Figure 1. Predicting carcass components of cull cow.
Live Weight (LW)
Starting at the point of slaughter, live weight is reduced to hot carcass weight (HCW) by eliminating the hide, head, feet, tail, entrails and gut fill. Variables that affect this weight reduction in cull cows are stage of
pregnancy, udder size and gut fill.
Hot Carcass Weight (HCW) 44%55% Range of LW
HCW can range from 44%55% of live weight with the very lean, poorly muscled cows at the bottom of the range and fat, heavy muscled cows at the top of the range. Some Jersey cows will dress as low as 35%.
Cold Caracass Weight (CCW) Approx. 99% of HCW
Cold carcass weight (CCW) is the weight of the carcass after chilling. CCW is about 1% less than HCW and is due to the loss of water content during the cooling period. Very lean carcasses will have greater moisture losses than fat carcasses.
CCW Percentage of bone, fat and muscle content
Content of bone, fat and muscle as a percentage of the CCW varies with fat cover and muscling of the carcass.
Bone can range from 17%32% of the CCW. Fat, well-muscled cows are at the lower percentage range whereas very lean, poorly muscled cows are at the top of the range.
Fat can range from 7%30% of the CCW. The greater the backfat on the cow the greater the percentage fat will be.
Muscle content of the CCW can vary from 49%63%, but it is not the same linear relationship as exists with fat and bone. Percent muscle is lowest with fat cows and highest for cows that are heavily muscled, with an ideal body condition score. Very lean, poor muscled cows fall in the 58%60% range.