ENV007
Development of a Dynamic Model of Ca and P flows in Layers

Principal Investigator: James France, University of Guelph

Co-investigators: Steve Leeson, University of Guelph, E. Kebreab, University of Manitoba

Funding: $60,180 (CPRC $20,060, NSERC/AAFC $40,120)
Start date: November 2005
Expected end: October 2007
Interim report received: July 31, 2006
Final report received: January 30, 2008
Status: complete

Background:
The main objective of this project was to develop a mathematical model to describe and predict calcium (Ca) and phosphorus (P) flows in layer chickens. A functional model would help industry (producers, nutritionists etc.) make dietary and management decisions to optimize Ca intake and reduce P excretion in manure. This process has the potential economic impact of saving dietary input costs while maximizing layer productivity and will help mitigate the environmental impact of commercial layer production.

Research progress:
The first step in this project was to perform a literature review to collect relevant data regarding the interactions of Ca and P in layers. Data collected were entered into a database that was used to develop a model of Ca and P flow in layers. Using data from the literature, the research team was able to enter variables into the model and accurately predict outcomes that matched those measured in real experiments. There were few data representative of Canadian field conditions in the literature, however, so the model was not tested as vigorously as the research team hoped. Based on tests that were performed, it is anticipated that the model will serve as a useful tool to help the industry adjust layer diets and make management decisions that will optimize Ca intake and minimize P excretion in layer manure.

Publications:
Kebreab, E., J. Dijkstra, R. P. Kwakkel, S. Leeson, H. Darmani Kuhi, R. S. Diaz and J. France. 2008 Development and evaluation of a dynamic model of calcium and phosphorus metabolism in layers. Submitted to J. Poultry Science.

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