Use of Bedding Materials in Beef Bedded Manure Packs at Hot and Cold Ambient Temperatures: Effects on Odorous Volatile Organic Compounds and Odor Activity Values

Abstract

HighlightsAromatic compounds generated 72.6% of the total odor activity values (OAVs) over time.Cold treatments had significantly lower total OAVs than hot treatments regardless of the age of the bedded pack.Abstract. Beef cattle producers are beginning to raise cattle in confinement facilities such as slatted-floor barns, hoop barns, and mono-slope facilities. Hoop and mono-slope facilities typically use bedding packs as part of their manure management system, with crop residues being the most commonly used bedding material. This study was conducted to determine the effects of bedding material, i.e., corn stover (CS), bean stover (BS), wheat straw (WS), or pine wood chips (PC), and environmental ambient temperature, i.e., cold (15°C) or hot (30°C), on the concentrations of odorous volatile organic compounds (VOCs) in air samples collected in the headspace above lab-scale bedded packs over a 42-day period. Total aromatic compounds, sulfide compounds, straight-chain fatty acids (SCFAs), and branched-chain fatty acids (BCFAs) were measured and used to calculate total odor activity values (OAVs) for each bedding and temperature effect. No significant three-way interactions for bedding material × ambient temperature × age of bedded pack were observed. Significant bedding material × ambient temperature interactions were observed for total aromatic compounds and total sulfide compounds (p = 0.0455 and p = 0.0083, respectively). The concentration of total aromatic compounds was greater for all hot treatments compared to cold treatments, with hot-CS and hot-WS bedding types (389.83 and 365.5 ng L-1, respectively) significantly (p < 0.05) greater than all other bedding types, while total aromatic compounds were lowest (87.09 ng L-1) for BS across cold treatments. Total sulfide compounds from cold-PC (51.69 ng L-1) were significantly (p = 0.0143) greater than all other treatments. Within hot treatments, total sulfide compounds were similar across all bedding materials. Total SCFAs for both cold and hot treatments decreased significantly from weeks 4 to 6. Total SCFA concentrations within weeks were significantly (p < 0.0001) greater for WS and CS compared to BS and PC but similar across bedding materials at week 6. Total BCFA concentrations from bedded packs containing CS and WS were significantly (p < 0.0001) higher at week 4 compared to concentrations from bedded packs containing BS or PC. As bedded packs aged, total BCFA concentrations for all bedding materials were similar at week 6. Total OAVs decreased over time for both hot and cold treatments, although cold treatments had significantly (p < 0.0001) lower total OAVs regardless of the age of the bedded pack. Aromatic compounds generated 72.6% of the total OAV over the 42-day study. Bedding types BS and PC had the lowest total OAVs across all weeks. The results indicate that feedlot operators maintaining bedded pack facilities will achieve the greatest overall odor reduction when using BS or PC bedding material, no matter the ambient temperature. Keywords: Bedding, Beef, Odor, Volatile organic compounds.