Digestive efficiency predicted via near infrared spectrometry (NIRS) is a new indicator of interest for pig selection schemes, making it possible to target a particularly interesting component of feed efficiency in a context in which feed contains more dietary fibre. The objective of this study was to compare the variance components of digestive coefficients predicted at 16 and 21 weeks of age to assess the sensitivity of genetic parameters to the time of sampling and identify possible genetic × age interactions. Faecal samples at both ages were taken from 629 Large White male pigs, whereas 1663 additional pigs had measurements at 16 weeks of age only. All animals were genotyped, and digestibility coefficients (DC) for organic matter, energy and nitrogen were predicted from faecal samples by NIRS. Bivariate genetic models were applied to estimate the heritability of digestive coefficients at 16 and 21 weeks of age separately, as well as the genetic correlations between measurements at the two ages, and with production traits. The heritability estimates were moderate (0.17-0.35), and similar at 16 and 21 weeks of age. The genetic correlations with production traits were negative for growth rate and feed intake, and null for carcass leanness. The genetic correlations between the DCs at the two ages were 0.65-0.70, suggesting a tendency to differ from 1. The genetic determinism of DCs could therefore differ between 16 and 21 weeks, which should deserve further analysis to develop sampling strategies adapted to pig selection schemes.