Daytime shelter-seeking behavior in domestic horses

We examined daytime shelter-seeking behavior (SSB) in domestic horses housed outdoors and studied the relationship of temperature, precipitation, and wind speed with SSB. We studied 50-60 Arabian horses (depending upon time of year) and 3-5 draft horses. Horses were divided among 8 pastures containing sheds. There were 2 study phases. In the first, up to 676 scan samples were taken for each pasture over a 12-month period (total observations = 5,025). At each observation, we noted whether or not a shed was being used. In the second phase, randomly selected focal animals were chosen from each pasture and observed twice per week for 16 weeks. Forty-four focal animals were observed (total observations = 3930). At each sampling time, we noted weather conditions and recorded whether each subject was standing or lying inside or next to shelters. Shelter usage ranged from a low of <10% of observations in many weather conditions to a high of 62% of observations when it was snowing and wind speed was >4.9 m/s. When wind was >2.2 m/s, there was a significant effect of rain on shelter usage, that is, more horses used shelters in rainy, breezy conditions (P < 0.01). When wind was >2.2 m/s, there was a significant effect of snow on shelter usage, that is, more horses used shelters in snowy, breezy conditions (P < 0.01). Though overall shelter usage was typically <10%, it appears that shelter access is very important in certain weather conditions.