These outcomes advance the current underst and ing of Ca digestibility and utilisation , and should contribute towards establishing requirements for digestible Ca .
Consequently , pig diets will be more correctly formulated if digestible Ca values are used in estimating requirements for Ca
Ca digestibility and utilisation in growing pigs are not well understood , and are usually neglected in diet formulation .
This has implication s not only for the accurate determination of its requirements but also for its interactions with other nutrients .
A systematic review and meta- analysis ( meta-regression ) of published trials was carried out to quantify factors affecting Ca absorption and utilisation , and to derive an estimate of Ca endogenous excretion .
Random-effects models for longitudinal data.
Models for the analysis of longitudinal data must recognize the relationship between serial observations on the same unit . Multivariate models with general covariance structure are often difficult to apply to highly unbalanced data , whereas two-stage r and om-effects models can be used easily . In two-stage models , the probability distributions for the response vectors of different individuals belong to a single family , but some r and om-effects parameters vary across individuals , with a distribution specified at the second stage . A general family of models is discussed , which includes both growth models and repeated- measures models as special cases . A unified approach to fitting these models , based on a combination of empirical Bayes and maximum likelihood estimation of model parameters and using the EM algorithm , is discussed . Two examples are taken from a current epidemiological study of the health effects of air pollution
These outcomes advance the current underst and ing of Ca digestibility and utilisation , and should contribute towards establishing requirements for digestible Ca .
Consequently , pig diets will be more correctly formulated if digestible Ca values are used in estimating requirements for Ca
Ca digestibility and utilisation in growing pigs are not well understood , and are usually neglected in diet formulation .
This has implication s not only for the accurate determination of its requirements but also for its interactions with other nutrients .
A systematic review and meta- analysis ( meta-regression ) of published trials was carried out to quantify factors affecting Ca absorption and utilisation , and to derive an estimate of Ca endogenous excretion .