ENRIQUECIMENTO AMBIENTAL SOCIAL E SENSORIAL COMO ESTRATÉGIAS PARA OTIMIZAR O BEM-ESTAR DE EQUINOS EM CONDIÇÕES DE ESTRESSE DE CURTA DURAÇÃO

Abstract

The research was developed to evaluate the effect of different sensory and social environmental enrichment (EE) strategies on the welfare of horses under short-term stress conditions (social isolation and movement restriction). In chapter 1, there is a literature review, which initially addresses the challenges faced by horses in the domestic environment and characterized the physiological and behavioral stress responses. Next, strategies for reducing stress are described, highlighting the relevance of sensory and social EE as potential alternatives to improve the well-being of the species. Chapter 2 presents the article in which it was proposed to evaluate the effect of non-contact social EE on horses subjected to movement restriction imposed by restraint handling in stocks, and its ability to facilitate social buffering by promoting the reduction of stress responses. Pantaneiro horses (n=11) were evaluated in a crossover design with EAS treatment (Social environmental enrichment during restraint handling in stocks) and IS treatment (Social isolation during restraint handling in stocks). Physiological parameters and facial expressions (EquiFACS) were assessed throughout the 24 minutes that the animals remained restrained. When horses were subjected to handling in social isolation (IS), heart and respiratory rates were higher (p<0.05) than when accompanied by a conspecific (EAS). The frequency of facial expressions associated with the stress response such as nostril dilation (AD38), inner brow raiser (AU101), upper lid raiser (AU5), eye white increase (AD1), ears forward (EAD101) and ear rotator (EAD104), were also greater (p<0.05) for IS compared to EAS. Non-contact social EE proved to be an effective strategy to mitigate handling-induced stress, demonstrating that this practice can facilitate social buffering. Chapter 3 presents the article in which it was proposed to evaluate the effect of olfactory sensory EE with lavender essential oil on horses subjected to movement restrictions imposed by restraint handling in stocks and social isolation, and its ability to reduce stress responses. Pantaneiro horses (n=7) were evaluated in a crossover design with lavender treatment (Lavandula augustifolia essential oil) and control treatment (TACC). Physiological and behavioral (general behavior and facial expressions – EquiFACS) parameters were assessed throughout the 24 minutes that the animals remained restrained. When horses received the lavender treatment their heart rate was lower after olfactory stimulation (p<0.05). At the same time, an increase in ocular temperature (p<0.05) was observed for lavender enrichment. The frequency of facial expressions associated with the stress response, such as nostril dilation (AD38), chewing (AD81), tongue show (AD19) and blink (AU145), were also lower (p<0.05) for lavender. Olfactory EE with lavender essential oil influenced physiological parameters and facial expressions of Pantaneiro horses and proved to be an effective strategy to mitigate short-term stress induced by handling. Based on the promising observations of the use of sensory and social environmental enrichment on the welfare of horses in short-term stress conditions obtained in this thesis, it is recommended the implementation of both strategies in equestrian centers.