Activity Time Budgets—A Potential Tool to Monitor Equine Welfare?

Abstract

Horses’ behavior can provide valuable insight into their subjective state and is thus a good indicator of welfare. However, its complexity requires objective, quantifiable, and unambiguous evidence-based assessment criteria. As healthy, stress-free horses exhibit a highly repetitive daily routine, temporal quantification of their behavioral activities (time budget analysis) can assist in equine welfare assessment. Therefore, the present systematic review aimed to provide an up-to-date analysis of equine time budget studies. A review of the literature yielded 12 papers that fulfilled the inclusion criteria: assessment of equine time budgets for eating, resting and movement for a minimum of 24 continuous hours. A total of 144 horses (1–27 years old), 59 semi-feral and 85 domesticated horses, are included in this review. The 24 h time budgets for foraging or eating (10–6.6%), resting (8.1–66%), lying (2.7–27.3%), and locomotion (0.015–19.1%) showed large variance between studies, which can largely be attributed to differences in age and environmental conditions. Management interventions in domesticated horses (ad libitum access to food, increased space, decreased population density) resulted in time budgets similar to their (semi-)feral conspecifics, emphasizing the importance of environmental conditions and the ability of time budgets to assist in monitoring horses’ welfare.

Equine Activity Time Budgets: The Effect of Housing and Management Conditions on Geriatric Horses and Horses with Chronic Orthopaedic Disease

“…Horses in this study were eating 42% of their day, which is within the wide range of 10-64% measured in domestic horses but below the 50.82-66.6% reported for semi-feral horses [13,16,[23][24][25][26]36,[40][41][42][43][44][45]. Coinciding with the literature reporting 60-70% day-time and 30-40% night-time feeding [46], eating times were highest in the morning and the afternoon and lowest in the night and very early morning hours, even in horses that were turned out on pasture overnight during high summer temperatures.…”

“…The overall time budget for resting of 39%, which included periods of inactivity and sleep, was higher compared to free-ranging conspecifics (12.9-29.3%) but well within the 15.6-66% range reported for domestic horses [13,16,[23][24][25][26]36,[40][41][42][43][44][45]. As horses divide their day mostly between eating and resting behaviour, the time budget for resting expectedly correlated negatively with eating (p < 0.0001, r = 0-0.655) and thus was highest in stabled (mean 47.97% ± 14.62% s.d.)…”

“…Changes in horses' time budgets may reflect a coping mechanism to an inappropriate environment or health issues and indicate a potential welfare impairment [10][11][12][13]. The time budget of feral, free-ranging horses is typically used as a baseline for comparison with the view that optimal welfare is reflected in wild-type behaviour [7,[10][11][12][13][14][15][16][17][18].…”

“…Changes in horses' time budgets may reflect a coping mechanism to an inappropriate environment or health issues and indicate a potential welfare impairment [10][11][12][13]. The time budget of feral, free-ranging horses is typically used as a baseline for comparison with the view that optimal welfare is reflected in wild-type behaviour [7,[10][11][12][13][14][15][16][17][18]. However, the validity of such comparisons has not been assessed and the environment of most domestic horses is far removed from the wild, which rarely meets the five freedoms of animal welfare [3,4,11,14,15,[19][20][21][22].…”

“…Traditionally, equine behavioural activity time budgets were measured by direct observation or manual video analysis, which was prone to observer bias, often limited to daylight hours and too time-and resource-intensive to be feasible for welfare assessment [13]. Recent technological advances in automated biotelemetry and sensor systems reduce the potential of a possible observer influence and enable accurate staff-and costefficient, non-invasive 24 h-time budget analysis over several days [8,[34][35][36][37], which may facilitate their wide-spread adoption in welfare audits.…”