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Rutgers University, New Brunswick, New Jersey and and East African Agriculture and Forestry Research Organization, Box 30148, Nairobi, Kenya
Abstract
A study on voluntary intake of dry matter (DMI) was conducted using 108 Zebu steers approximately 2.5 years of age as determined from their dentition. Their average weight was 271 kg with a range from 184 to 332 kilograms. The animals were fed poor quality hay (7% CP, 80% CWC) ad libitum supplemented with restricted amounts of nine concentrates providing cassava and molasses for energy and urea for nitrogen (N). The concentrate supplied energy in g/kg0.60 and urea N as a percent of total N requirement in a central-composite design as follows (N values in parentheses): 20 (70), 32 (42), 32 (98), 60 (30), 60 (70), 60 (110), 88 (42), 88 (98) and 100 (70), in diets one to nine, respectively. The DMI and body weight data were collected during an 84-day feeding period.
Using six observations for each of 108 steers, the average reference base determined by regressing logarithm of DMI on the logarithm of body weight was kg0.79±0.03, which was not different (P>.05) from the reference bases of kg0.75 and kg0.73. The DMI was 80 g/kg0.79 and equivalent to 100 g/kg0.75, i.e. DMI=A (BW)b where DMI is in grams per kilogram metabolic mass, A equals a constant, and b equals a functional power of body weight.
1 Paper of the Journal Series, New Jersey Agricultural Experiment Station, New Brunswick 08903. This paper is published with the approval of the Director, E.A.A.F.R.O., Nairobi, Kenya.
2 Departments of Animal Sciences and Nutrition, Rutgers and Animal Production Division, E.A.A.F.R.O., Nairobi.
3 Partial support from The Rockefeller Foundation, New York, New York, is gratefully acknowledged by the authors.
4 From a thesis submitted by the Senior author to the Graduate School, Rutgers University, in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
5 E.A.A.F.R.O., P.O. Box 30148, Nairobi, Kenya.
6 Bartlett Hall, Rutgers University, P.O. Box 231, New Brunswick, N. J. 08903.
7 Department of Animal Sciences, Oklahoma State University, Stillwater 74074.
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