Abstract:
The increasing use of antibiotics in livestock farming raises concerns about environmental impacts. This study
examined the effects of three commonly used veterinary antibiotics – Tylosin, Enrofloxacin, and Oxytetracycline
– on manure greenhouse gas (GHG) emissions and fertilizer quality during solid manure storage. Aliquots of fresh
cattle manure (10 kg) were either spiked with high or low concentrations of each antibiotic, or left untreated as
Control, then incubated in open buckets for 110 days to simulate manure heaping. Emissions of CO2, CH4, and
N2O were measured using a static chamber with a laser spectrometer. Tylosin (High and Low) treatments and
High-dose Enrofloxacin significantly increased manure N2O emissions (2.1 ± 0.2 to 2.5 ± 0.4 %), exceeding the
IPCC default values of 1 % manure-N. All antibiotic treatments increased CH4 emission factors (6.4 ± 0.7 to
14.2 ± 1.1 g CH4 kg