Ken Olson: Snow as a water source for cattle
December 10, 2010
Late last winter I received questions from a number of producers asking whether cows could get adequate water from eating snow if they didn’t have access to drinking water. Now that we are entering winter again, it seems like a timely topic for this column.
The situation can arise in hard winters when rural electricity goes off for several days so water wells and tank heaters don’t function. Deep snow that prevents hauling water to the cattle exacerbates the situation.
The bottom line is that dry, pregnant cows and young stock can do well on snow without any drinking water, as long as a few caveats are understood. Lactating cows require more water to produce milk, so eating snow would not provide adequate water for them.
The first caveat is that a herd of cattle needs access to a lot of snow for each cow to consume adequate amounts of water. They need to be allowed to find it throughout a large pasture so they aren’t competing with each other for access to localized drifts in a small area. Research in Canada indicates that cows consume snow in small amounts scattered throughout the day, whereas cows drinking from a tank or waterer will drink water only once or twice a day. Thus, easy, continuous access to snow is important.
Another consideration is that the snow cannot be compacted or crusted over. Cattle do best with loose, powdery snow because it is easy to lick up. It may be necessary to break the crust of drifted or iced-over snow so that cattle can access loose powder that is underneath the crust. This may require driving through snow banks with the tractor to break them up.
Some people have wondered if the energy required to melt the snow once a cow has eaten it will reduce the energy available for her to maintain herself, causing her to lose body condition. Again, research conducted in Canada indicate there was not any difference in feed intake or body weight among cattle that received snow vs. drinking water. It may be that spreading the snow intake throughout the day allows a cow to melt small amounts at a time, thus requiring few calories to melt the snow and little influence on body temperature.
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A herd of cows that has never had to eat snow may need to learn to eat it. Apparently, knowing that snow is a source of water is not instinctual. Past research and producer experience indicates that cattle learn this quickly and will adapt to eating snow in about three days. This is quick enough that there should not be an impact on cattle performance from limited water intake. Observations indicate that once a few individuals in a herd start eating snow, the rest learn quickly by imitating the fast learners.
Research was conducted in the 1990s at the USDA Fort Keogh Research Station near Miles City, MT by Don Adams to evaluate amount and variation of water intake among individual cows in a herd grazing winter range. They set up a water fountain so that only one cow could drink at a time and used electronic ID to record when and how long each cow used the waterer, along with measuring the amount of water that each cow drank. Only about two-thirds of the cows drank water every day, with some cows drinking every other day; some going three- to four-days at a time between visits to the waterer; and a few cows (about 2 percent) never used the waterer at all (all of their water consumption was from snow). Researchers couldn’t tell by looking at the cows which ones used snow vs. the waterer, and there was no difference in performance.
In conclusion, dry, pregnant cows can consume adequate water from snow in the winter. Cattle producers in the Northern Plains region have been able to use this to get through emergencies. A few producers successfully graze specific pastures in the winter because those pastures don’t have water, and thus the cattle are dependent on snow as their only source of water for an extended period of time.