In vitro dry matter digestibility of Lehmann lovegrass (Eragrostis lehmanniana Nees) with grazed patches and lightly grazed areas.

Abstract

Cattle selectively graze grasses for green, leafy material, often restricting their foraging to localized patches surrounded by large, lightly grazed areas. A two year study was conducted on the Santa Rita Experimental Range in Southern Arizona to compare the effects of heavy grazing on Lehmann lovegrass (Eragrostis lehmanniana Nees.) digestibility. Lehmann lovegrass was clipped from within heavily grazed patches and adjacent ungrazed areas. Green and dry plant materials were separated and analyzed for percentage in-vitro dry matter digestibility (IVDMD). Results indicated a significant difference existed in the IVDMD of the total standing crops (p $\le$ 0.005). When analyzed separately, the IVDMD for both the green and dry plant materials from the grazed patches was significantly higher (p $<$.05) than that from the ungrazed areas. Seasonal trends indicated a greater difference in digestibility during periods of active plant growth. Patch maintenance apparently maintains plants with higher forage values for grazing animals than surrounding ungrazed areas.