Estimated difference between animals in bone-out carcass weight
adjusted to 650 days of age
Eye Muscle Area
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
Retail Beef Yield %
Estimates the difference between animals in percentage retail
beef yield in a 300kg carcass
Intra Muscular Fat %
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
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.