title: Genetic relations of yolk proportion and chick weight with production traits in a White Leghorn line.
abstract: 1. The main purpose of this study was to estimate genetic correlations between yolk proportion, chick weight and production traits using an animal model. 2. Direct-direct genetic correlations were estimated between yolk proportion and age at first egg (-0.34), body weight at 20 (0.10), 40 (0.58) and 60 (0.52) weeks of age, egg number (0.56), egg mass (0.59), feed intake (0.64) and feed conversion (-0.25). 3. Maternal-direct genetic correlations were estimated between chick weight and age at first egg (0.40), body weight at 20 (0.57), 40 (0.66) and 60 (0.56) weeks of age, egg number (-0.50), egg mass (0.21), feed intake (0.45) and feed conversion (0.17), respectively. 4. In conclusion, the results suggest that selection on a higher yolk proportion would not have any unfavourable effects on egg production. Maternal-direct genetic correlations between chick weight and production traits resembled direct-direct genetic correlations between egg weight and production traits found in other studies.
authors.affiliation: Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Hartmann
authors.forename: E
authors.initials: E
authors.lastname: Strandberg
authors.forename: L
authors.initials: L
authors.lastname: Rydhmer
authors.forename: K
authors.initials: K
authors.lastname: Johansson
mesh_terms: D000367:Age Factors; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002642:Chick Embryo / Q000502:physiology*; D002645:Chickens / Q000235:genetics* / Q000502:physiology; D004530:Egg Yolk / Q000502:physiology*; D005260:Female; D008297:Male; D010058:Oviposition / Q000235:genetics*; D012641:Selection, Genetic