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An evaluation of the Gompertz model in degradability studies of forage chemical components

Published online by Cambridge University Press:  02 September 2010

A. Lavrenčič ,
B. Stefanon  and
P. Susmel
A. Lavrenčič
Affiliation:
Zootechnical Department, University of Ljubljana, Groblje 3, SLO-1230 Domžale, Slovenija
B. Stefanon
Affiliation:
Department of Animal Production Science, University of Udine, Via San Mauro 2, 33010 Pagnacco (UD), Italy
P. Susmel
Affiliation:
Department of Animal Production Science, University of Udine, Via San Mauro 2, 33010 Pagnacco (UD), Italy
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Abstract

The in situ dry matter (DM) and neutral-detergent fibre (NDF) degradability kinetics of eight forages (four grass hays and four legume hays, harvested at two different dates) were compared to assess the fitting ability of a first-order and a Gompertz model.

The Gompertz model fitted DM degradability data as well as the first-order model and differences between fitted and observed data for the two models were very small but the Gompertz model proved to be statistically superior for the NDF degradability data, especially for the early hours of incubation.

A numerical but not significant difference was observed in the estimated rapidly available fraction for DM and NDF, which zvas respectively lower (mean values 24·4 v. 27·8%) and higher (mean values 5·8 v. 1·8%) with the first-order model. More pronounced differences were observed for the estimates of total potential degradability of NDF, which were often significantly lower with the Gompertz model (average values for the eight forages 75·1 v. 72·3%;.

The sigmoidal shape of the Gompertz model was more biologically appropriate to describe the initial phases of NDF degradation and was thus applied to the cellulose and hemicellulose degradability data.

As the harvesting date progressed through the season, a decrease of the immediately available fraction of DM and nitrogen was generally observed but the effect of harvesting date was not so evident for fibre fractions; the differences within forages were very low. Correlation coefficients between lignin content and total potential degradability of fibre were always high (for NDF, r = −0·96; for hemicellulose r = −0·95; for cellulose r = −0·79; P < 0·001), while the acid-detergent fibre content influenced DM and nitrogen total potential degradability (r = −0·91 and −0·82, respectively).

Keywords

fibremathematical modelsnitrogenrumen degradability
Type
Research Article
Information
Animal Science , Volume 64 , Issue 3 , June 1997 , pp. 423 - 431
Copyright
Copyright © British Society of Animal Science 1997

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References

Akin, D. E. and Chesson, A. 1989. Lignification as the major factor limiting forage feeding value especially in warm conditions. Fifteenth international grassland Nice, France, pp. 1753–1760. INRA, Paris.Google Scholar
Association of Official Analytical Chemists. 1990. Official methods of analysis, 15th edition. Association of Official Analytical Chemists, Washington, DC.Google Scholar
Babnik, D. 1995. Some environmental effects on the relationship between in sacco degradability of protein and dry matter and chemical composition of Italian ryegrass. Archives of Animal Nutrition 48: 303–317.Google Scholar
Balde, A. T., Vandersall, J. H., Erdman, R. A., Reeves, J. B. and Glenn, B. P. 1993. Effect of stage of maturity of alfalfa and orchardgrass on in situ dry matter and crude protein degradability and amino acid composition. Animal Feed Science and Technology 44: 29–43.CrossRefGoogle Scholar
Beuvink, J. M. W. and Kogut, K. 1993. Modelling gas production kinetics of grass silages incubated with buffered ruminal fluid. Journal of Animal Science 71: 1041–1046.CrossRefGoogle ScholarPubMed
Bidlack, J. E. and Buxton, D. R. 1992. Content and deposition rates of cellulose, hemicellulose, and lignin during regrowth of forage grasses and legumes. Canadian Journal of Plant Science 72: 809–818.CrossRefGoogle Scholar
Brink, G. E. and Fairbrother, T. E. 1994. Cell wall composition of diverse clovers during primary spring growth. Crop Science 34: 1666–1671.CrossRefGoogle Scholar
Buxton, D. R. 1989. In vitro digestion kinetics of temperate perennial forage legume and grass stems. Crop Science 29: 213–219.CrossRefGoogle Scholar
Buxton, D. R. and Brasche, M. R. 1991. Digestibility of structural carbohydrates in cool-season grass and legume forages. Crop Science 31: 1338–1345.CrossRefGoogle Scholar
Chesson, A. 1993. Mechanistic models of forage cell wall degradation. In Forage cell wall structure and digestion (ed Jung, H. G., Buxton, D. R., Hatfield, R. D. and Ralph, J.), pp. 347–376. American Society of Agronomy, Madison, WI.Google Scholar
Cockburn, J. E., Dhanoa, M. S., France, J. and Lopez, S. 1993. Overestimation of solubility by polyester bag methodology. Animal Production 56: 466–467 (abstr.).Google Scholar
Commissione proteine nella nutrizione e nella alimentazione dei poligastrici. 1994. Valutazione degli alimenti di interesse zootecnico. 3. Degradabilita e valore proteico degli alimenti per ruminanti. Zootecnica e Nutrizione Animale 20: 281–291.Google Scholar
Ford, C. W. and Elliott, R. 1987. Biodegradability of mature grass cell walls in relation to chemical composition and rumen microbial activity. Journal of Agricultural Science, Cambridge 108: 201–209.CrossRefGoogle Scholar
France, J. and Thornley, J. H. M. 1984. Growth functions. In Mathematical models in agriculture, pp. 75–94. Butterworths, London.Google Scholar
Giger-Reverdin, S. 1995. Review of the main methods of cell wall estimation: interest and limits for ruminants. Animal Feed Science and Technology 55: 295–334.Google Scholar
Goering, H. K. and Van Soest, P. J. 1970. Forage fiber analyses (apparatus, reagents, procedures and some applications). Agricultural handbook no. 379, ARS, USDA, Washington, DC.Google Scholar
Hoffman, P. C., Sievert, S. J., Shaver, R. D., Welch, D. A. and Combs, D. K. 1993. In situ dry matter, protein, and fiber degradation of perennial forages. Journal of Dairy Science 76: 2632–2643.Google Scholar
Iiyama, K., Lam, T. B. T. and Stone, B. A. 1994. Covalent cross-links in the cell wall. Plant Physiology 104: 315–320.CrossRefGoogle ScholarPubMed
Institut National de la Recherche Agronomique. 1988. Alimentation des bovins, ovins et caprins (ed. Jarrige, R.). INRA, Paris.Google Scholar
McDonald, I. 1981. A revised model for the estimation of protein degradability in the rumen. Journal of Agricultural Science, Cambridge 96: 251–252.Google Scholar
Nocek, J. E. and Russell, J. B. 1988. Protein and energy as an integrated system. Relationship of ruminal protein and carbohydrate availability to microbial synthesis and milk production. Journal of Dairy Science 71: 2070–2107.CrossRefGoogle Scholar
Ørskov, E. R. and McDonald, I. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. Journal of Agricultural Science, Cambridge 92: 499–503.CrossRefGoogle Scholar
Sauvant, D., Bertrand, D. and Giger, S. 1985. Variations and prevision of the in sacco dry matter digestion of concentrates and by-products. Animal Feed Science and Technology 13: 7–23.CrossRefGoogle Scholar
Statistical Analysis Systems Institute. 1988. SAS/STAT user's guide, release 6·03 edition. SAS Institute Inc., Cary, NCGoogle Scholar
Van Milgen, J. and Baumont, R. 1995. Models based on variable fractional digestion rates to describe ruminal in situ digestion. British Journal of Nutrition 73: 793–807.CrossRefGoogle ScholarPubMed