Social distances of goats at the feeding rack: Influence of the quality of social bonds, rank differences, grouping age and presence of horns

To minimise social conflicts between goats and improve pen design, knowledge of factors affecting social distances at the feeding rack is needed. In our study, we investigated the influence of the quality of social bonds, rank differences, grouping age and presence of horns on two types of social distances: (1) the distance goats choose freely at feeding when they have the option of keeping a large distance between each other; (2) the minimum distance possible without agonistic interactions if the goats are forced to feed in close proximity. We used eight groups consisting of nine goats of different Swiss milking breeds and their crossbreeds that were kept in eight identical pens. Goats in four groups each either had horns or were hornless, and had been grouped either as juveniles or adults (2 x 2 factorial design). Information on social parameters (rank difference, quality of social bonds using the categories amicable, neutral and antagonistic) was collected for each dyad in the groups' home pens. For each dyad within a group, we recorded the freely chosen distance at a 6-m-long hayrack (experiment 1) and the individual distance (=minimum distance possible in which no agonistic interactions occur) when two small mobile hayracks (one for each goat) were moved towards each other (experiment 2). The two types of social distances measured in the experimental situations were analysed using linear mixed-effects models. The social distances in both experiments were significantly influenced by the quality of social bonds and age at grouping. Dyads with an amicable bond showed smaller distances than neutral or antagonistic dyads (experiment 1: p = 0.05, experiment 2: p = 0.001), and goats grouped as juveniles kept smaller distances apart than goats grouped as adults (p = 0.01 in both experiments). Rank differences and the presence of horns had no significant influence on the sizes of social distances. In conclusion, our results stress the importance of a sensible grouping management in goats aiming at grouping the animals early in ontogeny and keeping group composition stable. (C) 2008 Elsevier B.V. All rights reserved.