title: Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter.
abstract: Crocodile morphometric (head, snout-vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (+/-SE) is 265.1 +/- 0.4 days] and slaughter (average age is 1037.8 +/- 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common-sized skin sold having 35-45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (+/-SE) estimates for the traits hatchling snout-vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (-0.81 +/- 0.08) and phenotypic (-0.82 +/- 0.02) correlations between age at slaughter and inventory head length.
authors.affiliation: Centre for Advanced Technologies in Animal Genetics and Reproduction, Faculty of Veterinary Science, University of Sydney, NSW, Australia.
authors.forename: S R
authors.initials: SR
authors.lastname: Isberg
authors.forename: P C
authors.initials: PC
authors.lastname: Thomson
authors.forename: F W
authors.initials: FW
authors.lastname: Nicholas
authors.forename: S G
authors.initials: SG
authors.lastname: Barker
authors.forename: C
authors.initials: C
authors.lastname: Moran
mesh_terms: D000367:Age Factors; D000489:Alligators and Crocodiles / Q000033:anatomy & histology* / Q000254:growth & development*; D000822:Animal Husbandry / Q000379:methods*; D000818:Animals; D001837:Body Weights and Measures; D001947:Breeding / Q000379:methods*; D004780:Environment, Controlled; D005260:Female; D016013:Likelihood Functions; D008297:Male; D015233:Models, Statistical; D019655:Quantitative Trait, Heritable