Wyoming

Northeast Wyoming ranchers may want to provide custom mineral supplements containing phosphorus, magnesium and zinc to their cattle and sheep, according to a three-year study by a University of Wyoming Cooperative Extension Service educator in Johnson and Sheridan counties.

Blaine Horn said producers running cattle should consider adding manganese and copper to the supplement, while those raising sheep may want manganese and sulfur mixed in.

In a 10-page report, Horn emphasized that producers should have range grasses from several pastures analyzed for their mineral content before having a custom mix developed. Optimum times to collect the grasses are early and late spring and late fall, according to his research.

"This time of year and through the rest of winter, some of the minerals will continue to decline. Sampling grasses in late fall and early winter will help give ranchers a better idea of what minerals are needed in a supplement," Horn said. "Come March, it wouldn't hurt to sample again."

Horn recommends that livestock producers share the results with a reputable livestock nutritionist so an appropriate mineral supplementation mix can be developed to meet the needs of their animals.

"In addition, other feed sources raised or purchased such as hays and silages should also be analyzed for their mineral content. These feed sources could serve as a supplement for some of the minerals that may be lacking in dormant range grass," he said.

Horn launched the study in 2002 to help northeast Wyoming livestock producers cut production costs while maintaining or improving the performances of their cattle and sheep.

"For the cow or the ewe, it could be weight gain or at least the maintenance of their weight, improved conception rates, possibly improved birth weights and calf or lamb weight gain," Horn said. "Depending on what the deficiency is, improvements in overall performance may be subtle and actually be the maintenance of health of the dam, allowing her to stay in the production herd longer."

Studies by other researchers were previously conducted to determine the mineral content of grasses of the Northern Great Plains, Horn said, but it was not known if the results were applicable to rangeland grasses of northeast Wyoming.

"To maintain healthy, productive livestock, it is important for ranchers to know what the quality of range grass their livestock are grazing is as well as that of provided harvested forages," Horn emphasized.

"Forage quality includes not only crude protein and energy but also minerals. By knowing how much of each quality component range grass and harvested forages contain, ranchers can provide their livestock custom-made supplements that meet their nutrient needs."

Horn sampled range grasses from several ranches throughout Johnson County between 2002 and 2004.

A copy of his report along with tables and figures are available at: http://www.uwyo.edu/CES/NEW_WEB/Johnson/publications.htm.

Click on the "Mineral Content of Range Grass" link.

The report contains information on the mineral needs of cattle and sheep and how ranch location and time of year affect the mineral content of range grasses.

"Forage mineral analysis can be expensive, so the minimum number of samples taken to obtain useful information is paramount in order for there to be a positive cost-benefit ratio of this practice," he writes.