Ebenezer
Well-known member
You can't hurt my feelings if you don't tell the truth.
SAV Resource died today
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Richnm
Well-known member
Resource calves make me doubt EPD's. I don't care what "bull of the month" AI calf I had. Resource calves always grew faster and weighed more at weaning than thier higher numbered co-calves. Here is a Resource heifer I bought that's DNA tested. AAA# 19154266
Redgully
Well-known member
Richnm said:
EPDs are just a tool, some think they are the be all and end all of breeding but there is way more to it. My biggest heaviest calf this year had the lowest growth on EPDs. But usually as a general guide they are pretty good. I personally rate phenotype and fertility as the most important traits and then once i have selected on those traits use EPDs to help sort the next phase of selection. My best rated EPD cow is the lowest fertility in my herd and i am culling her line from my breeding.
I totally agree. He did a lot for the Angus breed. Son of Resource:
Attachments
Right on LC!
Haven't used him or a lot of SAV genetics but had a long discussion with a friend about epds.CEM is a heifer only EPD. I'd take the extra 5 percentage assistance on heifers to actually have cattle with dimension and substance to them. We haven't assisted any Resource heifers at birth.
"On paper" his marbling is low, but his progeny have produced nearly 100 percent choice or prime.
Breed some cows to him and compare them vs The high $B Sires out there and you'll be a believer in type and kind. Unless you prefer to breed GiraffesWhat sires do you like?
With his progeny grading so well and Schaffs weaning weights so high why don't the numbers reflect it? That's the only thing I don't understand fully. Not discrediting the bull or any Schaff bulls but if we are to use epds as a tool one would think these bulls would score a lot higher epds based off performance and real life data. I just don't get why the epds do not reflect that
simme
Old Dumb Guy
This is a simplified explanation. But it is still somewhat complicated. WW EPD calculations are not based on the actual numerical weaning weight. They are based (and change) based on the differences in weaning weight of the calves in a contemporary group based on who the sire is. If there were 50 calves in a contemporary group (means they were born and raised on the same farm in the same pastures and all treated the same - environment and feed are the same for all) and the 50 calves were sired by 5 different bulls (for simplicity, lets say that all 50 cows were full sisters - genetically equal). This farm has ideal conditions and feeds the cows and calves well. The five sire groups wean at 700, 725, 750, 775, and 800 pounds on average. This would indicate that the first sire ww EPD should be 25 pounds less than sire 2 and 100 pounds less than sire 5. Another farm has 50 full sisters bred to the same 5 bulls. Environmental conditions here are tough. No extra feed, bad weather, etc. The weaning weights here are 500, 525, 550, 575 and 600. Again sire 1 WW EPD effect would indicate that calves would wean 25 pounds less than sire 2. Essentially the same DIFFERENCES as seen for the same 5 sires at the other farm where nutrition is much higher. Numbers are way different between the two farms, but calculation of genetic potential are the same. EPD's only change based on actual submitted data within a contemporary group - not sire 2 calves weaning at a higher weight on farm 1 that sire 1 calves weight on farm 2. Adjustments are only made based on differences between sire groups on the same farm in the same pasture treated the same.
If all 50 calves weaned at the same weight (say 900 pounds on one farm and 400 pounds on another farm), EPD's would indicate equal WW EPD for all five bulls based on the difference, not actual weights. EPD's are not adjusted by comparing performance on one farm vs another farm. Too many other variables that can't be accounted for.
So, if you have a calf with a 900 pound weaning weight and your friend a couple states over have calves by a different sire that wean at 800 pounds, you can't make any conclusion about EPD's from that. EPD calculations and changes require comparison of actual weights from calves in the same contemporary group with multiple sires represented. More data from more calves from more sire groups in the same contemporary group is what drives EPD's and accuracy.
That is the simplified version. In actual practice, the cows are not all full sisters. So there are calculations taking into account the data from all the animals in the pedigrees - bits and pieces of statistical data from all the contemporary groups reported. Then there are calculations based on antagonistic traits. For instances, high growth in a calf will result in a DECREASE in the dam's milk EPD. I have always thought that high weaning weight would be an indication that the dam was a good milker. I can't rationalize how high weaning weight causes the dam's mild EPD to decrease, but am told that is the case. Maybe someone can explain that.
I am no expert. If anyone has better or more info, please share. The above is my understanding.
wbvs58
Well-known member
Good explanation Simme. I would say that most of the deficiencies in SAV EPD's is in the carcase attributes in particular the marbling which from my understanding is calculated from the IMF scans and compared to their contemporary groups and a lot of herds use SAV genetics so there is a lot of usefull data out there and yet beef from SAV genetics seems to eat as well as the high marbling EPD carcases. Maybe scan results are not true reflection of marbling????
From my observations it is very easy to breed cattle with high EPD's and indexes simply by chasing the numbers. A lot of people do this and are not concerned in recording the data as their calves will inherit the average of their parents EPD's as a starting point so why record data and muck up these EPD's that they get allocated to start with.
Ken
From my observations it is very easy to breed cattle with high EPD's and indexes simply by chasing the numbers. A lot of people do this and are not concerned in recording the data as their calves will inherit the average of their parents EPD's as a starting point so why record data and muck up these EPD's that they get allocated to start with.
Ken
FungusProudKY31
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That makes no sense, to be honest. You contribute all WW to the calf group to calf performance only and not divide it between MM and WW. And if high WW means low MM then the Angus EPDs for MM would not still be climbing. AAA shows no correlation between MM and WW. AAA chart
simme
Old Dumb Guy
Good point. I mentioned my comments were a simplified explanation. My thinking - If the 50 cows are all genetic equals, then their milk contributions are equal for my simple made up example. Main point I was making was that high numeric weaning weights of calves do not guarantee high ww EPD for the sire. Differences in multiple sire groups do that. When you turn in weaning weights on a group of calves, some of that weight has to be attributed to the growth ability of the animal and some to the milk factor from the dam. I have never seen an explanation of how (equations, factors, etc) those reported weights are split into growth and milk. Would love to see an explanation of that if anyone has one. How do the models and equations determine how much weaning weight to attribute to growth and how much to attribute to milk? Units of both EPD's are in pounds of weaned calf.
I added the words on growth and milk being antagonistic as an example of something that makes no sense to me either. As I stated "I have always thought that high weaning weight would be an indication that the dam was a good milker. I can't rationalize how high weaning weight causes the dam's milk EPD to decrease, but am told that is the case." My source of that is from the Simmental association about 20 years ago. EPD's are calculated based on averages of the EPD's of the sire and dam IF no additional data is turned in (no BW or WW turned in). So when the milk EPD for a calf was less than the average of sire and dam, the answer from the association was that the growth EPD was high and milk and growth are antagonistic. So their calculations at that time reduced the calf's milk EPD slightly due to the high growth EPD. Again, I would like to have a better understanding of the models and equations used to calculate the EPD's. Lots of info available on how to use, apply and interpret the EPD's. Never seen much info at all on the equations/data models used to turn the submitted interactive data into the numeric EPD values. I know it is complex.
FungusProudKY31
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I've never heard of that antagonism. What I do believe is that there is scientific fog on the differences of predictable WW and MM. I do not think that they can easily separate the two and that makes them both less accurate.
On the full sisters: still a lot of genetic variability in that type of population and if some were fed heavy and some average then you have to account for the lesser milk of the heavy feds with the fat deposits in the mammary glands. I think that the chance of two full sibs being identical is about 1: 500,000 to boot. I do not remember the exact # and it does not matter much in most herds that are continually outcrossed with various lines.
On the full sisters: still a lot of genetic variability in that type of population and if some were fed heavy and some average then you have to account for the lesser milk of the heavy feds with the fat deposits in the mammary glands. I think that the chance of two full sibs being identical is about 1: 500,000 to boot. I do not remember the exact # and it does not matter much in most herds that are continually outcrossed with various lines.
FungusProudKY31
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"... there are 1,073,741,824 possible combinations of the sire's paternal and maternal chromosomes (See Figure 1). And, this number ignores the swapping of parts between paternal and maternal chromosomes in a biological process called recombination. So, the number of possible chromosome combinations is in the billions! We often state this as progeny receive a random sample of the sire's genes, and with billions of possible combinations no two sperm are exactly alike (the same is true for eggs produced by the dam). "
Source: https://beef-cattle.extension.org/the-random-shuffle-of-genes-putting-the-e-in-epd/
Source: https://beef-cattle.extension.org/the-random-shuffle-of-genes-putting-the-e-in-epd/
simme
Old Dumb Guy
Sure. I just used that assumption to remove any differences in milk. Impractical to think that anyone would have 50 full sisters and if they did they would still not be genetically equal. Just for illustration of my growth point on EPD calculations.
You make a good point for those who tend to think/hope that a mating will result in meeting their expectation of a mathematical average of the sire and dam. Could get the worst of both, the best of both, or something in between. Many possible combinations. Something in between is most likely.
Agreed
