PORK & PORK QUALITY
PIH-42
pork industry handbook
COOPERATIVE EXTENSION SERVICE • PURDUE UNIVERSITY • WEST LAFAYETTE, INDIANA
Carcass Evaluation
Authors
Robert G. Kauffman, University of Wisconsin
Richard J. Epley, University of Minnesota
John R. Romans, University of Illinois
Gary C. Smith, Texas A & M University
David G. Topel, Iowa State University
Reviewers
J. Nick Hahn, Bellevue, Ohio
Allen Keppy, Wilton, Iowa
Introduction
Carcass evaluation is an essential part of determining relative success in pork production. Following reproduction, feeding and marketing of the hog, the final step is its transformation to food for humans. Through these processes, swine producers can effectively evaluate their progress in selection and management. In addition to measuring efficiency in terms of producing large, healthy litters that gain rapidly using a minimum of feed, producers should also be concerned about how much lean, edible pork is produced, and how desirable it is to process and consume. It is the purpose of this fact sheet to describe quantitative and qualitative characteristics associated with pork carcass desirability, and to identify procedures that can be practically standardized and applied to measure these characteristics throughout the pork industry.

Transforming the Pig to Pork
Identification. Each pig is tattooed with approved edible ink at two locations on each side of the pig. If pigs are skinned rather than dehaired, metal tags can be clipped to both ears. After bleeding and before the head is removed, the tags are removed, placed in a plastic bag and securely pinned to the foreshank.

Inspection. The veterinarian in charge of inspection at the slaughter plant can be asked to record information concerning any specific abnormalities that are observed during ante-mortem and post-mortem inspection. Even though carcasses may pass inspection, some abnormalities may exist (e.g., jowl abscesses, arthritis, and cryptorchidism). The producer should be informed if such conditions are present in his swine. It is recommended that such carcasses be eliminated from competition.

Hot carcass weight and belly dimension. The hot weight is observed and then written on the carcass with an
edible ink marker, or if time and space do not permit this, weight may be recorded sequentially on a weigh sheet. One advantage of writing on the carcass is that fewer are lost in the coolers. If chilled weights are recorded, convert to a hot weight basis by dividing by .985 (most carcasses shrink about 1.5% during drying and chilling). For skinned carcasses, adjust to a skin-on basis by dividing the hot weight by 0.94 (the skin accounts for about 6% of hot carcass weight).

If jowls are removed, or if muscle, fat or bone have been removed from locations where measurements need to be taken, or if excessive muscle, fat and/or bone have been removed because of bruises or localized infections, the carcass should not be considered for competition. If the trim loss is not excessive, the amount missing should be estimated and added to the hot carcass weight.

A minimum carcass weight of 140 lb. is recommended for competition. However, if there is a concern about thin bellies at this weight, then the minimum carcass weight requirement should be increased. To date, there is no objective definition of a belly that is too thin; such descriptions have not been standardized and there is no clearly interpreted and practical method for identifying such cuts. Most carcasses weighing 150 lb. or more will be free of the thin-belly problem. Once bellies meet minimal dimensions for subsequent processing, the major concern is desirable composition and quality.

Ribbing the carcass. To measure quantitative and qualitative characteristics, the vertebra of the untrimmed carcass is first cut with a saw perpendicular to the long axis of the loin between the 10th and 11th ribs or between the 6th and 7th ribs, depending upon which method described in the next section is used. Start adjacent to the 11th or 7th rib to permit a square cut across the loin muscle without cutting into the 10th or 6th rib. After the vertebra is sawed,
Cooperative Extension Work in Agriculture and Home Economics, State of Indiana, Purdue University and U. S. Department of Agriculture Cooperating. H. G. Diesslin, Director, West Lafayette, IN. Issued in furtherance of the Acts of May 8 and June 30, 1914. It is the policy of the Cooperative Extension Service of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, color, sex, religion, national origin, age or handicap.