Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

Lawrence B. Embry


The need for minimum amounts of protein and energy by animals for maintenance, growth and production has been recognized for many years. It is also well known that the requirements will vary depending on species, age, weight and rate of growth or production. In order to provide livestock feeders with useful guides in feeding, several feeding standards containing recommended nutrient requirements have been prepared. The most commonly used standards for beef cattle are the “Morrison Feeding Standards” (1956) and the National Research Council’s “Nutrient Requirements of Beef Cattle” prepared by the Subcommittee on Beef Cattle Nutrition (1959). Feeding standards give recommended requirements for protein and other nutrients for various weight and age groups of beef cattle for different types of production. The standards are based on results of research, and the recommended requirements appear reasonably accurate for the conditions specified. There are some shortcomings to feeding standards. For the most part, they are based on the results of short-term trials. Only in a few experiments have nutritive requirements of beef cattle been studied during both growing and fattening phases of the same animals. Much of the data on protein and energy requirements have been compiled from experiments which were not designed to specifically study these requirements. Beef cattle are the only farm animals that can be marketed profitably over a wide range of weights and ages. This fact has resulted in the use of many systems of feeding for growing and fattening beef cattle. Nutritive requirements will vary depending on the type of feeding system used and the level pf production sought. Several studies have been made to determine the effects of limited amounts of protein and energy on rate of gain, feed requirement and subsequent production. In general, it has been shown that restricted feeding for a limited period of time reduces gain and increases feed requirement per unit of gain during the period of restriction. When put on liberal rations or turned to pasture, the animals on the restricted feeding systems gain more rapidly and more efficiently than those on previous liberal rations. The importance aspects of restricted feeding for certain periods are the effects on amount, kind and cost of feed during the period of restriction and the later effects on gain, feed efficiency, time required to produce slaughter cattle, total feed requirement and carcass grade, weight and composition. While the inverse relationship of gain and feed efficiency between different phases of production has been demonstrated, more work is needed on the effects of the feeding system on the other factors listed. This information would be valuable in selecting the most economical feeding system to meet the producer’s feed supply and desired type of operation. The work reported in this thesis was undertaken with these practical considerations in mind. The study dealt with the rate of feeding protein and energy on gains and feed requirements with wintering rations and effects on subsequent production under two feeding systems.

Library of Congress Subject Headings

Calves -- Feeding and feeds
Beef cattle -- Feeding and feeds


Includes bibliographical references



Number of Pages



South Dakota State University