InraPorc: A model and decision support tool for the nutrition of sows

From results obtained over the last 20 years on energy and amino acid utilisation in reproductive sows, it has become possible to improve the determination of nutrient requirements (factorial approach) and the prediction of an animal’s response to nutrient supplies (modelling). The objective of this project was to integrate the current state of knowledge in a nutritional model for growing pigs and for sows and make it available as a software tool to end-users, mainly nutritionists involved in the pig industry and students in animal nutrition. The aim of this paper is to describe the basis of the sow model. The sow is represented as different compartments that change over the reproductive cycle. Nutrient flows considered are those of energy and digestible amino acids. Nutrients are used with the highest priority for maintenance and uterine growth or milk production. Subsequently, deposition and/or mobilisation of body proteins and lipids are determined and used for estimating the changes in body weight and backfat thickness of the sow. A decision support tool was built from the set of equations given, with additional modules to describe animal’s characteristics and adjust some model parameters to account This paper is part of a special issue entitled “Mathematical Methods that Predict the Effects of Feed Characteristics on Animal Performance” guest edited by Essi Evans, Daniel Sauvant and Peter Udén. Abbreviations: ADGlitter, average daily weight gain of the litter during lactation; BT, backfat thickness; BW, body weight; EBW, empty body weight; dlact, duration of lactation; Emilk, energy in milk; ERc, energy retained in conceptus; ERmp and ERmf, energy retained as protein in maternal tissue as protein and fat, respectively; kc, efficiency of using ME for conceptus growth; kf, efficiency of using ME for lipid deposition; km, efficiency of using ME for milk production; kp, efficiency of using ME for protein deposition; kr, efficiency of using energy from body reserved for pregnancy; krm; efficiency of using energy from body reserves for milk production; LCT, lower critical temperature; LD, lipid deposition; LS, litter size; MEm, metabolisable energy for maintenance; ERm, energy from body reserves for milk production; Nmilk, nitrogen in milk; NR, retained nitrogen; NRc, retained nitrogen in conceptus; PD, protein deposition; PDmax, maximum protein deposition ∗ Corresponding author. Tel.: +33 223 48 50 00; fax: +33 223 48 50 80. E-mail address: [email protected] (J.-Y. Dourmad). 0377-8401/$ – see front matter © 2007 Published by Elsevier B.V. doi:10.1016/j.anifeedsci.2007.05.019 J.-Y. Dourmad et al. / Animal Feed Science and Technology 143 (2008) 372–386 373 for variations in genotypes and performance. This tool can be used to determine energy and amino acids requirements of sows according to production objectives, or to predict body composition changes according to a given feeding strategy. The use of the decision support tool is illustrated through some examples. © 2007 Published by Elsevier B.V.