Digesta kinetics, energy intake, grazing behavior, and body temperature of grazing beef cattle differing in adaptation to heat

James E Sprinkle, J. W. Holloway, B. G. Warrington, W. C. Ellis, J. W. Stuth, T. D A Forbes, L. W. Greene

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31 Scopus citations

Abstract

The objective of this study was to determine whether digesta kinetics, energy intake (EI, kcal ME intake·kg-.75·d-1), grazing behavior, or body temperature differed by breed, lactational state, or season of the year among cattle presumed to vary in adaptability to the subtropics. Two-year-old lactating and nonlactating Brahman × Angus (BA; n = 5, n = 5), Tuli × Angus (TA; n = 5, n = 4), and Angus (A; n = 4, n = 4) cows were used. During both early (ES) and late summer (LS), lactating cattle vs nonlactating cattle had greater gastrointestinal tract load (CM2) and EI (P < .01), although passage rate did not differ (P > .48). During LS, lactating cattle had decreased early morning rectal temperatures (P < .05) and spent more time grazing during the day compared with nonlactating cattle (P < .001). Among breeds, A had the largest CM2 (P < .01 compared with BA and P = .068 compared with TA) and accumulated the greatest heat during the day (P < .05). Due to greater daytime shading (P < .01) and less daytime grazing (P < .05), A had lower (P < .05) early morning and comparable (P > .26) late afternoon rectal temperatures compared with BA and TA. With data pooled over both grazing trials, BA cattle had the smallest CM2 (P < .01), and in ES they spent the least amount of time in the shade (P < .001). The TA spent more time in the shade than did BA (P < .001) during ES and less during LS (P < .001) and had similar (P > .28) early morning rectal temperatures compared with BA during ES and LS. During LS, TA spent more time in the sun and less time in the shade than did either A or BA (P < .001). During ES, EI did not differ among breeds (P > .50). During LS, EI for lactating A was greater than for BA and TA (P < .05), and EI for nonlactating BA was less than for A and TA (P < .05). Bite rate per minute for lactating cattle during ES was reduced (P < .03) by increased body condition score. Tuli × Angus cattle appear to be comparable to BA with respect to heat adaptation. It appears that EI demands are greater in a hot environment.

Original languageEnglish (US)
Pages (from-to)1608-1624
Number of pages17
JournalJournal of Animal Science
Volume78
Issue number6
Publication statusPublished - Jun 2000
Externally publishedYes

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Keywords

  • Beef Cattle
  • Breeds
  • Grazing Behavior
  • Kinetics
  • Temperature

ASJC Scopus subject areas

  • Animal Science and Zoology

Cite this

Sprinkle, J. E., Holloway, J. W., Warrington, B. G., Ellis, W. C., Stuth, J. W., Forbes, T. D. A., & Greene, L. W. (2000). Digesta kinetics, energy intake, grazing behavior, and body temperature of grazing beef cattle differing in adaptation to heat. Journal of Animal Science, 78(6), 1608-1624.