The great advantage of grazing livestock is that they convert grass on unproductive land, which would otherwise be wasted, into the many useful products emanating from them.
Livestock affect their pastures through mouth action, consumption, hoof action and deposition of manure and urine. Benefits of cattle grazing due to each action are wide ranging.
Mouth action removes both dead and live forage. Cattle prefer grasses and weeds to more woody plants. Instead of having upper front teeth, cattle have a hard leathery pad (known as the “dental pad”), so they graze by swinging their head after biting the grass. The grass is removed more by tearing than by slicing. This leaves some length of grass on the ground as their grazing progresses. A typical cow consumes around 27 pounds of forage per day, or almost five tons of forage per year.
Removal of dead dry forage (thatch) allows sunlight and moisture to reach the soil so regrowth of established grasses and forbs can flourish and seeds to germinate and grow. Increases in newer and more nutritious younger forage benefit both livestock and wildlife from antelope to birds and insects. Grassland birds require a grassland environment for breeding and foraging, as well as habitat for some native animals. Larger patches of open grassland support a more species-rich, abundant grassland bird community.
Fire fuels are removed as the cattle consume grasses and shrubs and trample plants with their hooves. This decreases the fire’s temperature and duration that could scorch the soil surface. Non-native grassland plants (Lehmann lovegrass, yellow bluestem) produce high levels of fine fuels, which are very flammable. Shrubs that invade ungrazed lands burn hotter and longer than grass in grazed grasslands.
Cattle manure and urine are rich in nutrients that benefit the micro-organisms in the soil. Grazing in large pastures of over 30 acres per cow spreads those nutrients across a wider area as opposed to feedlots and confined pastures. Organic components of feces and urine from grazing animals can build soil organic matter, resulting in improved structural stability and increased water infiltration rates and water-holding capacity.
Hoof action digs manure, urine, and dead plant mulch into the soil surface, where it can be more quickly broken down by soil organisms. Their decomposition provides much needed nutrients for micro-organisms that plants depend on for healthy growth. Hooves break the ground crust to allow more rain infiltration and stimulate the growth of grass. Cattle grazing can improve the diversity of grasses by dispersing seeds with their hooves and in their manure. Soil surfaces can become pocked from animals’ hoof marks especially when the surface is softened by rain, helping to trap seeds and moisture essential for establishing desirable vegetation. Pocking also can increase surface roughness in disturbed areas, slowing erosion associated with surface water runoff.
Soil compaction does not occur from extended grazing on pastures requiring 30 to 60 acres per animal unit month due to the short time the cattle spend grazing in one place. Soil compaction generally occurs only in areas around water and salt and along trails.
Without natural disturbance, grasslands will accumulate large amounts of dead plant material (thatch and litter) that can choke out new growth of grasses and forbs. Given a long enough period without disturbance, grasslands will often convert into brush dominated shrub lands. The shrubs inhibit the germination and growth of native and non-native grassland plants by shading out the sun and using the available water and mineral resources in the soil. This ultimately leads to reduced production, more bare ground, and increased sheet erosion. It is important to maintain sufficient grasslands because of the many species that depend on them for habitat.
Ponds developed for livestock watering support large numbers of breeding amphibians, which also feed on the abundant insect life found in the surrounding grasslands. Troughs maintained by ranchers provide much needed water in dry areas for the benefit of wildlife as well as cattle.
Editor’s note: Bill Schock is a Supervisor for the Santa Cruz Natural Resource Conservation District.