Page 28 - CON Boardpack FEBRUARY 2020 FINAL (v5) P1 - 75_Neat

Class Current system New proposed New Intrascope

HGP and ZP (mm fat)

P ≥70 ≥60 ≤13
O 67-69 55-59 14-19
R 64-66 50-54 20-24
C 61-63 45-49 25-30

U 58-60 40-44 31-34
S ≤57 <40 ≥35
Head off Head on
P1 (45mm) P2 (60mm)

• The Bruwer recommendation was based on carcass lean content
calculated as a percentage of carcass weight without the head, while
the rest of the world do not remove the head for the calculation so
that the percentage lean was higher in the current system. Also, the
intervals were only 2% which means that the deviation can be more
than two classes. Because the carcasses were smaller when the old
system was developed, measurement at the so called P1 level 45 mm
from the midline was chosen for the measurement site. The rest of the
world measure further (60 mm) at the P2 site. The new proposed system
is based on this measurement site with the head on.

• The new regression equation for the Hennessy grading probe (HGP) is:
pLean+Head = 68,05238-0,82985*X1+0,068052*X2 where X1 is fat
thickness (P2) and X2 is muscle thickness at the same spot. (RMSEP 2.34)

• A new comparable regression was also developed for the Intrascope
namely: pLean+Head = 70,9521- 0,8913*IntrascopeP2. (RMSEP 2.36)

• Since the production of the Intrascope had been discontinued, the
European experts suggested that the so-called ZP method be used.
Therefore, a prediction equation was also developed for lean
prediction from ZP measurements using a simple ruler or calliper:
pLean+Head = 59,73 - 0,5172*Fat-ZP + 0.0984*Musc-ZP (RMSEP 2.24)

• These results now need to be presented for amendment of the
regulations.

• It should be remembered that a classification system merely classifies
carcasses on their lean content. The meat trade may (or may not) use
it to establish prices. It makes international comparisons possible for fair
trade.

28