Knowledge Bank

Colored buckets are used by owners and nutritionists for color coding as this can reduce the potential for mistakes. When using colored buckets for research, it is important to know whether color biases results. Horses have dichromatic vision, which limits equine color perception. Additionally, bucket color can affect the absorption of solar radiation and temperature of the contents (P < 0.0001) as determined in our pilot study. To test if horses have color preferences for buckets, two trials were conducted. In the first trial, 32 horses were stalled overnight with access to eight different colored buckets each containing 4000 g of water. In the second, eight horses were used eight times with the colored buckets in a different order each time. Each bucket contained ~55 g of chopped hay. Four of the horses had been used for forage preference testing 10 months prior with the same set of buckets. These horses were included to determine if they had retained their previous preference. The horses were fasted for 20 min prior to preference testing for 20 mins. The amount consumed and first choice were recorded in both trials. We found in the first trial that color had no effect on water consumption (P > 0.05). However, bucket location had an effect (P = 0.03), with buckets closer to the stall door being selected more. For the feed trials neither order nor color had an effect on hay consumption (P > 0.05). As a population, the horses previously used in preference testing did not have first choices statistically different than the naïve horses (P = 0.78) or chance (P = 0.86). However, one outlier horse did tend to have a different first choice frequency (P = 0.051), but did not consume more from his first choice buckets. These findings support the use of color coded treatments in nutrition research, especially when conducted out of direct sunlight. Colored bucket preference of owners and managers should not affect equine consumption indoors.