title: Effects of forage-to-concentrate ratio and dietary fiber manipulation on gas emissions and olfactometry from manure of Holstein heifers.
abstract: The objective of this experiment was to determine the effects of differing ratios of forage to concentrate (F:C) and fiber levels on odor and gas emissions from manure. Eight Holstein dairy heifers (362.45±4.53 d of age and 335.6±7.41 kg of body weight) were randomly assigned to a split-plot, 4×4 Latin square design (21-d periods) with F:C as the whole plot (20 or 80% forage) and fiber level as sub-plot (0, 20, 40, or 60% inclusion of corn stover). Gas concentration was determined using an infrared photoacoustic analyzer over a 24-h period using a steady-state flux chamber setup. Odorous air samples were collected from chamber headspace and evaluated by 6 human assessors using a forced-choice dynamic olfactometry technique. Emissions of CO2 were greater for the low than high concentrate diets, and no differences were observed for NH3 and CH4 emissions between F:C. Although F:C had no effect on NH3 emissions, as dietary fiber increased, a linear interaction with opposite effects was found for high and low concentrate diets. Nitrous oxide emissions were below minimum detectable levels. Neither F:C nor neutral detergent fiber level affected odor intensity. Odor emissions were successfully assessed, and manipulation of dietary fiber has the potential to influence CH4 and NH3 emissions.
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lascano
authors.affiliation: Department of Animal Science, The Pennsylvania State University, University Park 16802. Electronic address: ajh@psu.edu.
authors.forename: A J
authors.initials: AJ
authors.lastname: Heinrichs
authors.affiliation: Department of Dairy Science, The California Polytechnic State University, San Luis Obispo 93407.
authors.forename: R R
authors.initials: RR
authors.lastname: Gary
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park 16802.
authors.forename: P A
authors.initials: PA
authors.lastname: Topper
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park 16802.
authors.forename: R C
authors.initials: RC
authors.lastname: Brandt
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park 16802.
authors.forename: A
authors.initials: A
authors.lastname: Adviento-Borbe
authors.affiliation: Department of Agricultural and Biological Engineering, The Pennsylvania State University, University Park 16802.
authors.forename: E E
authors.initials: EE
authors.lastname: Fabian
mesh_terms: D000641:Ammonia / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D002245:Carbon Dioxide / Q000032:analysis; D002417:Cattle / Q000378:metabolism*; D004032:Diet / Q000662:veterinary; D004043:Dietary Fiber / Q000008:administration & dosage* / Q000378:metabolism; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008372:Manure / Q000032:analysis*; D008697:Methane / Q000032:analysis*; D009812:Odorants / Q000032:analysis*; D064367:Olfactometry / Q000379:methods; D003313:Zea mays
chemical_list: D004043:Dietary Fiber; D008372:Manure; D002245:Carbon Dioxide; D000641:Ammonia; D008697:Methane
keywords: dietary fiber; forage to concentrate ratio; greenhouse gas emissions; heifer; olfactometry