Etude des paramètres génétiques des poids et rendements de pièces estimés à partir d'un scanner à ultrasons

International audienceStudy of genetic parameters of weight characteristics and meat-cut yields estimated using a ultrasound scanner The economic value of a carcass depends not only on its weight or quality, but also on the relative proportions of its meat cuts. Indeed, some cuts, such as the ham or loin, have more value than other cuts. It would therefore be interesting to increase the weight of these specific cuts while maintaining a standard carcass weight. AutoFom III ™ is a tool that scans the back of a pig using 16 ultrasound probes by measuring thicknesses along the carcass. It then uses equations to estimate the weights and yields of the cuts. These estimates can be used to calculate a value for each carcass based on the mean price of each cut. The aim of this study was to estimate genetic parameters of these new measurements in the Pietrain breed and their relationship with traits measured in breeding candidates. Eight thousand Pietrain pigs from two breeding farms were studied for both measurements from AutoFom and traits of selection interest, such as growth and conformation. The heritabilities of cut weights and yields were relatively high (0.43-0.52). The genetic correlations between estimated cut weights and yields and traits of selection interest, especially backfat thickness, were relatively strong and favorable. The selection objectives currently in place are therefore already helping to improve the economic value of carcasses.La valeur économique d’une carcasse ne dépend pas uniquement de son poids brut ou de sa qualité, mais aussi de la proportion entre les différentes pièces qui la composent. En effet, certaines pièces, comme le jambon ou la longe, sont mieux valorisées que le reste de la carcasse. Il serait donc plus intéressant d’augmenter spécifiquement le poids de ces pièces tout en maintenant un poids de carcasse standard. L’AutoFom III™ est un outil qui permet de prédire les poids et rendements de pièces des carcasses entières. Cette étude a pour but d'estimer les paramètres génétiques de ces prédictions en race Piétrain ainsi que leurs relations avec les caractères d’intérêt en sélection

Évaluation de la puberté de cochettes Landrace français et indentification de facteurs de variation

International audienceWhile insemination at first estrus is not recommended, most studies agree on the benefits of early puberty, both for reproductive performance and sow longevity. In the swine population in France, sexual maturity is expected at ca. 200 days of age. Although age at puberty is crucial information, it is not recorded on farms. Since selection for low boar taint influences male puberty, it raises questions about its potential side effects on female reproductive ability. This study was carried out as part of a project that assessed impacts of selection against boar taint on the reproduction of Landrace females. The sexual maturity of 1878 gilts at ca. 200 days of age was evaluated on five farms using quantitative plasma progesterone analysis in two blood samples taken 10 days apart. Cutoff values of 2.5 or 5.0 ng/mL gave similar estimates of 19% immature gilts, with a large variation among farms (8-49%). Insemination was not performed for 4% of gilts, 9% were re-inseminated during the first cycle and 15% did not farrow. The rate of earlyreproduction difficulties varied greatly among farms. The influence of immaturity at 200 days was generally low, with a large farm effect. Further investigation is required to analyze long-term effects of late puberty