Investigation of donkeys learning capabilities through an operant conditioning

Despite donkeys being involved in various activities with humans, their cognitive and learning abilities are still little known. A deeper understanding of their perceptive, cognitive and learning processes is, thus, necessary to preserve their well-being and establish a good human-animal bond. An operant conditioning task was applied to explore donkeys’ learning abilities. Nine out of 14 adult and non-working donkeys of both sexes fully completed a three-phases training procedure. In the first phase, animals could approach the manipulandum, a specifically designed cabin with a button on the front side. Thereafter, donkeys had to learn how to interact with the button to obtain a feed reward. To evaluate donkeys’ learning capabilities, two linear models were built: i) a fixed effects model, exploring how the average between-pressures time (BPT) was affected by individual characteristics (i.e. age, sex, and donkeys’ height at the withers) and the training session; and ii) a mixed-effects model to evaluate the difference in the average between-pressures time among consecutive sessions (BPTcs) in the function of the animals’ characteristics, including the sessions-lags as the random effect. In the first model, all the explanatory variables resulted significantly associated with the BPT observed variability. Male donkeys presented a BPT significantly higher, increased by 23.14 s (S.E.=9.71, p = 0.003) compared to females of the same height and age. Age was significant with a positive coefficient (Est.=1.21, S.E.=0.55, p = 0.032). The ‘high’ height class estimate was significant (Est.=13.06, S.E.=6.26, p = 0.032), while no significant effects were identified between the ‘medium’ and ‘short’ and the ‘medium’ and ‘high’ height classes. Lastly, the variable ‘session’ was significant with a negative coefficient (Est.=–10.64, S.E.=1.56, p < 0.0001), indicating an increase in the average speed to perform the desired behaviour for each additional training session. In the second model, the variable ‘sex’ was the only predictor significantly associated with the BPTcs, indicating that the male group progressively improved performance time faster than females (Est.=–8.71, S.E.=4.19. p = 0.045). This pilot study: i) provides insights into donkeys learning abilities by applying an effective methodology for operant conditioning; ii) it highlights how intrinsic animal characteristics might affect asses training performances, although further points need to be explored in future research; iii) it confirms that feed represents an effective positive reinforcement in operant conditioning with donkeys. The development of appropriate handling and training methods, respectful of animals’ subjective experiences and based on positive practices, can improve donkeys’ welfare and their relationship with humans

A Pilot Study on Behavioural and Physiological Indicators of Emotions in Donkeys

Recognizing animal emotions is critical to their welfare and can lead to a better relationship with humans and the environment, especially in a widespread species like the donkey, which is often prone to welfare issues. This study aims to assess the emotional response of donkeys through an operant conditioning task with two presumed different emotional contents. Specifically, a within-subject design including positive and negative conditions was conducted, collecting behavioural and physiological (heart rate variability and HRV) parameters. Facial expressions, postures, and movements were analysed by principal component analysis and behavioural diversity indexes (frequencies, activity budgets, richness, Shannon and Gini-Simpson). During the positive condition, both ears were held high and sideways (left: r = −0.793, p p = 0.011), while the ears were frontally erected (left: r = 0.924, p p p = 0.001), walk away (r = 0.578, p = 0.012), more frequent changes in the body position (VBody position = 0, p = 0.022), and greater behavioural complexity (VGini-Simpson Index = 4, p = 0.027). As for HRV analysis, the root mean square of successive beat-to-beat differences (rMSSD) was significantly lower after the negative condition. These non-invasive parameters could be considered as possible indicators of donkeys’ emotional state

Donkey Heart Rate and Heart Rate Variability: A Scoping Review

Heart rate (HR) and heart rate variability (HRV) are commonly used physiological measures in animals. While several studies exist on horse HRV, less information is available for donkeys. This scoping review aims to understand the extent and type of published evidence on donkey HR and HRV, their clinical and research applications, the devices used, and the analysis performed. Only quantitative primary studies published in English were considered. Four different databases were queried through theWeb of Science platform, with additional evidence identified by citation chasing. After a two-stage screening phase, data were extracted considering study and population characteristics, information on HR/HRV analysis, and applications. The majority of the 87 included articles (about 80%) concerned a sample size of up to 20 individuals and were published since 2011 (about 65%). Forty-one articles employed an electronic device for signal acquisition (mainly electrocardiographs and heart rate monitors), yet only two articles reported HRV parameters. The literature on donkey HRV is lacking, and this gap can be filled by gaining knowledge on donkey characteristics and finding useful tools for welfare assessment. Comparison with what is known about the horse allows a discussion of the technical and interpretative difficulties that can be encountered with donkeys