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 Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Urick, J. J. Articles by Riley, T. M. Search for Related Content PubMed PubMed Citation Articles by Urick, J. J. Articles by Riley, T. M.

Heterosis in Postweaning Traits among Lines of Hereford Cattle¹

U. S. Department of Agriculture and Montana Agricultural Experiment Station, Bozeman

Abstract

Data collected on 229 bulls and 226 heifersat the United States Range Livestock Experiment Station, Miles City, Montana, were used to estimate the amount of heterosis in postweaning growth traits resulting from crossing five inbred lines of Hereford cattle. Data were obtained on all possible straight-line and linecross combinations from calves born in each of the years 1962 through 1965.

The data were analyzed by least-squares procedures. The model included line of sire, line of dam, line of sire x line of dam, years, line of sire x year, line of dam x year, age of dam and the regression of the traits on age of animal.

Percent heterosis obtained for bulls for weaning weight and for weights taken every 28 days during a 196-day feed period was: weaning weight, 4.9; initial weight on feed, 6.7; period 1, 7.3; period 2, 6.4; period 3, 5.6; period 4, 5.3; period 5, 5.0; period 6, 4.9; and final weight, 4.5. Percent heterosis for gain made within each period ranged from 13.0 for period 1 to –2.2 for period 7, and was 2.9 for total 196-day gain.

Percent heterosis obtained for heifers was: weaning weight, 9.0; 12-mo. weight, 9.4; 18-mo. weight, 6.6; gain from weaning to 12 mo., 9.5; gain from weaning to 18 mo., 3.7; gain from 12 to 18 mo., 1.1; and 18-mo. conformation score, 4.6. Discussions on the difference between the two sexes in the amount of heterosis expressed and on the trends in the amount of heterosis expressed at different stages of life are presented. Information on the average performance of the lines is presented and discussed.

Discussions on the difference between the two sexes in the amount of heterosis expressed and on the trends in the amount of heterosis expressed at different stages of life are presented. Information on the average performance of the lines is presented and discussed.

¹ This Study was conducted under Western Regional Research Project W-1, The Improvement of Beef Cattle Through the Application of Breeding Methods, at the U. S. Range Livestock Experiment Station, Miles City, Montana, in Cooperation with the Montana Agricultural Experiment Station, Bozeman, Montana.

² U. S. Range Livestock Experiment Station, Miles City, Montana.

³ Animal Husbandry Research Division, A.R.S., U.S.D.A., Fort Collins, Colorado.