Grazing of Grass and Cicer Milkvetch-Grass Pastures with Yearling Calves1
- C. B. Rumburg2
Nitrogen fertilization rather than legumes is relied upon for increasing pasture and hay production in the Northern Rocky Mountains because of the difficulty of maintaining stands and the danger of bloat when legumes are used. Cicer milkvetch (Astragalus cicer L.) offers the promise of overcoming both of these objections. This study reports a comparison of N fertilized grass, and cicer milkvetch-grass pastures (on an Aridic Agriboxolls) when grazed by three classes of cattle over a 3-year period. Pasture quality was estimated by grazing with two testers each of long-yearling steers, short-yearling steers, and short-yearling heifers which were about 14 and 7-months old, respectively, at beginning grazing. Pasture production was estimated by addition or removal of stockers to harvest the pasture. Pastures were grazed 10 and rested 30 days in a four-pasture rotation. The two pasture treatments were similar in average daily gain (0.99 kg/day); however, fertilized grass pastures produced a higher yield of digestible energy (15,000) than cicer milkvetch-grass (13,000 Meal/ha), which resulted in live weight gains of 514 and 434 kg/ha, respectively. The older and heavier long yearlings consistently gained weight more rapidly (1.14 kg/day) than younger and lighter short-yearling cattle (0.92 kg/day), but short yearlings produced more gain per hectare. Cicer milkvetch-grass pastures may be an alternative for N fertilized grass pastures depending upon relative cost of N. The inclusion of cicer milkvetch added nothing to forage quality, and was 14% less productive than grass pastures fertilized with 1.12 kg N/ha.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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