Cookies on CAB eBooks

Like most websites we use cookies. This is to ensure that we give you the best experience possible.

 

Continuing to use www.cabi.org  means you agree to our use of cookies. If you would like to, you can learn more about the cookies we use.

CAB eBooks

Ebooks on agriculture and the applied life sciences from CAB International

CABI Book Chapter

Nutrient digestion and utilization in farm animals: modelling approaches.

Book cover for Nutrient digestion and utilization in farm animals: modelling approaches.

Description

This book contains 34 chapters on nutrition physiology and presents scientific research in modelling nutrient digestion and utilization in domestic animals, including cattle, sheep, pigs, poultry and fishes. It is divided into 6 parts that cover fermentation, absorption and passage; growth and development; mineral metabolism; methodology and model development; environmental impacts and animal prod...

Metrics

Chapter 20 (Page no: 211)

Estimating the risk of hypomagnesaemic tetany in dairy herds.

A model of magnesium dynamics in sheep has been adapted and improved as part of a programme to develop a tool that will assist dairy farmers to assess the risk of animals in a milking herd suffering from hypomagnesaemic tetany. The terms in the model for hindgut absorption have been altered to better represent the process of magnesium absorption and secretion in this region of the gastrointestinal tract, a term representing lactation has been introduced and the equation for urinary magnesium flux has been altered so that it no longer saturates at high plasma magnesium concentrations. Because the concentration of magnesium in cerebrospinal fluid (CSF) is strongly related to the onset of tetany, we have introduced a CSF compartment. We have also made allowance for diurnal feeding patterns. The improved model, scaled to represent dairy cattle, gives good agreement with a published experiment in which plasma and CSF magnesium concentrations were measured in animals on a magnesium-deficient diet. To obtain an estimate of the risk of tetany, we included diurnal feeding patterns and information about animal variation in the model parameters and carried out Monte Carlo simulations. If at any time during a simulation run the value of the magnesium concentration in CSF were less than 0.6 mmol/l, the simulation was assumed to represent an animal at risk. With sufficient simulations we obtained an estimate of the risk of tetany for a herd as a whole. A sensitivity measure was used to determine which parameters significantly affected magnesium concentration in CSF and hence the importance of knowing their distributions. To make the risk estimate more specific to the herd under investigation, we calibrated the model using herd samples of milk and estimated urine magnesium flux. As the latter is a model output, a fitting procedure was required to use this information to improve the estimates of the sensitive model parameters. Although we have initially used a very simplistic fitting procedure, the calibrated model gave very reasonable estimates of risk.

Other chapters from this book

Introduction Introduction: history, appreciation and future focus. Author(s): France, J.
Chapter: 1 (Page no: 1) The Nordic dairy cow model, Karoline - development of volatile fatty acid sub-model. Author(s): Sveinbjörnsson, J. Huhtanen, P. Udén, P.
Chapter: 2 (Page no: 15) A three-compartment model of transmembrane fluxes of valine across the tissues of the hindquarters of growing lambs infected with Trichostrongylus colubriformis. Author(s): Roy, N. C. Bermingham, E. N. McNabb, W. C.
Chapter: 3 (Page no: 28) Using rumen degradation model to evaluate microbial protein yield and intestinal digestion of grains in cattle. Author(s): Paengkoum, P.
Chapter: 4 (Page no: 33) Simulation of rumen particle dynamics using a non-steady state model of rumen digestion and nutrient availability in dairy cows fed sugarcane. Author(s): Collao-Saenz, E. A. Bannink, A. Kebreab, E. France, J. Dijkstra, J.
Chapter: 5 (Page no: 40) Modelling fluxes of volatile fatty acids from rumen to portal blood. Author(s): Nozière, P. Hoch, T.
Chapter: 6 (Page no: 48) The role of rumen fill in terminating grazing bouts of dairy cows under continuous stocking. Author(s): Taweel, H. Z. Tas, B. M. Tamminga, S. Dijkstra, J.
Chapter: 7 (Page no: 54) Functions for microbial growth. Author(s): López, S. Prieto, M. Dijkstra, J. Kebreab, E. Dhanoa, M. S. France, J.
Chapter: 8 (Page no: 69) Obtaining information on gastric emptying patterns in horses from appearance of an oral acetaminophen dose in blood plasma. Author(s): Cant, J. P. Walsh, V. N. Geor, R. J.
Chapter: 9 (Page no: 84) A model to evaluate beef cow efficiency. Author(s): Tedeschi, L. O. Fox, D. G. Baker, M. J. Long, K. L.
Chapter: 10 (Page no: 99) Prediction of energy requirement for growing sheep with the Cornell Net Carbohydrate and Protein System. Author(s): Cannas, A. Tedeschi, L. O. Atzori, A. S. Fox, D. G.
Chapter: 11 (Page no: 114) Prediction of body weight and composition from body dimension measurements in lactating dairy cows. Author(s): Yan, T. Agnew, R. E. Mayne, C. S. Patterson, D. C.
Chapter: 12 (Page no: 121) Relationships between body composition and ultrasonic measurements in lactating dairy cows. Author(s): Agnew, R. E. Yan, T. Patterson, D. C. Mayne, C. S.
Chapter: 13 (Page no: 127) Empirical model of dairy cow body composition. Author(s): Martin, O. Sauvant, D.
Chapter: 14 (Page no: 135) Simulating chemical and tissue composition of growing beef cattle: from the model to the tool. Author(s): Hoch, T. Pradel, P. Champciaux, P. Agabriel, J.
Chapter: 15 (Page no: 144) Representation of fat and protein gain at low levels of growth and improved prediction of variable maintenance requirement in a ruminant growth and composition model. Author(s): Oltjen, J. W. Sainz, R. D. Pleasants, A. B. Soboleva, T. K. Oddy, V. H.
Chapter: 16 (Page no: 160) Growth patterns of Nellore vs British beef cattle breeds assessed using a dynamic, mechanistic model of cattle growth and composition. Author(s): Sainz, R. D. Barioni, L. G. Paulino, P. V. Valadares Filho, S. C. Oltjen, J. W.
Chapter: 17 (Page no: 171) A kinetic model of phosphorus metabolism in growing sheep. Author(s): Dias, R. S. Roque, A. R. Nascimento Filho, V. F. Vitti, D. M. S. S. Bueno, I. C. S.
Chapter: 18 (Page no: 180) Dynamic simulation of phosphorus utilization in salmonid fish. Author(s): Hua, K. Cant, J. P. Bureau, D. P.
Chapter: 19 (Page no: 192) Development of a dynamic model of calcium and phosphorus flows in layers. Author(s): Dijkstra, J. Kebreab, E. Kwakkel, R. P. France, J.
Chapter: 21 (Page no: 229) Modelling the effects of environmental stressors on the performance of growing pigs: from individuals to populations. Author(s): Wellock, I. J. Emmans, G. C. Kyriazakis, I.
Chapter: 22 (Page no: 242) Empirical modelling through meta-analysis vs mechanistic modelling. Author(s): Sauvant, D. Martin, O.
Chapter: 23 (Page no: 251) Iterative development, evaluation and optimal parameter estimation of a dynamic simulation model: a case study. Author(s): Barioni, L. G. Oltjen, J. W. Sainz, R. D.
Chapter: 24 (Page no: 257) Segmented, constrained, non-linear, multi-objective, dynamic optimization methodology applied to the dairy cow ration formulation problem. Author(s): Boston, R. C. Hanigan, M. D.
Chapter: 25 (Page no: 275) A model to simulate the effects of different dietary strategies on the sustainability of a dairy farm system. Author(s): Prado, A. del Scholefield, D. Brown, L.
Chapter: 26 (Page no: 281) Advantages of a dynamical approach to rumen function to help to resolve environmental issues. Author(s): Bannink, A. Dijkstra, J. Kebreab, E. France, J.
Chapter: 27 (Page no: 299) Evaluation of models to predict methane emissions from enteric fermentation in North American dairy cattle. Author(s): Kebreab, E. France, J. McBride, B. W. Odongo, N. Bannink, A. Mills, J. A. N. Dijkstra, J.
Chapter: 28 (Page no: 314) Investigating daily changes in food intake by ruminants. Author(s): Dryden, G. M.
Chapter: 29 (Page no: 328) An ingredient-based input scheme for Molly. Author(s): Hanigan, M. D. Bateman, H. G. Fadel, J. G. McNamara, J. P. Smith, N. E.
Chapter: 30 (Page no: 349) Metabolic control: improvement of a dynamic model of lactational metabolism in early lactation. Author(s): McNamara, J. P.
Chapter: 31 (Page no: 366) Rostock feed evaluation system - an example of the transformation of energy and nutrient utilization models to practical application. Author(s): Chudy, A.
Chapter: 32 (Page no: 383) The Nordic dairy cow model, Karoline - description. Author(s): Danfær, A. Huhtanen, P. Udén, P. Sveinbjörnsson, J. Volden, H.
Chapter: 33 (Page no: 407) The Nordic dairy cow model, Karoline - evaluation. Author(s): Danfær, A. Huhtanen, P. Udén, P. Sveinbjörnsson, J. Volden, H.
Chapter: 34 (Page no: 416) A composite model of growth, pregnancy and lactation. Author(s): Vetharaniam, I. Davis, S. R.

Chapter details

  • Author Affiliation
  • Animal and Veterinary Sciences Group, Lincoln University, Canterbury 8152, New Zealand.
  • Year of Publication
  • 2006
  • ISBN
  • 9781845930059
  • Record Number
  • 20063093905