Does hormonal profile influence behaviors in pubescent ewes?

Small ruminants farming systems are essential part of mountain ecosystems and rural economy, contributing to management, care, and conservation of a unique landscape. Therefore, research aims at improving the economic value of breeding, welfare, and productivity of animals identifying new examples of sustainable supply chain. The study presented here is part of the SmartSheep project, which wants to contribute in developing new efficient and sustainable systems. The purpose of this work is to better evaluate behaviour modification and adrenal response in relation to the stage of the first oestrous cycle. 20 ewes of Frabosana-Roaschina breed (10-12 months old) were checked during the first oestrus. The animals were synchronized with a standardised protocol. During two months of sampling, animals were monitored continuously with video camera and sampled for saliva and blood samples. Behavioural and hormonal data were analysed in relation to the oestrous cycle phases obtained from hormonal patterns (progesterone and 17β-estradiol) and ultrasound assessments (follicular waves, presence of corpus luteum). Video data, registered through scan sampling, were eventually related to an adaptive endocrine response (salivary cortisol). Parametric (hormone data) and non-parametric (behaviours analyses) tests were used to analyse the data in relation to the phases of the oestrus cycle. Statistical difference was determined if P ≤ 0.05. Data are presented as mean ± SEM. Significant difference was observed between progesterone concentration (ng/mL) at luteal and follicular phases. These hormonal levels, supported by ultrasonographic imagines analysis, confirmed proper cyclic activities in the ewes at first oestrus. However, despite this evidence, no differences were observed in the regular behavioural patterns (e.g., feeding, resting, and standing) as well as in social (i.e., displacing from resources, grooming, nudging, and sniffing) behaviours. Furthermore, the ewes didn’t show any sexual behaviours during the reproductive cycle. On the contrary, “play” activities (i.e., frontal butt, reciprocal butt, and side/rear butt) were observed. Finally, no significant differences were detected in the cortisol levels during the phases of cycle. Although these animals reached the age of puberty, like other Italian dairy breeds, our findings showed a silent ovulation. Play behaviours and specific features in breed of the animals may be reflected in reproductive functionality. In literature it is reported that young ewes show less reproductive behaviour and has a shorter oestrus compared to mature ewes. Lastly, Frabosana-Roaschina is an autochthonous and rustic breed in West North Alpine bioregion and a milder selection has been performed. Thus, even minor changing in animal welfare or managing may delay the ovulatory activity like wild sheep species.