Meeting the nutritional needs of ruminants on pasture
The producer of ruminant livestock can protect profits by managing land for optimal pasture production. A complex array of decisions on the use and manipulation of plant and animal species and management contribute to the central goal of meeting the livestock nutrient requirements primarily through grazing, with a minimum of harvested forages and purchased feedstuffs.
A major problem encountered in trying to meet nutritional requirements of animals from pasture is that most ruminant nutrition research has been conducted with harvested forages.
Many of the typical livestock feeding recommendations are questionable, because they were either not developed from grazing based research at all or were developed under grazing that was poorly managed. For example, low forage quality is most frequently given as the reason for the poor performance of grazing animals. In reality, the reason is probably an inadequate availability of quality forage, which is primarily determined by how pastures are managed.
Nutritional Parameters and Forage Availability Estimates of dry matter intake based on nutritional parameters (acid detergent fibre and neutral detergent fibre) probably Underestimate potential intake by animals, under good grazing management with adequate amounts of forage. The most commonly published estimates of intake by livestock, particularly beef cattle, are too low for productive animals. How much cattle eat on pasture is determined not only by quality parameters but also by the amount of forage available and by the grazing behaviour of the animal. Research indicates that cattle will take about 30,000 bites a day. If the pasture is of sufficient eight or density, the animal can get a "mouthful" with each bite. For cattle, this height is 6-10 inches, averaging 1800-2400 pounds of dry matter per acre for cool-season grasses and legumes. Bermuda grass need not be as tall because it is denser. When dry matter availability drops below 1000-1200 pounds per acre, the intake decreases significantly. Sheep will graze closer to the ground than cattle or goats. Goats need a higher availability of forage than cattle or sheep, as they tend to graze higher on the plant.
For more of the article, please click here.