Particle retention in the forestomach of a browsing ruminant, the roe deerCapreolus capreolus

A combination of a flotation/sedimentation experiment and sieve analysis fo r the reticulorumen (RR) contents of roe deer Capreolus capreolus Linnaeus, 1758, a browsing ruminant, showed that there was no correlation between pa rticle size and particle density. Large particles were present in both the sedimented and the buoyant fraction, which is in accord with the reported a bsence of stratification of RR contents in browsing ruminants. Comparative sieve analysis of roe deer RR and caecal/rectal material demonstrated that there must be some selective particle retention in the browsing ruminant as well, as a certain fraction of large particles in RR contents does not occ ur in the caecal/rectal material. These results lead to the explanatory dil emma that, while selective particle retention is observed, it cannot be due to the mechanisms known to work in grazing ruminants.