Biomathematics Unit

University of Pennsylvania School of Veterinary Medicine | 382 West Street Road Kennett Square, PA 19348 | Phone: 610.444.5800

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Current Projects

CPM-Dairy 16 and 32 bit versions

CPM-Dairy version 1.0

Dairy cattle rations are evaluated and formulated by computer driven models. Nutrition models vary in complexity according to objectives. Models only need details that have significant bearing on consequences of
changes arising from inputs to the system (Production Model) or as much detail as is necessary to explore the system in new and different ways
(Scientific Model).

A theme for the development, refinement and deployment of production models is seen in the development and implementation of National Research Council (NRC) dairy cow models. NRC was based on responses equations used to predict crude protein and energy needs of the dairy cow. NRC proposed a system of protein utilization that partitioned dietary protein into rumen degradable (DIP) and rumen undegradable (UIP) fractions. Growth of microorganisms in the rumen was driven by energy intake (TDN, NEL). The NRC protein system was incorporated into the NRC dairy cow model.

Ration formulation tools were not provided by NRC. Rations were formulated by specifying details of the animal and rations were created by manual selection of ingredients to provide required nutrients. To reduce
the hunting and pecking burden imposed to meet the nutrient needs of animals and incorporate cost containment in ration formulation, linear optimization was integrated into the formulation environment. At the
University of Pennsylvania, NRC was programmed into Lotus 1-2-3 with auto-balancing provided by Einfin. Spartan represented an excellent effort in software development by the group at Michigan State University that was based on NRC and included auto-balancing.

The need for more accurate models to define rumen bacterial and whole animal requirements, to assess feed utilization and to predict production responses lead to the development of Cornell Net Carbohydrate and
Protein System (CNCPS). CNCPS contains sub-models to describe inputs (animal, environment and ration) and calculate digestion (rumen and intestine), nutrient (energy, protein and essential amino acid) metabolism and requirements, ration evaluation and nitrogen balance.

CPM-Dairy is programmed in Microsoft C. Rations are evaluated and formulated according to a modified NRC model (MNRC ) and to an up-dated version 3 of the Cornell Net Carbohydrate and Protein System (CNCPS).