Many areas in the Western United States are dominated by sagebrush. The increase in sagebrush density over the past century is generally attributed to: 1) reduced numbers of mixed feeders and browsers such as deer, antelope, goats and sheep, 2) increased numbers of cattle and elk, 3) repeatedly grazing the same grasses and forbs, particularly during spring, and 4) fire suppression.
Cattle grazing in grass and sagebrush pasture.
Though the decline in diversity is due in part to grazing, grazing may in fact be the answer to improving plant diversity and wildlife habitat in sagebrush-steppe ecosystems. For example, if sheep and cattle graze sagebrush during the fall, when grasses and forbs are dormant, we reduce sagebrush’s competitive advantage, leaving more room and resources for the grasses and forbs in the next growing season.
Research at Utah State University has shown that energy and protein supplements in the form of hay and alfalfa pellets or range cubes help livestock detoxify the terpenes found in sagebrush and can even double the amount of sagebrush they eat. In addition, some studies suggest that rumen microbes may need to adapt to sagebrush in order to use it. Researcher Chuck Peterson used this information to help cattle on Agee Smith’s Wells, Nevada ranch to begin eating sagebrush. After learning about this at a talk by Utah State University’s Dr. Fred Provenza, Mat Carter, an Oregon rancher, decided to try to use sagebrush as winter-feed and as a way to grow more grass for his cows.
That following winter, he corralled 150 cow-calf pairs with electric fence on 5 to 10 acres for 3 days and fed them 15 to 20 lbs of meadow hay. The pastures were a mix of low and big sagebrush, gray and green rabbit-brush, bitterbrush and an understory of grasses. Grazing decreased the amount of brush and increased grass and new sagebrush seedlings.
The following year, Mat used 400 dry pregnant cows. That year snow cover was light so he fed 3 to 10 lbs/hd/day of meadow hay and moved his cows about every 3 days. The amount of hay fed depended on weather and available forage. Mat noted that as he turned his cattle onto a new strip some ate grass, others bitterbrush and others sagebrush.
In 2007-08, he grazed rangeland where the canopy cover of big sagebrush was 50 to 70%. Some of the shrubs stood 4 to 6 feet tall. Snow was deep that year, 2 to 4 feet. For about a month his cattle were fed 10 to 15 lbs/hd/day of hay. The rest of their diet was sagebrush.
In 2008, he leased some cattle and trained them to eat sagebrush. Snow was deep so only sagebrush was available. He started feeding 20 lbs of hay and over a 2-week period he reduced hay to 6 lbs/hd/day. Cattle were in good body condition when they came to the ranch and remained in good condition throughout the winter.
Besides saving on hay and increasing the amount of grasses and forbs on his rangeland, Mat has noted several other benefits to using sagebrush as winter forage. His cattle eat sagebrush even when other forage is available. They also eat plants he had never seen them eat before like stinging nettle, whitetop, lupine and various wild flowers. Finally, when cattle graze sagebrush rather than hay, they require less water.
This graph shows weight changes in animals in Chuck Peterson’s research project. Cows with calves grazed sagebrush plots in 2007. In 2008, a subset of the 2007 calves grazed sagebrush plots as experienced bred heifers, and in 2009 they grazed again as experienced, first-calf cows.
If you’re considering trying this, be sure to consider the kinds of animals you’ll be using. Mat calves in June so during the middle of winter his cows have relatively low nutrient requirements. Browsing sagebrush has had no adverse effect on his calf crop and his cattle seem to breed back just fine and he’s found no down side to encouraging his cattle to eat sagebrush. But you should be aware that not all animals will gain weight well. Chuck Peterson found that calves tended to gain weight during the feeding trials, smaller framed cows generally maintained their weight or gained, and larger framed cattle tended to lose weight, and animals inexperienced with grazing sagebrush lost more weight.
The upside with helping cattle become better sagebrush grazers are changes in the forage in pasture. Chuck Peterson found that Fall grazing was increasing the understory of grasses and forbs and changing the age class structure of the sagebrush in the treatment plots. The graphs below show data from Chuck’s plots (grazed and not grazed) that were grazed in 2007 and then sampled in July of 2009 for percent cover, production, and % species composition. In general, grazed plots contained more grasses and forbs and less sagebrush and other shrubs. This is good news for both cattle and the other wildlife that share their habitat.
The yellow bars show what happened in areas grazed by sagebrush eating cattle. You can see that the grazed areas produced a lot more grass and forbs and less shrubs and sagebrush than the ungrazed areas.
In this graph you can see how the composition of the pastures changed when they were grazed by sagebrush eating cows. Ungrazed areas continued to increase in sagebrush, while sagebrush decreased in grazed areas. Way to go cows!
