Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus Seasonal faecal excretion, gut fill, liquid and particle marker retention in mouflon ovis ammon musimon, and a comparison with roe deer capreolus capreolus AbstractFive mouflon (average body mass [BM] 33 kg) and two roe deer (average BM 20 kg) with rumen cannulas were kept in large enclosures under semi-natural conditions and were used for seasonal studies on gastrointestinal tract (GIT) indigestible fill and digesta passage kinetics. As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h-1 kg-0.75) than the roe deer (19.2 ± 0.2 ml h-1 kg-0.75), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg-1 and 13.3 ± 1.0 g kg-1). As the mouflon were not fully mature, both species had similar digesta volumes in the reticulorumen (RR; mouflon 5.5 ± 1.8% of BM; roe deer 5.4 ± 1.5% of BM); however, the mouflon had lower RR liquid flow rates (15.1 ± 4.3 ml h -1 kg -0.75 ) than the roe deer (19.2 ± 0.2 ml h -1 kg -0.75 ), and particle retention in the RR accounted for 68 ± 3% of total GIT retention in the mouflon versus 55 ± 6% in the roe deer. Annual average total GIT retention times for liquids and particles were longer in the mouflon (23.4 ± 0.9 h and 37.9 ± 4.0 h) than in the roe deer (18.4 ± 1.7 h and 22.4 ± 1.9 h). Similarly, annual average RR retention times for liquids and particles were longer in the mouflon (11.9 ± 0.9 h and 25.8 ± 3.3 h) than in the roe deer (8.1 ± 1.7 h and 12.5 ± 2.3 h). The factor of selective particle retention in the RR (retention of particles/retention of liquid) was 2.10 ± 0.09 in the mouflon versus 1.54 ± 0.01 in the roe deer. These observations are in accord with differences in digesta passage characteristics postulated between browsing and grazing ruminants. Total GIT indigestible fill was lower in the mouflon than in the roe deer (10.7 ± 2.1 g kg -1 and 13.3 ± 1.0 g kg -1 ).

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The European roe deer (Cupreolus cupreolus) is the smallest wild ruminant species in the northern hemisphere. Capreolini are represented in the fossil record of Eurasia by an array of forms extending from the Miocene to the Recent. Interestingly, a map of fossil occurrences shows that the historical range is fairly congruent with the recent distribution of Capreolirs; roe deer have always been temperate-zone animals of Eurasia (Lister et al. 1998). In contrast to many other large herbivores the roe deer population in Europe increased both in terms of distribution and density during the last 100 years. This emphasises the flexible response of the species to rapidly changing environmental conditions and their potential to adapt to new resources in modern agriculture and forestry.This paper reviews aspects of evolution, dietary selection, digestion and adaptation of the European roe deer to the changing environment.In terms of feeding type, roe deer have been classified as a typical concentrate selector (Hofmann 1989), browsing on highly digestible plant parts. However, this feeding strategy can not be sustained during winter when forage is less available and its digestibility is reduced. Body reserves generally play no major role in roe deer (Holand 1992).Roe deer have developed several mechanisms to adapt to seasonal variations in their environment. It is the only ungulate that is strictly monestric with a genetically fixed diapause. Fawns are born in May when the quality of browse is at an optimum, and twins or even triplets are common. It is concluded that the perfect synchrony between seasonal changes of the resources and the demand due to reproductive investment may be the key function for the success of roe deer in temperate and northern climates.

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