Contamination of hay and haylage with enteric bacteria and selected antibiotic resistance genes following fertilization with dairy manure or biosolids.

The present study evaluated if enteric bacteria or antibiotic resistance genes carried in fecal amendments contaminate the hay at harvest, representing a potential route of exposure to ruminants that consume the hay. In field experiments, dairy manure was applied to a hay field for three successive growing seasons, and biosolids applied to a hay field for one growing season. Various enteric bacteria in the amendments were enumerated by viable plate count, and selected gene targets were quantified by qPCR. Key findings include the following: At harvest, hay receiving dairy manure or biosolids did not carry more viable enteric bacteria than did hay from unamended control plots. Fermentation of hay did not result in a detectable increase in viable enteric bacteria. The application of dairy manure or biosolids did result in a few gene targets being more abundant on hay at the first harvest. Fermentation of hay did result in an increase in the abundance of gene targets, but this occurred both with hay from amended and control plots. Overall, application of fecal amendments will result in an increase in the abundance of some gene targets associated with antibiotic resistance on first cut hay.

Energy Efficiency and Econometric Analysis of Organic Kiwifruit (Actinidia Deliciosa A. Chev.) Production

The energy exchange ratio of cultivation and different parameter values of input affecting the organic production of kiwifruit in the mid-hill Himalayan region of India during 2017 and 2018 was determined. The experimental trial was divided into 7 organic treatment i.e. T1 to T3 was sole application on equivalence 100 per cent Dairy manure (DM), Vermicompost (VC) and Poultry manure, T4 to T7 was a compound application of 50: 50 DM: PM, DM: VC and VC: PM and T7 in which DM = PM = VC applied on N equivalence. Five foliar sprays of organic formulation were applied in each of the treatment. The Energy efficiency and econometric analysis of organic kiwifruit production were examined. The highest energy inputs unit per hectare was utilized by T1 out of which over 86 per cent were from organic manure inputs and provided 26401.02 MJ/ha. The highest yield per hectare, as well as the output energy were observed in the treatment T5. Whereas the highest energy ratio, energy productivity, and specific energy were recorded under T2. Likewise, the highest productivity ratio and benefit-cost ratio were recorded under T7 which was followed by T2. From a farming point of view, the T2 gave the superior result because it has provided optimum amount output along with maximum returns. Bangladesh J. Bot. 50(4): 1051-1057, 2021 (December)

Quantification of antibiotic resistance genes and mobile genetic in dairy manure

Background Antibiotic resistance genes (ARGs) are considered to be emerging environmental contaminants of concern potentially posing risks to human and animal health, and this research studied the prevalence of antimicrobial resistance in dairy manure. Methods This study is focused on investigating prevalence of ARGs in California dairy farm manure under current common different manure management. A total of 33 manure samples were collected from multiple manure treatment conditions: (1) flushed manure (FM), (2) fresh pile (FP), (3) compost pile (CP), (4) primary lagoon (PL), and (5) secondary lagoon (SL). After DNA extraction, all fecal samples were screened by PCR for the presence of eight ARGs: four sulfonamide ARGs (sulI, sulII, sulIII, sulA), two tetracycline ARGs (tetW, tetO), two macrolide-lincosamide-streptogramin B (MLSB) ARGs (ermB, ermF). Samples were also screened for two mobile genetic elements (MGEs) (intI1, tnpA), which are responsible for dissemination of ARGs. Quantitative PCR was then used to screen all samples for five ARGs (sulII, tetW, ermF, tnpA and intI1). Results Prevalence of genes varied among sample types, but all genes were detectable in different manure types. Results showed that liquid-solid separation, piling, and lagoon conditions had limited effects on reducing ARGs and MGEs, and the effect was only found significant on tetW (p = 0.01). Besides, network analysis indicated that sulII was associated with tnpA (p < 0.05), and Psychrobacter and Pseudomonas as opportunistic human pathogens, were potential ARG/MGE hosts (p < 0.05). This research indicated current different manure management practices in California dairy farms has limited effects on reducing ARGs and MGEs. Improvement of different manure management in dairy farms is thus important to mitigate dissemination of ARGs into the environment.

Differential Survival of Generic E. coli and Listeria spp. in Northeastern U.S. Soils Amended with Dairy Manure Compost, Poultry Litter Compost, and Heat-Treated Poultry Pellets and Fate in Raw Edible Radish Crops

Composted or heat-treated Biological Soil Amendments of Animal Origin (BSAAO) can be added to soils to provide nutrients for fresh produce. These products lower the risk of pathogen contamination of fresh produce when compared with use of untreated BSAAO; however, meteorological conditions, geographic location, and soil properties can influence the presence of pathogenic bacteria, or their indicators (e.g., generic E. coli) and allow potential for produce contamination. Replicated field plots of loamy or sandy soils were tilled and amended with dairy manure compost (DMC), poultry litter compost (PLC), or no compost (NoC) over two different field seasons, and non-composted heat-treated poultry pellets (HTPP) during the second field season. Plots were inoculated with a three-strain cocktail of rifampicin-resistant E. coli (rE.coli) at levels of 8.7 log CFU/m2. Direct plating and most probable number (MPN) methods measured the persistence of rE.coli and Listeria spp. in plots through 104 days post-inoculation. Greater survival of rE. coli was observed in PLC plots in comparison to DMC plots and NoC plots during year 1 (P &lt; 0.05). Similar trends were observed for year 2, where rE. coli survival was also greater in HTPP amended plots (P &lt; 0.05). Survival of rE. coli was dependent on soil type, where water potential and temperature were significant covariables. Listeria spp. were found in NoC plots, but not in plots amended with HTPP, PLC or DMC. Radish data demonstrate that PLC treatment promoted the greatest level of rE.coli translocation when compared to DMC and NoC treatments (P &lt; 0.05). These results are consistent with findings from studies conducted in other regions of the US and informs Northeast produce growers that composted and non-composted poultry-based BSAAO supports greater survival of rE. coli in field soils. This result has the potential to impact the food safety risk of edible produce grown in BSAAO amended soils as a result of pathogen contamination.

Impacts of FERC Order No. 2222 on Dairy Manure Processing in Wisconsin

The agricultural practice of spreading dairy manure to fertilize crop fields leads to widespread air and water pollution, due to uncontrolled release of greenhouse gases, nutrients, and pathogens. The associated environmental and health impacts can be mitigated by deploying manure processing (MP) systems that can capture methane to produce electricity and that facilitate nutrient management. Unfortunately, electricity rates available to MP systems in the United States (US) provide limited economic incentives to promote their deployment. Recent policy enacted by the Federal Energy Regulatory Commission (Order 2222) enables distributed energy resource (DER) systems (such as MP systems) to participate in wholesale electricity markets. We present supply chain and market analyses in Wisconsin showing that this order can help activate an electricity bioeconomy that can help mitigating environmental and health impacts resulting from manure spreading. We estimate that this bioeconomy could generate up to $131 million in revenue for dairy farms annually while averting $39 million in greenhouse gas emissions and $182 million in nutrient emissions.