Hostname: page-component-586b7cd67f-l7hp2 Total loading time: 0 Render date: 2024-12-01T00:01:54.390Z Has data issue: false hasContentIssue false
  • English
  • Français

Prediction of the voluntary intake of grass silages by beef cattle. 2. Principal component and ridge regression analyses

Published online by Cambridge University Press:  02 September 2010

A. J. Rook ,
M. S. Dhanoa  and
M. Gill
A. J. Rook
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
M. S. Dhanoa
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
M. Gill
Affiliation:
AFRC Institute for Grassland and Animal Production, Hurley, Maidenhead SL6 5LR
Get access

Abstract

Data on individually recorded silage intake (SDMI), concentrate intake and live weight of steers and data on silage composition including toluene dry matter, pH, total nitrogen, ammonia nitrogen, volatile fatty acids, digestibility and fibre measures obtained from experiments at three sites were used.

Correlation and principal component analyses indicated that there was severe collinearity among a number of the variables, particularly among various fermentation characteristics, between different measures of digestibility and between different measures of fibre. This collinearity was shown to have caused instability in least-squares multiple regression coefficients of silage intake on other variables previously obtained from the same data (Rook and Gill, 1990). Principal component regression and ridge regression allowed the derivation of new coefficients which were more stable and more in line with a priori expectations from experimental results. Linear functions of the original variables and the use of models containing fewer variables also proved effective in overcoming the problems of collinearity.

Fermentation characteristics were shown to be the most important silage factors affecting intake and butyric acid was shown to be more important than other volatile fatty acids or ammonia nitrogen. Neutral-detergent fibre was found to be better related to intake than other fibre or digestibility measures.

Keywords

beef cattleintakemathematical modelssilage
Type
Research Article
Information
Animal Production , Volume 50 , Issue 3 , June 1990 , pp. 439 - 454
Copyright
Copyright © British Society of Animal Science 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Chatterjee, D. and Price, B. 1977. Regression Analysis by Example. New York, Wiley.CrossRefGoogle Scholar
Ehle, F. R. and Stern, M. D. 1984. Physical and chemical variables influencing particle passage and size reduction. In Modeling Ruminant Nutrition and Metabolism (ed. Baldwin, R. L. and Bywater, A. C.), Proceedings of 2nd International Workshop, University of California, Davis, pp. 27–33.Google Scholar
Fkarn, T. 1983. A misuse of ridge regression in the calibration of a near infrared reflectance instrument. Applied Statistics 32: 73–79.Google Scholar
Hoerl, A. E. and Kennard, R. W. 1970a. Ridge regression: biased estimation for nonorthogonal problems. Technometrics 12: 55–67.CrossRefGoogle Scholar
Hoerl, A. E. and Kennard, R. W. 1970b. Ridge regression: application to nonorthogonal problems. Technomelrics 12: 69–82.CrossRefGoogle Scholar
Mertens, D. R. 1985. Effect of fibre on feed quality for dairy cows. Proceedings of the 46th Minnesota Nutrition Conference, pp. 209–224.Google Scholar
Morgan, D. J. and L'Estrange, J. L. 1977. Voluntary feed intake and metabolism of sheep when lactic acid is administered in the feed or intraruminally. Journal of the British Grassland Society 32: 217–224.CrossRefGoogle Scholar
Morrison, I. M. 1980. Changes in the lignin and hemicellulose concentrations of ten varieties of temperate grasses with increasing maturity. Grass and Forage Science 35: 287–293.CrossRefGoogle Scholar
Petchey, A. M. and Broadbent, P. J. 1980. The performance of fattening cattle offered barley and grass silage in various proportions either as discrete feeds or as a complete diet. Animal Production 31: 251–257.Google Scholar
Rohr, K. and Thomas, C. 1984. Intake, digestibility and animal performance. In Eurowilt. Efficiency of Silage Systems: a Comparison between Wilted and Unwilted Silages (ed. E. Zimer and R. J. Wilkins), Landbauforschung Volkenrode, Sonderheft 69, pp. 64–70.Google Scholar
Rook, A. J., Dhanoa, M. S. and Gill, M. 1990. Prediction of the voluntary intake of grass silage by beef cattle. 3. Precision of alternative prediction models. Animal Production 50: 455–466.Google Scholar
Rook, A. J. and Gill, M. 1990. prediction of the voluntary intake of grass silages by beef cattle. 1. Linear regression analyses Animal Production 50: 425–438.Google Scholar
Simkins, K. L., Suttie, J. W. and Baumgardt, B. R. 1965. Regulation of food intake in ruminants. 4. Effect of acetate, propionate, butyrate and glucose on voluntary food intake in dairy cattle. Journal of Dairy Science 48: 1635–1642.CrossRefGoogle Scholar
Steen, R. W. J. 1984. A comparison of two-cut and three-cut systems of silage making for beef cattle using two cultivars of perennial ryegrass. Animal Production 38: 171–179.Google Scholar
Thomas, C., Gill, M. and Austin, A. R. 1980. The effect of supplements of fishmeal and lactic acid on voluntary intake of silage by calves. Grass and Forage Science 35: 275–279.CrossRefGoogle Scholar
Ulyatt, M. J. 1965. The effects of intra-ruminal infusions of volatile fatty acids on food intake of sheep. New Zealand Journal of Agricultural Research 8: 397–408.CrossRefGoogle Scholar
Van soest, P. J. 1982. Nutritional Ecology of the Ruminant. O and B Books, Corvallis.CrossRefGoogle Scholar
Vinod, H. D. 1976. Application of new ridge regression methods to a study of Bell system scale economics. Journal of the American Statistical Association 71: 835–841.CrossRefGoogle Scholar
Wilkins, R. J. 1984. A review of the effects of wilting on the composition and feeding values of silages. In Eurowilt. Efficiency of Silage Systems: a Comparison between Wilted and Unwilted Silages (ed. Zimmer, E. and Wilkins, R. J.), Landbauforschung Volkenrode, Sonderheft 69, pp. 5–12.Google Scholar
Wilkins, R. J. and Zimmer, E. 1984. Summary andconclusions. In Eurowilt. Efficiency of Silage Systems: a Comparison between Wilted and Unwilted Silages (ed. Zimmer, E. and Wilkins, R. J.), Landbauforschung Volkenrode, Sonderheft 69, 71-72.Google Scholar
Wilkinson, J. M., Chapman, P. F., Wilkins, R. J. and Wilson, R. F. 1981. Interrelationships between pattern of fermentation during ensilage and initial crop composition. Proceedings of the 14th International Grassland Congress, Lexington, pp. 631–634.Google Scholar
Woolford, M. K. 1984. The Silage Fermentation. Marcel Dekker, New York.Google Scholar
Zimmer, E. 1966. Die Neufassung des Garfutterschlussels nach Fleig. Wirtschaftseigene Futter 3: 299–303.Google Scholar