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Effects of pre-cutting round hay bales during baling on forage quality and processing time.

W. E. Brown




Effects of pre-cutting round hay bales during baling on forage quality and processing time.
W. E. Brown*1, E. Harms2, J. Heimsoth2, J. McGinnis2, C. I. Vahl1, B. J. Bradford1, M. J. Brouk1. 1Kansas State University Manhattan, KS, 2John Deere Corporation Olathe, KS.

Innovative round hay balers with knives that cut the hay as it enters the baling chamber reduce the particle size upon baling and eliminating the need for a tub-grinder. The objective of this study was to evaluate the effects of a round hay baler with knives on forage quality at baling and after storage, and the processing time to reduce particle size before feeding. Alfalfa hay was baled (560 M Megawide HC2, John Deere, Moline, IL) with knives every 15.25 cm (CUT) or without knives (NORM). At baling and after 6 mo storage uncovered, bales were weighed, measured and 10 core samples obtained for nutrient analysis. Cores were separated into outer 15 cm and inner 15 to 46-cm segments to determine depth of spoilage. After storage, particle size was reduced to approximately 4 inches using a mixer wagon for CUT or a tub grinder for NORM. Grinding time and hay loss were analyzed as a completely randomized design. Bale dimensions, weight and density were analyzed as a split-plot design, while nutrient analysis was analyzed as a split-split plot design with treatment as the whole plot, storage period as the sub-plot, and core depth as the sub-sub-plot. Compared with NORM, CUT increased bale weight (513 vs. 581 � 19.8 kg DM; P < 0.001) and density (154 vs. 170 � 5.9 kg DM/m3; P < 0.001). Core depth interacted with storage time point whereby ADF concentration increased more for outer than inner cores from baling to storage (2.6 vs. 1.1 � 0.48%; P < 0.01), with similar effects for lignin (0.7 vs. 0.2 � 0.11%; P < 0.001) and 240-h uNDF (1.9 vs. 0.8 � 0.52%; P = 0.01). Compared with NORM, CUT increased concentrations of ADF and aNDFom by 0.6% (P = 0.01), and decreased RFQ (117 vs 112 � 3.2 points; P = 0.02). The CUT treatment increased time to reduce particle size (11.0 vs 3.6 � 1.53 min; P < 0.001), but decreased grinding DM loss by 24.1 � 2.83 kg (P < 0.001). In summary, CUT produced larger, more dense bales and increased fiber content slightly; however, the increase may be negligible in ration formulation when hay is fed as part of a TMR. In view of DM loss advantages for CUT during grinding, post-grinding nutrient analysis should be considered.

Keywords: processing, harvest, shrink.