Unusual methods yield valuable data for cattle producers

When I was told that someone put GPS collars on cows and I’d be writing about it, I wasn’t sure what was in store. Having grown up on a farm, I’ve seen how global positioning systems are used in planting, spraying and harvesting. I’ve even used it to find new restaurants, but cattle?

Iowa State animal science professor and researcher Jim Russell has a long history of collaboration with the Leopold Center.  His work covers rotational grazing, factors that contribute to successful management and profitability, as well how to maintain water quality in pasture-based production systems.  His most recent competitive grant project looked at cattle movements and preferences in a pasture, and GPS collars were the best way to keep track of them.

The experiment called for recorded data on movements of two or three cows in eight different pastures on five cow-calf farms in the Rathbun Lake watershed area. Each cow wore a GPS collar for two weeks during the spring, summer and fall of 2007, 2008 and 2009. Temperature and humidity also were recorded.

“We wanted to find out how much time cattle really were spending near waterways and if they were, why,” said Russell. “After three years, we noticed that they don’t spend nearly as much time in or near the water as people generally think.”

The location of the cattle in relation to creeks or other sources of water is very important information for the Leopold Center’s grazing research program. It has been assumed that cattle in pasture-based systems are large contributors to the levels of sediment, nutrients and pathogens found in surface water.

Having only a limited amount of experience with cattle as a child (does riling my dad’s Charolais bulls count as experience?), I had to ask how they got the collars on the animals in the first place.

It really wasn’t that different from most cattle handling,” said Doug Bear, graduate research assistant on the project. He is from southern Iowa near the research sites, and had prior relationships with some of the producers, all of which helped the project run smoothly.

The producers did most of the handling as that was their major concern about the project,” Bear said. “We put the cows into a chute and fastened on the collar. We tried to avoid any cattle that might jump the chute."

I also was interested in learning about the biggest obstacles for getting farmer cooperators for this project.  I’ve known a few cattle and pork producers (probably related to me) and one thing I’ve noticed is that telemarketers and researchers don’t often make it to the top of the priority list.

They were a little hesitant because of the amount of handling,” Russell said. “We were limited by the two-week battery life on the GPS receivers in that respect. Several producers told us they would love to do it if we could put the collars on in May and take them off in September.”

But the effort paid off. Findings showed that the amount of time cattle spend in water varies by a specific pasture conditions. For example, size and shape are most important and smaller pastures generally mean more time in the water. But if all pastures are the same size, the shape will determine how long animals stay in the water. If all pastures are similar in size and shape, then shade placement becomes the variable that influences more or less time in the water.

It seems pretty obvious, but with the different-sized pastures we had to begin with, we didn’t see any differences,” said Russell. “When we controlled for different variables, it was pretty easy to see that size and shape of the pasture can greatly reduce the risk of water contamination.”

When asked what he had learned that producers could use right now, Russell’s answer was so direct that I thought for a second my dad had stepped into the room.

Creating buffer strips between pastures, providing off-stream water sources or stable crossing points, and using rotational grazing are good places to start,” he said. The size and shape of pastures does matter, and cattle don’t spend as much time in the water as we hypothesized so other factors may be contributing to the water quality, such as wildlife or even septic tank leakage. Sediment in the water is caused more by the hydrology than by cattle kicking it around.”

Recommendations for cattle producers

An example of a stabilized water source access.

Although cattle don’t spend as much time in the water as previously thought, they do tend to spend more time in water when temperatures rise. These suggestions are based on Russell’s previous research, summarized in a three-part series, Guide to Managing Pasture Water. Following these recommendations (and considering specific characteristics of the pasture) can greatly reduce the risk of stream pollution.

•Provide access to water away from the stream. This gives cattle an option and can reduce the amount of time they spend in the stream.
•Shade in the pasture’s uplands, away from the stream, will help cool cattle and reduce time spent around the water source.
•Supplements such as mineral blocks should be placed far from the stream because nutrients can build up and get into the stream via runoff.
•Stabilized water source access sites with exclusion fencing will control where cattle may congregate to get water, and also provide crossings for animals and truck or machinery traffic.
•Riparian buffers (areas of grasses, shrubbery and trees fenced from fields and pastures) also can reduce pollution risks as well as provide wildlife habitat.

By RUSSELL HINKELDEY, Leopold Center Communications Intern

For more information: http://www.leopold.iastate.edu/pubs/nwl/2010/2010-1-leoletter/grazing.html

Published by the Leopold Center for Sustainable Agriculture
Ames, Iowa 50011, (515) 294-3711
URL: www.leopold.iastate.edu