A pilot study investigating the behaviour of horses managed individually in small padocks and effects of a slow-feeding device : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand
his thesis discusses an observational pilot study, which explores the time budget of four horses kept individually in small paddocks. The horse (Equus caballus) evolved as a highly social, cursorial grazing mammal that roamed open grasslands in herds. Current research indicates domestic horses experience better physical and mental health outcomes when kept under similar conditions. Thus, through the lens of horse welfare, keeping horses at pasture is preferred to stabling or yarding. In New Zealand, most horses are kept at pasture year-round. However, the way horses are managed at pasture can vary significantly. Few studies have investigated how the size of a paddock or whether horses are kept alone or in company, affect a horse's welfare. This thesis begins to fill in the gap by characterising the behavioural time budget of horses kept alone in small paddocks. The findings are contextualised through a literature review of the time budgets of horses kept under different management conditions. This information could aid horse owners in making informed paddock management decisions that aim to improve horse welfare. Although the horses in this study could graze, the restrictions imposed by small, socially isolated paddocks were similar to that of stables. As seen in time budgets of stabled horses, I hypothesised that the horses would spend a large proportion of their time standing. Slow-feeding devices, such as 'foodballs', have been found to significantly increase the time horses spent eating concentrated feeds in stables and yards, and often reduced the time spent standing. As there has been no published research examining the use of foodballs when horses are on grass, this thesis also investigated whether horses will be motivated to use the device, and if so, how effective it is at slowing concentrate consumption and altering the overall time budget of paddocked horses. For the first part of the study, the behaviour of four privately-owned horses managed in their usual 132m2 paddocks at the Massey University Equestrian Centre, Palmerston North, was monitored through video recordings. Horses were filmed continuously during four, one-hour observation periods (7-8AM, 11AM-12PM, 4-5PM, 5-6PM) during daylight hours for three baseline days. A total 38 hours and 23 minutes of recordings were used in the baseline data analysis, 9 hours 48 minutes each for three horses, 8 hours 59 minutes for one horse. The proportion of time all horses spent in each behaviour during these four-hour time periods a day, was used to form a daily time budget. Horses spent a median (IQR) 75.4% (50.9%-94.5%) of their time grazing, 14.3% (2.9%-36.1%) standing and resting, 2.1% (1.1%-3.9%) in locomotion, and 0% (0%-0.2%) grooming. The data was then grouped into observation periods and analysed for time of day effects. Only the time spent in locomotion varied significantly with time of day (p=0.01), peaking at a median 5% during the evening period in which the horses received a concentrated feed, compared to median 1-3% for all other times of day. For the second part of this study, the horses were taught to use a foodball and a portion of their normal concentrated feed was supplied in the device for three days, before being filmed again on the fourth day. A total 11 hours 26 minutes of recordings were used in the data analysis, 3 hours 16 minutes each for two horses and 2 hours 27 minutes each for the other two horses. During the foodball condition, horses would use the device until empty, interspersing the activity with eating the concentrated feed supplied in a bucket and grazing. The time spent eating concentrates increased significantly from that of the baseline condition (p=0.045). However, the percentage of time spent in each other state behaviour during the evening periods was not found to be significantly different between conditions, and in both conditions horses spent most of the evening grazing (around 72%). In summary, the four horses were observed to spend most of their time grazing, similar to what is reported for feral horses and horses in large paddocks. However, these horses spent comparably very little time in locomotion or grooming, and had no physical social interactions. Providing a foodball slowed down concentrate consumption significantly, though did not significantly affect the time spent in other states. In a practical context, the results of this study suggest that keeping a horse in a small paddock does not reduce the time spent grazing compared to studies of horses kept in larger enclosures. Additionally, as this was the first study to use a foodball on grass, it was useful to find that the horses were motivated to use the device until empty.