Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Animal Science

First Advisor

George W. Libal


The current and somewhat controversial trend in swine selection is in the direction of a larger framed, later maturing animal. One goal of producers in changing to this type of animal is to produce a hog with more marketing flexibility, that is, a hog that may be carried to heavier weights without becoming over fat or that could be marketed at lighter weights and produce a very lean, muscular carcass. Excess fat is an unnecessary product in the meat animal industry that is expensive to produce from a feed efficiency standpoint. Research discussed later clearly indicated that changes in feed efficiency are closely related to the point at which an animal slows bone and muscle growth and begins to fatten. In theory, if this point can be delayed to a heavier weight, a desirable level of feed intake per unit of gain should also be observed at those heavier weights. Packer, retailer and consumer preference is also an important consideration. Generally, these people have preferred lighter carcasses, wholesale cuts and smaller retail cuts, respectively. However, it is difficult to determine exactly how much of this resistance to heavier hogs has been based on the association of higher fat content alone rather than weight. Since many of the meat processing costs can be attributed to a per head basis, the cost pf processing a heavier hog would be lower on a per kilogram basis. Very little research in the areas of frame size and live linear measurements has been done in swine, especially within the current trend. The literature contains much more work which explores carcass measurements as indicators of true carcass merit. With this in mind, the objectives of this study were (1) to study average daily gain, feed efficiency and carcass merit in relation to frame size in pigs taken to heavy weights, (2) to study a series of live measurements in relation to frame size and as a predictor of carcass merit and performance, (3) to study the relationship of average daily gain and rate of fattening across frame size groups and (4) to use as an end point kilograms of lean in the ham and loin and study traditional carcass measurements in relation to this end point.

Library of Congress Subject Headings

Swine -- Physiology
Swine -- Growth
Swine -- Carcasses



Number of Pages



South Dakota State University