Recycled Manure Solids (RMS) bedding can help dairy farms make better use of manure while reducing dependence on purchased bedding materials.
A manure separator produces a solid fraction. It does not automatically produce hygienically suitable dairy cow bedding.
The solids may still contain bacteria and other microorganisms originating from manure. Depending on local regulations and the intended use, further processing, quality testing, and a carefully managed bedding program may be necessary.
For commercial dairy farms, RMS should be considered as part of a complete manure-management and cow-comfort system.
That means evaluating five connected issues:
- The source of the manure and its potential disease risks.
- The separation and treatment process.
- The quality of the solids before bedding use.
- Daily freestall cleanliness and moisture management.
- Long-term equipment, operating, and animal-health costs.
This guide explains how RMS bedding is produced, what farms should monitor, how different processing methods compare, and what to check before investing in equipment.
1. What Is Recycled Manure Solids Bedding?
Recycled Manure Solids (RMS) bedding is an organic bedding material obtained from the solid fraction of cattle manure or slurry.
A mechanical separator removes part of the liquid, leaving a fiber-containing solid material.
Depending on the farm and local requirements, the material may undergo additional treatment before being considered for bedding use.
RMS is mainly discussed as a bedding option for freestall dairy housing, although permitted uses differ between countries.
Why Are Dairy Farms Interested in RMS?
The main reasons are practical:
- Manure is already produced on the farm.
- Recovered solids may reduce purchases of external bedding materials.
- Solid-liquid separation can improve the organization of manure handling.
- The solid fraction may be easier to transport and manage than untreated slurry.
- Farms can evaluate bedding production as part of a broader manure-management system.
However, the material is not free simply because it originates on the farm.
Separators, pumps, treatment equipment, electricity, labor, testing, maintenance, and bedding handling all create costs.
More importantly, manure-derived bedding introduces hygiene and biosecurity concerns that must be taken seriously.
Is RMS Bedding Safe for Dairy Cows?
There is no single answer that applies to every farm.
Published research has reported differences in bacterial counts and udder-health outcomes among farms using different RMS processing systems.
Some treatment methods can reduce certain microbial loads, but this does not make the finished material sterile or guarantee that mastitis will not occur.
A useful starting point is the peer-reviewed review Recycling Manure as Cow Bedding: Potential Benefits and Risks for UK Dairy Farms.
RMS suitability should be assessed through local requirements, treatment performance, bedding management, microbiological monitoring, and herd-health records—not appearance alone.
2. How Is RMS Bedding Produced?
RMS production begins with a manure collection and separation system.
The final arrangement depends on the farm's existing manure infrastructure, processing goals, and the regulations that apply at the intended location.
Step 1: Collect and Prepare the Manure
Before purchasing equipment, confirm:
- Daily slurry or manure volume.
- Whether bedding sand or other abrasive materials are present.
- Incoming dry matter and fiber content.
- Collection pit and agitation arrangements.
- Potential contamination from other waste streams.
- Available operating hours and utilities.
Manure composition can vary significantly between farms.
A separator that performs well on one farm's slurry may not achieve the same throughput or output consistency with another farm's material.
Step 2: Separate the Solid and Liquid Fractions
Screw press separators use mechanical pressure and a screen to divide incoming slurry into solid and liquid outputs.
The recovered solids contain retained fiber and other particles, while the liquid fraction must still be collected, stored, or treated appropriately.
Separation can reduce the water content of the solid fraction.
However, mechanical dewatering is not a validated pathogen-killing process.
This matters when the solids are being evaluated for direct animal contact.
For a commercial equipment purchase, request performance information based on manure with characteristics comparable to the farm's actual material.
Step 3: Evaluate Whether Further Processing Is Required
Several processing approaches appear in published RMS studies and commercial manure-management systems.
| Processing Method | Main Function | Important Limitations |
|---|---|---|
| Direct solid-liquid separation | Produces a solid fraction from manure slurry | Does not sterilize the solids; bedding use depends on local rules and risk assessment |
| Separation followed by composting | Uses controlled biological activity and heat | Results depend on process control, temperature distribution, time, and verification |
| Anaerobic digestion followed by separation | Recovers solids from digested manure | Pathogens may remain; permitted uses vary |
| Separation followed by mechanical drying | Reduces moisture and may provide a controlled heat-treatment opportunity | Hygienic performance depends on actual material temperature, residence time, and equipment validation |
| Combined processing systems | Integrates multiple treatment stages | Higher investment and operating complexity; no universal guarantee of pathogen elimination |
A 2025 study of Midwest dairy farms found that combining anaerobic digestion with secondary processing was associated with greater reductions in several investigated pathogens than less intensive processing routes.
However, the results do not establish that a particular treatment combination guarantees pathogen-free bedding on every farm.
Read the study: Relationships Between Bedding Processing Methods and Pathogens in Ready-to-Use RMS.
Does Every Farm Need a Composting or Drying System?
Not necessarily.
Processing requirements depend on the location, permitted RMS use, treatment objectives, and verified operating conditions.
For example, the UK AHDB guidance permits certain forms of RMS bedding only under specific conditions, including a minimum dry matter level and restrictions on the animals and areas where it is used.
The guidance also excludes composted and anaerobically digested materials from its defined permitted RMS system.
That differs from some processing arrangements investigated on North American farms.
See AHDB: Regulations for Using Recycled Manure Solids as Cattle Bedding.
Always confirm the applicable local regulations before deciding which RMS production process to install.
3. What Moisture Content Is Acceptable for RMS Bedding?
Moisture control is essential, but a single percentage should not be treated as a global bedding safety standard.
The first question is: Which material is being tested, and at what stage?
Understand Dry Matter and Moisture
Dry matter and moisture are commonly expressed as percentages of the same wet sample.
Dry Matter (%) = Dry Sample Mass ÷ Original Wet Sample Mass × 100
Moisture (%) = 100 − Dry Matter (%)
For example:
- A sample containing 40% dry matter contains approximately 60% moisture.
- A sample containing 35% dry matter contains approximately 65% moisture.
This distinction is important when reviewing separator quotations.
A supplier advertising 40% dry matter is not claiming the material contains only 40% moisture.
Check the Material at Different Stages
| Sampling Stage | What to Measure | Why It Matters |
|---|---|---|
| Incoming slurry | Dry matter, fiber, contaminants | Determines how the material may behave in the separator |
| Fresh separated solids | Dry matter, consistency, recovered solids | Evaluates actual dewatering performance |
| After further treatment | Dry matter and treatment-specific quality indicators | Assesses processing results |
| Ready-to-use bedding | Moisture, physical condition, microbiological indicators | Evaluates the material before application |
| Bedding in occupied stalls | Surface wetness, soiling, bacterial trends | Shows how the material performs during use |
Moisture content alone cannot establish whether RMS bedding is suitable for use. Assess the processing method, applicable local requirements and microbiological results together. A dry-looking sample can still contain microorganisms relevant to animal health.
How Can Farms Reduce Moisture Problems?
Start with the complete system:
- Keep the separator operating within its intended material and flow conditions.
- Protect stored solids from rain and contaminated runoff.
- Avoid unnecessary storage conditions that encourage uncontrolled heating or rewetting.
- Maintain suitable barn ventilation.
- Keep water trough overflow and washing water away from resting surfaces.
- Remove heavily contaminated material from the rear of stalls.
- Check bedding condition regularly.
Dry matter measurement is useful. It is not a substitute for hygiene control.
4. What Microbiological Risks Should Dairy Farms Monitor?
Manure-derived bedding may expose cows to microorganisms associated with environmental mastitis and other health concerns.
The actual risk depends on the manure source, production process, animal population, bedding conditions, and farm management.
Which Microorganisms Are Relevant?
Microbiological monitoring may include:
Coliform bacteria: Used to assess environmental contamination and may include organisms associated with mastitis.
Klebsiella species: Important environmental mastitis pathogens that can occur in organic bedding materials.
Streptococcus and related organisms: Some species are relevant to udder health, though testing and interpretation require care.
Staphylococcus species: A broad group with different implications depending on the organism identified.
Salmonella and other selected pathogens: May warrant specific surveillance depending on disease status, material source, risk assessment, and local requirements.
Not every organism has the same significance.
A total bacterial count also cannot be interpreted as a direct prediction of mastitis incidence.
Why Not Use One Universal Bacterial Limit?
Laboratories may report results in different ways, including colony-forming units per gram (CFU/g).
Reports may use a wet-weight or dry-weight basis.
Sampling location, sample storage, laboratory procedures, and detection limits can also affect results.
A meaningful test program should identify:
- The material and stage being sampled.
- The sampling location and collection method.
- The laboratory method.
- The reporting units.
- Whether results are based on wet or dry material.
- The applicable interpretation criteria.
- The action required when results are unusual.
A result reported as "not detected" means the target was not detected under the specified test conditions. It does not prove absolute absence from the entire material batch.
Connect Bedding Results to Udder-Health Monitoring
The value of bedding testing increases when the farm also monitors:
- Clinical mastitis cases.
- Milk somatic cell count trends.
- Bulk tank milk quality.
- Udder and teat cleanliness.
- Changes in bedding handling or treatment.
- Repeated abnormal results in particular barns or groups.
Bedding contamination should be investigated alongside milking hygiene, cow health, and other environmental conditions.
Review milking hygiene and other environmental sources of infection alongside bedding results.
5. Does Composting Automatically Make RMS Bedding Safe?
No.
Composting may reduce the abundance of some microorganisms when the process is properly controlled.
However, the actual effect depends on the material and process.
Why Temperature Alone Is Not Enough
A temperature measurement taken at one point does not necessarily represent the entire material batch.
Important variables may include:
- Material temperature distribution.
- Actual time at the required temperatures.
- Moisture and aeration.
- Mixing or turning efficiency.
- Batch size and equipment loading.
- Cold spots and poorly treated material.
- Recontamination during discharge, storage, or transport.
Therefore, a blanket instruction to maintain 55°C for five to seven days cannot be presented as a universal guarantee of hygienically safe RMS.
Any heat-treatment system should be assessed against a documented, validated process and the requirements that apply to its intended use.
Why Does Bedding Management Still Matter After Processing?
Processed bedding begins changing as soon as it is placed in a cow stall.
It comes into contact with:
- Manure and urine.
- Cow skin and teat surfaces.
- Moisture from the barn environment.
- Residual material from previous bedding applications.
Research comparing composted and fresh RMS in freestalls found that initial differences in certain bacterial counts did not necessarily remain after the material had been used in occupied stalls.
This reinforces the need to evaluate what happens after bedding application, not just what happens inside the treatment equipment.
Reference: Environmental Mastitis Pathogen Counts in Freestalls Bedded with Composted and Fresh RMS.
6. How Should RMS Bedding Be Stored and Applied?
An RMS bedding system should not end at the separator outlet.
The material must be handled and used in ways that limit unnecessary contamination.
Protect the Material Before Use
Check the storage and delivery arrangement for:
- Rainwater entry and runoff.
- Contact with fresh manure or dirty vehicle routes.
- Uncontrolled moisture accumulation.
- Mixing of treated and untreated material.
- Excessive or unverified storage periods.
- Cleaning access for handling equipment.
Storage time should follow the applicable treatment process, local requirements, and farm hygiene program.
Some jurisdictions restrict how long freshly separated RMS can be held before use.
Focus on the Rear of the Freestall
The rear section of a freestall is frequently exposed to manure, urine, and moisture.
It deserves particular attention during daily cleaning.
Workers should look for:
- Wet or compacted bedding.
- Visible manure contamination.
- Uneven bedding depth.
- A persistently dirty rear curb.
- Cows lying in unusually dirty positions.
- Water entering the resting platform from the alley.
The most easily overlooked tasks are checking surface dryness and inspecting stall cleanliness consistently.
A farm may invest heavily in processing equipment but still experience poor bedding performance if these daily checks are missing.
Ventilation Helps, but It Cannot Replace Cleaning
Good airflow can help manage barn humidity and cow comfort.
However, fans do not remove manure contamination from bedding surfaces.
Similarly, a manure scraper helps clean designated alleys but cannot guarantee that the resting surface will stay dry.
Bedding maintenance, floor drainage, water management, and ventilation must work together.
7. Does RMS Fiber Structure Affect Cow Comfort?
Yes. The physical character of bedding affects how it behaves under the cow.
But longer fibers are not always automatically better.
Particle size, moisture, cushioning, material distribution, and compression all matter.
What Should Be Checked?
Particle consistency: Look for material that can be distributed evenly and maintained in the intended bedding system.
Cushioning: The complete resting surface should support normal lying and rising behavior.
Compaction: Material that becomes dense or hard may require changes to the bedding depth, maintenance, or underlying surface.
Moisture retention: Observe whether the top layer remains wet or becomes soiled quickly.
Dust: Excessively dry or fine material may produce unwanted dust during handling or application.
Does RMS Work With Cow Mattresses?
Some freestall systems use a layer of loose bedding on top of a mattress.
Whether RMS is appropriate depends on the local rules, mattress system, bedding depth, and hygiene-management program.
The material should not be selected solely because it looks soft.
Observe how cows use the stalls, whether the bedding stays clean, and whether the system can be maintained consistently.
8. RMS vs. Sand vs. Sawdust: Which Bedding Is Better?
No single bedding material is automatically the best option for every commercial dairy farm.
The decision should consider animal comfort, sanitation, manure handling, material availability, and total cost.
| Factor | RMS Bedding | Sand Bedding | Sawdust or Wood Shavings |
|---|---|---|---|
| Material source | Recovered from farm manure | Purchased or locally sourced mineral material | Purchased or locally sourced wood material |
| Initial system investment | May require separation and additional treatment | May require sand-compatible handling and recovery | Usually less specialized processing at the farm |
| Main hygiene concern | Manure-origin microorganisms and contamination during use | Soiling and bacterial growth after contamination | Moisture accumulation and microbial growth |
| Comfort | Depends on bedding depth, texture, and stall base | Can provide good cushioning when properly managed | Depends on material quality and maintenance |
| Manure system compatibility | Must suit slurry, separator, and bedding flow | Abrasive to some pumps and handling systems | Depends on fiber, collection, and downstream processing |
| Routine operating costs | Power, labor, treatment, testing, repairs | Purchasing, transport, replenishment, equipment wear | Purchasing, transport, storage, replenishment |
| Main management challenge | Processing consistency and ongoing hygiene | Sand recovery, contamination, and machinery wear | Supply stability and keeping bedding dry |
What Is the Most Common Costing Mistake?
Comparing the purchase price of bedding while ignoring the complete system.
For example, RMS may use material already available on the farm, but its processing equipment can require significant capital investment.
A screw press, pumps, collection pit, electrical controls, solids transport, and possible post-treatment equipment all add to project cost.
Sand may require specialized manure-handling arrangements.
Sawdust and wood shavings may depend heavily on local supply and seasonal prices.
The best choice is the material that the farm can use and manage successfully at an acceptable long-term cost.
9. How Do You Size an RMS Bedding Production System?
Before selecting a separator, estimate how much manure is available and how much recovered material the barn actually needs.
Do not choose the machine only from the total number of cows.
Step 1: Confirm Daily Manure Volume
Estimate the actual manure or slurry volume reaching the separator.
This may differ from the volume excreted by the herd because of washing water, rainwater, bedding materials, and collection practices.
Step 2: Confirm Available Processing Hours
A simple first calculation is:
Required Average Feed Rate (m³/h) = Daily Slurry Volume (m³/day) ÷ Available Processing Hours (h/day)
For example, assume a farm needs to process 24 m³ of slurry during a six-hour operating period.
24 ÷ 6 = 4 m³/h
A nominal 4 m³/h requirement is a starting point, not the final equipment specification.
The selected separator must still be checked for actual material consistency, sustainable operating rate, downtime, cleaning, and any required operating reserve.
Step 3: Calculate Recoverable Solids
The volume of incoming manure alone does not tell you how much separated material will be recovered.
A simplified mass-balance relationship is:
Recovered Solids Dry Mass = Incoming Slurry Wet Mass × Incoming Dry Matter Fraction × Solids Capture Fraction
If the final separated material has a measured dry matter fraction:
Wet Separated Solids Mass = Recovered Solids Dry Mass ÷ Output Dry Matter Fraction
These formulas describe physical material recovery.
They do not establish that the recovered material is hygienically suitable for bedding.
Illustrative Material-Balance Example
Assume:
- Incoming slurry: 20,000 kg/day.
- Incoming dry matter: 8%.
- Captured fraction of incoming dry solids: 40%.
- Separated solids output: 35% dry matter.
Then:
Incoming dry solids = 20,000 × 0.08 = 1,600 kg/day
Captured dry solids = 1,600 × 0.40 = 640 kg/day
Wet separated solids = 640 ÷ 0.35 ≈ 1,829 kg/day
This produces approximately 1.83 tonnes of wet separated solids under the stated assumptions.
It does not mean the farm has produced 1.83 tonnes of ready-to-use RMS bedding.
Actual yield, subsequent processing losses, material rejection, and permissible bedding use must be considered separately.
Step 4: Compare Output With Bedding Demand
Estimate:
- Number of stalls intended to receive RMS.
- Bedding quantity required per stall.
- Application and replacement frequency.
- Material rejected or lost during processing.
- Any additional treatment or storage requirements.
If more solids are produced than the bedding program needs, plan a permitted use or disposal route for the excess.
The separated liquid also requires a suitable storage, treatment, or land-application plan.
Step 5: Evaluate Maintenance Before Purchasing
For a screw press separator, pay special attention to:
Screen wear and blockage: Fiber, solids loading, and abrasive materials can affect operation.
Screw-shaft wear: Long operating hours and abrasive material may increase replacement or refurbishment needs.
Adjustments and cleaning: Maintenance access and cleaning procedures influence downtime.
Replacement parts: Confirm screen availability, screw components, seals, bearings, and the supplier's support arrangements.
Real operating performance: Request testing with comparable manure rather than relying solely on catalogue values.
When possible, observing a similar farm's system in normal operation is more useful than watching a short unloaded equipment demonstration.
10. Is an RMS Bedding System Worth the Investment?
RMS can be economically attractive, but the decision should be based on complete project cost and the quality of usable bedding.
Include All Major Investment and Operating Costs
| Cost Category | What to Include |
|---|---|
| Initial equipment | Separator, pumps, controls, conveyors and any confirmed additional treatment equipment |
| Civil and utility work | Collection pit, foundation, drainage, water and electrical connections |
| Installation | Transport, installation, commissioning and operator training |
| Energy | Electricity or fuel for separation, transport and treatment |
| Labor | Equipment operation, monitoring, bedding application and cleaning |
| Maintenance | Screens, screw components, seals, motors, bearings and servicing |
| Monitoring | Material sampling, laboratory testing and related quality control |
| Bedding management | Storage, handling, replacement and rejected material |
| Risk management | Contingency planning, equipment downtime and herd-health investigation |
Compare the Annual Cost per Tonne of Usable Bedding
A practical planning metric is:
RMS Bedding System Cost per Usable Tonne = Annual RMS System Cost ÷ Annual Tonnes of Usable RMS Bedding
Annual RMS system cost may include:
- Annualized equipment and infrastructure investment.
- Routine operating expenses.
- Maintenance and spare parts.
- Testing and quality management.
- Material storage and handling.
- Other costs directly attributable to the bedding system.
The denominator should reflect material actually suitable for use under the farm's applicable program—not simply the gross mass discharged from the separator.
What About Animal-Health Losses?
Mastitis and other health problems may have substantial economic consequences.
However, those losses should not be converted into a guaranteed RMS cost penalty or a guaranteed saving without farm-specific evidence.
Use scenario analysis when evaluating uncertain outcomes.
For example, compare operating costs under normal equipment performance, higher maintenance requirements, and a situation where a significant portion of the produced material cannot be used.
An RMS project that looks economical only under its best-case assumptions may require reconsideration.
11. RMS Bedding Monitoring Checklist for Commercial Dairy Farms
A useful RMS quality-management program should connect processing records with bedding observations and herd-health monitoring.
| Control Area | What to Check | When to Check | Responsible Party |
|---|---|---|---|
| Incoming manure | Source, composition and unusual contamination | During collection or batch review | Manure system operator |
| Separator | Feed rate, blockages, output consistency | During operation | Equipment operator |
| Output dry matter | Actual material sampling and measurement | According to process plan | Quality or farm supervisor |
| Treatment process | Required temperatures, times, alarms and other validated conditions | Each applicable treatment cycle | Trained operator |
| Ready-to-use material | Appearance, moisture and required testing | Before use under farm protocol | Quality or veterinary team |
| Bedding storage | Rainwater, recontamination and material handling | Routine inspection | Barn supervisor |
| Freestall surface | Wetness, manure contamination and compaction | Daily | Barn staff |
| Cow cleanliness | Udder and body cleanliness trends | During routine herd checks | Herd manager |
| Milk and udder health | SCC trends, clinical mastitis and relevant test results | According to herd-health program | Herd manager and veterinarian |
| Equipment maintenance | Screen, screw, seals, electrical and mechanical condition | According to maintenance plan | Maintenance team |
The most important control is not simply completing the checklist.
When a problem is identified, someone must decide what action is needed, who will carry it out, and when the result will be checked again.
Abnormal bedding or herd-health findings should trigger investigation rather than automatic assumptions about one specific cause.
How Can NexAgri Support Dairy Manure Separation and Bedding Planning?
NexAgri Solutions supplies equipment for commercial dairy manure management and barn infrastructure.
Relevant product lines include solid-liquid manure separators, automatic manure scrapers, barn ventilation fans, and cow comfort equipment.
For a farm evaluating RMS bedding, the starting point should be the incoming manure volume, material composition, expected solids recovery, required downstream processing, and actual bedding demand.
Equipment configuration should also account for collection systems, power supply, maintenance access, solids handling, and liquid storage.
The separator's published specifications are useful for preliminary selection, but actual throughput and output dry matter should be confirmed against the intended manure characteristics.
Any additional RMS treatment process, hygienic performance, installation service, or local regulatory responsibility must be confirmed separately.
For an RMS project, confirm which separation, treatment and verification steps are included in the equipment proposal.
Frequently Asked Questions
Can separated cow manure be used directly as dairy bedding?
Not automatically. Physical separation does not sterilize manure. Direct bedding use depends on local regulations, material quality, disease risk, and the farm's documented management program.
What is the ideal moisture content for RMS bedding?
There is no single globally applicable figure. Requirements and practical targets depend on the production stage, process, climate, and location. Dry matter and moisture should always be clearly distinguished.
Does a manure separator kill bacteria?
No. A conventional screw press separator is designed for solid-liquid separation, not validated pathogen destruction.
Does composting eliminate all RMS bedding pathogens?
No treatment should be assumed to eliminate every relevant organism under all operating conditions. Temperature, exposure time, process consistency, testing, and recontamination all matter.
Is RMS bedding associated with mastitis?
RMS can contain microorganisms relevant to udder health. Research findings vary across farms and processing systems, so bedding practices should be assessed alongside herd-health and milk-quality records.
Is RMS cheaper than sand or sawdust?
It may be, but the answer depends on equipment investment, local bedding prices, energy, labor, maintenance, treatment and quality control. Compare full annual system costs rather than material prices alone.
What should I ask before buying an RMS manure separator?
Ask for testing with comparable manure, realistic throughput, output dry matter, solids recovery, screen and screw maintenance requirements, spare parts, and downstream handling responsibilities.
Can RMS bedding be used for calves or calving pens?
Do not assume it is permitted or appropriate. Some jurisdictions explicitly restrict RMS to older cattle in specific cubicle arrangements and exclude calving areas and young calves. Follow applicable local requirements and veterinary biosecurity guidance.
Conclusion
Recycled Manure Solids bedding should be evaluated as a complete management system, not as a simple by-product of manure separation.
Successful planning starts with manure source and disease risks, then considers separation performance, any required treatment, bedding application, daily maintenance, and ongoing monitoring.
For equipment buyers, an important question is not only how many cubic meters of slurry a separator can process.
It is also how much recoverable material the farm will produce, what additional steps are required, how the system will be maintained, and whether the final bedding program can be operated consistently.
RMS may reduce dependence on purchased bedding materials under suitable conditions.
But material reuse, equipment performance, and cow health must be evaluated together.
A well-managed RMS system starts with the right process and continues with everyday bedding hygiene—not simply with a dry-looking pile of separated manure.
