This paper is only available as a PDF. To read, Please Download here.
Abstract
Hay crops that were predominately alfalfa, clover or grass, and silage corn were harvested at early and late maturities to give a wide range in fiber contents. Hay crops were stored as field-cured hay and wilted silage. Each was fed for ad libitum intake to three or more nonlactating digestibility and calorimetry to measure DM intake, TDN, digestible energy, and metabolizable energy. Various fiber components (ADF, NDF, lignin), and expressions computed from them, were used to estimate TDN and digestible energy of forages or groups of forages having homogenous relationships. Stepwise backward elimination procedure was employed to discard independent variables or their squared terms at 5% probability to develop significant, biologically sound, practical predictive relationships. Standard NRC equations were used to extend energy densities to NEL. Free choice DM intake of forages (fed alone) was not closely related to NDF percentages. Estimates of NEL generally were higher when computed via TDN as opposed to digestible energy or metabolizable energy, which did not differ. We present equations to predict NEL from ADF via digestible energy for legumes, grasses, and corn silage, which differ markedly, in some cases, from those m current use. Equations for grasses had low r2, but these could not be compared with published ones, which apparently are based on treatment means rather than individual-animal observations. The NEL of hay crops and corn silages also were predicted from an expression of lignified NDF in DM with moderate precision.
Key words
Abbreviation Key:
ADL (acid detergent lignin), CWC (cell wall constituents), DDM (digestible dry matter), DE (digestible energy), EE (ether extract), HAYK (hay constant), LIG (lignin), LIGNDF (lignified NDF [% DM]), ME (metabolizable energy), NDS (neutral detergent solubles), NDSMP (neutral detergent solubles minus crude protein), NEDHIC (Northeast Dairy Herd Improvement Cooperative), NSC (nonstructural carbohydrates), pr2 (pooled r2), TEB (total energy balance)References
- The energy metabolism of ruminants.Hutchinson and Co., Let, London, Engl.1962
- Effects of neutral detergent fiber and roughage source on dry matter intake and milk yield and composition of dairy cows.J. Dairy Sci. 1987; 70: 298
- Estimating net energy lactation from components of cell solubles and cell walls.J. Dairy Sci. 1984; 67: 427
- Improved energy prediction equations for dairy cattle rations.J. Dairy Sci. 1989; 72: 2942
- Mathematical models for estimating energy and protein utilization of feedstuffs..Int.Feedstuffs Inst., Utah Agric. Exp. Stn, Logan1984 (Bull. No. 508)
- Forage fiber analyses (apparatus, reagents, procedures, and some applications).ARS-USDA, Washington, DC1970 (Agric. Handbook No. 379)
- Aspects of storing and ensiling forages.J. Dairy Sci. 1982; 66: 1403
- Varying protein content and nitrogen solubility for pluriparous lactating Holstein cows: digestive performance during early lactation.J. Dairy Sci. 1985; 68: 1995
- Utilization of three maturities of alfalfa by dairy cows fed rations mat contain similar concentrations of fiber.J. Dairy Sci. 1989; 72: 2301
Mertens, D. R. 1973. Application of theoretical mathematical models to cell wall digestion and forage intake in ruminants. PhD. Diss., Cornell Univ., Ithaca, NY.
- Fiber content and nutrient density in dairy rations.Proc. Dist. Feed Conf. (Cincinnati, OH). 1980; 35: 35
- Using neutral detergent fiber to formulate dairy rations and estimate the energy content of forages.in: Proc. Cornell Nutr. Conf. Feed Manuf. Cornell Univ., Syracuse, NY1983: 60
- Predicting intake and digestibility using mathematical models of ruminal function.J. Anim. Sci. 1987; 64: 1548
- Net energy value of feeds for lactation.J. Dairy Sci. 1972; 55: 945
- Nutrient requirements of dairy cattle.5th rev. ed. Natl. Acad. Sci., Washington, DC1978
- Nutrient requirements of dairy cattle.6th rev. ed. Nad. Acad. Press, Washington, DC1989 (update)
SAS® User's Guide: Statistics, Version 5 Edition. 1985. SAS Inst, Inc., Cary, NC.
- Symposium on factors influencing the voluntary intake of herbage by ruminants: voluntary intake in relation to chemical composition and digestibility.J. Anim. Sci. 1965; 24: 834
- Development of a comprehensive system of feed analyses and its application to forages.J. Anim. Sci. 1967; 26: 119
- Nutritional ecology of the ruminant.O & B Books, Inc., Corvallis, OR1982
- Regulation of forage intake in ruminants.in: Proc. Trilateral workshop: forage legumes for energy-efficient animal production, Palmerston, NZ1984: Page 233
- Physical parameters of fiber affecting passage from the rumen.J. Dairy Sci. 1986; 69: 2750
Article info
Publication history
Accepted:
October 26,
1990
Received:
August 6,
1990
Identification
Copyright
© 1991 American Dairy Science Association. Published by Elsevier Inc.
User license
Elsevier user license | How you can reuse 
Elsevier's open access license policy
Elsevier user license
Permitted
For non-commercial purposes:
- Read, print & download
- Text & data mine
- Translate the article
Not Permitted
- Reuse portions or extracts from the article in other works
- Redistribute or republish the final article
- Sell or re-use for commercial purposes
Elsevier's open access license policy
