Does your sports horse need a friend?

Many horses kept for sports or recreational use are housed in individual stables, some only for a part of the day and others permanently. Some of these stables allow some form of contact with a neighbouring horse, while others minimize social contact. The reasons for housing horses in single pens are various; cleanliness of the horse, ease of getting close to the horse, protection from the elements, lack of pastures and some owners even believe that their horse has no need for social contact. However, could horses have a strong need for social contact with other horses, and could restricting social contact between horses have a detrimental impact on their welfare?

Horses can tolerate cold very well.
Make them wear a rug if you're worried about cold.

Feral horses are very social, and their survival depends on strong social bonds between families or bachelors. For example, the (early) detection of a predator and the following flight are important defence mechanisms for a group of horses. There is strong evidence that our modern sports horses still have a very basic need for social contact (from now on, when I speak of social contact, I mean social contact with other horses, not with other species including humans): former domesticated horses that have become feral display many social interactions and a very structured social organization. However, a main difference between feral horses and domesticated horses is that our domesticated horses generally do not choose their own social groups (we decide what individuals share a paddock) and paddock space may be limited. In addition, in domesticated horse groups there are generally more males (geldings) than in feral groups.

So what kind of social behaviours do horses engage in? First of all, there are agonistic interactions that help determining the hierarchy in the group. All social groups form hierarchies to determine which individuals get first access to the best food, shelter and mates. Hierarchies also ensure that it is “clear” what individuals have the highest rank in the group, which then minimizes aggression. The main agonistic behaviours that horses show are 1) threat behaviours consisting of attack, bite, threat to bite, and approach with ears flattened and 2) submissive avoidance behaviour. Kicking with the hind legs is used both while attacking and while defending from an attack, and is therefore context dependent.

This is my 21 year old (now retired) horse.
He always had plenty of time at pasture with his friends,
even when competing at advanced level dressage
(a long time ago...). 

Another important social behaviour is allogrooming when two horses groom each other. Foals start allogrooming within the first two weeks of life, usually with their mother or brothers and sisters. Research has shown that allogrooming is rewarding for horses, meaning that it results in the release of “pleasure” hormones (endorphins). Horses that are housed in single pens with minimal social contact are very keen to have physical head and neck contact with an unfamiliar horse. However, when two grooming horses were separated after 5 min of the social contact, the horses showed physiological and behavioural signs of frustration, again showing that allogrooming is important for horses. Play is most likely an equally important and rewarding behaviour in foals and geldings, although it may be less important for mares.

So does your horse suffer when it cannot experience the joys of allogrooming and play, or perhaps any other social behaviour that is rewarding? Unfortunately, very few studies have investigated this question directly and little data is available. However, it is known that chronic stress in horses leads to stereotypic behaviours which are repetitive behaviours that seemingly have no function, such as weaving, wind sucking, crib-biting, box-walking and wood-chewing. Stereotypic behaviours are generally interpreted as a sign of poor welfare. Several studies have shown that individual housing, irregular social contact and limited access to pasture are among the highest risk factor for developing stereotypic behaviours. Therefore, it is likely that limited social contact leads to suffering in horses.

To ensure the welfare of your horse, give it plenty of access to pasture and allow it to play and interact with other horses!

Reference: Vandierendonck et al., 2012. Applied Animal Behaviour Science 138, 194-202.