The process of reproduction, from conception to weaning, can be considered as directed to buffer the developing progeny from nutritional distress (Oldham, 1991) and involves both homeostatic and homeorhetic controls of nutrient partitioning (Bauman and Currie, 1980). Reproductive problems, which may result in the reduction of sows productivity or early culling, are often related to extreme variations in body reserves (Dourmad et al., 1994), although body reserves should be considered more as an indicator of the risk for rather than as the real cause of problems. During pregnancy, sufficient body reserves must be built to compensate for the eventual nutritional deficit that may occur in the following lactation. However, these reserves should not be excessive in order to avoid the occurrence of farrowing problems that are typical for fat sows, or to impair feed intake after farrowing. During lactation, it is recommended to adapt nutritional supplies to requirements in order to maximise milk production and piglet\u2019s growth, and minimize reproductive problems of sows after weaning. Consequently, nutritional supplies to sows must be adapted to maintain body reserves in optimal condition all along their productive life and optimise their reproductive performance. On farm, this requires a precise adjustment of the feeding level and the feed composition according to the performance of sows but also to housing conditions, which may affect nutrient utilisation and voluntary feed intake. Experimental results obtained during the last 20 years on energy and amino acid utilization by the pregnant or lactating sow allow improvements in the determination of nutritional requirements according to a target performance (factorial approach), and to predict the response of the animal to nutrient supplies (modelling). Compared to growing pigs, only a few models have been published for sows (Williams et al., 1985; Dourmad, 1987; Pomar et al., 1991; Pettigrew et al., 1992; NRC, 1998), and most of these were research models. In this project, we have integrated the available information on nutrient utilisation by sows to build a decision support tool allowing a global approach to understanding sow nutrition and the associated performance. This decision support tool includes a simulation model that represents on a daily basis (dynamic) the utilisation of key nutrient pools (mechanistic) for a given sow (deterministic). The end-users of these decision support tools are mainly nutritionists involved in pig production and teachers and students in animal nutrition. The aim of the present paper is to describe the basis and the main principles of this tool, which is also available for download at http:\/\/www.rennes.inra.fr\/inraporc\/(INRA, 2006). 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 mobilization 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\u2019s characteristics and adjust some model parameters to account 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.<\/p>\n","protected":false},"excerpt":{"rendered":"
The process of reproduction, from conception to weaning, can be considered as directed to buffer the developing progeny from nutritional distress (Oldham, 1991) and involves both homeostatic and homeorhetic controls of nutrient partitioning (Bauman and Currie, 1980). Reproductive problems, which may result in the reduction of sows productivity or early culling, are often related to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[930],"tags":[1809,8882,580,640,10033,13816,4262,5117,1972,2472,4023,19644,6806,7486,23694,12670,27278,6104,5886,103,2851,6904,46,1594,925,108,20007,651,517,158,47,26989,25078,8516,15213,17553,6009,5683,6825,61,2897,7258,2781,25904,615,10859,14784,79,7545,63,22808,14,1635,126,33,16262,15416,19940,17743,27282,13636,23005,4168,2365,14980,20912,104,8077,96,16840,110,20911,4874,6053,24533,22992,1055,77,1301],"class_list":["post-4110","post","type-post","status-publish","format-standard","hentry","category-production","tag-acid","tag-al","tag-amino-acids","tag-animal","tag-arc","tag-ass","tag-backfat","tag-body-weight","tag-condition","tag-culling","tag-cycle","tag-dd","tag-decision-support-tool","tag-dha","tag-dir","tag-down","tag-energy","tag-equations","tag-farrow","tag-farrowing","tag-fat","tag-fee","tag-feed","tag-feed-composition","tag-feed-intake","tag-feeding","tag-gh","tag-growing-pig","tag-growing-pigs","tag-growth","tag-housing","tag-inra-porc-sow-model-dourmad-et-al","tag-inra-swine-nutritional-requirements","tag-inraporc","tag-inraporc-a-model-and-decision-support-tool-for-the-nutrition-of-sows","tag-inrapork","tag-integrated","tag-lactating","tag-lactating-sow","tag-lactation","tag-mating","tag-milk","tag-milk-production","tag-milk-production-of-sows","tag-model","tag-nat","tag-ness","tag-nutrition","tag-optimal","tag-performance","tag-pic","tag-pig","tag-pig-production","tag-piglet","tag-pigs","tag-pl","tag-pomar","tag-porc","tag-prod","tag-production","tag-project","tag-protein-requirements-pig","tag-requirement","tag-risk","tag-search","tag-some","tag-sow","tag-sow-nutrition","tag-sows","tag-sows-nutrition","tag-stress","tag-t","tag-tan","tag-use","tag-user","tag-van-dijk-et-al-2005-farrow","tag-variation","tag-weaning","tag-weight"],"_links":{"self":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/4110","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/comments?post=4110"}],"version-history":[{"count":0,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/posts\/4110\/revisions"}],"wp:attachment":[{"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/media?parent=4110"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/categories?post=4110"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/prairieswine.com\/rsc\/wp-json\/wp\/v2\/tags?post=4110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}