SafeBed: Improving safety and sustainability of recycled manure solids as bedding material for dairy cows

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Safebed : improving safety and sustainability of recycled manure solids as bedding material for dairy cows

Publication . Pires, Ana José de Oliveira Nunes; Oliveira, Maria Manuela Castilho Monteiro de; Bexiga, José Ricardo Dias; Fangueiro, David Paulo

ABSTRACT - SAFEBED: IMPROVING SAFETY AND SUSTAINABILITY OF RECYCLED MANURE SOLIDS AS BEDDING MATERIAL FOR DAIRY COWS - Antimicrobial resistance (AMR) and the environmental impact of livestock production pose significant challenges to sustainable dairy farming. The use of recycled manure solids (RMS) as bedding material offers economic and environmental benefits but raises concerns regarding microbial safety, including the persistence of antimicrobial-resistant bacteria and potential pathogens. This study evaluated the effects of biochar supplementation in RMS to mitigate AMR risks, enhance microbial safety, and reduce environmental emissions. Fresh RMS samples were collected from a commercial dairy farm and divided into five treatments: non-supplemented RMS (C-), acidified RMS (C+), and RMS supplemented with 2.5%, 5%, or 10% biochar. Samples were incubated for 30 days at ambient temperature, with assessments on Days 0, 5, 15, and 30. Two assays were conducted: one in a humid period (April–May) and another in a dry period (June–July). Microbial analyses included bacterial quantification, Escherichia coli and Enterococcus spp. isolation, AMR and virulence profiling, and 16S rDNA sequencing for microbial community shifts. In parallel, the environmental study examined RMS characteristics, nutrient retention, and greenhouse gas (GHG) emissions. Results from the bacterial quantification revealed no statistically significant reduction in E. coli and Enterococcus spp. counts with biochar supplementation. However, trends suggested a potential decrease in AMR and virulence factors, with reductions observed in oxytetracycline resistance and biofilm formation. In contrast, the microbiome analysis demonstrated a significant reduction in bacterial loads, with 5% biochar leading to a 59.50% decrease under humid conditions. However, Brucella spp. and Pseudomonas spp. increased in biochar amended RMS. Environmentally, the supplementation with 10% biochar significantly reduced CO₂ (32%) and N₂O (47%) emissions, stabilized nitrogen, and minimized volatilization losses. However, methane emissions were largely unaffected. Addicionally, Biochar supplementation increased micronutrient and heavy metal concentrations (except for molybdenum), as well as potassium and magnesium levels, while decreasing sodium, phosphorus, and total organic carbon content. This study highlights biochar’s potential for improving microbial safety and environmental sustainability in dairy farming. Further research should optimize biochar concentrations, assess long-term effects, and evaluate field-scale applications to fully harness its role in sustainable manure management

2025-06-23Doctoral thesis

Open access

When the solution becomes the problem: a review on antimicrobial resistance in dairy cattle

Publication . Pires, Ana José; Pereira, Gonçalo; Fangueiro, David; Bexiga, Ricardo; Oliveira, Manuela

Antibiotics' action, once a ‘magic bullet’, is now hindered by widespread microbial resistance, creating a global antimicrobial resistance (AMR) crisis. A primary driver of AMR is the selective pressure from antimicrobial use. Between 2000 and 2015, antibiotic consumption increased by 65%, reaching 34.8 billion tons, 73% of which was used in animals. In the dairy cattle sector, antibiotics are crucial for treating diseases like mastitis, posing risks to humans, animals and potentially leading to environmental contamination. To address AMR, strategies like selective dry cow therapy, alternative treatments (nanoparticles, phages) and waste management innovations are emerging. However, most solutions are in development, emphasizing the urgent need for further research to tackle AMR in dairy farms.

2024-04Journal article

Restricted access