J. Anim Sci.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J. Anim Sci. 1985. 61:1345-1353.
© 1985 American Society of Animal Science
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Holloway, J. W.
Right arrow Articles by Backus, W. L.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Holloway, J. W.
Right arrow Articles by Backus, W. L.

Breed x Nutritional Environment Interactions for Intake and Digestibility of Forage Grazed by Lactating Beef Females

J. W. Holloway1, W. T. Butts, Jr.2, J. R. McCurley3, H. L. Peeler4, E. E. Beaver5 and W. L. Backus6

University of Tennessee and U.S. Department of Agriculture, Knoxville, TN 37091

Abstract

Seasonal patterns of forage digestibility and intake were measured over 3 yr for 120, 2-yr-old lactating Angus, Hereford, Angus x Hereford and Hereford x Angus females. These females calved January through March and grazed either fescue-legume (60% fescue, 40% red and ladino clover and lespedeza) or fescue pastures. Forage digestibility and intake were measured with a fecal index developed in a companion study involving 119 in vivo determinations. Dry matter (DM) intake, output and digestibility of forage consumed were calculated weekly from March 1 through September 1. Fecal output was calculated by the Cr2O3-dilution technique. Females grazing fescue-legume consumed 1.3 kg·d–1 more forage DM that was 9.7 percentage units more digestible than those grazing fescue. Among-animal range in digestibility varied from 25% (45 to 70% DM digestibility) in April to 37% (47 to 74%) in June for fescue and from 18% (60 to 78%) in May to 31% (45 to 76%) in September for fescue-legume. Breed x pasture type interactions were detected (P<.05) for average and seasonal patterns of both digestibility and intake. The primary interactions involved the crossbreds. Angus x Herefords responded in a similar manner to Hereford x Angus and these were pooled. Crossbreds consumed more (P<.10) DM of lower (P<.10) digestibility than straightbreds when grazing fescue. The opposite trend was detected for females grazing fescue-legume. The opposite nature of the interactions for digestibility and intake effectively countered each other so that breed x pasture type interactions were generally not important (P>.10) for digestible DM intake. Interactions were important (P<.01) when intake was expressed as ratio of metabolic weight. Seasonal pattern of intake and digestibility was also different for crossbreds than for straightbreds grazing either fescue or fescue-legume. Interactions were important for digestibility during seasons of high digestibility and for intake during seasons of low digestibility.

Footnotes

1 Present address: Texas Agr. Exp. Sta., Uvalde 78801.

2 Present address: USDA-ARS, Brooksville Beef Cattle Res. Sta., Brooksville, FL 33512.

3 Present address: Dept. of Anim. Sci., West Virginia Univ., Morgantown 26505.

4 Present address: 1202 Poplar Street, Selmer, TN 38375.

5 Present address: Anim. Sci. Dept., Univ. of Missouri, Columbia 65201.

6 Anim. Sci. Dept.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1985 by the American Society of Animal Science.