Paramètres génétiques des caractères de poids corporels, de production d’oeufs, et de qualité de la coquille chez la cane pondeuse Tsaiya Brune

Heritabilities and genetic correlations were estimated for 5 575 laying Brown Tsaiya ducks on performance data from 5 generations of a selection experiment, by means of a multivariate, multimodel, restricted maximum likelihood method (MM-REML) applied to an animal model on the 12 traits: feather length at 20 weeks of age (FL20); body weight at 20 and 40 weeks of age (BW20; BW40); age at first egg (AGElEGG); number of eggs laid up to 40 and 52 weeks of age (NEGG40; NEGG52); eggshell strength at 30 and 40 weeks of age (ES30; ES40); egg weight at 30 and 40 weeks of age (EW30; EW40); egg yolk weight at 40 weeks of age (EYW40); and the proportion of egg weight to body weight at 40 weeks of age (EW40/BW40). Adult females were heavier than adult males (BW40: 1391 g vs 1 310 g). ES40 was lower than ES30 (3.5 kg/cm2 vs 3.8 kg/cm2. Heritabilities were found to be low (0.094, 0.107, 0.118, 0.160, 0.169, 0.191 and 0.201 for ES40, ES30, NEGG52, NEGG40, FL20, EYW40 and AGE1EGG, respectively), to medium (0.327, 0.329, 0.353, 0.425 and 0.499 for EW40/BW40, EW40, EW30, BW20 and BW40, respectively). Fifty genetic correlations were tabulated. The pattern of the genetic correlations for the traits to be selected showed that NEGG52 was highly positively correlated with NEGG40 (rg = 0.948), uncorrelated with the body weight and was negatively correlated with AGE1EGG (rg = -0.749), EW40 (rg = -0.323), EW30 (rg = -0.200), EYW40 (rg = -0.340), ES30 (rg = -0.194), ES40 (rg = -0.203), FL20 (rg = -0.131) and EW40/BW40 (rg = -0.259). Egg weights, body weights and eggshell strength traits were positively genetically correlated among themselves. The results suggest that a linear selection index for NEGG52 with constraints for EW40, BW40 and ES40 could be an efficient tool for improving the efficiency of egg production with this small body type laying duck. Les héritabilités et corrélations génétiques ont été estimées pour 5 575 pondeuses Tsaiya Brune, sur la base de performances concernant les 5 premières générations d’une expérience de sélection par la méthode du REML-MM (maximum de vraisemblance restreinte-multivariate multimodèle) appliquée à un modèle animal sur 12 caractères : la longueur de la plume à l’âge de 20 sem (FL20), le poids corporel à 20 et 40 sem (BW20 ; BW40), l’âge au premier oeuf (AGE1EGG), les nombres d’oeufs à 40 et 52 sem (NEGG40; NEGG52), la solidité de la coquille à 30 et 40 sem (ES30 ; ES40), le poids des oeufs à 30 et 40 sem (EW30 ; EW40), le poids des jaunes