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Fiche PPA (fièvre porcine africaine)

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Depuis 10 ans, la fièvre porcine africaine s’étend géographiquement et est devenue européenne. Une vigilance toute particulière doit donc être accordée à cette maladie qui pénaliserait la filière porcine. Les porcs peuvent être contaminés par un contact direct avec des porcs infectés ou par ingestion de déchets alimentaires contenant de la viande de porc non transformée contaminée, ou des produits qui en sont issus. Les locaux contaminés, les véhicules, le matériel ou les vêtements peuvent aussi transmettre le virus à des animaux sensibles...

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2018

Développement de nouveaux outils haut débit pour l’évaluation précoce de la qualité de la viande de porc

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Visuels d'intervention présentés par Antoine Vautier, à la 7ème journée de restitution des programmes de R&D financés par le Casdar "Innovation et partenariat" et "Recherche finalisée et innovation", le 17 janvier 2018, Paris

PDF icon visuels de Antoine Vautier, journée CASDAR du 17 janvier 2018, Paris
2018

Bien-être animal en élevage : un challenge croissant ; de nouveaux leviers d’action. Labels « bien-être animal », des obligations de moyens aux indicateurs de résultat : exemples anglais et allemand

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Visuels d'intervention présentés par Christine Roguet, à Space 2018 (Les Matinales de l'Ifip), le 11-14 septembre 2018, Rennes

PDF icon Visuels de Christine Roguet, aux Matinales au Space IFIP, le 11-14 septembre 2018, Rennes
2018

Bien-être : placer l’éleveur au cœur du dispositif

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Visuels d'intervention présentés par Valérie Courboulay, à Space 2018 (Les Matinales de l'Ifip), le 11-14 septembre 2018, Rennes

PDF icon Visuels de Valérie Courboulay, Matinales au Space IFIP, le 11-14 septembre 2018, Rennes
2018

Porsim, outil web d’aide à la décision technique, économique et financière pour l’éleveur de porc

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Visuels d'intervention présentés par Alexia Aubry, à Space 2018 (Matinales de l'Ifip), le 11-14 septembre 2018, Rennes

PDF icon Visuels de Alexia Aubry, Matinales au Space IFIP, le 11-14 septembre 2018, Rennes
2018

Comment définir une « Bonne viande de porc » sur le plan organoleptique

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Visuels d'intervention présentés par Gilles Nassy, à Space 2018 (Matinales de l'Ifip), le 11-14 septembre 2018, Rennes

PDF icon Visuels de Gilles Nassy, Matinales au Space IFIP, le 11-14 septembre 2018, Rennes
2018

Ecology of Salmonella and antimicrobial resistance in a pig slaughterhouse

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Arnaud Bridier et al., Food Micro, 3-6 septembre 2018, Berlin, Allemagne et I3S, 24-26 septembre 2018, Saint-Malo, France

Salmonella is a bacterial pathogen responsible for a large number of food associated infections. In order to guarantee food safety, a better understanding of Salmonella ecology and adaptation strategies on the food production chain constitutes a prerequisite. In a One Health perspective, data on Salmonella antibiotic resistance in food environments are also crucial to decipher transmission routes of resistant foodborne pathogens as well as resistance genetic determinants involved, and the role of process and selection pressures underwent in food industries (as cleaning and disinfection) in bacterial adaptation and antimicrobial resistance emergence.
Using a pig slaughterhouse as a model food environment, occurrence of Salmonella was investigated at six different areas along the slaughter chain and through 4 sampling campaign, each time before and after cleaning and disinfection procedures (a total of 48 surface samples). Characterization of isolated Salmonella strains using serotyping and pulsotyping enabled to identify and trace persistent strains in the slaughterhouse. Minimal inhibiting concentrations (MIC) were also determined for various relevant antibiotics and for biocides used in the slaughterhouse. In addition, associated indigenous bacterial communities were characterized using 16S rRNA amplicon sequencing. 
Results revealed the presence of Salmonella at all sampling area. Five serotypes were identified: S.4,5,12:i:- (50%), Rissen (16%), Typhimurium (16%), Infantis (10%) and Derby (8%). Strains were found at different dates and potentially at the same sampling area suggesting they persist in the slaughterhouse despite of the cleaning and disinfection procedures. Approximately 70% of isolated Salmonella strains exhibit resistance to ampicillin and sulfamethoxazole, 80% to tetracycline and 10% to chloramphenicol. There was no evolution of CMI comparing strains before and after cleaning and disinfection procedures concerning both biocides and antibiotics. Bacterial diversity analyses showed that populations in slaughterhouse were highly dominated by &a1;-proteobacteria and especially by the Moraxellaceae family (genus Psychrobacter, Moraxella, Enhydrobacter and Acinetobacter) at the different sampling areas. Population compositions were overall stable in time at a given sampling area suggesting that the surface populations are resident populations within the slaughterhouse, rather than populations introduced each week by the new swine bands. Cleaning and disinfection procedures tend to reduce bacterial diversity by eliminating the minority species but did not greatly impact the composition of bacterial communities with regards to the dominant species.
Together, such data participate to the construction of a comprehensive view of Salmonella ecology in food environments integrating associated resident microbial flora and the distribution of antimicrobial resistance in relation to processing conditions.

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2018

Population genetic structure of Listeria monocytogenes strains isolated from the pig and pork meat production chain in France

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Benjamin Félix (Anses) et al., Food Micro, 3-6 septembre 2018, Berlin, Allemagne

Listeria monocytogenes is an ubiquitous pathogenic bacterium, transmissible to humans through the consumption of contaminated food. The pork production sector has been hit hard by a series of L. monocytogenes-related food poisoning outbreaks in France. An overview of the diversity of strains circulating at all levels of the pork production chain, from pig farming to finished food products, is needed to identify the contamination routes and improve food safety. Until now, no typing data has been available on strains isolated across the entire pig and pork production chain. 
Here, we analyzed the population genetic structure of 687 L. monocytogenes strains isolated over the last 20 years in virtually all the French départements from three compartments of this production sector: pig farming (PF), the food processing environment (FPE) and finished food products (FFP). The genetic structure was described based on MLST clonal complexes (CCs). The CCs were obtained by mapping the PFGE profiles of the strains. The distribution of CCs was compared firstly between the three compartments and then with CCs obtained from 1106 strains isolated from other food production sectors in France. 
The predominant CCs of pig and pork strains were not equally distributed among the three compartments: the CC37, CC59 and CC77 strains, rarely found in FPE and FFP, were prevalent in PF. The two most prevalent CCs in the FPE and FFP compartments, CC9 and CC121, were rarely or never detected in PF. No CC was exclusively associated with the pork sector. Three CCs (CC5, CC6, CC2) were considered ubiquitous, because they were observed in comparable proportions in all food production sectors. The two most prevalent CCs in all sectors were CC9 and CC121, but their distribution was disparate. CC9 was associated with meat products and food products combining several food categories, whereas CC121 was not associated with any given sector. Based on these results, CC121 is likely able to colonize a larger diversity of food products than CC9. Both CCs being associated with the food production suggests, that certain processing steps, such as slaughtering or stabilization treatments, favor their settlement and the recontamination of the food produced.

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2018

Global sensitivity analysis of a pig fattening unit model simulating technico-economic performance and environmental impacts

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Alice Cadéro et al., Agricultural Systems, volume 165, septembre, p. 221-229

Livestock farming system (LFS) models are used to produce key technical or economic outputs. Current models simulate multicriteria performance of LFS, i.e. technical, economic and environmental outputs. Therefore, conducting sensitivity analysis (SA) of these models is increasingly challenging. We developed a pig fattening unit model which is a stochastic, discrete-event mechanistic model with a one-day time step. An individual-based model is used to represent the pigs. Our objective was to perform a global SA of this model while accounting for effects of parameters on all outputs. Due to the model's long computational time, we first performed screening SA using the Morris method to identify and exclude non-influential parameters, and then performed variance-based SA of the influential parameters using metamodels. The most influential parameters were mainly pig characteristics and the disinfection period. This study provides a generic SA sequence adapted for models with a high computational cost and multiple outputs.

2018

Chemical and nutritional value of organic feedstuffs: A need to address in monogastric feeding

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A. Roinsard et al., 68th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018

As it is mandatory since January 2019 to feed organic pigs and poultry with 100% organic feeds in the EU, a better knowledge of the nutritional value of organic raw materials is, more than ever, a key for farmers to develop efficient nutrition systems for organic livestock farming. Studies are being conducted in the French CASDAR programme SECALIBIO to compare organic raw materials to conventional ones, to establish the composition and nutritional value of organic feeds, and to evaluate their variability. A database of 6,577 samples of 94 organic raw materials, most of them commonly used in monogastric feeding (soybean meals, maize, faba bean, etc.), was constituted using data from the French Feed Database of the AFZ, from previous research programmes and from feed companies participating in SECALIBIO. In vivo digestibility trials on pigs and poultry were conducted to evaluate the specificities of organic raw materials and provide new data (for forage peas for example). The variability of organic raw materials was generally comparable to that of conventional ones. However, the fat content of organic sunflower (6.2 to 25.2% MS) and soybean (5.37 to 22.6% MS) meals varied a lot due to processing technologies, and it was suggested to delineate categories with consistent crude protein and fibre content. In connection with it, for poultry, the digestibility of protein could vary a lot for sunflower (76.5-83.0%) and soybean (74.4-87.32%) meals.
Organic soybean meals was reported to have a lower lysine/crude protein ratio than the conventional one (5.75 vs 6.14%): further investigations will determine the impact of this difference on feed formulation. The first practical result of this study will be the creation of specific tables of composition and nutritional value of organic feeds for pigs and poultry which represents a key for farmers to develop an efficient nutrition system in organic farming.

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2018

Precision feeding with a decision support tool dealing with daily and individual pigs’ body weight

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Nathalie Quiniou (IFIP) Michel Marcon (IFIP) et Ludovic Brossard (INRA), 69h Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018 

Nutritionists, feed companies and equipment manufacturers look for solutions that help farmers to improve sustainability of pig production. Based on experimental results obtained in silico or in vivo, a better adequacy between amino acid supplies and requirements increases feed efficiency and farmer’s income and reduces the environmental impact of growing pigs, highlighting the interest for precision feeding. Data are collected to characterize daily animal traits (e.g. body weight, BW) and their variation from one day to another (e.g. growth rate, &‘6;BW). They are used to determine the requirement for maintenance and growth on the next day, respectively. Therefore, adequacy between requirements and supplies depends on these predicted BW and &‘6;BW. The double exponential smoothing (Holt-Winters) method with a smoothing parameter &”5;=0.6 (HW0.6), presents a low sensitivity to the number of latest values used to forecast BW. It seems to allow for a secured prediction of BW soon after the beginning of the growing phase (at least after 4 days). A group of pigs was used in restricted feeding conditions to compare results obtained either with a 2-phase feeding strategy, considered as the control treatment, or a precision feeding strategy based on BW forecasting with the HW0.6 method. Pigs allocated to both treatments were group-housed in the same pen, equipped with the decision support system built in the Feed-a-Gene project to manage the data, to determine in real-time the corresponding nutritional requirements, and to adapt the feed characteristics provided to each pig through the blend of two diets (9.75 MJ net energy/kg, 0.5 or 1.0 g of digestible lysine per MJ). Available results from 24 pigs per treatment indicate that overall average growth performance were not influenced by the feeding strategy (P>0.58 for both average daily gain and feed conversion ratio) but digestible lysine intake was reduced by 6% (1,774 vs 1,879 g, P<0.01) and N output by 7% (P<0.01) with precision feeding. Results will be completed by a second group using the same treatments. This study is part of the Feed-a-Gene project and received funding from the European Union’s H2020 program under grant agreement no. 633531.

PDF icon Nathalie Quiniou et al., 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018
2018

Relationship between age and body weight at farrowing over 6 parities in Large White × Landrace sow

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Nathalie Quiniou, 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018 

At the beginning of the gestation, parity and back fat (BT) thickness are frequently used by farmers to choose among different feeding plans the most adapted one to feed each sow if individual feeding is possible. Otherwise, BT is used to allocate the sows to one of the available pens and to adapt the feed allowance at the group level. Usually a single target of BT at farrowing is retained at the herd scale, and each sow is expected to make up its BT for the difference between the target and its own initial BT. According to the factorial approach used to assess nutrient requirements, achieving an expected BT gain implies that enough energy is supplied above maintenance. Based on equation published by Dourmad et al., expected energy retention is obtained by the difference between the initial (calculated from measured BT and BW) and the final amount of energy (calculated from expected BT and BW).
When no information is collected on BW during the gestation, the expected final BW is also used to assess daily BW and corresponding maintenance requirement and to take into account impacts of housing conditions (temperature, activity level). Then, adequacy of the energy supply depends not only on initial and final BT, but also on initial BW and final BW. Individual BW have been collected over successive parities in the IFIP facilities (n=6,288 from Large White × Landrace sows born since 2000). Data of 90 sows born between 2012 and 2015, studied over at least 6 parities and group-housed from the 28th to the 108th day of gestation, were used to characterize the relationship between age and BW after farrowing based on BW at the first farrowing (BW_P1) and BW gain afterwards, with BW at the 6th parity considered as the mature BW: BWi(Age), kg = 145.6 + 0.171 × Age_P1i+ 111.4 × (1 – exp(- 1.453/1000 × (Age-Age_P1i)1.084)), RMSEP=16 kg; with Age_P1i: the individual age at the first farrowing used to adjust the mean BW_P1. Based on this equation, the individual expected BW gain (both growth and recovering parts) can be calculated and, combined with BT gain, used to assess the corresponding energy requirement for precision feeding during gestation. Its calibration for other lines or farms will require specific measurements due to interactions with management.

PDF icon Nathalie Quiniou, 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018
2018

Relationship between age and body weight at farrowing over 6 parities in Large White × Landrace sow

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Nathalie Quiniou, 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018 

At the beginning of the gestation, parity and back fat (BT) thickness are frequently used by farmers to choose among different feeding plans the most adapted one to feed each sow if individual feeding is possible. Otherwise, BT is used to allocate the sows to one of the available pens and to adapt the feed allowance at the group level. Usually a single target of BT at farrowing is retained at the herd scale, and each sow is expected to make up its BT for the difference between the target and its own initial BT. According to the factorial approach used to assess nutrient requirements, achieving an expected BT gain implies that enough energy is supplied above maintenance. Based on equation published by Dourmad et al., expected energy retention is obtained by the difference between the initial (calculated from measured BT and BW) and the final amount of energy (calculated from expected BT and BW).
When no information is collected on BW during the gestation, the expected final BW is also used to assess daily BW and corresponding maintenance requirement and to take into account impacts of housing conditions (temperature, activity level). Then, adequacy of the energy supply depends not only on initial and final BT, but also on initial BW and final BW. Individual BW have been collected over successive parities in the IFIP facilities (n=6,288 from Large White × Landrace sows born since 2000). Data of 90 sows born between 2012 and 2015, studied over at least 6 parities and group-housed from the 28th to the 108th day of gestation, were used to characterize the relationship between age and BW after farrowing based on BW at the first farrowing (BW_P1) and BW gain afterwards, with BW at the 6th parity considered as the mature BW: BWi(Age), kg = 145.6 + 0.171 × Age_P1i+ 111.4 × (1 – exp(- 1.453/1000 × (Age-Age_P1i)1.084)), RMSEP=16 kg; with Age_P1i: the individual age at the first farrowing used to adjust the mean BW_P1. Based on this equation, the individual expected BW gain (both growth and recovering parts) can be calculated and, combined with BT gain, used to assess the corresponding energy requirement for precision feeding during gestation. Its calibration for other lines or farms will require specific measurements due to interactions with management.

PDF icon Nathalie Quiniou, 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018, visuels
2018

On the influence of host genetics on gut microbiota composition in pigs

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J. Estellé et al., 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018

Gut microbial population acts in complement with its host through nutrient digestion and health of the gastrointestinal tract. Changes in microbiota composition may then lead to changes in nutrient digestibility. The present study aimed at determining the effects of dietary fibre content on gut microbiota composition and apparent faecal nutrient digestibility in pigs. Furthermore, the relationships between microbiota and digestibility coefficients were investigated. Growing-finishing pigs (from 35 to 74 kg mean body weight) were fed alternatively a low-fibre (LF) and a high-fibre (HF) diet during 4 successive 3-week periods. Data collection for digestibility measurements was achieved during the last week of each period and faecal microbiota was collected at the end of each period for 16S rRNA gene sequencing. The two diets fed by the pigs could be discriminated using 31 predicting OTUs in a sparse partial least square discriminant analysis (mean classification error-rate 3.9%). Furthermore, microbiota was resilient to diet effect. Pearson correlations between microbiota composition and apparent digestibility coefficients of energy, protein, cellulose and hemicellulose emphasized the fact that in LF group, Clostridiaceae and Turicibacter were negatively correlated with protein and energy digestibility coefficients whereas Lactobacillus was positively correlated. In addition, Lachnospiraceae and Prevotella were negatively correlated with cell wall components digestibility. In HF diet, no significant correlation between microbiota and digestibility was found. The present study demonstrates that 3 weeks of adaptation to a new diet seem to be sufficient to observe resilience in growing pigs gut microbiota. In addition, faecal microbiota can be used to classify pigs according to their diet. Because some bacterial family and genera are favourable to digestibility, this study suggests that manipulations of bacterial populations can improve digestibility and feed efficiency. This study is part of the Feed-a-Gene Project, funded from the European Union’s H2020 Programme under grant agreement no. 633531.

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2018

Gut microbiota analyses for sustainable European local porcine breeds: A TREASURE pilot study

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J. Estellé et al., 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018

The study of gut microbiota and its effects on hosts has emerged as an essential component of host homeostasis and global efficiency. Besides host’s influence on gut microbiota, major quantitative and qualitative changes may occur in the composition of the intestinal microbiota due to the influence of diet and other environmental factors.
In accordance with the TREASURE project global aim of enhancing sustainability of production systems for local pig breeds, the objective of our task was to conduct a pilot characterisation of intestinal microbiota in order to test its usefulness to characterize several local European pig populations and their production systems. This approach has been applied to populations belonging to the following European traditional breeds: Gascon (France), Iberian (Spain), Krskopolje (Slovenia), Mangalitsa (Serbia), Moravka (Serbia) and Turopolje (Croatia). For each breed, faecal samples have been collected along different experiments performed in the TREASURE project targeting the comprehension of a particular traditional production system (e.g. open-air farming), management practice, or the comparison of breeds. In all experiments, the metagenomics technique employed is the re-sequencing of the bacterial 16S in an Illumina MiSeq system. Overall, the results have shown that the gut microbiota analysis is a promising approach for the characterisation of these local breeds, by allowing a deeper understanding of their production systems and potentially allowing the development of new certification approaches. Preliminary results will be summarized in this communication. Funded by European Union’s H2020 RIA program (Grant agreement no. 634476).

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2018

Integrating blood transcriptome and immunity traits to identify markers of immune capacity in pigs

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T. Maroilley et al., 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018

Understanding individual variability of immune capacity in livestock has become a priority to improve sustainability, with the aim to increase disease resistance and resilience in breeding programs. In this study, 550 60-day-old French Large White pigs vaccinated against Mycoplasma hyopneumoniae (M hyo) were monitored for 55 immunity traits (ITs) measured from blood samples (SUS_FLORA ANR funded project). The ITs included two types of parameters. First, parameters directly measured from blood: complete blood counts, counts of various cell subsets by flow cytometry, serum dosage of anti-M hyo IgG and haptoblobin. Second, parameters measured after in vitro stimulation of total blood: phagocytosis, production of cytokines (IL-1&”6;, IL-8, IL-10, IL-17, TNF&”5;, IFN&”7;) after stimulation by LPS or mitogenic agents. All animals were genotyped with 60K Illumina SNP chips. A subset of 243 piglets was chosen for blood transcriptome analysis using Agilent microarrays. We explored covariations between blood expression profiles and IT levels, and could draw lists of the most correlated genes with each IT. Each list represented candidate blood biomarkers potentially predictive of IT variations. As an example, we found 134 genes associated with phagocytosis capacity and we identified a subset of genes that could significantly predict levels of eight ITs related to phagocytosis by a sPLS approach. This gene subset included CXCR1, CCR1 and TLR2. Few candidate biomarkers were previously shown to be genetically controlled for their transcription in blood by eGWAS. Thus, our results provide new data to decipher the genetic architecture of IT variations. A next step will be to understand how IT variations could reflect individual robustness while facing pathogens, and how blood biomarkers could be used as predictors of immune capacity.

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2018

Retrospective by sex of the new EU lean meat content of pig carcasses

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Gérard Daumas, 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018, poster

A new EU regulation on carcass classification applies from July 2018. This regulation changes the definition of the reference lean meat percentage (LMP) which becomes the LMP in the carcass (from total dissection). Nevertheless, each Member State can choose when he will update its grading methods. The aim of this work is to simulate this change on the last 5 years in France for each sex.
Conversely to most of European countries sex is registered online in France during pig classification. Statistics per sex are regularly published by the regional classification organisations.
The production of entire males started in France in 2013 (13% of the males), increased quickly and is now stable (27% of the males in 2017), around 2.5 million a year. More than 95% of entire males are classified with the classification method CSB Image-Meater® (IM) approved by the EU in 2013. The present LMP prediction equation contains two fat depths (G3 and G4) and two muscle depths (M3 and M4).
A sample of 180 pigs was uniformly stratified on sex: 60 entire males, 60 females and 60 castrated males. All cuts were CT scanned allowing to calculate the LMP. Prediction equation was calculated by a general linear model including the 4 depths as well as the interactions with sex. The stepwise procedure by using BIC selected a model with 1 fat depth (G3) and 2 muscle depths (M3 and M4), G3 and M3 coefficients depending on sex. The RMSE was 2.15. Removal of M4 only decreased the RMSE of 0.01. The fat coefficient of entire males was more than twice that of females, while that of castrates was in the middle. Differences on M3 coefficient had lower impact on LMP.
The equation was applied on the annual classification averages from 2013 to 2017. In 4 years LMP increased, but differently according to sex: +0.11 for entire males, +0.25 for females and +0.34 for castrated males. In the same period the difference between entire and castrated males decreased from 4.02 to 3.79, while the difference between entire males and females decreased from 1.37 to 1.24.
When the Image-Meater method will be updated, it seems worthwhile to consider separate slopes for entire males, females and castrated males.

PDF icon Gérard Daumas, 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018, abstract, PDF icon Gérard Daumas, 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018, poster
2018

A pan-European computed tomography procedure for measuring the new EU lean meat content of pigs

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Gérard Daumas et Mathieu Monziols, 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018, poster

A new EU regulation on carcass classification applies from July 2018. The new reference to calibrate the pig classification methods is a lean meat percentage based on total dissection (LMPtd). Manual dissection can be replaced by an unbiased computed tomography (CT) procedure. If the national pig population to be sampled has the same characteristics as the population for which a CT procedure has been previously corrected, no additional dissection is required. In most of the national applications for authorisation of classification methods the population characteristics are managed via a stratification on a fat depth, mimicking the LMP variation.
The aim of this paper is to propose a pan-European CT procedure to calibrate the pig classification methods without any additional manual dissection. A sample of 29 half-carcasses was CT scanned with 3 mm slice thickness and then fully dissected according to the EU regulation. The CT muscle volume was calculated by thresholding in the Hounsfield range 0-120. It was converted into muscle weight by applying a density of 1.04. The weight was divided by the carcass weight to obtain the lean meat percentage from CT (LMPct), in the same way as done for the LMPtd. LMPtd was regressed on LMPct. Only the slope was significant and was estimated at 0.965 (s.e.=0.002). The RMSE was 0.81. The plot of residuals against fitted values showed no pattern and no heterogeneity of variances. The main source of measurement error is the thresholding of the rind. As the thickness of the rind is very thin (2-3 mm), most of the voxels including rind are mixed voxels, either with air or with fat. Their Hounsfield values are therefore less than 0 and these voxels are classified in non-muscle. Only a few rind voxels have a Hounsfield value in the range [0-120 HU] and are thus misclassified in muscle. This is taken into account by the slope value which is slightly less than 1. The LMPtd range in the sample (53-68) covers the S+E classes (>= 55) which represent more than 90% of the EU pigs. It covers too more than 80% of all the national populations, excepted Italy. This robust CT procedure can therefore be applied in 27 Member States, by using a pan-European multiplicative factor of 0.965, without any additional national dissection.

PDF icon Gérard Daumas et Mathieu Monziols, 69th EAAP, Dubrovnik, Croatie, 27-31 août 2018, poster
2018

Genomic mating allocation model with dominance to maximize overall genetic merit in Landrace pigs

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D. Gonzalez-Dieguez et al., 69th Annual meeting of the european federation of animal science (EAAP), Dubrovnik, Croatie, 27-31 août 2018

Mating allocation strategies that account for dominance can be of interest for maximizing the overall genetic merit of future offspring. In a genomic context, accounting for dominance effects in genetic evaluations is easier than in a classical pedigree-based context. The objective of the present study was to evaluate, in terms of genetic gain, the efficiency of a genomic mating allocation model accounting for dominance in a Landrace pig population. Genetic variance components were estimated for three traits (age at 100 kg, backfat depth and average piglets weight per litter) using an additive and dominance GBLUP model with inbreeding. The estimated additive and dominance genetic variances were used to obtain additive and dominant SNP effects using a BLUP-SNP model. Then, additive breeding values (BV) and total genetic values (TGV, those including dominance) were predicted for the offspring of all possible matings between 40 boars and around 1,500 sows (the number of available sows depended on the trait). Following a traditional breeding scheme, the best matings resulting from 40 boars and 600 sows, were selected based either on BV or TGV using linear programming. The expected genetic gain was calculated as the difference between the mean BV (or the mean TGV) of selected matings and the mean BV (or the mean TGV) of all possible matings. Results show that, for the analysed traits, mating allocation is a feasible and a potential strategy to improve the productive performance of the offspring (i.e. to improve their TGV) without compromising the additive genetic gain in this Landrace pig population.

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2018

Treasure : Diversité des races locales de porcs et des systèmes de production pour des produits traditionnels de qualité élevée et des filières porcines durables

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Bénédicte Lebret (INRA), Marie José Mercat et Herveline Lenoir (IFIP),Salon International de l'Agriculture (SIA) 2018, 24 février-4 mars 2018, Paris, poster 

 

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2018

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