I have an EPD question

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Tod Dague

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If bull A has a wean EPD of 50 and bull B has a wean EPD of 30 bull A calves "should" average 20 lbs heavier at 205 than bull B when bread to identical cows.

If you have two cows with a milk of 20, one a wean of 50 and the other 30 shouldn't the cow with the 50 wean calves average 20 lbs heavier when bread to the same bull?

But when figuring added pounds from a cow you are suposed to look at total maternal which cuts the wean EPD in half. The reason that I have been told is the cow only contributes half of the genetics to the calf. Isn't that the same for the bull?
 
Tod Dague":1lztiphj said:
The reason that I have been told is the cow only contributes half of the genetics to the calf. Isn't that the same for the bull?

The cow contributes half the genetics; the bull the other half. I think the cow has more influence, though, because of how she's managed. If she doesn't get enough feed to milk properly, even though she may have a high EPD for milk, the calf may not show it. Or she may have a low BW EPD, but be fed hard and have a large calf.
 
Frankie":gxjldaeu said:
Tod Dague":gxjldaeu said:
The reason that I have been told is the cow only contributes half of the genetics to the calf. Isn't that the same for the bull?

The cow contributes half the genetics; the bull the other half. I think the cow has more influence, though, because of how she's managed. If she doesn't get enough feed to milk properly, even though she may have a high EPD for milk, the calf may not show it. Or she may have a low BW EPD, but be fed hard and have a large calf.
It is not the milk part that I don't understand. It is the TM that I have a problem with. Why do the cut the ween EPD in half when calculating the TM. As I understand it if one cows TM is 35 and the other is 45 then you should expect that the the calves to average 10 pounds different even though they both have a milk of 20 and one has a wean of 30 and the other has a wean of 50.

If bulls had those EPDs you would expect a 20 lb difference not 10.

I'm thinking that I may be misunderstanding the proper use of the TM EPD.
 
Tod, I think I have heard that a calf's weaning weight is only 1/2 dependent on mama's milk.

Instincts, eating and grazing habits, etc. are learned arts from the dam and just as important as milk.

Is that what you are asking?
 
Tod Dague":2ycdyvqm said:
Frankie":2ycdyvqm said:
Tod Dague":2ycdyvqm said:
The reason that I have been told is the cow only contributes half of the genetics to the calf. Isn't that the same for the bull?

The cow contributes half the genetics; the bull the other half. I think the cow has more influence, though, because of how she's managed. If she doesn't get enough feed to milk properly, even though she may have a high EPD for milk, the calf may not show it. Or she may have a low BW EPD, but be fed hard and have a large calf.
It is not the milk part that I don't understand. It is the TM that I have a problem with. Why do the cut the ween EPD in half when calculating the TM. As I understand it if one cows TM is 35 and the other is 45 then you should expect that the the calves to average 10 pounds different even though they both have a milk of 20 and one has a wean of 30 and the other has a wean of 50.

If bulls had those EPDs you would expect a 20 lb difference not 10.

I'm thinking that I may be misunderstanding the proper use of the TM EPD.
Is Tm nothing more than simple addition of ww and milk ?
edit:
What is a total maternal EPD?
Neither the direct nor maternal EPD predicts entirely the performance of offspring of an individual's daughters since that performance will be a function of both direct and maternal effects. A third EPD, the total maternal EPD, combines direct and maternal predictions. For weaning weight, the total maternal EPD predicts the relative performance of progeny daughters of an individual, taking into account both the inherent growth of those calves and the milking ability of their dams.
 
MikeC":ch81otg1 said:
Tod, I think I have heard that a calf's weaning weight is only 1/2 dependent on mama's milk.

Instincts, eating and grazing habits, etc. are learned arts from the dam and just as important as milk.

Is that what you are asking?
Forgive me, I'm slow. Lets just talk about the Wean and TM EPDs and pretend milk is not a factor.

If one bull has a wean EPD 20 lbs higher than another we would expect the wean wt. of the calves to be 20 lbs higher on the average. Is this true of cows?

If so then a cow with a Wean EPD 20 lbs higher than another we should expect her calves to wean 20 lbs heavier on the average.

If all of that is true then why is the wean EPD divided in half when calculating the TM?
 
Tod Dague":1qf03857 said:
Maybe another way to ask is what does the TM EPD tell us?
Oh Oooooo , Pick me , Pick me, I know the answer to that question. (with hand in the air)
 
ollie'":1pmhh8j5 said:
Is Tm nothing more than simple addition of ww and milk ?
That would make since to me. If it was used to calculate the performance of her dtrs wouldn't the milk be cut in half also since she is only contributing half of her milking genetics to her dtrs?
 
I do understand your problem though Tod. All other epd's are presented in a number that represents the actual genetics contributed only by the cow in this case. The bw, ww, yw, mm but the tm which should be just an addition of 1/2ww and mm doesn't make sense . Why half the ww when showing it in the tm epd when it's all the ww in the ww epd.
 
Maternal weaning weight EPD predicts the total difference in weight of a bull's daughters' calves at weaning. A portion of this difference in weight comes from the milking ability of the bull's daughters (milk EPD), and a portion comes from the genes for growth passed from the bull to his daughters and then on to their calves. Like milk EPDs, maternal weaning weight EPDs are expressed in the weaning weight of a bull's grandprogeny. By definition, maternal weaning weight is equal to the milk EPD + 1/2 the weaning weight EPD. For Bull A in the above example, maternal weaning weight EPD = 15 + (1/2 x 20) = 25. In this case, we would expect daughters of Bull A to wean calves that are a total of 10 pounds heavier at weaning (25 - 15 = 10) than daughters of Bull B. A portion of this weight advantage is due to the superior milking ability of Bull A's daughters, and a portion is due to superior growth genes for weaning weight passed on by Bull A.

Sometimes called "Combined EPD's".
 
MikeC":gvtw1vcm said:
Maternal weaning weight EPD predicts the total difference in weight of a bull's daughters' calves at weaning. A portion of this difference in weight comes from the milking ability of the bull's daughters (milk EPD), and a portion comes from the genes for growth passed from the bull to his daughters and then on to their calves. Like milk EPDs, maternal weaning weight EPDs are expressed in the weaning weight of a bull's grandprogeny. By definition, maternal weaning weight is equal to the milk EPD + 1/2 the weaning weight EPD. For Bull A in the above example, maternal weaning weight EPD = 15 + (1/2 x 20) = 25. In this case, we would expect daughters of Bull A to wean calves that are a total of 10 pounds heavier at weaning (25 - 15 = 10) than daughters of Bull B. A portion of this weight advantage is due to the superior milking ability of Bull A's daughters, and a portion is due to superior growth genes for weaning weight passed on by Bull A.
But shouldn't the milk be divided also since he is only passing on half of his milk genetics? I may be just to slow to pick this one up. To me the logic just doesn't work.
 
Did anyone when selecting their spouse take a gander at their mother and father and kin folks?

Where has the lost art gone.
 
From the Red Angus association

Total Maternal EPD (TM) predicts the rancher's
actual observation of weaning weights of calves
raised by an animal's daughters. TM includes the
daughters milk EPD plus half of her genetic contribution
to her calf's weaning weight EPD. The formula
for TM EPD is:
TM EPD = Milk EPD + 1/2 (WW EPD)
 
But shouldn't the milk be divided also since he is only passing on half of his milk genetics? I may be just to slow to pick this one up. To me the logic just doesn't work.

That's where my other feeble attempt at an answer came in:

Tod, I think I have heard that a calf's weaning weight is only 1/2 dependent on mama's milk.

Instincts, eating and grazing habits, etc. are learned arts from the dam and just as important as milk.
 
dun":2qars2dt said:
From the Red Angus association

Total Maternal EPD (TM) predicts the rancher's
actual observation of weaning weights of calves
raised by an animal's daughters. TM includes the
daughters milk EPD plus half of her genetic contribution
to her calf's weaning weight EPD. The formula
for TM EPD is:
TM EPD = Milk EPD + 1/2 (WW EPD)
The question is looking at the data from the cows side. Not looking at bull tm but females tm.
 

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