Estimated difference between animals in bone-out carcass weight adjusted to 650 days of age.
Estimates the difference between animals in eye muscle area at the 12/13th rib site in a 300kg carcass.
Estimates the difference between animals in fat depth at the 12/13th rib in a 300kg carcass.
Estimates the difference between animals in fat depth at the P8 rump site in a 300kg carcass.
Estimates the difference between animals in percentage retail beef yield in a 300kg carcass.
Estimates the difference between animals in percentage intra muscular fat at the 12/13th rib site in a 300kg carcass. Strongly correlated to marbling.
Carcass Weight (CW)
As this EBV is adjusted to a standard age, it represents little more than a growth indicator. Its strong correlation to growth, make it difficult to select animals for high carcass weight and moderate or below average growth (as in the vealer production scenario described earlier).
Eye Muscle Area (EMA)
As the eye muscle area represents the primal cut area of a carcass, it is an important trait, especially for sectors of the beef industry beyond the farm gate. Initially EMA was adjusted to a standard age, and like carcass weight now, was a growth indicator, and gave no useful guide to the actual muscularity of an animal. Nowadays it is calculated according to a standard carcass weight, regardless of age, and hence is a good guide to the genetic muscling ability of an animal.
While logically one would assume EMA is an indicator of overall muscling in a beast (eg Butt score), it is not a totally reliable guide. The EMA can take various shapes, and so it is possible to see high EMA beasts that exhibit low live muscle score assessments. More often than not, however, high EMA animals, will exhibit good live muscle scores.
From a production angle, it is important not to push muscling too hard. Anecdotally it seems there is some trade off between extreme muscling and cow fertility, although this theory too has its skeptics.
(This article is the property of Millah Murrah Angus and may not be reproduced without express permission of the writer. Views expressed herein are the writer’s opinion only and no liability is assumed for action taken by others based on this article.)