Improving Grazing Lands with Multi-Species Grazing
Multi-species grazing is when more than one kind of livestock (i.e. sheep, goats, cattle, or horses) graze a unit of land. The grazing can occur at the same time or at different times and still be considered multispecies grazing. Multi-species grazing is the norm for naturally regulated ecosystems. The grazers are a variety of wild animals like deer, elk, rabbits, rodents, and insects. On managed grazing lands, the norm is that grazing is dominated by a single species of livestock, usually cattle. However, few land managers appreciate the adverse impact that single-species grazing can have on the botanical composition of grazing lands.
Simply including sheep and goats in an extensive management system could have highly beneficial results in terms of vegetation composition. It can be argued that the current problem with invasive weeds in the Western United States has resulted from declining sheep numbers during the past 20 years. Many of the worst weeds we currently battle, like leafy spurge, yellow starthistle, and spotted knapweed, are forbs that sheep and goats find palatable and nutritious.
These advantages result from different dietary and topographic preferences of different species of livestock. These differences include the plants the animals prefer to eat and where they graze. Cattle are primarily grazers, and their diets across a wide array of grazing land types are typically 70% grass. In contrast, goat diets average about 60% browse. Sheep diets are about 50% grass, 30% forbs, and the rest browse. In addition to botanical differences in diet preference, cattle, sheep, and goats differ in the parts of the landscape on which they prefer to graze. Cattle prefer lower flatter areas, which can lead to degradation of riparian areas. Sheep and goats will utilize steep slopes, prefer to bed on open upland areas, and have a strong tendency to graze into the wind. This can result in overuse around bed grounds or on the side of a pasture from which prevailing winds blow. These are broad generalizations that vary seasonally and among different plant communities with different botanical compositions.
Grazing lands that contain a variety of grass, forb, and browse species are difficult to graze with a single species of livestock in a way that will avoid shifting the botanical composition to a less desirable condition than the original pasture. In contrast, grazing with multiple species of livestock will spread grazing pressure across a wider variety of the plants in a pasture, which reduces the tendency of some lesser-grazed species to develop a competitive advantage over other species.
Multi-species grazing can increase grazing land carrying capacity. Compared with grazing only cattle, grazing sheep and cattle increased production per unit area an average of 24% (range: 10 to 53%). In contrast, adding cattle to sheep-only grazing increased production an average of only 9%. In some instances, there was no benefit because ewes typically wean more pounds of offspring than cows, and lambs have a higher relative growth rate than calves. Competition for forage resources is always greater for two animals of the same species compared with two animals of different species. Because of this, grazing pressure is lower and individual animal performance higher at the same stocking rate under multi-species grazing compared to single-species grazing. Sheep grazed in combination with cattle gained an average of 30% more (range: 12 to 126%) than sheep grazed alone. The average gain was only 6% greater for cattle grazed with sheep than cattle alone. In some studies adding sheep to cattle-only grazing resulted in lower cattle gains. This indicates that when forage availability is low, sheep are more competitive for the limiting resource than cattle.
Benefits from multi-species grazing will be greatest when the different classes of livestock are balanced with the available forage resource and the total stocking rate does not exceed the carrying capacity of the land. A general rule of thumb is that on moderately stocked pastures one ewe can be added for each cow without affecting cattle performance or pasture condition. In areas with large amounts of undesirable brush that goats will consume (e.g., juniper or multiflora rose), the number of goats that can be added to a cattle- or sheep-grazed pasture can be much higher. However, not all brush is consumed by goats. For instance, mesquite, which infests millions of acres in the Southwest, receives only minor use by goats.
In many instances the most important decision in grazing management may be matching livestock dietary preferences to available forage, for example, using a class of livestock other than cattle to utilize the forage resource. This may also be the most difficult decision for land managers, especially livestock growers, because it can require a greater change in management, lifestyle, and self-image than any other decision relative to grazing management. However, for those committed to leaving the land in better condition than they received it, multi-species grazing may be the best way to fulfill that commitment.