Dairy Cattle Slurry Research Articles

Effects of Dairy Cattle Slurry Application on Alfalfa Biomass: Photosynthetic Characteristics and Nitrogen and Phosphorus Use Efficiency

Effects of Dairy Cattle Slurry Application on Alfalfa Biomass: Photosynthetic Characteristics and Nitrogen and Phosphorus Use Efficiency

Lower nitrate leaching from dairy cattle slurry compared to synthetic fertilizer calcium ammonium nitrate applied to grassland

Nitrate leaching from agriculture can be reduced by the choice of fertilizer and a proper timing of its application. For permanent grassland grown under temperate conditions, nitrate leaching was hypothesized to be lower from dairy cattle slurry (CS) compared to synthetic fertilizer calcium ammonium nitrate (CAN), based on differences in chemical composition, consequential effects on nitrogen (N) conversion processes in soil, and resulting differences in synchronization of (nitrate) N availability and plant N uptake. We tested the hypothesis in a two-year field experiment on cut grassland on a leaching-sensitive sandy soil, fertilized each year with 320 kg ha−1 of plant-available N from either 100% top-dressed CAN or a combination of 40% from CAN and 60% from sod-injected CS, and measured effects on grass herbage yield, herbage N uptake, and nitrate concentration in pore water at 1.0 m depth. Our results show a comparable level of herbage N uptake for both treatments, allowing for a proper comparison of nitrate leaching at a similar level of plant-available N. Average nitrate concentration in pore water in the main leaching period (over winter) was after the first (dry) growing season 44% lower for CS + CAN (41 mg l−1) compared to CAN only (73 mg l−1), and after the second (wet) growing season 35% lower for CS + CAN (32 mg l−1) compared to CAN only (49 mg l−1). Nitrogen application increased nitrate concentration at 1.0 m depth not only in winter but also in the growing season. We conclude that for permanent grasslands in temperate regions, nitrate leaching from timely applied CS may be considerably lower than from CAN, which is different from previous assumptions.

Anaerobic digestion of dairy cattle slurry—long-term effects on crop yields and chemical soil characteristics

Renewable energy in the form of biogas can be produced by anaerobic digestion (AD) of animal manure. However, there is still a lack of knowledge on the long-term effects of AD-treated manure on soil characteristics and crop productivity, compared with untreated manure. A field experiment was established in a perennial grass-clover ley in 2011 to study the effects on important soil and crop characteristics when the slurry from a herd of organically managed dairy cows is anaerobically digested. While the rate of manure application affected soil concentrations of extractable nutrients and pH, these variables were unaffected by AD. Soil organic matter (SOM) concentrations decreased in all plots and faster on the plots with high intrinsic SOM. The decrease was similar with application of untreated (non-digested) slurry (US) and anaerobically digested slurry (ADS), and it was not affected by application rates. The general decline may be explained by the initial high SOM content, the long-term effect of drainage, and higher temperatures with climatic change. US and ADS gave similar yields of grass-clover ley (2 cuts/year) and green fodder, on average 0.79 and 0.40 kg DM m−2, respectively. Clover yield was similar in manured treatments and the non-fertilized control. With respect to crop yields and chemical soil characteristics, long-term (10 years) effects of AD in an organic dairy cow farming system seem to be minor. The benefits of extracting energy from the slurry did not compromise grassland productivity or soil quality in the long term.Graphical

Effect of Dairy Cattle Slurry Application on Alfalfa Yield, Nitrogen Utilization, and Nitrogen Surplus

Effect of Dairy Cattle Slurry Application on Alfalfa Yield, Nitrogen Utilization, and Nitrogen Surplus

Reutilizar purines de tambo como oportunidad para reciclar nitrógeno y reducir su impacto ambiental

Dairy cattle slurry (liquid mixture of manure and water from the milking operation) can be reused for agricultural production in replacement for synthetic fertilizers. However, its high nitrogen (N) concentration could stimulate the volatilization of ammonia (NH3) and nitrous oxide (N2O) emission, with consequences for global warming. Our objectives were: to quantify NH3 and N2O loss in maize fertilized with surface-applied dairy cattle slurry or urea, and to relate N2O emission with soil ammonium, nitrate and water contents. We performed a manipulative field experiment where we measured both gaseous losses during an agricultural campaign. Slurry enhanced NH3 volatilization the day after the application (2.7±0.25 vs. 1.1±0.25 and 0.6±0.25 kg N-NH3.ha-1.day-1 for slurry, urea and the control, respectively) and direct N2O emission during three days after the application (75±13 vs. 28±5 y 26±6 µg N-N2O.m-2.h-1 for slurry, urea and the control, respectively). Four days after application, volatilization was higher with urea and N2O emissions were similar between treatments. The loss of NH3 accumulated throughout the maize growing season was higher for urea than for slurry, and the accumulated N2O emission was similar for both fertilizers. Nitrous oxide emissions were related to soil water content, initially introduced with slurry and then with rainfall. The loss of NH3 + N2O from the fertilizers after subtracting that of the control, was higher after the application of urea than slurry (10.8±1.2 and 3.1±0.7 kg N/ha or 0.53±0.06 and 0.18±0.04 kg N/t MS), and maize yield was similar for both fertilization treatments (19.0±0.7 t MS/ha). These results show that fertilization with dairy cattle slurry is a promising practice because it has a lower environmental footprint compared to synthetic fertilizers.

Investigation on the influence of inherent AAEMs on gasification reactivity of solid digestate char

Char reactivity usually determines the overall efficiency of the entire gasification process, while the presence of the alkali and alkaline earth metals (AAEMs) has a catalytic effect on char gasification. In this study, the influence of inherent AAEMs in the gasification behaviour of char was investigated. The char sample was prepared through the pyrolysis of solid digestate derived from anaerobic co-digestion of silage and dairy cattle slurry. The raw char and HCl-washed char were characterized by elemental analyzer, ICP-OES, SEM and XRD to explore their structural changes. HCl-char loses weight in the temperature range of 440–620 °C, and the weight loss percentage is significantly higher than that of char. Ash content of char is reduced by half after a pickling process. AAEMs are largely removed after char acid pickling, resulting in an increase in activation energy of the gasification reaction and a decrease in gasification reactivity, resulting in the gasification reaction time of HCl-char longer than char. Water-soluble AAEM and ion-exchange AAEM affect the evolution of carbon structure, which directly lead to char reactivity during the gasification reaction. As the carbon is consumed, the carbon microcrystalline structure of the residual carbon tends to be ordered, resulting in fewer active free carbon sites for the gasification reaction. Kinetic analysis showed that the loss and deactivation of AAEMs after char acid washing increased the average activation energy Ea by 115.76 KJ/mol compared with the original char.

Methane Emissions from Livestock Slurry: Effects of Storage Temperature and Changes in Chemical Composition

Livestock production contributes to releasing methane into the atmosphere. Liquid manure management offers significant opportunities to reduce these emissions. A better understanding of the factors controlling methane emissions from manure is necessary to select effective mitigation strategies. Our study aimed to identify the influence of storage temperature and the associated change in chemical composition on methane emissions from dairy and fattening pig manure. Storage temperature affects microbial activity and induces changes in chemical composition that are key influences in methane emissions. Dairy and fattening pig manure samples were stored at five different temperatures (5–25 °C) for 90 days in a laboratory-scale experiment to measure the methane production. The chemical composition of the slurry samples was analyzed, and the biochemical methane potential (BMP) tests were performed before and after storage. For pig manure stored at 25 °C and 20 °C, methane emissions accounted for 69.3% and 50.3% of the BMP, respectively. Maximum methane emissions for dairy slurry were observed at 25 °C but remained at a low level. Analyses of the accumulation of volatile fatty acids (VFAs) during storage are presented in few studies, this work revealed a potential inhibition of methane production, where the accumulation of VFAs was most elevated in samples stored at 20 °C and 25 °C. This partly counteracted the increase in methane emissions expected from the higher temperatures. The degree of VFA and dissociated fatty acids accumulation in dairy cattle slurry should be assessed for more accurate estimations of methane emissions from slurry stores.

Nitrogen Recovery from Different Livestock Slurries with an Innovative Stripping Process

Ammonia (NH3) emissions deriving from the management of livestock manure have a significant environmental impact, and therefore it is important to reduce them. Among the available options, the process of NH3 stripping is promising to remove NH3 from manures and digestates recovering it as a mineral fertilizer (e.g., ammonium sulfate) that is more widely adoptable on farms. The traditional stripping process takes place in batches; however, in this study, a continuous process was evaluated using a lab scale plant in which four reactors were used in series with different hydraulic retention times (HRTs) of 12 or 20 days. The NH3 recovery of each reactor was studied for the liquid fraction of pig slurry, dairy cattle slurry and digestate, applying simple headspace aeration. For 20 days of HRT, totals of 92%, 83% and 67% of NH3 were stripped from the digestate, pig slurry and dairy cattle slurry, respectively. For 12 days of HRT, total NH3 recoveries were 83%, 60% and 41% for the digestate, pig slurry and dairy cattle slurry, respectively. The inlet NH3 concentration and inlet total alkalinity had a positive and negative effect, respectively, on the specific NH3 removal rate for each reactor. Stripping NH3 on farm scale can abate NH3 emissions in response to the environmental concerns of European policies.

Quantitative microbial human exposure model for faecal indicator bacteria and risk assessment of pathogenic Escherichia coli in surface runoff following application of dairy cattle slurry and co-digestate to grassland

Animal waste contains high numbers of microorganisms and therefore can present a potential biological threat to human health. During episodic rainfall events resulting in runoff, microorganisms in the waste and soil may migrate into surface runoff, contaminating surface water resources. A probabilistic human exposure (HE) model was created to determine exposure to faecal indicator bacteria (FIB): total coliforms (TC), E. coli and enterococci following application of bio-based fertiliser (dairy cattle slurry, digestate) to grassland; using a combination of experimental field results and literature-based data. This step was followed by a quantitative microbial risk assessment (QMRA) model for pathogenic E. coli based on a literature-based dose-response model. The results showed that the maximum daily HE (HEdaily) is associated with E. coli for unprocessed slurry (treatment T1) on day 1, the worst-case scenario where the simulated mean HEdaily was calculated as 2.84 CFU day −1. The results indicate that the overall annual probability of risk (Pannual) of illness from E. coli is very low or low based on the WHO safe-limit of Pannual as 10 −6. In the worst-case scenario, a moderate risk was estimated with simulated mean Pannual as 1.0 × 10 −5. Unpasteurised digestate application showed low risk on day 1 and 2 (1.651 × 10 −6, 1.167 × 10 −6, respectively). Pasteurised digestate showed very low risk in all scenarios. These results support the restriction imposed on applying bio-based fertiliser if there is any rain forecast within 48 h from the application time. This study proposes a future extension of the probabilistic model to include time, intensity, discharge, and distance-dependant dilution factor. The information generated from this model can help policymakers ensure the safety of surface water sources through the quality monitoring of FIB levels in bio-based fertiliser.

Earthworm populations are stable in temperate agricultural soils receiving wood-based biochar

The application of decomposable organic residues such as manure and crop litter is generally beneficial to earthworms. There is an emerging interest in applying biochar, a carbonaceous product of pyrolysis, to temperate agricultural soils. The slow decomposition rate of biochar, which also contains ash and combustion byproducts, could be detrimental to earthworms. The objective of this study was to describe the earthworm populations in biochar-amended soils on a dairy farm in the St. Francis River watershed, Quebec, Canada. Earthworms were collected from replicated field plots under cereal production. Site A received three wood-based biochar types at two application rates (5 and 10 t ha-1 biochar) plus an unamended control, while Site B received wood-based biochar (7.5 t ha-1 biochar), dairy cattle slurry (10 t ha-1 manure), or a combination of the biochar and manure rates plus an unamended control. Earthworms were collected by hand sorting and formaldehyde expulsion from soil pits. Three species, Aporrectodea turgida, Aporrectodea tuberculata, and Lumbricus rubellus, were found at the sites, and Aporrectodea was the dominant genus. Biochar sources, rates, and application with dairy slurry did not affect the earthworm population, which had 52–218 individuals m-2 in 2010 and 4–96 individuals m-2 in 2011. The seasonal variation in earthworm population may be due to flooding in the spring of 2011, which apparently interfered with earthworm reproduction. The similarity in earthworm abundance and biomass in plots with and without wood-based biochar leads to the conclusion that earthworm populations are stable in biochar-amended soils in this cold, humid temperate region.

Environmental implications of stored cattle slurry treatment with sulphuric acid and biochar: A life cycle assessment approach

With the increase of animal slurry produced from livestock production, the monitoring and mitigation of greenhouse gas (GHG) and ammonia (NH3) emissions represent a major issue. Life cycle assessment (LCA) has been used to evaluate the long-term environmental effects of applied strategies and technologies on cattle slurry management for mitigation of environmental harmful gases. This study was carried on two main aims: first, the effect of the addition of sulphuric acid (SA), biochar (SBi) or A + Bi to liquid cattle-slurry (treated systems) on gas emissions during storage compared to the untreated system (S) was investigated in a laboratory-controlled experiment; second, the environmental implications of each treated or untreated system were assessed through a LCA approach according to ISO 14040/44. Five CML 2001 impact categories were used: eutrophication potential (EP), acidification potential (AP), global warming potential (GWP), human toxicity potential (HTP) and Ozone Layer Depletion Potential (ODP). Comparisons were based on 1 ton fresh dairy cattle slurry. The environmental profile of untreated system showed lower efficiency in mitigation of total GHG and NH3 emissions (0.0312 and 0.0001 kg CO2-eq respectively), during storage period and greater impact on GWP and HTP categories. The electricity consumption in mechanical separation dominated the environmental impacts. From the three proposed treated systems, SA showed the highest efficiency on mitigation of gas emissions compared to the other treatments, reducing NH3, CH4 and CO2 emissions respectively in 61%, 98% and 15%, when compared to the SBi system. In all categories, acidified slurry also showed the lowest environmental impact relative to other treated systems and the benefit was more evident when the impacts were expressed per kilogram of nitrogen in the slurry. Therefore, LCA methodology was of great importance to assess the environmental implications of the treatments and acidification can be considered as an effective technique on the mitigation of environmental implications of livestock production and cattle-effluent valorization. Optimization and uniformity of performed studies are essential to validate new strategies to improve the sustainability of this sector in the management of animal wastewater.

Dairy cattle slurry fertilization management in an intensive Mediterranean agricultural system to sustain soil quality while enhancing rapeseed nutritional value

Animal excreta are commonly recycled as fertilizers, although attention should be given to environmental impacts. Legislation must also be adapted to new research findings. The framework of this study is an intensive fodder Mediterranean agricultural system affected by EU legislation on the protection of waters against nitrate pollution. This paper studies the effect of two N based dairy cattle slurry (DCS) rates (170 vs. 250 kg N ha−1 yr−1) plus additional mineral N (up to 450 kg N ha−1 divided between two crops), on different soil quality parameters. A control (no N applied) was included. The experiment, which lasted for 8 years, included forage maize followed by ryegrass, grain maize and rapeseed. In the whole period, the organic carbon inputs from the DCS treatments comprised C slurry inputs (14.8 or 21.9 Mg ha−1) plus the C input difference in crop residues (8.3 Mg ha−1) between DCS and the control treatment. In the 0–0.3 m soil depth, slurries significantly increased soil organic carbon (SOC) from by 2.3 or 2.7% yearly (c. 2.8 Mg C with 10 Mg C ha−1 input) mainly in its light fraction. The size of the microbial biomass increased by 5.1% yearly (c. 0.12 Mg C with 10 Mg C ha−1 input). A higher aggregate stability against slaking disruption was observed. Soil pH slightly decreased, P (Olsen) fertility increased (up to 10 mg P kg−1) as did K availability (up to 140 mg K kg−1) and Mn and Ni bioavailability. In rapeseed plants, seed Ca, S, Cu and Mn content increased as did K, S, Fe, Mn and Zn in the rest of the plant biomass. These changes were within acceptable concentration ranges. The higher N rate from DCS has proved useful for the circular nutrient economy, while improving soil physical and chemical quality and the sustainability of the agricultural system as a whole.

Root growth and turnover in perennial forages as affected by management systems and soil depth

AimsExtensive knowledge of perennial forage root systems is essential, given their critical role in below-ground C input.MethodsRoot length and diameter were quantified periodically from 2016 to 2018 with minirhizotrons in a field experiment with three forage management systems: mixture of timothy (Phleum pratense L.) and tall fescue (Festuca arundinacea Schreb.) fertilized with (i) dairy cattle slurry or (ii) calcic ammonium nitrate, and (iii) mixture of timothy, tall fescue, and alfalfa (Medicago sativa L.) without N fertilization. Root biomass was measured yearly by coring.ResultsManagement systems with the two fertilization sources did not differ in root elongation, but the management system with alfalfa resulted in a slower root elongation after the first defoliation and a lower root mortality in the fall. Root length turnover was greater in the topsoil with dairy cattle slurry than with calcic ammonium nitrate. Fine roots dominated the surface soil and coarse roots the deeper soil layers.ConclusionsRoot growth and mortality were more contrasted between systems that differed by the presence of alfalfa than by fertilizer source. As many root characteristics are drivers of soil C storage, the choice of perennial species in mixtures appears as a key management factor for sustainable farming systems.

A multi-region study reveals high overwinter loss of fall-applied reactive nitrogen in cold and frozen soils

In cold agricultural regions, animal manure and synthetic fertilizers may be applied in the fall for convenience. However, the fate of applied nitrogen (N) is unclear and may differ depending on N source and interannual and regional variations in winter conditions. A multi-region study using 15N-labelled reactive N (NH4-15N) applied in the fall with pig slurry, dairy cattle slurry, and ammonium sulfate was carried out under a range of climatic conditions. Nitrification and immobilization of applied NH4-N occurred throughout the winter period at all sites. Transformation and losses were slower and less at the sites where significant soil freezing occurred than at the site where soil rarely froze, highlighting the repressive effect of frost. Nevertheless, losses were similar among sites with significant freezing despite marked differences in duration and extent of freezing. This suggests that soil microbes were adapted to prevailing winter conditions at each site and able to use and transform fall-applied N throughout the winter period. Overall, 47%–94% of fall-applied NH4-N was lost from the top 30 cm of soil before seeding in the next spring. Losses were generally greater with synthetic fertilizer than manures, likely because fresh carbon added with manures stimulated immobilization of NH4-N. This multi-region assessment indicates that reactive N applied in the fall has high vulnerability to loss in cold and frozen soils, and strategies for improving N retention over the winter are required even in areas where prolonged freezing occurs.

Band application of acidified slurry as an alternative to slurry injection in Mediterranean winter conditions: Impact on nitrate leaching

The aim of the present work was to assess the impact of raw slurry injection and band application of acidified slurry upon nitrate leaching in two different soils under Mediterranean conditions. A lysimeter experiment with a winter crop (oat - Avena sativa) was performed over three years presenting significant inter-annual precipitation variability. Four fertilization treatments using dairy cattle slurry were implemented. Nitrate leaching was estimated using nitrate concentration in soil solution assessed through ceramic suction cups and drainage calculated using the Agricultural System Root Zone Water Quality Model (RZWQM2). Results show that the RZWQM2 was able to predict drainage with an average efficiency of 89%. Cumulative drainage averaged 69 and 65% of the precipitation for the sandy and the sandy loam soils, respectively. The application of acidified slurry did not lead to any increase of nitrate leaching relative to band application or injection of raw slurry. Soil incorporation following soil application of acidified slurry is highly relevant regarding nitrate leaching since it significantly reduced nitrate leaching in more than 50% in the sandy soil and close to 40% in the sandy loam soil. A severe risk of pollution swapping was observed with slurry injection since it led to an increase of nitrate leaching relative to band application of raw or acidified slurry (more than 100% in the sandy soil and around 30% in the sandy loam soil for the rainiest year). According to the results, band application of acidified slurry is an efficient alternative to raw slurry injection to minimize nitrogen losses by leaching. Nevertheless, soil incorporation of acidified slurry, not necessary in terms of ammonia emissions, is strongly recommended to reduce nitrate leaching.

Influence of Tillage Practices, Organic Manures and Extrinsic Factors on β-Glucosidase Activity: The Final Step of Cellulose Hydrolysis

β-glucosidase is a key enzyme in the C-cycle, and its activity is strongly influenced by soil management practices and by extrinsic factors such as weather conditions. However, the variability of β-glucosidase activity (BGa) over time and how this variability is affected by tillage and organic fertilization remain poorly elucidated. We investigated how contrasting tillage practices (zero, minimum, conventional or deep) and organic amendment application (dairy cattle slurry or green compost) govern BGa. Strong correlations (r = −0.98; p < 0.001) were found between BGa and preceding cumulative rainfall for soil without crops. Under cropped soil conditions, BGa was 53% greater under zero and minimum tillage than under ploughed treatments (p < 0.05) six years after their applications. These differences could be explained by associated effects of tillage on organic matter content, electrical conductivity and water stable aggregates. The separated organic residue experiment showed that BGa was 36% greater in soil amended with slurry than in soil amended with compost (p < 0.05) five years after their applications. Finally, the response ratio of BGa was calculated in order to study the effect size of each treatment at each sampling period. This simple strategy mitigated the variation on BGa measurements between two sampling periods, and may be applied in future studies to improve the interpretation of other potential soil quality indicators that are sensitive to seasonal changes.

Bamboo biochar does not affect paddy soil N2O emissions or source following slurry or mineral fertilizer amendment—a15N tracer study

AbstractNitrogen (N)‐containing fertilizers, such as slurry and ammonium nitrate (NH4NO3), can significantly increase soil nitrous oxide (N2O) emissions following addition to agricultural soil. Biochar amendment to soil has been observed to suppress N2O emissions in a number of studies. However, the effect varies depending on many factors, including when biochar is added to soil concurrently with organic or mineral fertilizers. An incubation was conducted in which bamboo biochar (created at 800°C) was added to an ex‐rice paddy soil (1% rate) concurrently with dairy cattle slurry or NH4NO3(100 mg N kg−1). At three time points, following biochar amendment,15N‐labelled NH4NO3(50 mg N kg−1) was added to the soil to determine the N2O emissions derived from nitrification and denitrification in the 24 h that followed (at 70% water filled pore space; days 0, 7, and 28). Nitrous oxide emissions from slurry‐amended soils were much greater than those from NH4NO3‐amended soils, as well as the proportion of soil N2O emissions derived from denitrification. Biochar amendment did not significantly affect soil N2O emissions or consistently affect the percentage of soil N2O emissions derived from nitrification in slurry or NH4NO3‐amended treatments. The lack of N2O‐emission suppression with biochar amendment may have been due to the relatively‐low addition rate of a biochar that had a low content of volatile organic carbons and redox‐reactive organic/inorganic compounds, and did not greatly increase the pH of the acidic soil (pH 5). These results suggest that bamboo biochar produced at such a high temperature may not be suitable for mitigation of soil N2O emissions.

Improving the product stability and fertilizer value of cattle slurry solid fraction through co-composting or co-ensiling

Separating dairy cattle slurry in a liquid and solid fraction (SF) is gaining more interest, since it enables a more targeted use of both fractions. However, the valorization of the SF is limited on P-rich soils, due to its high P content, and the export or use as bedding material requires sanitation. Therefore, we investigated the influence of composting or ensiling the SF, whether or not mixed with bulking agents, on the product quality in terms of fertilizer value, sanitation and stability. Ensiling can be considered as a controlled storage method for conserving C and nutrients. Soil amendment with co-ensiled SF resulted in a higher N mineralization and crop growth compared to amendment of co-composted SF. Co-composting SF with structure-rich feedstock materials optimized the composting process and sanitation when compared with composting pure SF and did not increase the risk for extreme-heat-resistant spores of thermophilic aerobic spore-forming bacteria (X-TAS). Further, the composts contained more P per unit of fresh weight than the silages, beneficial for the export of the composted SF. The oxygen uptake rate was found to be less powerful to determine the stability of fresh, composted and ensiled SF.

STUDY ON BIOGAS UNIT USING DAIRY CATTLE DUNG DURING WINTER IN EGYPT

Anaerobic digestion (AD) become a crucial method for obtaining a green energy that represented in biogas from organic wastes particularly the animal wastes in rural areas instead of its incineration. This study aims to investigate the biogas yield of a constructed Indian type biogas unit with an approximately volume of 3m3 at Faculty of Agriculture, Zagazig University, Sharkia Governorate, Egypt for biogas generation from dairy cattle dung under cold climate conditions during winter season of 2015. The results revealed that, the dairy cattle dung proved a suitable substrate for the installed biogas digester and produced an average 105L biogas per day for one cubic meter of dairy cattle slurry (8% of TS) without any feedstock for 30 days in winter season in Egypt under psychrophilic conditions of 16.3 to 20.5oC temperature range. Therefore, the environmental affordability of the biogas technology, as a zero-waste engineering and unsound waste management system warrants further study in Egypt.

Effectiveness of Clinoptilolite Zeolite for Mycobacterium avium subsp. Paratuberculosis (MAP) Control in Dairy Slurry

The use of slurry as a fertilizer on grassland efficiently spreads infectious agents. Among those using the fecal– oral way of transmission, Mycobacterium avium subsp. Para tuberculosis (MAP) represents an interesting pathogen model to be studied in slurry management systems. In order to fulfill the requirements of a practical control implementation, we aimed to investigate the effect of natural zeolite on MAP viability and concentration in dairy cattle naturally contaminated slurry. MAP viability and number in dairy cattle slurry following a physical separation treatment was estimated. A randomized block design constituted by four separation phases of treated slurry (solid supernatant, liquid supernatant, zeolite with slurry, liquid residue) plus one control (not filtered) was used. To assess MAP detection, each obtained sample was evaluated by culture sampling along with MAP quantification. Zeolite+slurry treatment showed the lowest number of viable MAP. The zeolite-based treatments reduced significantly the survival of MAP in treated slurry. The results suggest that zeolite treatments using the zeolite filter may be an interesting alternative of MAP control in slurry. The use of zeolite treatments to control MAP, and maybe other pathogens too, seems promising, however further research is needed to understand and clarify the mechanisms that explain these results in detail.