HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Eaton, H. D. Articles by Lucas, H. L. Search for Related Content PubMed Articles by Eaton, H. D. Articles by Lucas, H. L., Jr.

Effect of Duration of Experiment on Experimental Errors in Calf Nutrition Growth Studies¹

Storrs (Connecticut) Agricultural Experiment Station

H. L. Lucas, Jr.

North Carolina State College, Raleigh

ABSTRACT

Estimates of experimental errors of growth are of importance for efficient planning and adequate interpretation of calf nutrition studies. For example, they are of value in estimating the number of calves required per treatment to obtain a specified statistically significant difference in growth between treatments (2, 4). As early as 1913, Mitchell and Grindley (5) demonstrated that the size of the experimental errors for increases in live weight, expressed as percentages of mean gains, of beef cattle, sheep, poultry, and swine, decreased with increasing time on experiment. The rates of change of these decreases were most rapid during the early parts of the experiments and, thereafter, were at considerably slower rates or had a tendency to approach constant values. Somewhat similar findings have been reported (3) for increases in several linear growth measurements as well as live weight of dairy calves fed a single ration, uniformity data, and for increases in live weight of dairy heifers (1).

¹ This study was supported in part with funds provided by Wirthmore Feeds Inc., Waltham, Mass. The authors are grateful to Mrs. Mae Miller, Mrs. Elaine Trantum, R. T. Chatterton, Jr., A. P. Grifo, Jr., H. A. Kemmerer, Jr., and R. Teichman, for assistance in computations. We are especially indebted to Dr. R. L. Anderson for discussing the statistical aspects of this study.