| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
ANIMAL NUTRITION |
USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933
4 Correspondence: P.O. Box 166 (phone: 402-762-4202; fax: 402-762-4209; e-mail: freetly{at}email.marc.usda.gov).
Abstract
Twenty wether lambs (46 ± 2 kg) fitted with ruminal and abomasal infusion catheters were used in a completely randomized design to determine the effects of differing proportions of ruminal and abomasal casein infusion on N balance in lambs fed low-quality brome hay (0.8% N, DM basis) for ad libitum intake. Wethers were infused with 0 (control) or 10.7 g/d of N from casein with ratios of ruminal:abomasal infusion of 100:0 (100R:0A), 67:33 (67R:33A), 33:67 (33R:67A), or 0:100% (0R:100A), respectively, over a 12-d period. Total N supply (hay N intake + N from casein infusion) was greater (P = 0.001) in lambs receiving casein infusion than in controls. Urinary N excretion (g/d) was greater (P = 0.001) in lambs receiving casein infusion than in controls. Urinary N excretion decreased as casein infusion was shifted from 100R:0A to 33R:67A and then slightly increased in lambs receiving 0R:100A (quadratic, P = 0.02). Total N excretion was greater (P = 0.001) in lambs receiving casein infusion than in controls and decreased linearly (P = 0.005) as casein infusion was shifted to the abomasum. Retained N (g/d, % of N intake, and % of digested N) was greater (P = 0.001) in lambs receiving casein than in controls. Retained N increased as infusion was shifted from 100R:0A to 33R:67A and then slightly decreased in lambs receiving 0R:100A (quadratic, P < 0.07). Based on regression analysis, the predicted optimum proportion of casein infusion to maximize N retention was 68% into the abomasum. The regression suggests that supplementation with undegradable intake protein had an additional benefit over supplementation with ruminally degradable intake protein (100R:0A) and that changing the percentage of ruminally undegradable intake protein in supplemental protein from 33 to 100% resulted in minimal differences in N retention. Apparent N, DM, OM, and energy digestibility (% of intake) was greater (P < 0.03) in lambs infused with casein than controls but did not differ among casein infusion groups. These data suggest that feeding protein supplements containing a portion (greater than 0%) of the crude protein as ruminally undegradable intake protein, as compared to 100% ruminally degradable intake protein, to lambs consuming low-quality forage increases N retention and the efficiency of N utilization without influencing total-tract nutrient digestion.
Key Words: Nitrogen Metabolism • Nutrient Balance • Sheep • Supplementation
This article has been cited by other articles:
|
|
 |
|
  J. R. Fincham, A. O. Abaye, V. R. Mulkey-Olson, and J. P. Fontenot Apparent Digestibility and Nitrogen Balance in Lambs Fed Matua or Matua-Alfalfa Hay Professional Animal Scientist, June 1, 2009; 25(3): 296 - 299. [Abstract] [PDF]
|
|
|
|
 |
|
 S. L. Archibeque, H. C. Freetly, and C. L. Ferrell Feeding distillers grains supplements to improve amino acid nutriture of lambs consuming moderate-quality forages J Anim Sci, March 1, 2008; 86(3): 691 - 701. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. L. Atkinson, C. D. Toone, T. J. Robinson, D. L. Harmon, and P. A. Ludden Effects of supplemental ruminally degradable protein versus increasing amounts of supplemental ruminally undegradable protein on nitrogen retention, apparent digestibility, and nutrient flux across visceral tissues in lambs fed low-quality forage J Anim Sci, December 1, 2007; 85(12): 3331 - 3339. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. J. Reed, M. R. O'Neil, G. P. Lardy, K. A. Vonnahme, L. P. Reynolds, and J. S. Caton Effect of undegradable intake protein supplementation on intake, digestion, microbial efficiency, in situ disappearance, and plasma hormones and metabolites in steers fed low-quality grass hay J Anim Sci, April 1, 2007; 85(4): 1092 - 1101. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. I. Zanton, M. T. Gabler, and A. J. Heinrichs Manipulation of Soluble and Rumen-Undegradable Protein in Diets Fed to Postpubertal Dairy Heifers J Dairy Sci, February 1, 2007; 90(2): 978 - 986. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. W. Salisbury, C. R. Krehbiel, T. T. Ross, C. L. Schultz, and L. L. Melton Effects of supplemental protein type on intake, nitrogen balance, and site, and extent of digestion in whiteface wethers consuming low-quality grass hay J Anim Sci, December 1, 2004; 82(12): 3567 - 3576. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
