Functional stomach chamber strategy of red deer in relation to sex and mating season

Stomach chambers of hinds (H), winter (WB) and rutting bulls (RB) of red deer (Cervus elaphus L.) were examined during the fall hunting season and wintertime. The stomach content of bulls was the highest (P>0.01) in winter (WB, 19.0 kg) and the lowest (RB, 3.7 kg) during rutting season. But the relative food content for total stomach (IR index) as well as for rumen (180.2), abomasum (4.1) and omasum (7.4) was the greatest in hinds (H). However, the total stomach tissue (SCT) weight increased together with the enhancement of carcass weight (Cw), the percentage of participation relative SCT to Cw, thus by contrast the IW index was the lowest P>0.01 in the heaviest RB (2.23). For WB it equaled 4.03 and for H - 3.99. Moreover, the total stomach volume, Iᵥ index was the highest in hinds (82.90) and differed P>0.01 from that of RB which was the lowest (36.70). Similar trends occurred in the individual stomach chamber areas. The greatest IT index-expressing ratio of stomach tissue weight to its area was markedly (P>00.5) higher in RB (0.20) in comparison to the remaining groups (WB 0.11, H 0.09), indicating a thicker and shrunken stomach wall. The study demonstrates that variability in the stomach chambers (its characteristics and indexes) of female and male deer depend upon seasonal physiological changes, including the most important season, which is the mating season. Stomach size and its individual chamber indexes are consequences of diet segregation and different feeding behavior between sexes, including foraging activity of males in the rutting season.