|AKINS, MATTHEW - University Of Wisconsin|
Submitted to: Popular Publication
Publication Type: Popular Publication
Publication Acceptance Date: 3/14/2014
Publication Date: 3/14/2017
Citation: Coblentz, W.K., Akins, M.S. 2017. Interaction of bale size and preservative rate for large-round bales of alfalfa hay. Popular Publication. 2017.
Technical Abstract: Recently, two studies conducted at the US Dairy Forage Research Center have reported inconsistent storage responses following the application of propionic-acid-based preservatives to alfalfa or alfalfa-orchardgrass hays. One of these studies utilized 5-foot-diameter round bales, and produced disappointing results across a wide range of moisture concentrations (10 to 40%) relative to untreated control hays. In contrast, large-rectangular (3 × 3 × 6-ft) bales of alfalfa-orchardgrass hay made at 20, 24, and 27% moisture exhibited clear suppression of spontaneous heating and preservation of nutritive value when preservatives were applied at rates of either 0.6 or 1.0% of wet bale weight. Our objective for this experiment was to assess the potential effects of (round) bale diameter on the effectiveness of acid-based preservatives applied to alfalfa/mixed grass hays (83% alfalfa) with the Harvest Tec 647C application system. A total of 18 bales were made at 21% moisture at 2 bale diameters (4 or 5 feet), and with acid preservative applied using 3 application strategies: i) CON, control (no preservative); ii) FULL, fully automated, with automatic adjustments for bale moisture and baling rate; and iii) CONRATE, constant baling rate, which assumes a constant baling rate, but adjusts for bale moisture. All bales were stored outdoors on wooden pallets for 75 days. Measures of spontaneous heating differed between 4-ft and 5-ft diameter bales for maximum bale temperature (107 vs. 115oF; P = 0.012) and heating degree days (HDD) > 86oF (191 vs. 601 HDD; P = 0.024). Effects of preservative application on bale temperature were not observed (P = 0.181); however, large numerical differences were observed between preservative-treated hays and CON baled at a 5-ft diameter (846 vs. 481 HDD; P = 0.144). Unlike measures of spontaneous heating, concentrations of NDF and TDN exhibited interactions (P = 0.044) of main effects, with little change for 4-ft bales, but increased NDF (P = 0.001) and concomitantly decreased TDN (P = 0.011) in response to the additional heating observed in CON. Based on these preliminary findings, bale size/diameter likely plays an important role in the effectiveness of propionic-acid-based preservatives, but more field replications will be required to fully evaluate these relationships.