Lamb Carcass Evaluation

Before beginning the evaluation, the carcasses must be identified as to their sex, condition or class and their maturity group or kind. The classes or sex groups of sheep are ewe (female), wether (castrated male), and ram (male). The classes are then further subdivided by kind or maturity groups into lambs, yearling mutton, and mutton. It is necessary to identify kinds and class of sheep carcasses prior to grading so that one can apply the correct set of standards and grades.

To Determine How Much Lean Meat an Sheep Will Yield:

Pounds of Meat= (Dressing Percent x Carcass Cutting Yield) x Live Weight

Two Factors Affecting the Percentage of Lean Meat:

1. Dressing Percentage
2. Carcass Cutting Yield

Dressing Percentage

The percentage of the live animal that ends up as carcass.
Dressing Percentage= Carcass Weight / Live Weight x 100

Dressing Percentage is affected by:

1. Gut fill-- The more gut fill at the time the live weight is taken, the lower the dressing percentage will be. If an animal is weighed right off of full feed, the dressing percentage will be 2% to 5% lower than if the animal is fasted for 24 hours prior to weighing.

2. Muscling-- A heavier muscled animal will have a higher dressing percentage than a light muscled animal.

3. Fatness-- A fatter animal will have a higher dressing percentage than a lean animal.

4. Mud-- Animals with a lot of mud attached to their hide will have a lower dressing percentage than clean animals.

5. Wool-- Lambs with long wool will have a lower dressing perdentage than recently-shorn lambs.

Average dressing percentage for SHORN market lambs: 54%

Carcass Cutting Yield

The percentage of the carcass that end up as meat.

Carcass Cutting Yield= Pounds of Meat / Carcass Weight x 100

Carcass Cutting Yield is affected by:

1. Fatness-- Leaner animals will have higher carcass cutting yields than fatter animals.

2. Muscling-- More muscular animals will have higher carcass cutting yeilds than less muscular animals.

3. Bone-in versus Boneless-- This will dramatically affect carcass cutting yield. If more boneless cuts are made, then the carcass cutting yield will be lower than if bone-in cuts are made. If bone-in chuck roasts, rib steaks, T-bones, and bone-in sirloin steaks are made, the carcass cutting ield will be much higher than if boneless chuck roasts, ribeye steaks, strip steaks, and boneless sirloin steaks are made. It is important to note that the amount of edible meat will not change, but boneless cuts will take up less room in your freezer. If you get soup bones and short ribs, the carcass cutting yield will be higher than if you have these items boned and put into ground beef.

4. The Amount of Fat Remaining on the Meat Cuts-- If the meat cutter leaves more surface fat on the meat cuts, then the carcass cutting yield will be higher than if the meat cuts are closely-trimmed.

5. The Leanness of the Ground Product-- If the ground product (ground beef, ground pork, pork sausage, ground lamb) is made very lean, then the carcass cutting yield will be lower than if the ground product is made with more fat. For example, a typical beef carcass could have 20 more pounds of ground beef if it is made into 70% lean ground beef than if it is made into 92% lean ground beef.


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