounds apart. I don't understand how they can have similar EPDs when their offspring are so different. Shouldn't the second bulls EPDs be lower for WW and YW if his offspring are 250# lighter at weaning and 400# lighter at a year?

You're dealing with Red Angus, so I'm not going to try to talk about specific bulls. But, in general, EPDs are built by using data from individuals, their offspring, their sisters, brothers, aunts, uncles, and their offspring. Management plays a big role in actual weights. For example, if you breed a bull to a Charalois cow and a Jersey cow, would you expect the calves to have similar BW, WW and YWs? Or if you creep feed, you'd likely get heavier weaning weights. BUT if you take the actual weights of the several hundred calves these bulls have sired across the country, plus the weights of calves his brothers, sisters, uncles, etc., have produced, you'll get a pretty good indicator. That's what EPDs do. (More data is better than less, of course) EPDs are much more reliable than using actual data. As Dun says, accruacies are important. In a young bull, accuracies may change over time. I've seen flush brothers, same EPDs when born, but with very different EPDs as older bulls.

 

[dun]

I've seen flush brothers, same EPDs when born, but with very different EPDs as older bulls.

Like the split egg clones consistance and convergence that ABS used to have

 

[Frankie]

I've seen flush brothers, same EPDs when born, but with very different EPDs as older bulls.

Like the split egg clones consistance and convergence that ABS used to have

No, the bulls I had in mind were O S U 6T6 Integrity and Ultra. Integrity was used a lot as a heifer bull (BW EPD 1.9) and Ultra wound up with a 5.3 BW EPD. Yet when they were born they had identical EPDs and stood as Grand and Reserve Grand at Denver (If I remember correctly). Their WW and YW EPDs stayed similar, though.

I don't see Consistence and Convergence in the ABS catalog anymore, but I thought their EPDs stayed pretty close?

 

[ArmyDoc]

Well, maybe it's just the low accuracy and relatively low number of offspring. I'll try looking for bulls with higher accuracies and more progeny data.

 

[dun]

I don't see Consistence and Convergence in the ABS catalog anymore, but I thought their EPDs stayed pretty close?

There EPDs got so far apart that it was as if they weren;t even remotely related. Based on the photos of them they didn;t resemble each other in any way other been both being black

 

[dun]

Well, maybe it's just the low accuracy and relatively low number of offspring. I'll try looking for bulls with higher accuracies and more progeny data.

And try to find 2 that don;t have black in their first 5 generations of pedigree

 

[dun]

Convergence - http://abs-bs.absglobal.com/beef/angus. ... o=29AN1464
Consistence - http://abs-bs.absglobal.com/beef/angus. ... o=29AN1463

 

[ArmyDoc]

And try to find 2 that don;t have black in their first 5 generations of pedigree

Ok, have looked at a couple with Accuracies >90%, and the numbers for their progeny are much closer.

Haven't checked about their ancestors being cross registered with AAA yet, though. Why do you think that would matter, by the way?

 

[dun]

And try to find 2 that don;t have black in their first 5 generations of pedigree

Ok, have looked at a couple with Accuracies >90%, and the numbers for their progeny are much closer.

Haven't checked about their ancestors being cross registered with AAA yet, though. Why do you think that would matter, by the way?

It matters because the conversion of one breeds EPDs to anothers is an imperfect science. Those corrections work on averages and one animal may be one extreme or the other.
On the RA site, when you call up an individual animal you can look at it's pedigree and see it's ancestors. If they have a code in parentheses by there registration number that indicates the breed association they are registered in. Click on that and you will see the data from their parent association.

 

[ArmyDoc]

Thanks Dun.