PSXI-12 Effect of application rate of sodium lignosulfonate and propionic acid on in vitro digestibility and gas production kinetics of high moisture alfalfa hay mini bales

Abstract

Abstract Our objective was to evaluate the effects of application rate (AR) of sodium lignosulfonate and propionic acid on the in vitro fermentation measures of high moisture alfalfa hay. Treatments (TRT) were sodium lignosulfonate (NaL) and Propionic Acid (PRP), which were applied at four AR: 0 (CON), 0.25, 0.5 and 1% (w/w fresh basis) to 20% bloom alfalfa hay (second cut) at 68.5% DM and packed into mini bales (10.3×10.8×13cm; 346 kg fresh/m3). The treated bales were stored for 33 days in open-top insulation boxes in a room kept at 22°C, after which they were dried, ground to 1 mm and incubated in vitro for 48hr with ruminal fluid from two ruminally cannulated Holstein cows in lactation. Gas kinetics were recorded using the Ankom RF Gas Production System. Data were analyzed as a randomized complete block design (5 blocks) with a 2 (TRT) x 4 (AR) factorial arrangement, and differences were declared at P ≤ 0.05. Both TRT increased apparent in vitro DM digestibility (DMD) at all AR relative to CON (54.3 vs 50.1 ± 1.20%, respectively). PRP increased asymptotic maximal (188.4) and rate of gas production (9.46) compared to NaL (179.7 ± 4.82 ml/g of incubated DM and 8.72 ± 0.45%/h, respectively). Total VFA were higher for PRP (117.5) vs NaL (114.8), and for both TRT at 1% relative to CON (118.9 vs. 113.8 ± 1.68mM). Acetate (A) was increased by both TRT at 1% (~73.5) and propionate (P) was increased by PRP at 1% (26.1) relative to CON (69.9 ± 1.10 and 24.2 ± 0.29mM, respectively), but the A:P ratio was higher for NaL at 1% (3.02) vs. CON (2.89 ± 0.04). In conclusion, NaL and PRP at 1% improved the rumen in vitro fermentation measures of high moisture alfalfa hay but PRP did so to a greater extent.