4.6.1 Current industry methods
At present both the beef and lamb industries rely on rudimentary tissue depth measurements to reflect the composition of a carcass. This is based upon the assumption that the depth of fat measured at one location will correlate with the amount of fat in the entire carcass. In the beef industry this fat depth is measured at the P8 site (on the rump). For MSA graded cattle, rib fat depth is also measured over the loin-eye muscle at the quartering point.
In the lamb industry tissue depth is measured at the GR site which is located 110mm from the mid-line over the 12th rib. This can be measured in millimetres using a GR knife, or it can be estimated by palpating the spinal processes in the lumbar region of the carcass which is then related to GR tissue depth as fat scores which are reported in GR increments of 5mm.