Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Animal Science


Current meat consumption patterns and competition from other meats and meat substitutes present a challenge to today’s pork producer to produce a higher quality product with a larger lean to fat ratio. One avenue or approach toward meeting the challenge could be through selection of superior breeding animals. Thus the major challenge at the producer level is that of accurately determining the meatiest individuals for replacements. Historically man has relied upon the visual appraisal, however, few of the live animal. Therefore, the majority must depend upon selection aids. Actual carcass cut-out data can be obtained, but this results in the loss of the breeding animal. The backfat probe is an accurate measure of fat thickness, however it is limited to that determination. Thus the challenge becomes that of a means of measuring the meatiness of the individual live breeding animal. One of the more recent developments toward a means or method of accurately determining what is under the hide of the live animals has been the adaptation of ultrasonics or high frequency sound to the measurement of the fat and lean in the live animal. Ultrasonics, or the sonoray, can be used to measure the thickness of the fat and lean because sound travels through different density tissues at different speeds. The basic principal is that the high frequency sound is directed through the tissues of the animal, and echo representing each layer of fat or lean is reflected upon the cathode ray tube. The fat and muscle depths are determined by the proper interpretation of these echoes. Early attempts were directed toward the measurement offered little advantage over the probe. The longissimus dorsi muscle area. The fat thickness measurement offered little advantage over the probe. The longissimus dorsi muscle area measurements were time consuming and the accuracy depended to a large extent upon the operator, the type of restraining device. More recent work has been directed toward the prediction of the lean cut or ham and loin percentage with the ultrasonic measurements taken at various locations upon the animal body. (see more in text)

Library of Congress Subject Headings

Ultrasonic testing
Swine -- Weight




South Dakota State University