Répulsion alimentaire chez trois espèces d'ongulés en situation de pâturage : effet des excréments de chien

Abstract

In a previous study the odour of dog faeces has been demonstrated to induce a food repulsion in sheep tested indoor (Arnould and Signoret, in press). The aim of this study was to determine the effectiveness as food repellent of dog faeces in sheep (Ovis aries), but also in roedeer (Capreolus capreolus) and red deer (Cervus elaphus) in pasture situation. In the first experiment, 6 sheep were placed for 2 h 30 in a 12 x 12m pen. On 2 patches of 1 m2 each, the grass had been sprayed with a dilution of dog faeces in water. One sheep was observed only once grazing in a treated area versus 21 times (and all the 6 sheep) on the 2 control patches of 1 m2 sprayed with water. In 4 additional trials, leaves of freshly cut yoke-elm (Car pinus betulus) branches placed in the pen and sprayed with dog faeces were not browsed contrary to control ones that were totally eaten after 1 h trials. In the second experiment, oak (Quercus sp.) branches spread with diluted faeces were similarly not eaten by a group of 6 roedeer. The repulsion was still effective five days after spraying the leaves. In the third experiment, 3 groups of red deer living in a pasture, were tested by presenting their daily ration of barley together with the odour of dog faeces (in pans underneath). Only one out of the 61 deer tested ate a few grains of barley, and only in 3 out of the 7 trials. The odour of dog faecal matter had a food repellent effect on the 3 species of ungulates tested, and animals did not habituate to it over 3 to 7 successive daily trials. The adaptive value of this phenomenon is discussed.