Stocking Rates: Let Your Cows Tell You!

Dr. Bob Lyons is an Extension Range Specialist based in Uvalde. He has done a lot of research into grazing habits and stocking rates. In a recent program Dr. Lyons showed some really neat information about a research project he conducted on a South Texas ranch. Basically what they did was to put Global Positioning Satellite collars on a herd of cattle at a 2000 acre ranch. These collars signaled back to the researchers exactly where all the cattle were at all times and even plotted if they were grazing (moving) or resting. All of this information could then be plotted out on aerial photos to determine where cattle were spending their time and consequently where they were grazing. This tracking information was then followed up with visual on the ground investigations of what was in an area that was grazed or not grazed.
For instance they found that there was an area of the ranch that the cattle just would not go into but from the aerial photos the ground looked like good grass. When they went to look they found that there was lots of grass, good grass, but there was also a lot of rock. In fact they found that with as little as 30% rock cover cattle will not go into a pasture. They will only use an area about 35% of the time if there is as little as 10% rock cover.
They also took soil survey information and laid it over the aerial photos to plot out grazing patterns by soil type. In this ranch they looked at two soil types, Rumple-Comfort and Comfort-Rock. Cattle consistently preferred Rumple-Comfort to Comfort Rock about 2.5 to 1. This means that cattle were in these areas 2.5 times more because the better soil grew better grass.
In another example a pasture section had no cattle grazing, in fact it showed up as a big hole in a pasture on their photos. When they went to investigate, this particular area was ringed in cedar. Now a cow could certainly get into this pasture area but she wasn’t going to simply because it was “walled” off with cedar.
In another example they found that no cattle had been in a pasture that looked like a “sea of grass.” Even from their pickups they couldn’t figure out why the cattle wouldn’t graze the grass until they got out and started walking. This particular pasture was almost solid threeawn grass species. This is a beautiful looking grass but unfortunately not at all palatable or nutritious and the cattle showed them it wasn’t by not eating it.
It doesn’t take long to understand that even though this ranch was 2000 acres, only a limited amount of it was available for grazing. In Williamson County there is lots of pasture and rangeland but of the over 300,000 acres that could be grazed how much really can be grazed. Use your livestock to show you any barriers to grazing and either fix them or subtract them from your grazing plans.