|Kanneganti, V - UNIV OF WISCONSIN-MADISON|
Submitted to: Journal of Sustainable Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 17, 1997
Publication Date: N/A
Interpretive Summary: Because of high cost of inputs (feed, fertilizer, pesticide, etc.) relative to income from milk and meat, dairy farmers are demanding information on managing pastures at low to moderate levels of input while promoting pasture persistence to reduce cost of reseeding pastures. Much of the 15 million acres of non-crop pasture land in the northeastern and north central US is under mixed species pastures, also called "natural" or "permanent" pastures. These pastures are well adapted to the region, but their potential to produce forage profitably and sustainably under low input rotational grazing management needs to be quantified. In this study, pasture species persistence and amount and nutritional quality of forage available for daily consumption by dairy cattle grazing natural pastures were quantified. Besides providing management guidelines for grazing natural pastures, the research produced quantitative data that help producers to match animal feed requirement with pasture forage availability, thus minimizing wasteful over-feeding of feed supplements, reducing feed costs, and lowering nutrient over-loading on farms. The data indicate that natural pastures have the potential to provide significant amounts of good quality forage for 5 to 6 months in a year, but some additional feed may be needed for a month or two under extended periods of drought. This information is applicable to the vast resource of under- utilized natural pastures found on many livestock farms in the Midwest and Northeast United States.
Technical Abstract: Sustainable use of mixed species pastures under rotational grazing requires information on forage dry matter availability on a daily basis for feed budgeting purposes. Forage availability, nutritive quality, and species composition were measured during 1994 and 1995. Forage availability declined in both years as the season progressed, but the magnitude of this decline varied between years during summer, which was attributed to differences in soil moisture availability. Under adequate rainfall observed in 1994, forage was available at a rate of 70, 68, 51, 66, 24 and 11 kg ha**-1 d**-1 during May, June, July, August, September and October, respectively. Extended period of drought in the summer of 1995 reduced forage yield during July, August and September to 26, 47 and 11 kg ha**-1 d**-1, respectively. Total forage consumed during 1994 and 1995 was 8580 and 6460 kg ha**-1, respectively. Averaged over the years, forage consumed contained 22% crude protein, 45% neutral detergent fiber, and 24% acid detergent fiber. Pasture was composed of 22% Kentucky bluegrass, 33% of mostly smooth bromegrass and quackgrass, 13% legumes (mostly white clover), 27% senesced forage, and 5% of other species. These fractions remained stable during the season, except under intense drought when senesced forage increased as bluegrass and clover fractions declined. However, bluegrass and clover recovered quickly upon return of favorable moisture conditions. The results indicate that these pastures can provide significant amounts of good quality forage under rotational grazing, but additional feed may be needed for a month or two under extended periods of drought.