Menu
Forums
New posts
Search forums
What's new
New posts
New media
New media comments
New profile posts
Latest activity
Media
New media
New comments
Search media
Members
Current visitors
New profile posts
Search profile posts
Log in
Register
What's new
Search
Search
Search titles and first posts only
Search titles only
By:
New posts
Search forums
Menu
Log in
Register
Forums
Cattle Boards
Artificial Insemination (AI) for Cattle
SAV Resource died today
JavaScript is disabled. For a better experience, please enable JavaScript in your browser before proceeding.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an
alternative browser
.
Reply to thread
Help Support CattleToday:
Message
<blockquote data-quote="simme" data-source="post: 1647696" data-attributes="member: 40418"><p>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.</p><p></p><p>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.</p></blockquote><p></p>
[QUOTE="simme, post: 1647696, member: 40418"] 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. [/QUOTE]
Insert quotes…
Verification
Post reply
Forums
Cattle Boards
Artificial Insemination (AI) for Cattle
SAV Resource died today
Top