Optimizing selection with several constraints in poultry breeding

Poultry breeding schemes permanently face the need to control the evolution of coancestry and some critical traits, while selecting for a main breeding objective. The main aims of this article are first to present an efficient selection algorithm adapted to this situation and then to measure how the severity of constraints impacted on the degree of loss for the main trait, compared to BLUP selection on the main trait, without any constraint. Broiler dam and sire line schemes were mimicked by simulation over 10 generations and selection was carried out on the main trait under constraints for coancestry and for another trait, antagonistic with the main trait. The selection algorithm was a special simulated annealing (adaptative simulated annealing (ASA)). It was found to be rapid and able to meet constraints very accurately. A constraint on the second trait was found to induce an impact similar to or even greater than the impact of the constraint on coancestry. The family structure of selected poultry populations made it easy to control the evolution of coancestry at a reasonable cost but was not as useful for reducing the cost of controlling evolution of the antagonistic traits. Multiple constraints impacted almost additively on the genetic gain for the main trait. Adding constraints for several traits would therefore be justified in real life breeding schemes, possibly after evaluating their impact through simulated annealing

Assessing organic phosphorus status of Cerrado oxisols (Brazil) using 31P-NMR spectroscopy and phosphomonoesterase activity measurement

International audienc

Des pistes pour améliorer l'utilisation du parcours chez les poulets de chair biologiques

National audienc

Can plumage score be improved using an automatic measurement of pecking at a bunch of feathers

International audienc

Quantitative genetics of feed efficiency in ducks

Given the worldwide diversity of duck production, genetics aspects of feed efficiency of ducks should be addressed depending on the production (broilers, layers, and “foie gras”) and on the genetic types (Muscovy duck, common duck, and their intergeneric cross mainly used in France for “foie gras” production after force-feeding, i.e. the mule duck). The two main criteria to characterize feed efficiency are the feed conversion ratio (FCR), computed as the ratio of food quantity divided by the output, and the residual feed intake (RFI) which is obtained through a multiple linear regression of feed intake by output and metabolic requirements. The former is a ratio, with undesirable statistic properties. In addition, it is uneasy to disentangle variations in net feed efficiency from variations in FCR due to production traits. The latter is supposed to be, at least phenotypically, independent from the constituent production traits. This is the reason why it gained popularity, even though it requires a thorough analysis of metabolic requirements, as in the overfed mule ducks, where the fat deposition capacity should not be impaired. In the literature, the values found for FCR depend on the genetic type and on the production: FCR≈2.5 at 12 wk. for male Muscovy and FCR >3.2 at 13 wk. for fatty mule ducks; FCR ≈ 1.9 at 42d for Pekin broilers; FCR ≈2.8 for layers. Usually RFI is moderately heritable (h²≈0.25 in layers; 0.3<h²<0.4 in Pekin broilers) and slightly more heritable than FCR. RFI heritability of fattened mule ducks needs to be refined. Genetic correlations between FCR and RFI vary between studies, from moderate (ρG=+0.34) to high (ρG=+0.99). Reliable assessment of individual feed intake is an issue. Development of RFID based automatic feeders greatly helped the improvement of feed efficiency in duck breeding programs. Such devices open the field for new studies, as they give access to feeding behavioral traits. They also allow for the joint modeling of trajectories for feed intake and production traits. Finally, as a complex trait, selection for feed efficiency should benefit from the availability of molecular tools

Accuracy of BLUP breeding values in a factorial mating design with mixed families and marker-based parentage assignment in rainbow trout Oncorhynchus mykiss

Marker-based parentage assignment provides the opportunity to investigate factors of efficiency for mixed-family designs and factorial mating. In such designs, family size is both uncontrolled and small, which may be thought to limit the accuracy of estimated breeding values (EBVs). The objective of this work was to estimate the accuracy of EBVs of growth and quality traits in a large factorial mating design and in commercial breeding conditions. An expected six hundred full-sib families of rainbow trout Oncorhynchus mykiss (2042 fish in total) were produced by ten factorial matings of six dams with ten sires. Fish were phenotyped for body weight, carcass yield, fillet yield, fillet fat content and fillet colour, and family information was recovered using microsatellite markers. The accuracy of EBVs was estimated using or removing individual performance to mimic combined family selection (with individual phenotype) or sib selection (without individual phenotype). The traits investigated had medium to high heritability (0.17–0.58). High to very high accuracy (0.630–0.817) was estimated for combined family selection. The accuracy of sib selection (not using individual phenotype) was 18–22% lower (0.542–0.638), but remained in the upper range reported for such traits. This level of accuracy was higher than those reported in conventional breeding programs using separate family rearing. This was true even for families with a very low number of full-sibs. Individual EBV accuracy was more closely linked to the total number of full- and half-sibs of each fish than to its number of full-sibs. We hypothesize that this was due to the factorial mating, which led to a high number of the genetic ties between sibs. These results highlight the possibility of introducing precise estimated breeding values for quality traits into combined or sib selection in breeding programs when using mixed families from factorial designs and marker-based parentage assignment in aquaculture species

Accuracy of BLUP breeding values in a factorial mating design with mixed families and marker-based parentage assignment in rainbow trout Oncorhynchus mykiss

Marker-based parentage assignment provides the opportunity to investigate factors of efficiency for mixed-family designs and factorial mating. In such designs, family size is both uncontrolled and small, which may be thought to limit the accuracy of estimated breeding values (EBVs). The objective of this work was to estimate the accuracy of EBVs of growth and quality traits in a large factorial mating design and in commercial breeding conditions. An expected six hundred full-sib families of rainbow trout Oncorhynchus mykiss (2042 fish in total) were produced by ten factorial matings of six dams with ten sires. Fish were phenotyped for body weight, carcass yield, fillet yield, fillet fat content and fillet colour, and family information was recovered using microsatellite markers. The accuracy of EBVs was estimated using or removing individual performance to mimic combined family selection (with individual phenotype) or sib selection (without individual phenotype). The traits investigated had medium to high heritability (0.17–0.58). High to very high accuracy (0.630–0.817) was estimated for combined family selection. The accuracy of sib selection (not using individual phenotype) was 18–22% lower (0.542–0.638), but remained in the upper range reported for such traits. This level of accuracy was higher than those reported in conventional breeding programs using separate family rearing. This was true even for families with a very low number of full-sibs. Individual EBV accuracy was more closely linked to the total number of full- and half-sibs of each fish than to its number of full-sibs. We hypothesize that this was due to the factorial mating, which led to a high number of the genetic ties between sibs. These results highlight the possibility of introducing precise estimated breeding values for quality traits into combined or sib selection in breeding programs when using mixed families from factorial designs and marker-based parentage assignment in aquaculture species

Conditioning and monitoring the patient for the helicopter flight; [Mise en condition et surveillance du patient pour le vol héliporté]

International audienceHelicopter medical assistance, also known as the Helicopter Emergency Mobile Service (HEMS), is one of the main vectors of providing rapid care to patients. Its raison d’être lies in its ability to reduce response times, enabling victims to receive the care their condition requires as quickly as possible. This concept of rapid life-saving action is an essential medical principle and an evolution in emergency medical services and rescue. It allows medical teams to act more quickly and complements land-based medical rescue. The HEMS has become an operational unit combining a medical team, a set of technical and medical equipment for care and resuscitation enabling the care of patients in critical condition using a helicopter equipped and adapted for these missions. However, to be fully efficient and carry out a wide range of missions of varying complexity, it must be part of a coordinated health system. This synthetic review explains the complex organisation of HEMS and the constraints to which they are subject. It gives an indication of the fundamental principles that are essential for doctors and carers who have to use this medium. It covers the safety conditions required for these missions, the consequences of altitude and the rotary wing on patient care, the use of the equipment and the minimum training required, as well as the essential knowledge needed to join an EMS. For practitioners, it covers the indications for these missions, the preparation of the patient before transport to the hospital relay, the management procedures linked to the use of the winch and the physiological constraints linked to flying. Finally, specific situations related to the type of patient and the clinical presentation are discussed, providing a comprehensive overview of the practice of heliborne emergency medicine. © 2023 l'Académie nationale de médecin