Investigation of nitrogen balance in dairy cows and steers nourished by intragastric infusion. Effects of submaintenance energy input with or without protein.
Orskov, E. R.; MacLeod, N. A.; Fahmy, S. T.et al.
1983 • In British Journal of Nutrition, 50 (1), p. 99-107
Animal Nutritional Physiological Phenomena; Animals; Cattle; Dietary Proteins/administration & dosage; Energy Intake; Energy Metabolism; Enteral Nutrition; Fasting; Female; Male; Nitrogen/metabolism
Abstract :
[en] Two dairy cows were maintained by intragastric infusion of volatile fatty acids and casein. Except when fasting, the casein-nitrogen was held constant, while total gross energy supply was varied from zero during fasting to 650 kJ/kg body-weight (W)0 . 75. One cow was estimated to attain zero N balance at an energy intake of 255 kJ/kg W0 . 75 and the other at 307 kJ/kg W0 . 75, which was calculated to be substantially below the estimated energy required for zero energy balance. When the cows were later given an N-free infusion for a period preceding the trial, N balance occurred at 98 kJ/kg W0 . 75 for one cow and 115 kJ/kg W0 . 75 for the other. Four steers were similarly nourished by intragastric infusion and the energy nutrient increased from 0 at fasting to 450 kJ/kg W0 . 75. The protein was held constant at 1 g N/kg W0 . 75 except at fasting. The energy level at which N balance occurred was 154 (SE 38) kJ/kg W0 . 75 or approximately equal to the energy content of the protein. The practical implications of these findings are discussed.
Disciplines :
Veterinary medicine & animal health
Author, co-author :
Orskov, E. R.
MacLeod, N. A.
Fahmy, S. T.
Istasse, Louis ; Université de Liège - ULiège > Département de productions animales > Nutrition des animaux domestiques
Hovell, F. D.
Language :
English
Title :
Investigation of nitrogen balance in dairy cows and steers nourished by intragastric infusion. Effects of submaintenance energy input with or without protein.
Publication date :
1983
Journal title :
British Journal of Nutrition
ISSN :
0007-1145
eISSN :
1475-2662
Publisher :
Cambridge University Press, Cambridge, United Kingdom
Webster, A. J. F. (1980). In Digestive Physiology and Metabolism in Ruminants, pp. 469-484 [Y. Ruckebusch and P. Thivend, editors]. Lancaster: MTP Press Ltd.