Lying behaviour of group-housed horses in different designed areas with rubber mats, shavings and sand bedding

Abstract

One of the biggest concerns about group housing of horses is insufficient or interrupted lying behaviour, which might lead to sleep deprivation, and as a consequence thereof reduced performance and health. To address this concern the lying behaviour of 56 horses in a modern group housing system over four seasons was studied. This paper focuses on the lying behaviour of horses on different bedding materials. The reason behind is that rubber mats instead of natural bedding material have recently found an increase in the lying areas of group housings. Previous studies showed a reduced daily lying time on pure rubber mats. Therefore investigations were made on the lying behavior on sponge-filled rubber mats (7.5 cm in height, HIT-Softbed ® plus) in combination with a minimal amount of shavings (ca. 1 cm in height) and additional lying materials such as pure shavings (ca. 15 cm in height), both in three lying halls, sand in a shelter and sand in an open paddock. A particular concern of the study was, if rubber mats in combination with a minimum amount of shavings meet the horses demands as bedding material and provide a good stable climate. Moreover we investigated: preferences for different lying areas, individual differences in lying behaviour, influence of lying space, horses rank, daytime, and interruptions by group members. The mean daily total lying time per horse was significantly the longest on shavings (74.3 ± 2.87 minutes) and rubber mats (62.3 ± 2.27 minutes) both in the halls (in total 91.1± 2.7 minutes allocated on 3.2 ± 0.1 lying bouts) followed by sand bedding in the shelter (43.0 ± 2.33 minutes) and sand in the open paddock (26.7 ± 2.93 minutes). Despite horses laid down the longest in the lying halls, the shelter with sand was used more per surface area for resting recumbent, especially by low-rank horses. Hence, shelter is recommendable as an additional lying surface in group housings. No more than 50 % of the horses laid down simultaneously, although the lying space met the minimum requi-rement of the guidelines with 3 ×wither height 2 per horse (FMFAC 2009). A more diverse number of horses used the biggest lying hall for recumbency more often and for a longer daily period than the two smaller lying halls. Furthermore 32.7 % of the horses did not lie down every day. The horses of low rank showed a significantly shorter length (69.31± 3.9 min per horse per day) and a lower number of lying bouts (2.58 ± 0.1 per horse per day) when compared to horses of higher rank (90.9 ± 4.5 min high rank and 92.7 ± 3.6 min middle rank with 3.35 ± 0.1 and 3.12 ± 0.1 lying bouts per horse per day). Previous studies showed no differences in daily lying time if the lying space is twice the guidelines (FMFAC 2009). Therefore a lying space 6 × wither height 2 per horse is advisable for group-housed horses. Horses laid down synchronously and with 71.8 % of lying bouts (N = 1730 of 2410) mainly between midnight and 6 a.m. Non-eatable bedding material instead of straw only lead to 16.5 % interrupted lying bouts by group members, because foraging horses cannot disturb resting horses. Rubber mats with a minimum amount of shavings have no negative effect on stable climate. Crucial are: good ventilation and manure removed multiple times a day. In conclusion, horses accept rubber mats as a bedding material if they are at least minimally covered with natural bedding materials such as shavings. Group housing systems, which offer the choice between shavings, rubber mats covered with shavings, a shelter with sand and a sand paddock, can be qualified as suitable for horses in terms of animal welfare. Citation: Baumgartner M., Zeitler-Feicht M. H., Wöhr A.-C., Wöhling H., Erhard M. H. (2015) Lying behaviour of group-housed horses in different designed areas with rubber mats, shavings and sand bedding. Pferdeheilkunde 31, 211-220