| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* USDA-ARS Conservation and Production Research Laboratory, Bushland, TX 79012;
and
Texas Agricultural Experiment Station, Amarillo 79106,
and
Texas Cooperative Extension Service, Amarillo 79106, and
and
West Texas A&M University, Canyon 79016
4 Correspondence: USDA-ARS-CPRL, P.O. Drawer 10 (phone: 806-356-5748; fax: 806-356-5750; E-mail: nacole{at}cprl.ars.usda.gov).
Decreasing dietary N inputs into beef cattle feeding operations could potentially decrease environmental concerns relating to air and water quality. Previous studies with sheep suggest that oscillating dietary CP concentrations may improve N use efficiency and thereby decrease dietary N requirements. Therefore, two studies were conducted to determine the effects of oscillating dietary CP concentrations on performance, acid-base balance, and manure characteristics of steers fed high-concentrate diets. Steers were fed to a constant backfat thickness in both studies. In the first trial, 92 steers (mean BW = 408 ± 2.8 kg; four pens/treatment) were fed the following diets: 1) constant 12% CP, 2) constant 14% CP, and 3) 10 and 14% CP oscillated at 2-d intervals. Steer performance and carcass characteristics were measured. In the second trial, 27 steers were individually fed the same three experimental dietary regimens (nine steers/treatment). Animal performance, arterial acid-base balance, plasma metabolites, and fecal characteristics were measured. In both trials, steers fed the 14% CP diet tended (P < 0.10) to have greater ADG and gain:feed than steers fed the 12% CP diet. Steers fed the oscillating CP regimen had intermediate performance. In Trial 1, steers fed the 14% CP diet tended (P = 0.09) to have smaller longissimus area and higher quality grades than steers fed the oscillating CP regimen. Protein retentions (g/d) calculated from NRC (2000) equations were greater (P = 0.04) for steers fed the 14% CP diet than steers fed the 12% CP diet. Steers fed the oscillating CP regimen tended (P = 0.08) to have greater calculated protein retention (g/d) than steers fed the 12% CP diet. Steers fed the 14% CP diet had greater (P < 0.05) calculated urinary N excretion than steers fed the 12% CP or oscillating CP regimens. Venous plasma concentrations of urea N were greater (P < 0.001) in steers fed the 14% CP diet than in steers fed the 12% CP diet; steers fed the oscillating CP regimen were intermediate but fluctuated over days. Based on arterial blood gas concentrations, acid-base balance was not significantly affected by dietary CP regimen. Results of these trials suggest that the CP requirement of steers in these studies was greater than 12% of the diet DM, and/or that the degradable CP requirement was greater than 6.3% of diet DM. However, the effects of oscillating dietary CP were minimal.
Key Words: Acid-Base Balance • Beef Cattle • Nitrogen • Protein
This article has been cited by other articles:
|
|
 |
|
  P. J. Gunn, A. D. Weaver, R. P. Lemenager, D. E. Gerrard, M. C. Claeys, and S. L. Lake Effects of dietary fat and crude protein on feedlot performance, carcass characteristics, and meat quality in finishing steers fed differing levels of dried distillers grains with solubles J Anim Sci, September 1, 2009; 87(9): 2882 - 2890. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. K. Reynolds and N. B. Kristensen Nitrogen recycling through the gut and the nitrogen economy of ruminants: An asynchronous symbiosis J Anim Sci, April 1, 2008; 86(14_suppl): E293 - E305. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. A. Cole and R. W. Todd Opportunities to enhance performance and efficiency through nutrient synchrony in concentrate-fed ruminants J Anim Sci, April 1, 2008; 86(14_suppl): E318 - E333. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Archibeque, H. C. Freetly, N. A. Cole, and C. L. Ferrell The influence of oscillating dietary protein concentrations on finishing cattle. II. Nutrient retention and ammonia emissions J Anim Sci, June 1, 2007; 85(6): 1496 - 1503. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Archibeque, D. N. Miller, H. C. Freetly, E. D. Berry, and C. L. Ferrell The influence of oscillating dietary protein concentrations on finishing cattle. I. Feedlot performance and odorous compound production J Anim Sci, June 1, 2007; 85(6): 1487 - 1495. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Archibeque, H. C. Freetly, and C. L. Ferrell Net portal and hepatic flux of nutrients in growing wethers fed high-concentrate diets with oscillating protein concentrations J Anim Sci, April 1, 2007; 85(4): 997 - 1005. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. A. Cole, P. J. Defoor, M. L. Galyean, G. C. Duff, and J. F. Gleghorn Effects of phase-feeding of crude protein on performance, carcass characteristics, serum urea nitrogen concentrations, and manure nitrogen of finishing beef steers J Anim Sci, December 1, 2006; 84(12): 3421 - 3432. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. T. Vasconcelos, L. W. Greene, N. A. Cole, M. S. Brown, F. T. McCollum III, and L. O. Tedeschi Effects of phase feeding of protein on performance, blood urea nitrogen concentration, manure nitrogen:phosphorus ratio, and carcass characteristics of feedlot cattle J Anim Sci, November 1, 2006; 84(11): 3032 - 3038. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. W. Todd, N. A. Cole, and R. N. Clark Reducing Crude Protein in Beef Cattle Diet Reduces Ammonia Emissions from Artificial Feedyard Surfaces J. Environ. Qual., February 2, 2006; 35(2): 404 - 411. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Hao, P. S. Mir, M. A. Shah, and G. R. Travis Influence of Canola and Sunflower Diet Amendments on Cattle Feedlot Manure J. Environ. Qual., July 5, 2005; 34(4): 1439 - 1445. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. C. Marini and M. E. Van Amburgh Partition of Nitrogen Excretion in Urine and the Feces of Holstein Replacement Heifers J Dairy Sci, May 1, 2005; 88(5): 1778 - 1784. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. A. Cole, R. N. Clark, R. W. Todd, C. R. Richardson, A. Gueye, L. W. Greene, and K. McBride Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure J Anim Sci, March 1, 2005; 83(3): 722 - 731. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Gleghorn, N. A. Elam, M. L. Galyean, G. C. Duff, N. A. Cole, and J. D. Rivera Effects of crude protein concentration and degradability on performance, carcass characteristics, and serum urea nitrogen concentrations in finishing beef steers J Anim Sci, September 1, 2004; 82(9): 2705 - 2717. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
