Masters Theses

Date of Award

12-1965

Degree Type

Thesis

Degree Name

Master of Science

Major

Animal Husbandry

Major Professor

C.C. Chamberlain

Committee Members

Harold J. Smith, Robert Dotson

Abstract

Improvement in the field of swine husbandry is needed both in the efficiency of production and the quality of product. While recent developments in this field have resulted in improvement in both the efficiency of production and carcass quality, further improvement is needed. The pork carcass being sold on the American market today still has too high a percentage of fat for maximum consumer's acceptability.

During the eighteenth and nineteenth centuries there was a world market for pork products of all types. Lard was the standard of excellence in edible fats. The average American swine breeder produced an animal in those days which did an excellent job of converting carbohydrates into edible fats and proteins. The consumer's preference has gradually changed due to a desire for lower caloric intake and the increasing availability of other meats such as beef and poultry. Recently, the repeated assertion of the relationship between animal fat and certain cardiovascular disorders have exerted considerable additional pressure upon the contemporary swine producers to produce pork with less fat.

Swine utilize concentrate feed more efficiently than other mammals. They readily convert feed into body tissue. Self-feeding high energy rations intensifies the deposition of fat. An average hog carcass contains approximately enough pork for two people for 1 year, whereas the same carcass supplies enough lard for three people for the same period. This situation places lard in the category of a by-product. Since 1949 the wholesale price of lard has been less than the price paid for an equivalent weight of live animal as indicated in Table I.

A study of the table shows that, prior to the 1940-45 period, lard was worth more per pound than live hogs. Since that date live hogs were worth more per pound than lard, except during 1947-48. Since the 1940-46 period, there was a steady decline in the yearly per capita consumption of lard in the U.S.A.

Present thinking concerning the surplus lard problem is to reduce the amount of lard produced per animal. Scientists working on this problem have followed two general paths in their investigations. Through selection and other breeding programs, the animal breeder has strived to develop a leaner type hog which still retains rapidity of growth. Other scientists have studied the effects of regulating feed consumption and its relation to carcass quality. Research in swine nutrition has shown that the plane of nutrition exhibits an influence upon the physiological development. Concerning the latter school of thought, Morrison (1959) made the following statement:

The net effect of limited feeding can be determined only by experiments in which pigs are fullfed in direct comparison with others that receive limited amount of the same feeds. It is important that such tests be continued until the limited fed pigs have reached market weights, which has not been done on some of the experiments on this problem.

It is the subject of this thesis to analyze the effects of regulating feed intake of the pigs under pasture and confinement systems on the rate of gain, economy of gain, carcass yield, and carcass quality.

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