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

Posted in: Production by admin on January 1, 2008 | No Comments

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’s 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’s 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.

Frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead and nonambulatory-noninjured pigs on arrival at the packing plant

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Four Midwestern packing plants (designated as plants A, B, C, and D) were visited on 53 occasions, and tissue samples were collected postmortem from a total of 2,019 pigs to determine the frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead (DOA), nonambulatory-noninjured (NANI), and normal animals. The mutation was present in all 3 classes of pig. There was a greater frequency of carriers in DOA animals than in the normal or NANI pigs. The 55 pigs that had at least 1 copy of the mutation came from 53 farms; therefore, the mutation was relatively widespread, being present in approximately 11% of the farms sampled. Therefore the data shows that the HAL-1843 mutation is still present in US commercial pig populations, it is low in frequency and therefore not a major cause of transport losses.

Optimized management of genetic variability in selected pig populations

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The results of this research showed the potential value of completing each periodical
calculation of estimated breeding value by optimizations considering genetic variability and
of releasing corresponding information to breeders, in order to enhance
maintenance of genetic variability.

Survey on Salmonella prevalence in slaughter pigs from Saskatchewan

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Organic acids in diets for entire male pigs: Effect on skatole level, microbiota in digesta, and growth performance

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Supplementing diets with formic acid, benzoic acid,
sorbic acid, or normal coated or inulin coated butyric
acid did not affect skatole or indole levels or organic
acid levels in colon of entire male pigs. Formic acid or
benzoic acid supplemented diets resulted in lower
plasma skatole levels than the control or the sorbic
acid supplemented diets. Adding formic acid, benzoic
acid, sorbic acid to diets for entire male pigs reduced
microbial population in the gastro-intestinal tract, but
this did not coincide with changes in skatole production
in the hind-gut.

Investment in swine research is money well spent

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Research has improved
feed efficiency by more
than five per cent over the
last 10 years, reducing feed
costs per market pig by
more than $3.50 – just one
example of the dividends
that flow from investment
in applied research

Effects of breed, sex and halothane genotype on fatty acid composition of triacylglycerols and phospholipids in pork longissimus muscle

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The two major types of lipids in the longissimus muscle (LM) are triacylglycerols (TAG) and phospholipids (PL). The objective of this study was to determine the effects of breed, sex and HAL-1843TM genotype on the fatty acid composition of TAG and PL in LM using purebred pigs fed the same diets. It was found that this report demonstrates that breed and sex were significantly associated with the content of TAG and with the fatty acid composition of
TAG and PL in LM. The HAL-1843TM genotype had minor effects on the concentrations of a few fatty acids in TAG and PL. These results suggest that the effects of breed and sex on fatty acid composition of LM observed in our previous study (Zhang et al. 2007) are the net results of the influences of breed and sex on TAG content and the impact of breed
and sex on TAG and PL fatty acid composition.

Factors affecting length of productive life in Swedish commercial sows

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The objective of this study was to investigate
factors that might influence the length of productive
life in Swedish crossbred (Landrace × Yorkshire)
sows. If was found that days after farrowing
was the main risk factor for sow removal. Removal
hazard was greatest shortly after weaning, and this
peak increased with greater parity number.

Genetic components of heat stress in finishing pigs: Parameter estimation

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This study describes the genetic variability of pig carcass weight as a function of heat stress. It was found that heritability for growth was greater under heat stress. Selection for crossbred performance would be optimal when data for periods both in the absence and presence of heat stress were considered.

Prediction of in vivo apparent total tract energy digestibility of barley in grower pigs using an in vitro digestibility technique

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The objective of this study was to establish and evaluate an in vitro digestibility technique to predict in vivo ATTD of energy of barley in grower pigs. It was concluded that the 3-step in vitro energy digestibility technique can accurately predict the ATTD of energy in barley in grower pigs. The 3-step in vitro digestibility technique, thus, might be useful as the reference laboratory procedure to calibrate analytical equipment to rapidly predict the ATTD
of energy in barley.