title: Genetic analysis of leg problems and growth in a random mating broiler population.
abstract: Improvement in growth has been widely reported as the cause of increased incidence of leg problems in broiler chickens. We report herein the genetic relationship between growth and leg problems in a random mating broiler control population. The traits studied were valgus (VL), varus (VR), and tibial dyschondroplasia (TD), which were expressed on a binary scale of 0 (normal) and 1 (abnormal); growth rates from 0 to 4 wk (BWG 0-4) and from 0 to 6 wk of age (BWG 0-6); and residual feed intake from 5 to 6 wk of age (RFI 5-6). A threshold-linear mixed model was employed for the joint analysis of the categorical and linear traits. Incidences of VL, VR, and TD were 26, 4, and 2%, respectively. Heritability of leg problems ranged from 0.11 to 0.13. Phenotypic correlations alluded to an unfavorable relationship between growth and leg problems; however, the genetic relationship between growth and leg problems was extremely weak, ranging from 0.01 to 0.08. There is, therefore, a basis for genetic improvement in leg problems. However, improved management practices would also be important to reduce incidence of leg problems in broiler chickens.
authors.affiliation: NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens 30602.
authors.forename: F
authors.initials: F
authors.lastname: González-Cerón
authors.affiliation: Department of Animal and Dairy Science, University of Georgia, Athens 30602.
authors.forename: R
authors.initials: R
authors.lastname: Rekaya
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville 72701.
authors.forename: N B
authors.initials: NB
authors.lastname: Anthony
authors.affiliation: NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens 30602 saggrey@uga.edu.
authors.forename: S E
authors.initials: SE
authors.lastname: Aggrey
mesh_terms: D000818:Animals; D001835:Body Weight / Q000235:genetics; D002645:Chickens / Q000254:growth & development; D005260:Female; D020022:Genetic Predisposition to Disease; D006614:Hindlimb / Q000473:pathology*; D007794:Lameness, Animal; D008297:Male; D011201:Poultry Diseases / Q000235:genetics*
keywords: genetics; growth; leg problem