Model of Dairy Feed Nutrition

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Richard Dudley
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Location: Etna, New York, USA
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Model of Dairy Feed Nutrition

Post by Richard Dudley » Mon Oct 06, 2014 11:30 am

I thought that those of you interested in the application of system dynamics to real world problems might be interested in the dissertation recently completed by Ryan Higgs in Cornell's Department of Animal Science. About a year ago Higgs suggested I come over to look at the SD work he was doing but I never got around to that. When I contacted him last week I found that he had already completed his dissertation and had returned to New Zealand.

As I understand it, his work concerns the application of system dynamics modeling to the question of optimal feeding of dairy cattle. His dissertation involves, among other things, dynamic improvements to a long standing nutritional model called the Cornell net carbohydrate and protein system (CNCPS). It is my understanding that this is a commercially available (since the early 1990s) model that is used by dairy enterprises worldwide in order to optimize the nutrient uptake by dairy cattle, minimize costs, and minimize nutrient loss to manure, urine, and ultimately to agricultural runoff.

Specifically Higgs created "a new, dynamic version of the rumen and gastrointestinal submodel which was constructed in the system dynamics modeling software Vensim. The new model included, among other things, estimations of protozoal growth, endogenous N transactions along the entire gastrointestinal tract, a the new system to estimate N digestion in the small intestine."

Animals fed diets according to the new model performed significantly better than older versions of the model but I will let you read the dissertation to see the details. It is my understanding that the dynamic version of the models will be incorporated into the commercial software.

Ryan says that those interested in the pdf version of this dissertation or who have questions can contact at Ryan Higgs rjh257@cornell.edu . Ryan is currently working with Synlait Farms  http://www.synlaitfarms.co.nz .

Higgs, Ryan J. 2014. Development of a dynamic rumen and gastrointestinal model in the Cornell net carbohydrate and protein system to predicted the nutrient supply and requirements of dairy cattle. PhD dissertation. Cornell University. 291p.

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