Breedplan In Focus

Index INTRODUCTION CALVING EASE GROWTH & MATERNAL FERTILITY TRAITS CARCASS TRAITS NET FEED CONVERSION EFFICIENCY $ INDICES CONCLUSION    Appendix A: Trait Correlations

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CARCASS TRAITS

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.