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CABI Book Chapter

Modelling nutrient utilization in farm animals.

Book cover for Modelling nutrient utilization in farm animals.

Description

This book presents edited and revised versions of papers presented at the Fifth International Workshop on Modelling Nutrient Utilization in Farm Animals, held at the University of Cape Town, Cape Town, South Africa, 25-28 October 1999. There are 31 chapters and 6 sections entitled ruminal metabolism, absorption and metabolism, growth and development, ruminant production in various situations, nutr...

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Chapter 22 (Page no: 289)

Challenge and improvement of a model of post-absorptive metabolism in dairy cattle.

We have been conducting research to improve quantitative descriptions of metabolism in lactating dairy cows depicted in an existing mechanistic, computer-assisted model. The objective was to challenge this model with data collected in in vivo and in vitro experiments on high-producing dairy cattle fed a range of energy. Cows that varied in genetic propensity for milk production and dietary fat intake were used. Dietary inputs, milk component outputs, body fat, nutrient concentrations in blood and maximal velocity and substrate sensitivity of adipose-tissue metabolic reactions were observed. The model simulated yields of milk components within 5% of observed means. Simulated lipid metabolism and accumulation of body fat were adequate in many situations; however, the model response to changes in energy intake was too sensitive. This inadequacy was especially noticeable in later lactation, when body fat accumulation was simulated to be too high. Lack of precision in longterm dynamic changes indicates inadequacy in parameters describing energy-utilizing reactions. This severe challenge of the model supports its functionality. The model can be used to test hypotheses concerning the relation of body fat and protein use to milk production. Current knowledge as depicted in the model would suggest that a wide range of body fat at calving does not change milk production or body protein loss for cows fed adequately. In simulations, decreasing body protein at calving decreases milk production, while increasing body protein results in a greater loss of body protein without altering milk production. Unknown variation in use of amino acids by muscles hinders our ability to predict milk protein responses to changes in nutrient intakes. Further experiments must be designed to determine utilization of nutrients in viscera, muscle and adipose tissue, and must encompass sufficient range in genetic ability, nutrient input and time to adequately describe the dynamic and integrated nature of metabolic reactions.

Other chapters from this book

Chapter: 1 (Page no: 11) The role of thermodynamics in controlling rumen metabolism. Author(s): Kohn, R. A. Boston, R. C.
Chapter: 2 (Page no: 25) Modelling lipid metabolism in the rumen. Author(s): Dijkstra, J. Gerrits, W. J. J. Bannink, A. France, J.
Chapter: 3 (Page no: 37) Towards a more accurate representation of fermentation in mathematical models of the rumen. Author(s): Nagorcka, B. N. Gordon, G. L. R. Dynes, R. A.
Chapter: 4 (Page no: 49) Simple allometric models to predict rumen feed passage rate in domestic ruminants. Author(s): Cannas, A. Soest, P. J. van
Chapter: 5 (Page no: 63) Ruminal metabolism of buffersoluble proteins, peptides and amino acids in vitro. Author(s): Udén, P.
Chapter: 6 (Page no: 73) Models to interpret degradation profiles obtained from in vitro and in situ incubation of ruminant feeds. Author(s): López, S. France, J. Dijkstra, J. Dhanoa, M. S.
Chapter: 7 (Page no: 87) Modelling production and portal appearance of volatile fatty acids in dairy cows. Author(s): Bannink, A. Kogut, J. Dijkstra, J. France, J. Tamminga, S. Vuuren, A. M. van
Chapter: 8 (Page no: 103) Modelling energy expenditure in pigs. Author(s): Milgen, J. van Noblet, J.
Chapter: 9 (Page no: 115) Aspects of modelling kidney dynamics. Author(s): Robson, B. Vlieg, M.
Chapter: 10 (Page no: 127) Evaluation of a representation of the limiting amino acid theory for milk protein synthesis. Author(s): Hanigan, M. D. France, J. Crompton, L. A. Bequette, B. J.
Chapter: 11 (Page no: 145) Multiple-entry urea kinetic model: effects of incomplete data collection. Author(s): Zuur, G. Russell, K. Lobley, G. E.
Chapter: 12 (Page no: 163) Evaluation of a growth model of preruminant calves and modifications to simulate shortterm responses to changes in protein intake. Author(s): Gerrits, W. J. J. Togt, P. L. van der Dijkstra, J. France, J.
Chapter: 13 (Page no: 175) Simulation of the development of adipose tissue in beef cattle. Author(s): Sainz, R. D. Hasting, E.
Chapter: 14 (Page no: 183) A simple nutrient-based production model for the growing pig. Author(s): Boisen, S.
Chapter: 15 (Page no: 197) Second-generation dynamic cattle growth and composition models. Author(s): Oltjen, J. W. Pleasants, A. B. Soboleva, T. K. Oddy, V. H.
Chapter: 16 (Page no: 211) Modelling interactions between cow milk yield and growth of its suckling calf. Author(s): Blanc, F. Agabriel, J. Sabatier, P.
Chapter: 17 (Page no: 227) A mechanistic dynamic model of beef cattle growth. Author(s): Hoch, T. Agabriel, J.
Chapter: 18 (Page no: 241) Modelling nutrient utilization in growing cattle subjected to short or long periods of moderate to severe undernutrition. Author(s): Witten, G. Q. Richardson, F. D.
Chapter: 19 (Page no: 253) An integrated cattle and crop production model to develop whole-farm nutrient management plans. Author(s): Tylutki, T. P. Fox, D. G.
Chapter: 20 (Page no: 263) Modelling nutrient utilization by livestock grazing semiarid rangeland. Author(s): Richardson, F. D. Hahn, B. D. Schoeman, S. J.
Chapter: 21 (Page no: 281) Using the cornell net carbohydrate and protein system model to evaluate the effects of variation in maize silage quality on a dairy farm. Author(s): Tylutki, T. P. Fox, D. G. McMahon, M. McMahon, P.
Chapter: 23 (Page no: 303) A rodent model of protein turnover to determine protein synthesis, amino acid channelling and recycling rates in tissues. Author(s): Johnson, H. A. Baldwin, R. L. Calvert, C. C.
Chapter: 24 (Page no: 317) Modelling relationships between homoeorhetic and homoeostatic control of metabolism: application to growing pigs. Author(s): Sauvant, D. Lovatto, P. A.
Chapter: 25 (Page no: 329) Model for the interpretation of energy metabolism in farm animals. Author(s): Chudy, A.
Chapter: 26 (Page no: 347) Linear models of nitrogen utilization in dairy cows. Author(s): Kebreab, E. Allison, R. Mansbridge, R. Beever, D. E. France, J.
Chapter: 27 (Page no: 353) Isotope dilution models for partitioning amino acid uptake by the liver, mammary gland and hindlimb tissues of ruminants. Author(s): Crompton, L. A. France, J. Bequette, B. J. Maas, J. A. Hanigan, M. D. Lomax, M. A. Dijkstra, J.
Chapter: 28 (Page no: 361) The conversion of a scientific model describing dairy cow nutrition and production to an industry tool: the CPM dairy project. Author(s): Boston, R. C. Fox, D. G. Sniffen, C. Janczewski, E. Munson, R. Chalupa, W.
Chapter: 29 (Page no: 379) The utilization of prediction models to optimize farm animal production systems: the case of a growing pig model. Author(s): Bailleul, P. J. dit Bernier, J. F. Milgen, J. van Sauvant, D. Pomar, C.
Chapter: 30 (Page no: 393) A pig model for feed evaluation. Author(s): Danfær, A.

Chapter details

  • Author Affiliation
  • Department of Animal Sciences and the Nutrition Program, Washington State University, Pullman, WA 99164-6351, USA.
  • Year of Publication
  • 2000
  • ISBN
  • 9780851994499
  • Record Number
  • 20083014704