Effects of dry matter intake restriction on diet digestion, energy partitioning, phosphorus retention, and ruminai fermentation by beef steers

J. H. Clark, K. C. Olson, T. B. Schmidt, M. L. Linville, D. O. Alkire, D. L. Meyer, G. K. Rentfrow, C. C. Carr, E. P. Berg

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Two experiments were conducted to determine the effects of DMI restriction on diet digestion, ruminai fermentation, ME intake, and P retention by beef steers. In Exp. 1, twelve Angus x steers (average initial BW = 450 ± 18 kg) were assigned randomly to 1 of 3 diets that were formulated to promote a 1.6-kg ADG at intake levels corresponding approximately to 100% (ad libitum, AL), 90% (IR90), or 80% (IR80) of ad libitum DMI. In Exp. 2, twelve crossbred steers (aver-age initial BW = 445 ± 56 kg) fitted with ruminai cannulae were randomly assigned to 1 of 2 diets that were formulated to promote a 1.6-kg ADG at AL or IR80. All diets delivered similar total NE, MP, Ca, and P per day. During both experiments, fecal DM output by IR80 was less (P < 0.03) than that of AL; IR90 was similar (P = 0.51) to AL during Exp. 1. Digestion of DM by IR80 cattle was greater (P < 0.03) than that of AL during both experiments; IR90 was similar (P = 0.31) to AL during Exp. 1. Metabolizable energy intake was similar (P > 0.20) among treatments during both experiments, whereas P retention was similar (P > 0.46) among treatments during Exp. 1. Total VFA and the molar proportion of acetate of AL were greater (P < 0.03) than that of IR80 during Exp. 2; however, IR80 had a greater (P = 0.03) molar proportion of propionate. Under the conditions of these studies, restricting DMI while holding NE, ruminally degradable protein, and MP intakes constant decreased fecal DM output and changed ruminal fermentation patterns in finishing steers. Improvements in performance associated with programmed-feeding regimens of the type studied here do not appear to be related to changes in diet digestion or ME intake.

Original languageEnglish
Pages (from-to)3383-3390
Number of pages8
JournalJournal of Animal Science
Volume85
Issue number12
DOIs
StatePublished - Dec 2007

Keywords

  • Beef steer
  • Digestion
  • Energy partitioning
  • Intake restriction

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology
  • Genetics

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