Rhythmicity as a welfare indicator – investigating the effect of extrinsic zeitgebers in equines as a model organism

This dataset includes data on lying behaviour (computed with triact R Package) and degree of functional coupling (computed with Digirhytym R package) from an randomized horse trial with three different feeding intervals. Pre-processed dataset and script for statistical Analysis is provided. 

Abstact: To effectively assess and maintain animal well-being, reliable and accessible indicators are crucial. Researchers have proposed using rhythmicity as a measure of animal welfare. An animal in a good state of welfare would, ideally, follow the same daily rhythmic patterns while disruptions in these patterns may signal stress or illness. Although promising in certain cases, it remains unclear how rhythmicity reflects the well-being of animals in managed husbandry systems, where external (human) factors might impact their rhythmicity. This study investigated how extrinsic factors, such as feeding times, affect the rhythmicity of domesticated horses, aiming to assess their value as a welfare indicator. Twenty horses were divided into four groups and subjected to three different feeding regimes, assigned using a randomized Latin square design. We retrieved time-series data from accelerometers attached to the horses’ left front legs and analyzed them using Fourier transform to compute the Degree of Functional Coupling (DFC). This indicator measures how well the horses synchronize with their environment, quantifying their rhythmicity. We established a linear mixed-effects model with DFC as the response variable. Bayesian Information Criterion based model selection revealed that lying duration and feeding regime were the most effective predictors of DFC. Our analysis showed a significant influence of external motivations on horses’ rhythmicity. In conclusion, DFC should be used cautiously within managed husbandry systems. One needs to carefully consider extrinsic factors that artificially retain the horses rhythmic before comparing the DFC between different systems.