Adequate space for rest crucial in group-housed horses, research shows

Group housing helps to meet the social needs of horses, but do they still get adequate opportunities to lie down and sleep?

The issue has been examined in a study published this week in the open-access journal Animals.

Linda Kjellberg and her fellow researchers at the Swedish University of Agricultural Sciences said sleep is crucial to the wellbeing of horses, and their lying time can vary according to such factors as climate, exercise, bedding, and housing.

The sleeping behavior of group-housed horses may also be influenced by social relations and competition for space, they said.

The study team set out to analyze behavior and time spent in barns for resting, called lying halls, of various sizes. They also examined the influence of housing systems on total lying time and behavior, and how changes to available lying area can affect this resting time.

Two open barns were used in the study with lying areas of 8, 15, and 18 square metres available inside for each horse.

The behaviors of the horses were recorded on video and logged using scan sampling and interval observations. Individual stalls were used as a control.

The horses were found to spend a longer time off their feet in the hall when the available lying area was 18 square metres each, compared with the hall offering 8 square metres per horse – the minimum requirement under Swedish legislation.

Increasing the area of the lying hall also increased the overall time spent there, they reported.

Overall, they found that increasing the lying area boosted the animals’ use of the lying hall and their total lying time.

They also found that the lying time of a horse housed in a single box was equivalent to the lying time of a horse in group housing with access to 18 square metres per horse.

“To ensure access to sufficient resting space for all horses in group housing, we recommend that the minimum requirement should be reassessed and increased,” they said.

The authors noted that when the horses had access to a lying area of only 8 square metres per horse, their lying times were no shorter than those observed in feral horses, based on the findings of three previously published studies.

However, overall, their observations suggest that the current minimum lying area requirements – at least those stipulated by Swedish legislation – might be too small for the domesticated horse, and that the minimum requirement could be increased to better safeguard their welfare.

“Our recommendation, in order to improve the welfare of horses kept in open barns, is to increase the minimum requirement of the lying area by a factor of 20 to 100%.”

This was based on the finding that to offer a lying area extended by only 20% encouraged the horses to prefer that specific lying hall.

“Furthermore, increasing the available lying area increased both the use of the lying area and the lying time.

“Since it is crucial to the welfare of horses that they have the opportunity to get enough sleep, the choice of bedding is an important factor to consider. However, further studies are needed to ascertain the optimal lying area per horse and bedding material in a lying hall, in order to maximize the sleeping comfort of each individual.”

The researchers said they believe there is demand for research into “best practice” for planning and managing animal welfare in open barns, which they said should not be dictated solely by minimum requirements.

The study team comprised Kjellberg, Jenny Yngvesson, Hanna Sassner and Karin Morgan.

Kjellberg, L.; Yngvesson, J.; Sassner, H.; Morgan, K. Horses’ Use of Lying Halls and Time Budget in Relation to Available Lying Area. Animals 2021, 11, 3214. https://doi.org/10.3390/ani11113214

The study, published under a Creative Commons License, can be read here.