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 HighWire Citing Articles via Google Scholar Google Scholar Articles by Cundiff, L. V. Articles by Pratt, C. A. Search for Related Content PubMed Articles by Cundiff, L. V. Articles by Pratt, C. A.

Effects of Certain Factors and Their Two-Way Interactions on Weaning Weight in Beef Cattle

Oklahoma State University, Stillwater

Abstract

The adjusted 205-day weaning weights of 13,937 Hereford and Angus calves recorded in the Oklahoma Beef Cattle Improvement Program from 1959 through 1962 were used in this study. Each calf was classified according to age of dam, sex, breed, type of pasture, area of the state, month of birth and type of management. The data were analyzed by least squares to investigate the main effects of these seven factors. To investigate two-way interactions least-squares analyses were computed within each sex, breed, type of pasture, season of birth and type of management. The importance of interactions was examined by comparing least-squares constants computed for a given level of one factor within different levels of another factor. The criterion for assessing the significance of interaction was whether or not 95% confidence intervals for the least-squares constants overlapped.

The results of the analysis of main effects indicated that age of dam, sex, area, month of birth and type of management had significant (P<.01) and important influences on weaning weight, each accounting for more than 5% of the total variance. The least-squares estimates for age of dam indicated that weaning weight increased 22 kg. as cows increased in age from 2 to 4 years, suggesting that classifying cows into 3- to 5-month increments between 2 and 4 years of age would result in more accurate corrections than those that result from yearly increments. The results of interaction analyses indicated that the effect of age of dam was essentially the same regardless of sex, breed, type of pasture, season of birth or type of management. Sex by type of management, month of birth by type of pasture and month of birth by type of management appear important enough to be taken into account in adjusting weaning weights.

¹ Present address: Department of Animal Science, University of Kentucky, Lexington.

² Department of Animal Science.

³ The authors acknowledge R. D. Morrison and Wayne Berry of the Department of Mathematics for their assistance in programming and analysis of data.

This article has been cited by other articles:

				C. A. Lents, R. P. Wettemann, M. J. Paape, M. L. Looper, and D. S. Buchanan Effects of dry cow treatment of beef cows on pathogenic organisms, milk somatic cell counts, and calf growth during the subsequent lactation J Anim Sci, March 1, 2008; 86(3): 748 - 755. [Abstract] [Full Text] [PDF]