Eighteen adult (2.5 years old) Romanov ewes were used. Since AM 114 influence stress sensitivity  and , it is necessary to study stress levels in steroid-stable castrated animals  and . Thus, the animals were ovariectomized (ovx) at least 2 months before the beginning of the study. Moreover, twelve other adult ewes were used as familiar conspecifics (6 ovx and 6 non-ovx ewes allocated in controlled order with the three other groups). The ovariectomy was conducted as previously reported  and the animals were maintained in post-operative observation for one week. All the animals were housed in a large rearing room (5 m × 5 m) under freely moving conditions with controlled environmental temperature and light (12:12 h light–dark cycle), at least two weeks before being moved to the experimental room. For all the period preceding experimentation, the same experimenter visited the animals once a day, then twice a day and finally gently approached each animal.