BK9954
Well-known member
I have been reading EPD ratings and googled how they work but I dont find the answer. I was looking for semen of a low birthweight bull. I found one that is -1.2 on the BW catagory. That is -1.2 of what??
EPD translation
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branguscowgirl
Well-known member
Every breed association should have "a translation" of their EPDs on there website.
It is important to remember that each breed has a little different numbers. So be sure to research through the breed that you are considering.
I am not super knowledgable on EPDs myself. But a minus birth weight, is a low birthweight bull.
For example a -2.4 BW is even a lower BW than a -1.2 BW bull. But besides BW, calving ease is important.
It is important to remember that each breed has a little different numbers. So be sure to research through the breed that you are considering.
I am not super knowledgable on EPDs myself. But a minus birth weight, is a low birthweight bull.
For example a -2.4 BW is even a lower BW than a -1.2 BW bull. But besides BW, calving ease is important.
Supa Dexta
Well-known member
-1.2 pounds from the breed average, at the time it was calculated. Numbers will change over time - as the breed avg shifts, and when other info is submitted from the bull and/or his relatives.
Katpau
Well-known member
At some point in time, each breed calculated the average birth weight for all reported births. That weight was set at 0. The number you see indicates how this bulls progeny might compare to that original average. His calves should weigh 1.2 pounds less at birth on average than was the average back in 1982 for example. As time goes on birth weights may have risen or lowered. Today the average might be -1.2 and this bull would be average. Or it could be +1.2 and his calves could be expected to weigh 2.4 pounds less. You should be able to find a table somewhere on what the currant breed average is. For example, Angus current sires average +1.7.
When you consider these numbers, it is important to look at the accuracy. There will be a percentage shown below the BW Epd that say acc. This tells you how reliable the number is. A .05 means the numbers are a simple average of the parents. The bull may actually be very different. Young bulls in AI studs start with low accuracy. As time goes on more data is collected from those who use the bull and a better idea of what you can really expect evolves. When choosing a bull for heifers, you should consider accuracy as much as the EPD. A bull with a .80 or .90 accuracy is more likely to produce what his EPD says.
If you are wanting a low birth weight bull because you are worried about calving difficulty, you should be looking at the Calving Ease EPD instead. (CED for Angus). A higher value indicates greater calving ease in first-calf heifers. It predicts the average difference in ease with which a sire's calves will be born when he is bred to first-calf heifers. A lower negative birth weight EPD may not always go with greater calving ease, and a higher one may not always cause more problems. Shape of the calf is as important as weight. The current average CED for all Angus bulls is now 4. Many people now like to see a CED of +10 or more when breeding heifers. The size and maturity of your heifers will be a factor in how low of a CED you feel comfortable with.
When you consider these numbers, it is important to look at the accuracy. There will be a percentage shown below the BW Epd that say acc. This tells you how reliable the number is. A .05 means the numbers are a simple average of the parents. The bull may actually be very different. Young bulls in AI studs start with low accuracy. As time goes on more data is collected from those who use the bull and a better idea of what you can really expect evolves. When choosing a bull for heifers, you should consider accuracy as much as the EPD. A bull with a .80 or .90 accuracy is more likely to produce what his EPD says.
If you are wanting a low birth weight bull because you are worried about calving difficulty, you should be looking at the Calving Ease EPD instead. (CED for Angus). A higher value indicates greater calving ease in first-calf heifers. It predicts the average difference in ease with which a sire's calves will be born when he is bred to first-calf heifers. A lower negative birth weight EPD may not always go with greater calving ease, and a higher one may not always cause more problems. Shape of the calf is as important as weight. The current average CED for all Angus bulls is now 4. Many people now like to see a CED of +10 or more when breeding heifers. The size and maturity of your heifers will be a factor in how low of a CED you feel comfortable with.
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BK9954
Well-known member
Thanks. That clears it up for me.
