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Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only Publication Acceptance Date: 5/25/1995 Publication Date: N/A Citation: N/A Interpretive Summary: NA Technical Abstract: Support software was needed to synchronize alternatives for nutrition with genetic capabilities for particular ambient conditions. This simulation software presents in spreadsheet form results in graphical as well as tabular form. Input parameters describe genetically influenced performance potentials separately for a barrow and gilt in terms of mature e protein mass, appetite and minimum lipid to protein gain ratio plus protein and lipid mass for pigs of a specified age starting on the feeding program. Parameters describing schedule require starting and ending weights or ages for up to ten phase-feeding periods. Nutrition parameters describe rations for each of these periods as digestible energy density, ideal protein to digestible energy ratio, ideal protein to digestible protein ratio, palatability and feeding level. Ambient conditions are input as expected (or historical) daily temperatures. Two primary uses are intended 1) calibration of genetic parameters for each gender to experimental observations on growth and fatness, and 2) optimization of diet nutritional characteristics for calibrated genetic potentials and expected ambient conditions. Calibration for genetic differences uses nonlinear optimization to minimize a weighted sum of squares of deviations of observed values from model predictions. Optimization of diet for performance with ad lib feed consumption is accomplished by finding the ideal protein to digestible energy ratio for each period that makes deamination nonnegative for all days in the period. Experience with this model will also demonstrate principles used in the growth phase of the herd-level SPECIAL model. This support model will be known as PIGLET for Preliminary Investigation of Genetic, Logistic and Environmental Targets. |
