Forage Value of Target Plants

Efficiently producing lambs, kids, wool, and mohair requires knowing the animal’s specific nutrient requirements – protein, energy, vitamins, minerals, and water. Proper nutrients are especially critical during breeding, late gestation, and early lactation, so it’s important, when possible, to match livestock needs with the proper feed. Most plant species targeted in grazing projects make fairly good forage because of their high protein and energy content. For instance, leafy spurge, an invasive plant that infests vast tracts of land in the Intermountain West and Northern Great Plains, is nutritionally similar to high quality alfalfa. The nutrient composition of early-growth leafy spurge is 18-20% crude protein and 65% total digestible nutrients, making it ideal for lactating ewes or nannies. However, as plants mature their nutritive value decreases, so managers should try to use animals that have lower nutrient requirements, such as those not lactating, at times when the plant nutrients are low.

Livestock perform well on annual grass diets in spring, producing weight gains similar to those from uninfested rangeland. Animals grazing mature or dormant stands of cheatgrass, Japanese brome, medusahead, ripgut brome, or several other annual grasses risk flesh or fleece damage from seeds with long, sharp awns. The awns can become embedded in an animal's nose or mouth, causing cysts and inflammation. In severe cases, these grass awns can penetrate the gums and jaw, causing irritation and infection in a condition called lump jaw. When embedded in fleeces, seeds and awns of annual grasses can reduce the commercial value of wool or hair clips.

Many undesirable shrubs and trees are sufficiently nutritious to meet livestock energy and protein demands. Woody plants are generally less digestible and nutritious than grasses and forbs during the growing season but are important forages in the fall and winter when their stems provide relatively high amounts of protein, minerals, and vitamins. Evergreen shrubs can be particularly good sources of nutrients in the winter.

Grazing or browsing animals may need to be supplemented with protein or energy, depending on the deficiencies in the vegetation, desired plant utilization, body condition, weather, and topography. A balanced, chelated mineral and vitamin mix containing less than 10% salt should be available free choice at all times. A base mix can be formulated and individual ingredients added as the chemical composition of the vegetation changes. Sea kelp meal supplies many of the micro elements needed to stimulate the immune system and effectively utilize other macro mineral elements. The mineral and vitamin mix and products like sea kelp meal should be provided in separate all-weather feeders.

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