STORAGE METHOD AND NUTRITIVE-VALUE OF LARGE ROUND BALES HARVESTED WITH DIFFERENT PROPORTIONS OF LEGUMES

Production of hay in large round bales (LRB) has gained popularity bec ause of reduced cost and ease of harvest. However, storage of LRB with out protection reduces the quality and quantity of hay. This study was conducted to evaluate the benefits of plastic covering on retention o f nutritive value in LRB containing different proportions of legume. E ighty-four grass-legume LRB containing high (45-100%) or low (0-40%) l egume percentages were harvested from 14 Michigan farms located in fiv e different countries and stored for 10 mo. Percentages of legumes wer e visually determined at each farm. Six bales per farm were either unc overed or covered with plastic. Bales in each treatment were stacked i n a pyramid style. Plastic was placed over the pyramid with only 3 ft of exposed hay on all sides. Plastic was held in place with rope and t ires placed every 3 ft. Bales were weighed and subsampled with a forag e probe during the summer of 1990 and spring of 1991 to determine chem ical composition (dry matter [DM]; organic matter [OM]; crude protein [CP]; structural carbohydrates-neutral detergent fiber [NDF], acid det ergent fiber [ADF], hemicellulose), in vitro DM and OM degradability, and nutrient recovery. At the end of the storage period, covering LRB with plastic was more beneficial for DM and nutrient recoveries in LRB containing greater legume content. Storage of LRB under plastic cover increased (P < 0.05) recoveries of degradable DM and OM over uncovere d bales regardless of legume proportion. Based on the recovery of degr adable OM, covering with plastic was more cost effective, with LRB con taining greater legume content. In summary, storage of LRB under plast ic was beneficial for retention of nutritive value regardless of the p roportion of legume. However, more benefit due to covering can be expe cted for LRB containing higher legume levels.