EPD's

[Brandonm2]

If you bred a set of cows that were on Fescue and the EPD didn't live up to his EPD's from Wyoming shortgrass country, would you think it was the environment? or the cow difference?

ACTUALLY, Mike he SHOULD (in theory) still express his EPDs. In the fescue country. He SHOULD outperform the other sires being used on those fescue grazing cows by roughly the amount predicted in the EPDs. His calves might look better and perform better in Wyoming; but the Missouri guys SHOULD still have gotten the EPD predicted improvement. If there is a 20 pound spread between two bulls' EPDs, all the epd is telling us is that he should outperform the other bull by 20 pounds. This SHOULD be ~the case whether the average weaning weight in the herd is 500 lbs or if it is 600 pounds.

Being a relitive novice to EPD's I am forced to google up a lot of what you guy's are talking about and I have found this to be a great asset, or it can become even more confuseing.
The EPS's are taken within a contemporary group and only compared to other animals within that group. If you take that animal out of that group you cannot compare the animal to animals of another group in a different envionment.
Now go ahead and straighten me out.

The EPDs published by the breed association are crunched from the AVERAGE of all the contemporary groups in the nation. Your confusing inherd ratios with the EPDs. If a bull's progeny ratios high within a herd that ratio number can not be used with any accuracy outside that herd or outside that contemporary group. If you have 10 cows (whether you be in Florida, Wyoming, or Missourri) and those 10 cows have 8 calves....the heifers are one contemporary group and the 4 bulls are another contemporary group. If 878 (to pick an Angus Bull sample) and Scotch Cap are both used in that herd; the EPD is predicting that the Bon View New Design 878 calves will A V E R G E 9 pounds more at weaning than the Scotch Cap calves.

http://www.bovine-elite.com/angblkepd.asp?ID=25
http://www.bovine-elite.com/angblkepd.asp?ID=137

Every herd in America that has ever used either of those bulls has at least two contemporary groups (bulls and heifers) for every calf crop. The breed association takes those many many contemporary group records and crunches all the numbers to produce a set of EPDs for every animal in the data base. Since these two bulls have been used in herds in all 50 states and almost every reasonable level of management then 9 pounds difference would be the A V E R A G E across ALL contemporary groups. It is HIGHLY possible and even likely that in your little corner of the world with your management that you see more or less than a 9 pound weaning weight difference between the two popular Angus sires; but unless you actually have the data that says Scotch Cap does better or worse than 878 in your herd, statistically it is safe to ASSUME that the +9 EPD weanng advantage is correct for your herd like it is in the other thousand plus Angus cow herds out there in the real world. IF we did what ollie? suggests and published EPDs for only cattle in his state and his management style 1) we would never get enough numbers to achieve any accuracy and 2) people like Ollie? who don't want to believe the numbers probably still would not want to believe the numbers predicted by the computer in that system either. and 3) multiple different sets of EPDs for the same cattle would be confusing as all heck for just about everybody.

 

[Brandonm2]

A bull buyer that sees a bull when he is a 2 year-old only, really has no idea what that bull looked like when he was weaned or at the yearling stage.

Nothing irks me more than a buyer that walks up to a sale 15 minutes before sale time and makes a decision on what his future calves will look like by looking at an older bull. :roll:

I think I am causing more problems than Ollie? is in this discussion; but unless we are buying a show calf, who gives a rip what the bull looked like when he was 7 months old? The buyer has the EPDs telling him what the breed assn computer is predicting the calves will perform like. The seller is giving me the bull's adjusted birth weight, weaning weight, yearling weight, yearling frame score, breeding soundness and now ~15-17 mos ultrasound measurements. IF all of that and the pedigree is acceptable to the bull buyer, then all you really need to see is: will his feet legs and topline hold up breeding my cows, is his head too big or his shoulders too coarse to use on heifers, is he big enough, is he too big, do I think he is as thick as the ultrasound scan says he is, is he an easy keeping bull or will he melt in the first breeding season. If I was going to keep heifers out of a bull I would also like to see his dam; but most of the buyers (rightly or wrongly) TRUST that the breeder would not have kept a bull intact out of an incorrect structured or poor udder quality cow and won't take the time out of their busy schedules for a road trip to go look at a dozen cows (especially difficult in a consignment sale like the Auburn Bull test sale where 30 Angus bulls may come from 20 different counties).

 

[DOC HARRIS]

MikeC you're right! I forgot about that. I knew in the back of this old brain that ref sires weren't so important anymore but couldn't remember why. Thanks.
Anyway, small herd can be compared to huge herds all over for contemporaires.

`Jeanne and Novatech -

I concur with EVERYONE that this EPD business is confusing, because they attempted to make it simple at the outset by explaining in as few words as possible the entire concept.

Can't do it!

Bear in mind that CONTEMPORARY GROUPS can be "very small, small, medium small, medium large, large, and very large!" Isn't that ridiculous, when attempting to focus on a single group? But that is the way it is. Just like Nations, States, Counties, Cities, Towns, and Neighborhoods. All different sizes but Contemporary Groups just the same.

The confusing factor in our discussion is the fact that OUR contemporary group has become an entire Beef Species! And then compressed into a BREED! It is the responsibility of each individual breeder to decide for himself what will perform the best for his particular herd.

Tough job!

Requires knowledge of EPD's!

Which requires study and understanding!

Which requires time!

Which few of us have enough of!

Don't give up!

DOC HARRIS

 

[MikeC]

A bull buyer that sees a bull when he is a 2 year-old only, really has no idea what that bull looked like when he was weaned or at the yearling stage.

Nothing irks me more than a buyer that walks up to a sale 15 minutes before sale time and makes a decision on what his future calves will look like by looking at an older bull. :roll:

I think I am causing more problems than Ollie? is in this discussion; but unless we are buying a show calf, who gives a rip what the bull looked like when he was 7 months old? The buyer has the EPDs telling him what the breed assn computer is predicting the calves will perform like. The seller is giving me the bull's adjusted birth weight, weaning weight, yearling weight, yearling frame score, breeding soundness and now ~15-17 mos ultrasound measurements. IF all of that and the pedigree is acceptable to the bull buyer, then all you really need to see is: will his feet legs and topline hold up breeding my cows, is his head too big or his shoulders too coarse to use on heifers, is he big enough, is he too big, do I think he is as thick as the ultrasound scan says he is, is he an easy keeping bull or will he melt in the first breeding season. If I was going to keep heifers out of a bull I would also like to see his dam; but most of the buyers (rightly or wrongly) TRUST that the breeder would not have kept a bull intact out of an incorrect structured or poor udder quality cow and won't take the time out of their busy schedules for a road trip to go look at a dozen cows (especially difficult in a consignment sale like the Auburn Bull test sale where 30 Angus bulls may come from 20 different counties).

Brandon, If you are weaning on the trailer ( and most do), you should care what your calves look like at weaning. You will be paid commensurate upon this.

Those EPD's do not tell you what a bulls' calf will look like. You must base this on phenotype.

 

[ollie?]

I have another question Mike, I have always believed that the more heterosis , the better preformance. The less heterosis , the worse actual preformance but the more repeatability(or predictable type and size in a calf) in a sires offspring. When it comes to linebreeding or outcrossing, how does an epd reflect this? More specifically, as a bull is closer linebred, does his epd's reflect his actual preformance back on a similiar bred , same breed dam or does it reflect his preformance when bred to a cow of a different breed where the tightness of his genetics will really preform better?

I. J. M. de Boer1 and I. Hoeschele2

(1) Department of Animal Breeding, Wageningen Agricultural University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
(2) Department of Dairy Science, Virginia Polytechnic Institute and State University, 24061-0315 Blacksburg, VA, USA

Received: 8 August 1992 Accepted: 28 September 1992

Communicated by D. van Vleck
Summary The effect of inbreeding on mean and genetic covariance matrix for a quantitative trait in a population with additive and dominance effects is shown. This genetic covariance matrix is a function of five relationship matrices and five genetic parameters describing the population. Elements of the relationship matrices are functions of Gillois (1964) identity coefficients for the four genes at a locus in two individuals. The equivalence of the path coefficient method (Jacquard 1966) and the tabular method (Smith and Mäki-Tanila 1990) to compute the covariance matrix of additive and dominance effects in a population with inbreeding is shown. The tabular method is modified to compute relationship matrices rather than the covariance matrix, which is trait dependent. Finally, approximate and exact Best Linear Unbiased Predictions (BLUP) of additive and dominance effects are compared using simulated data with inbreeding but no directional selection. The trait simulated was affected by 64 unlinked biallelic loci with equal effect and complete dominance. Simulated average inbreeding levels ranged from zero in generation one to 0.35 in generation five. The approximate method only accounted for the effect of inbreeding on mean and additive genetic covariance matrix, whereas the exact accounted for all of the changes in mean and genetic covariance matrix due to inbreeding. Approximate BLUP, which is computable for large populations where exact BLUP is not feasible, yielded unbiased predictions of additive and dominance effects in each generation with only slightly reduced accuracies relative to exact BLUP.
Key words Best linear unbiased prediction - Dominance - Inbreeding

Don't think it hasn't been studied.. :lol:

Mike I can't pronounce all those words, much less have a clue what they're saying. My point is , there is a difference in how a linebred bull will preform if he's continued in a linebreeding population compared to how he's used as an outcross on a different breed, or for that matter as an outcross inside the same breed but on a unrelated population.

 

[KMacGinley]

Doesn't the fact that this discussion is being held with this intensity tell you that the emperor is not wearing any clothes here. We all know that epds do not really work. We all know that the traits they are attempting to measure except for Ribeye are very lowly heritable. Maybe it is true that they are the best tool that we have, but they do not really work. My own personal experience and that of many others tell us that. My heaviest milking cow has the lowest milk epd in my herd. Until you solve that problem your credibility on everything else is zero.

(You being the fathers of the epds)

 

[ollie?]

Mike or Jeanne how can I tell which bulls offspring excell on wyoming shortgrass or fescue?

Are you serious? You expect EPD's to give you a clear cut answer to this?

No, I thought you were the one saying that BLUP accounted for environment. If it does , my question is how is it expressed?

 

[MikeC]

Mike or Jeanne how can I tell which bulls offspring excell on wyoming shortgrass or fescue?

Are you serious? You expect EPD's to give you a clear cut answer to this?

No, I thought you were the one saying that BLUP accounted for environment. If it does , my question is how is it expressed?

Like this:

Common sense tells me that a bull's progeny that excelled in one environment will more than likely excell in another environment.

Maybe not to the extent of those in the other environment, but more likely than if you had NO EPD's and was basing a decision on Phenotype alone.

 

[Brandonm2]

Since when is there a huge phenotype spread between commercial frame 5 Anguses at weaning? or between frame 6 Charolais for that matter? I don't think I have ever seen a lite muscled 600 pound calf become a heavy muscled two year old. It MAY happen; but most of the time muscle expression is apparent early and is not something that develops real late in the growing cycle. If he is narrow made at two years of age, he was narrow built as a calf. A wide tracking meaty two year old was typically a thick calf at weaning. It is a lot more likely that a good looking calf developed into a bad structured lite muscled two year old than it is for poor structured or narrow built 7 month old calf too "outgrow" their problems. Sure, if a breeder wants to show me a photo of the bull as a calf I will look at it and be impressed that the guy made that much effort; but do I really need to actually see the bull as a weaned calf??? No not at all. Just give me a weaning weight and a fully developed two year old bull to evaluate and I know all that I wiull ever need to know about what he looked like 16 months ago.

 

[novatech]

Just a note.
One would think that one would have a little common sense about EPD's.
A lot of this environment talk will have to do with breed. You cannot take a brahman form south texas during the summer and expect that same animal to have the same EPD's in the dead of winter in Canada. The same in reverse for angus.
Maybe it,s up to the individul to consider what type of environment the animal came from and what type of environment it will be going to.
EPD's are as close as one can get in compareing a given type of animal overall. And there is no way of gaurateing which genes will be past on. That is where the % accuracy comes in. That % gives one the average between cattle from different contemporary groups.
The higher the % the more contemporary groups have been compared. The more envionments they will have come from.
I hope I am makeing sense. And this is what I think I understand from the above posts. So again please correct me if I am wrong.

 

[ollie?]

EPD's are as close as one can get in compareing a given type of animal overall. And there is no way of gaurateing which genes will be past on. That is where the % accuracy comes in.

You're wrong. EPD's only tell you pounds difference to be expected. They won't tell you which genes will be passed on.

 

[novatech]

EPD's are as close as one can get in compareing a given type of animal overall. And there is no way of gaurateing which genes will be past on. That is where the % accuracy comes in.

You're wrong. EPD's only tell you pounds difference to be expected. They won't tell you which genes will be passed on.

It seems to me that a high % would tell one that the accuracy is more conclusive and one would think it was because of genetic reasons, or could it have been divine.

 

[Brandonm2]

Just a note.
One would think that one would have a little common sense about EPD's.
A lot of this environment talk will have to do with breed. You cannot take a brahman form south texas during the summer and expect that same animal to have the same EPD's in the dead of winter in Canada. The same in reverse for angus.
Maybe it,s up to the individul to consider what type of environment the animal came from and what type of environment it will be going to.

Nobody that is sane is actually putting a nationwide expected weight number out there. Calf 100546 is not 72 lbs of birth wt, 610 lbs of weaning wt, and 990 lbs of yearling wt, cut a 14.2" REA and will grade low choice for example. Environment and management play too huge a role in that mathematically for accuracy to EVER be above 10% in that calculation. ACROSS the breed though, whether your Brahman semen was used in Canada or South Texas would not matter. You would still EXPECT the Brahman with the higher EPD too wean the heavier calves than the Brahman with the lower EPD even in Canada; because the computer assumes that the same percentage of Brahman calves will freeze to death from both Brahman sires in that environment. Likewise in a swamp in Florida, 430 lbs might be a good weaning weight for purebred Angus. Even though it is hot they are still ALL Black Angus so we would expect that the Angus with the higher EPD sires to be the bigger calves in that calf crop, even though the same cattle might be weaning a 600 pound calf crop if we moved them to a corn farm in Iowa where we would still expect the same EPD differences.

I don't give much credibility to cross breed adjustment factors because of this breeds matching environment argument; but when I am talking about the EPD I am ONLY talking about Angus EPDs within the Angus breed and Hereford EPDs within the Hereford breed, etc.

Most AI sires sit their butts in a climate controlled barn in Wisconsin or in a priviledged paddock on the farm waiting for their groomsman to bring them their morning 4 flakes of hay and six pounds of specially formulated mature bull maintenance ration. We really have no earthly idea whether they COULD hang with Caustic in Southeast Texas or not. Dittoe with Saskatchewan or some mountain in Colorado. Their semen rides in trucks all over the country though. We really don't have many regional sires any more. They are breeding EXT and Precision daughters to 1407 and 878 in Alabama just like they are doing in Montana and in Virginia, California, and South Texas. MOST of those ranchers are like me and they have only seen these sires in their spring semen catalogs. The environmentally adjusted EPDs are the only way we have to keep score until we see our own calfcrop on the ground and then the semen companies keep score by the number of reorders that they get.

 

[MikeC]

Doesn't the fact that this discussion is being held with this intensity tell you that the emperor is not wearing any clothes here. We all know that epds do not really work. We all know that the traits they are attempting to measure except for Ribeye are very lowly heritable. Maybe it is true that they are the best tool that we have, but they do not really work. My own personal experience and that of many others tell us that. My heaviest milking cow has the lowest milk epd in my herd. Until you solve that problem your credibility on everything else is zero.

(You being the fathers of the epds)

What a concept! :lol: :lol:

One question. How do you know this cow is your heaviest milker? Have you weighed all of your cows milk to see? :lol:

 

[Jeanne - Simme Valley]

ONE cow not fitting her EPD's for milk - WOW - ABSOLUTELY must mean EPD's DON'T WORK!!!
Sorry, couldn't help it. But, that's exactly why people don't think they work. They look at the SMALL picture. This is NATION wide.
You have to breed SEVERAL (like maybe 10+) cows to the same bull to see his influence - or accuracy of his EPD's. One breeding does not prove anything.

 

[DOC HARRIS]

:lol2: :lol2:I. J. M. de Boer1 and I. Hoeschele2

(1) Department of Animal Breeding, Wageningen Agricultural University, P.O. Box 338, 6700 AH Wageningen, The Netherlands
(2) Department of Dairy Science, Virginia Polytechnic Institute and State University, 24061-0315 Blacksburg, VA, USA

Received: 8 August 1992 Accepted: 28 September 1992

Communicated by D. van Vleck
Summary The effect of inbreeding on mean and genetic covariance matrix for a quantitative trait in a population with additive and dominance effects is shown. This genetic covariance matrix is a function of five relationship matrices and five genetic parameters describing the population. Elements of the relationship matrices are functions of Gillois (1964) identity coefficients for the four genes at a locus in two individuals. The equivalence of the path coefficient method (Jacquard 1966) and the tabular method (Smith and Mäki-Tanila 1990) to compute the covariance matrix of additive and dominance effects in a population with inbreeding is shown. The tabular method is modified to compute relationship matrices rather than the covariance matrix, which is trait dependent. Finally, approximate and exact Best Linear Unbiased Predictions (BLUP) of additive and dominance effects are compared using simulated data with inbreeding but no directional selection. The trait simulated was affected by 64 unlinked biallelic loci with equal effect and complete dominance. Simulated average inbreeding levels ranged from zero in generation one to 0.35 in generation five. The approximate method only accounted for the effect of inbreeding on mean and additive genetic covariance matrix, whereas the exact accounted for all of the changes in mean and genetic covariance matrix due to inbreeding. Approximate BLUP, which is computable for large populations where exact BLUP is not feasible, yielded unbiased predictions of additive and dominance effects in each generation with only slightly reduced accuracies relative to exact BLUP.
Key words Best linear unbiased prediction - Dominance - Inbreeding

Don't think it hasn't been studied..
Mike I can't pronounce all those words, much less have a clue what they're saying. My point is , there is a difference in how a linebred bull will preform if he's continued in a linebreeding population compared to how he's used as an outcross on a different breed, or for that matter as an outcross inside the same breed but on a unrelated population.

_________________
Alice wrote:
Shut up, Ollie...if you can't propose anything constructive, then shut up..

Alice

:lol2: :lol2: :lol2: If this isn't the funniest stuff put on the forum lately, I have missed whatever it is that is funnier! I will work on it and see if I can explain the rhetoric from I. J. M. de Boer1 and I. Hoeschele2. - - - - - - - - - - -- - - -I have thought about it!



I will think about it some more!






I'll tell you later! :lol2: :lol2: :lol2: (gasp) :lol2: :lol2:



DOC ( :lol2: ) HARRIS