The food bolus passes through the oesophagus into the stomach. Horses evolved to eat high fibre diets almost continuously i.e. they are 'trickle feeders'. The stomach is relatively inelastic and has a finite capacity.
The stomach volume of the adult horse is relatively small - between 9 - 15 litres - and provides approximately 8% of the capacity of the gastro-intestinal tract. In contrast to other domestic species, the storage function of the stomach is limited and relatively unimportant.