When cattle are on rangeland, and near a stream, just how much time do they spend in the water? Chances are it's less than you think, at least according to a new report from Oregon State University.

In a five-year study recently published in the Journal of Soil and Water Conservation, OSU researcher John Williams and his colleagues placed GPS tracking collars on cows and sent them out to graze, with their herds, across large tracts of eastern Oregon land. They found that cattle spend about an average of 1% to 2.5% of their time on the range in a stream.

Researchers mapped cow positions over the paths of rangeland streams across five spring-to-fall grazing seasons. Turns out cows only go down to the water when they needed to drink, but did not typically rest or hang out there. Most of their time was spent grazing on higher ground, or resting on dry areas away from the stream.

Williams said that this is the first good quantitative data about cow use of streams on a range. Public lands grazing has been controversial, and public pressure over concerns of rangeland damage from grazing led to adoption of grazing management practices to protect streams.

In 2008, Williams and his colleagues started tracking the movements of herds grazing three federal allotments in the Wallowa-Whitman National Forest in northeastern Oregon. The study sites comprise about 170 square miles of forest and rangeland. All grazing was conducted by private ranchers under approved grazing management plans.

In each allotment, 10 cows out of a herd of 300 to 400 head were fitted with GPS collars at the start of the grazing season — typically April to June. The collars recorded the cows’ locations about every five minutes, yielding more than 3.7 million data points over the five-year study.

They found that cattle movement patterns were influenced by a range of factors, including areas of preferred forage, and water sources, fences and areas previously logged or burned. Cattle were not particularly drawn to the streams; they went to water at favorable access points to drink or cross to other grazing areas, but they didn't linger.

And the cows used less than a quarter of the stream area. The rest of the streamside areas were lightly visited, or not visited at all, because streams were inaccessible or stream banks were too steep. Williams concluded that as long as cattle could get to water when they needed it, "it appeared that they were more influenced by where the best forage was than by anything else."

The results weren’t exactly a surprise, Williams said; OSU research dating from the 1980s suggests that cattle don’t spend much of their time in the water. “But how many data points can you get with a grad student out there watching a cow? Now, with this GPS technology, we can get a body of data we can really analyze, and we can start answering some of these controversial questions with confidence.”

The research was supported by the USDA's National Institute of Food and Agriculture, and Agricultural Research Service; the Oregon Beef Council; the Oregon Agricultural Experiment Station; the University of Idaho; and the International Center for Agricultural Research in the Dry Areas.

Source: Oregon State University