Tim S. Stahly

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science


The present trends toward the meat type hog and the consumer's demand for lean cuts have resulted in the investigation of methods to produce leaner pigs. During recent years there has been considerable interest in the effect of dietary protein levels on growth rate, feed efficiency and carcass characteristics of swine. Several reports have indicated that increased dietary protein levels may improve growth performance and/or carcass leanness without adversely affecting the quality of the pork produced. However, little research has been conducted to show if this decrease in carcass quality of pigs fed a low protein diet could be at least partially due to differences in age, not protein per se. Pigs fed low protein diets have been shown to reach market weight at an older age due to a decreased rate of gain. Carcass development of swine is characterized by a period of rapid muscle growth from birth to approximately eighty days of age; a transition period from 80 to approximately 120 days of age where the rate of muscle development stabilizes and then a stage of increased fat deposition from 120 days of age to slaughter. Thus, this increased fat to lean ratio in carcasses of pigs fed the low protein diets could be due to the longer period of time that these animals are in the stage of relatively high fat deposition compared to pigs fed high protein levels. The objectives of this study were to determine the effect of dietary protein level and age on the following characteristics of growing-finishing swine: 1. Growth rate 2. Feed efficiency 3. Carcass composition 4. Consumer acceptability and cooking characteristics of the longissimus dorsi muscle 5. Apparent ration digestibility.

Library of Congress Subject Headings

Swine -- Feeding and feeds



Number of Pages



South Dakota State University