Assessment of affiliative behaviour in mares

The first aim of study was to assess the feelings of friendship and companionship among mares released into a paddock in different combinations by analysing the duration of behaviours occurring there as well as changes in heart rhythm. The second aim of the study was to develop a procedure for creating different herd configurations based on the individual affiliative needs of horses, expressed as a score. The study was conducted on 12 one-year-old Thoroughbred mares. It was carried out on three consecutive days during the horses’ 30-minute stay in the paddock. On the first day, all mares were in the paddock together. On the second day, they were released in pairs, and on the third day, they were released individually. Expressions of affiliative behaviours (feelings of friendship and companionship) towards another horse were timed. The activity of the parasympathetic system was measured as well. The results were used to score the mares’ affiliative behaviour using a procedure of our own design. Feelings of friendship and companionship were found to be most strongly expressed when a herd of horses with an established hierarchy including each individual was present on the paddock. Releasing horses in pairs is a good substitute for releasing the entire herd, but cannot replace true herd relations, due to decreased expression of feelings of closeness and companionship, such as play or grooming. Releasing horses into the paddock individually is not recommended because it disturbs social behaviour, thus increasing emotional excitability. Emotional excitability is calmed when horses are released in pairs, so this configuration can be used for excitable horses. The best solution, however, seems to be the use of the affiliative behaviour score proposed in the study, as an indicator of the individual needs of mares when creating various herd configurations.