Differences in relative volume and weight of stomach among four free living ruminants

Abstract

The aim of this study was to estimate similarities in relative volume and weight of stomachs of free-living red deer, fallow deer, roe deer and moufflon to evaluate their feeding strategy and probability of their interspecific competition for food sources. Studied parameters were evaluated according to season, sex, age and locality. From 1995 to 1998, 176 adult (> 1 year) shot animals were examined in total. In all of the four studied species, rumen was larger in vegetation period than in winter (p < 0.01). The greatest differences between seasons were found in rumen volume (15-20% on average). Differences in the volume and weight of reticulum, omasum and abomasum were smaller or not significant. The roe deer females had a higher relative volume (by 40%) and weight (by 55%) of total stomach (p < 0.005) compared to males. Age of animals had no influence on size of reticulum, omasum and abomasum. The older animals had greater total stomach size. Rumen size of animals from different altitudes was the same (p < 0.05). The biggest relative size of total stomach and rumen was in moufflon (grazer), the smallest in roe deer (browser); fallow and red deer (both intermediate feeders) did not differ significantly. The differences between species are in agreement with their feeding strategy. Seasonal differences in rumen size correspond to the changes of their diet.