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Effect of chemical and biological preservatives on the dry matter loss, nutritional composition, microbial counts, and heating of aerobically exposed wet brewer's grain silage.

R. Hollandsworth

Abstract:

M5
Effect of chemical and biological preservatives on the dry matter loss, nutritional composition, microbial counts, and heating of aerobically exposed wet brewer's grain silage.
R. Hollandsworth*1, M. Killerby1, S. T. R. Almeida2, Z. X. Ma3, A. Y. Leon-Tinoco1, B. C. Guimaraes2, G. M. Oppong1, J. J. Romero1. 1University of Maine Orono, ME, 2University of Lavras Lavras, Brazil, 3University of Florida Gainesville, FL.

Our objective is to identify the most effective preservatives of wet brewer's grain (WBG) silage, especially during the feedout phase. Treatments (TRT) were sodium lignosulfonate at 1% (NaL1) and 2% (NaL2; wt/wt of fresh WBG), propionic acid (PRP; 0.5% wt/wt of fresh WBG), a combination inoculant (INO; Lactococcus lactis and Lactobacillus buchneri each at 4.9 log cfu/fresh WBG g), and untreated (CON). Five batches of unroasted WBG were collected from the same source right after lautering and cooled to room temperature for 1 d before treatments were randomly applied to each batch. Treated WBG were packed into 8.8 L mini-silos and stored for 60 d at 21�C. At opening, PRP had a lower DM loss (5.06) and a markedly better preservation of sugars (25.0) relative to all other TRT (~10.5 � 1.26% and ~13.6 � 1.36% of DM). Afterward, WBG silage was aerobically exposed for 10 d. Data were analyzed as a randomized complete block design (5 blocks) and differences were declared at P ≤ 0.05. NaL2 had the highest DM (23.6) and pH (4.96) and lowest NDF (38.3) relative to the other TRT (~22.9 � 0.158%, ~4.42 � 0.126, and ~50.4 � 1.03). PRP DM loss during aerobic exposure (11.7) was no different than CON (13.3) but both were lower than the other TRT (~18.2 � 1.19%). CON (3.24) had the lowest sugar concentration relative to PRP and NaL2 (~7.59) and INO (6.21 � 0.778% of DM). Moreover, PRP had the lowest ash concentration (3.92) relative to CON (4.25) and NaL1 and 2 (~5.89 � 0.104% of DM). PRP had a higher yeast count (8.23) relative to INO (6.69), but no different than CON (7.41 � 0.433 log cfu/g). Heating degree days across TRT (68.5) were similar to CON (62.2), except for NaL1 (86.0 � 6.42 ?-d). Furthermore, NaL1 and 2 had higher maximum temperatures (~38.7) relative to the other TRT (~36.5 � 0.82?). Considering that at silo opening PRP had preserved much more nutrients (especially sugars) than CON and thus was more susceptible to aerobic spoilage, its DM loss during aerobic exposure was no different than CON and it still preserved more sugars.

Keywords: silage, lignosulfonates, wet brewer's grain.

Biography: I moved from Valparaiso, Indiana to study Animal Science at the University of Maine. I am a senior now and I hope to continue my education in ruminal nutrition, particularly with dairy cows. I enjoy working with the dairy cattle at the university's farm, as well as the horses and sheep. Learning about animals to work towards more efficient and sustainable farming/livestock practices has always been a goal of mine.