Feeding strategies for grain-fed cattle in a hot environment

Holt, SM, Gaughan, JB and Mader, TL (2004) Feeding strategies for grain-fed cattle in a hot environment. Australian Journal of Agricultural Research, 55 7: 719-725. doi:10.1071/AR03261

Author Holt, SM
Gaughan, JB
Mader, TL
Title Feeding strategies for grain-fed cattle in a hot environment
Journal name Australian Journal of Agricultural Research   Check publisher's open access policy
ISSN 0004-9409
Publication date 2004
Sub-type Article (original research)
DOI 10.1071/AR03261
Open Access Status
Volume 55
Issue 7
Start page 719
End page 725
Total pages 7
Editor J. Fegent and S. Banerjee
Place of publication Collingwood, Victoria
Publisher CSIRO
Collection year 2004
Language eng
Subject C1
300499 Animal Production not elsewhere classified
630103 Beef cattle
Abstract Six Bos taurus (Hereford) steers (body weight 324 22 kg) were used in a 45-day study with a replicated 3 x 3 Latin-square design. Three treatments [ad libitum feeding (ADLIB); limit feeding, 85% of ad libitum (LIMIT); bunk management feeding where steers were only given access to feed from 1600 to 0800 hours the following day (BUNK)] were imposed over 3 periods, with 2 steers assigned to each treatment in each period. Cattle were managed in a temperature-controlled metabolism unit and were exposed to both thermoneutral (17.7degreesC-26.1degreesC) and hot (16.7degreesC-32.9degreesC) environmental conditions. By design, during the thermoneutral period, the ADLIB cattle displayed greater intake (P < 0.05) than the LIMIT group, with the BUNK group being intermediate. However, during the hot period, both the LIMIT and BUNK treatment groups increased feed intake 4-5%, whereas feed intake of the ADLIB treatment group declined nearly 2%. During both periods respiration rate (RR, breath/min) followed the same pattern that was observed for feed intake, with the greatest (P < 0.05) RR found in the ADLIB treatment group (81.09 and 109.55, thermoneutral and hot, respectively) and lowest (P < 0.05) RR in the LIMIT treatment group (74.47 and 102.76, thermoneutral and hot, respectively). Rectal temperature (RT) did not differ among treatments during the thermoneutral period or the first hot day, although during the thermoneutral period the ADLIB treatment group did tend to display a lower RT, possibly as a result of other physiological processes (pulse rate and RR) aiding to keep RT lower. During the hot period, differences in RT were found on Day 5, with the LIMIT cattle having lower (P < 0.10) RT (38.92degreesC) than the ADLIB (39.18degreesC) cattle, with BUNK cattle RT (39.14degreesC) being intermediate. However, when hourly data were examined, the ADLIB cattle had greater(P < 0.05) RT than the BUNK and LIMIT at 1800 hours and greater RT (P < 0.05) than the LIMIT group at 1400, 1500, and 1600 hours. Clearly, a change in diurnal RT pattern was obtained by using the LIMIT and BUNK feeding regimen. Both of these groups displayed a peak RT during the hot conditions, between 2100 and 2200 hours, whereas the ADLIB group displayed a peak RT between 1400 and 1500 hours, a time very close to when peak climatic stress occurs. Based on these results it is apparent that feedlot managers could alleviate the effects of adverse hot weather on cattle by utilising either a limit-feeding regimen or altering bunk management practices to prevent feed from being consumed several hours prior to the hottest portion of the day.
Keyword Agriculture, Multidisciplinary
Beef Cattle
Heat Stress
Feeding Regimen
Holstein-friesian Cows
Carcass Characteristics
Feedlot Steers
Dietary Energy
Beef Steers
Organ Size
Q-Index Code C1

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Created: Wed, 15 Aug 2007, 04:56:42 EST