Nutritive value and digestibility
Eragrostis lehmanniana is generally a low quality grass. In a year-long experiment in Arizona, the protein content of the leaves averaged about 5% DM, below the maintenance requirements for dry cows and dry ewes from May to January, and only met these requirements in spring. However, cattle graze selectively the seedheads, which contains more protein, and maintenance requirements can be met from late spring to late summer (Cox, 1992). In a 2-year trial in the same region, in vitro DM digestibility was found to be low (usually less than 40%) and highly variable, with values as low as 20% in late summer and as high as 50-60% in early summer. Standing hay was only slightly less digestible (-3.5 percentage units on average) than green forage (Renken, 1995).
Higher digestibility values have been obtained in South Africa. Early trials gave in vivo OM digestibility values of 60-65% (Botha, 1938). A more recent study found in vitro DM digestibility values to be in the 48-69% range (average 60%) for green material and 40-58% (average 51%) for dead standing material (Fourie et al., 1985).
The palatability of Eragrostis lehmanniana, while variable, is generally low (Cable, 1971). Selective animal avoidance may be partially responsible for its spread in Arizona and Southern Africa (Cox et al., 1990).
In its native Southern Africa, Eragrostis lehmanniana is a major range grass. In Botswana, its overall nutritive value was considered to be below the minimum required to sustain animal production, reflected by the protein content, which was below 7% during the wet season (Setshogo et al., 2011).
In the United States, Eragrostis lehmanniana's greatest forage value for cattle is its ability to produce more green herbage in the winter and early spring than native grasses. Cattle make greater use of this grass and graze it readily during the fall, winter and spring because the foliage remains green longer than most native grasses. During summer, its palatability is low and it is generally lightly grazed at that time (Uchytil, 1992). Treatment with sulfur-coated urea increased the protein content of the grass, carrying capacity and weight gain in yearling heifers. However, although this treatment was profitable for raising growing beef cattle, it wasn’t for maintenance of a breeding cow herd (McCawley, 1983).