Orchardgrass Ley for Improved Manure Management in Wisconsin: II. Nutritive Value and Voluntary Intake by Dairy Heifers

ABSTRACT: Confinement dairy feeding operations in the Upper Midwest could benefit from utilizing a wider range of forages than alfalfa (Medicago sativa L.) and corn silage (Zea mays L.). A short term ley of orchardgrass (Dactylis glomerata L.) (OG) frequently treated with manured, was compared with corn silage (CS) in a 2 by 2 factorial trial conducted across 3 yr at two locations in Wisconsin. Nutrients were applied as either manure (M) or fertilizer (F) to meet crop N needs. Weighted on the basis each cut contributed to the total annual yield of OG, concentrations of crude protein (163 g kg-1) and 48-h neutral-detergent fiber (NDF) digestibility (657 g kg-1 NDF) were suitable for incorporation into the diets of dairy cows and replacement heifers. Tissue concentrations of P and K were 3.7 and 32.0 g kg-1, respectively. High tissue concentrations of P can help with soil-test P drawdown, and reduce purchases of supplemental dietary P. Although heavy manuring resulted in high tissue K, especially in late-season cuts, K concentrations were not significantly greater in the hay-production years relative to the seeding year in either M or F. Based on results with 483 ± 37.6-kg Holstein heifers (Bos taurus), there were no differences in voluntary intake by heifers offered commercially fertilized compared to manured OG hays. These results indicate that a OG ley system could be part of a larger alfalfa-corn silage rotation, providing confinement dairies with an alternative forage option, and additional manuring opportunities during summer months.

Authors: Janet Hedtcke, Joshua Posner, Wayne Coblentz, John Hall, Richard Walgenbach, and Jill Davidson

Published in Agronomy Journal (2011) 103:1106-1114