with correlation coefficients of
0.856 and 0.848 between observed and predicted values for chickens and pigs, respectively.
This relationship also allows the proportion of intensively raised pigs to be predicted with similar
levels of accuracy (r = 0.878), and allows inferences to be made as to how the modeled proportion
of pigs raised under extensive, semi-intensive, and intensive production systems vary
with increasing wealth at the country or province level (Fig 3).