RESUMEN
Eighteen lactating dairy cows were used to elucidate their preference for green, grey, or red troughs. The herd was managed under a rotational grazing system with ad-libitum access to water until 11:30 h. For 9 days, all cows were tested individually following the afternoon milking. Cows drank similar quantities, spent a similar amount of time drinking, and took a similar number of sips from the 3 trough colors (p > .05). In 75% of the tests, cows drank more than 95% of the test period from the same trough. Within this time, the percentage of choices did not differ among colors (33.3% green, 39.0% grey, and 27.7% red). When they chose the red trough, cows spent less time drinking (p ≤ .05) and tended to take fewer sips (p = .07), which could suggest a partial aversion to this color. Suboptimal water trough design may have long-term negative effects on both the production and welfare of dairy cattle; however, the results suggest that color does not play a major role in the drinking behavior of dairy cows.