Determination of Phosphorus Requirement for Post Molted Laying Hens using Nonlinear and Multivariate Nonlinear Mixed Effects Models

Estimating digestible methionine requirements for laying hens using multivariate nonlinear mixed effect models.

The purpose of this paper was to develop a unified framework for analyzing dose-response data in farm animals and apply it to meta-analysis of digestible Met requirement studies in laying hens. A database containing Met dose-response data from 23 trials originating from 15 peer-reviewed publications was constructed. A multivariate nonlinear mixed effects model was chosen as the statistical fram...

Phytase effects on amino acid digestibility in molted laying hens.

Two hundred sixteen previously molted Dekalb Delta Leghorn laying hens (78 wk of age) were utilized to determine the effect of phytase on the ileal digestibility of amino acids. The hens were randomly arranged in a 3 x 2 factorial to evaluate three diet types that were corn-soybean meal (C-SBM), C-SBM-meat and bone meal (C-SBM-MBM), and C-SBM-wheat middlings (C-SBM-WM) and two levels of phytase...

estimation of iron requirement for broiler breeder hens at the late stage of production cycle using nonlinear models

background: no study has been conducted on iron requirements of broiler breeder hens until now. objectives: the purpose of the present study was to determine the iron requirement of broiler breeder hens using nonlinear models. methods: forty eight (cobb 500) broiler breeder hens were individually placed in galvanized wire cages. in order to depletion of hens iron reserved, hens were offered a s...

Model Building for Nonlinear Mixed-Effects Models

Nonlinear mixed-effects models involve both fixed effects and random effects. Model building for nonlinear mixed-effects models is the process of determining the characteristics of both the fixed and the random effects so as to give an adequate but parsimonious model. We describe procedures based on information criterion statistics for comparing different structures of the random effects compon...

Nonlinear mixed effects models for longitudinal data