After a short adaptation period, pregnant beef cows will consume snow in amounts equivalent to the water intake of cows receiving liquid water. Through extensive testing in the early 1980's, the University of Alberta found insignificant differences in cow performance or body stress levels when asked to eat snow as their sole water source.
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¨ Wintering beef cows are able to consume snow as their sole water source given that the snow is in a form that the cows can easily eat. The snow must be soft and friable so that the cows can lick a significant quantity into their mouths for melting.
¨ Once cows are used to consuming snow as their sole water source, they will consume small amounts of snow throughout the day during their free time. Cows can be seen licking snow before, during and after their primary feeding times.
¨ Although it takes ten times the amount of energy to melt a gram of snow from it's solid state to it's liquid state compared to heating the similar quantity of a liquid one degree Celsius, the key to energy use difference is found in the rate of consumption. Cows eating snow take all day to do so. Cows drinking cold trough water will consume their daily needs within minutes.
¨ Because of the slow and ongoing process of eating and melting snow, cows in effect use their waste heat to melt their snow. Because the melting process is such a slow process, the cow's body temperature never drops below it's critical point. Hence, the body's metabolism never needs to kick in to raise it's temperature as it does when a cow drinks large quantities of near freezing water from a waterer.
¨ The best indicator of whether a herd is getting enough water from melting snow is to monitor feed consumption. As long as feed consumption is adequate and consistent from day to day, the cows are getting enough water from the snow. Should feed consumption drastically drop over a short time period, water shortage may be the cause.
¨ The biggest stress for cattle eating snow is the transition period. Cattle that have never needed to eat snow and have only consumed water will vocalize to show their discontent. Following a day or two of discontent, the herd soon learns from the early learners that snow can be licked with positive results.
¨ Once cattle have learned to eat snow, the transition period is much shorter. Eventually cattle will eat snow without little discontent.
¨ Once cattle are accustomed to eating snow, they will often stay out in the fields where the feed is placed rather than walk home for water. The observation is that animals find it easier to eat snow rather that expend the energy to walk home to drink water.