Under temperate weather conditions, dairy goats use an outdoor run more with increasing warmth and avoid light wind or rain.

Access to an outdoor run might provide some benefits for the social and activity behavior of dairy goats. The aim of this study was to investigate the influence of weather parameters on outdoor run use by dairy goats under temperate weather conditions. Data were collected from February to April and in October, 2014, on 14 commercial dairy goat farms in Switzerland and Germany for 14 d per farm. Temperature, humidity, solar radiation, wind speed, and rain amount were measured continuously using a weather station. The outcome variables, average proportion of the herd in the outdoor run (proportion of herd in run) and average frequency of goats entering the outdoor run per hour in relation to group size (frequency of entries to run), were assessed by video data. Temperature, humidity, and solar radiation were combined to create the parameter "warmth" by means of a principal component analysis, whereas wind speed and rain (rain events and rain amount) were used in their original form as explanatory variables. Additionally, the effect of the comprehensive climate index on outdoor run use was investigated. Data were analyzed using linear mixed effects models. Increasing "warmth" increased, whereas increasing wind speed reduced, the proportion of herd in run. With increasing comprehensive climate index, the proportion of herd in run and the frequency of entries to run increased. On days without rain, the proportion of herd in run and the frequency of entries to run were markedly higher than during comparable daytime hours with rain. In the hour before the rain started and after it had stopped, more goats were in the outdoor run than during rain hours, but still fewer than during comparable daytime hours on days without rain. Furthermore, the proportion of herd in run and the frequency of entries to run decreased to a very low level when the rain amount exceeded 1 mm/h. To conclude, in the measured ranges of temperature (-0.8 to +16.5°C), humidity (34.8 to 99.2%), solar radiation (25.9 to 519.8 W/m), and wind speed (0 to 4 m/s), warmer conditions increased the outdoor run use, whereas the goats clearly avoided light wind and rain. Therefore, in the outdoor runs, protection against rain and wind could promote their use under temperate weather conditions. Furthermore, ensuring optimized access to solar radiation by considering the exposure of the outdoor run might be of advantage, as direct sun exposure induces warmer conditions.