A farm with 300 beef cattle might need a 10 m³ mixer, a 15 m³ mixer, or something much larger. The difference usually comes down to how much feed is prepared in the largest batch, how bulky the ration is, and how often the farm can mix and deliver it.
For buyers comparing cattle feed mixers, the most useful starting information is the as-fed ration weight, the feeding groups, the number of batches, the forage being handled, and the available tractor or electrical power. The machine also has to fit the loading area, pass through the barn, and discharge where the cattle are fed.
This guide walks through the capacity calculation, vertical and horizontal mixer choices, power and layout checks, and the equipment tests worth including in a purchase agreement.
1. Size the Mixer From the Largest Feed Batch
A herd count helps estimate feed demand. The largest batch that enters the mixer determines the capacity it must handle. A farm with separate starter, growing and finishing rations should calculate the feeding groups individually.
Begin with four inputs:
- As-fed intake (kg/head/day): the weight of the complete ration as loaded, including its moisture. Dry matter intake (DMI) is a different measure.
- Animals per ration group: the number of cattle receiving the same formulation.
- Batches for that group: how many separate loads will be mixed each day.
- Bulk density (kg/m³): the weight of the prepared ration occupying one cubic metre.
If the farm only knows dry matter intake, convert it before sizing: as-fed intake = dry matter intake ÷ ration dry-matter fraction. For example, 10 kg of dry matter at 40% dry matter is 25 kg of as-fed TMR. Use the finished ration's moisture content, not the moisture of a single ingredient.
For a group receiving equal batches:
Batch weight (kg) = Cattle in the group × Daily as-fed ration (kg/head) ÷ Batches per day
Feed volume per batch (m³) = Batch weight (kg) ÷ TMR bulk density (kg/m³)
Finally, if the chosen machine is specified by its nominal or rated tub volume:
Estimated required rated volume (m³) = Feed volume per batch (m³) ÷ Assumed usable fill fraction
This converts the physical feed volume into a preliminary nominal mixer size. The final specification also checks the machine's minimum working batch, maximum permitted load and ability to circulate the intended ingredients.
Example: 300 Beef Cattle With Different Batch Schedules
Assume 300 cattle receive the same ration at 25 kg/head/day as fed. For this planning example, the prepared ration has a bulk density of 350 kg/m³ and the usable fill fraction is 75%.
Daily feed weight = 300 × 25 = 7,500 kg.
| Mixing schedule | Weight per batch | Feed volume per batch | Estimated rated mixer volume at 75% fill |
|---|---|---|---|
| One batch/day | 7,500 kg | 21.43 m³ | 28.57 m³ |
| Two equal batches/day | 3,750 kg | 10.71 m³ | 14.29 m³ |
| Three equal batches/day | 2,500 kg | 7.14 m³ | 9.52 m³ |
The two-batch schedule points toward a machine with roughly 14.3 m³ rated volume under these assumptions, subject to the manufacturer's usable-load and power limits. In practice, the purchasing decision also considers the available model sizes and whether two full mixing, loading and delivery cycles fit the feeding window.
If the herd is split into different rations, calculate each group separately. A 100-head growing group may need a smaller batch than a 200-head finishing group even when both are fed twice a day. Select against the largest actual batch, rather than dividing the entire farm's daily tonnage evenly across recipes that cannot be combined.
Why TMR Bulk Density Deserves a Real Measurement
Corn silage, wet by-products, dry hay and straw occupy different volumes for the same weight. The 350 kg/m³ value above is an example, not a fixed density for beef or dairy rations.
For a practical check, fill a container of known volume with the ration, weigh the contents and divide net weight by container volume. Repeat using representative samples. Record moisture and forage length when the ingredients change.
A density sensitivity check is more useful than choosing a value from an unrelated farm. For 3,750 kg in one batch, the calculation changes as follows:
| Density entered | Feed volume | Estimated rated mixer volume at 75% fill |
|---|---|---|
| 250 kg/m³ | 15.00 m³ | 20.00 m³ |
| 350 kg/m³ | 10.71 m³ | 14.29 m³ |
| 450 kg/m³ | 8.33 m³ | 11.11 m³ |
The table shows how strongly the chosen density changes mixer size. For multiple recipes, estimate density separately and select for the largest batch.
2. Use the TMR Mixer Capacity Calculator
Enter the cattle count, as-fed kilograms per head, estimated or measured ration density, and the number of equal batches. The calculator gives the volume of feed in each batch and an estimated nominal mixer size using a 75% fill assumption.
🧮 Interactive TMR Mixer Capacity Calculator
Estimate the feed volume per batch and the required rated mixer volume for one ration group, using a 75% usable fill assumption.
Include moisture. Do not enter dry matter intake (DMI) without converting it to as-fed weight.
Use the measured or estimated bulk density of the complete ration.
Default values are examples, not feeding recommendations. Calculate each ration group separately and size for the largest actual batch. This calculation assumes equal batches; feed deliveries are not always separate mixing batches.
Confirm the selected model's usable-load range, maximum batch weight, minimum working batch and power requirements. Apply the 75% allowance only when the quoted capacity is nominal tub volume; do not apply it again to a manufacturer's stated usable mixing volume.
For a quick check against the original example: 100 cattle × 18 kg/head/day = 1,800 kg/day. At 260 kg/m³, the feed occupies 6.92 m³. With one daily batch and 75% fill, the estimated required rated mixer volume is 9.23 m³. With two equal batches, the corresponding rated-volume estimate is 4.62 m³.
For multiple feeding groups, run a separate calculation for each ration and use the largest load for the machine shortlist. Then check the selected model's working-load range and available mixing window.
3. Vertical vs. Horizontal TMR Mixers
The ration determines much of the mixing mechanism. Large dry bales and long forage behave differently from finely chopped silage and concentrate-heavy mixtures.
| Selection point | Vertical auger mixer | Horizontal auger/paddle mixer |
|---|---|---|
| Long hay and whole bales | Often a practical choice, using augers and cutting knives | May require pre-cut material, depending on the internal design |
| Chopped silage | Suitable with the correct loading and mix sequence | Suitable, including many chopped-forage recipes |
| High-concentrate or dense mixtures | Check batch size, loading order and circulation | Can work well; actual uniformity depends on the mixer mechanism |
| Building height | Check high tub rim and loader reach | Some models offer a lower loading profile |
| Forage processing | Knife condition and auger configuration matter | Paddle/auger geometry and residence time matter |
| Best comparison | Test the actual ration and inspect the discharge | Test the actual ration and inspect the discharge |
When a Vertical Mixer Makes Sense
Vertical mixers are frequently considered where the ration includes long dry hay, straw or large bales. An upright auger moves material through the tub while knives process the long forage. Check bale dimensions, the amount of dry material, knife configuration, and the tractor or motor power required when the tub is loaded.
An important detail is fiber length after mixing. The machine needs enough time to distribute ingredients, but unnecessary extra cutting can shorten forage beyond the ration's intended particle profile. Compare the fresh mix with the nutritionist's physical-fiber target.
When a Horizontal Mixer Makes Sense
A horizontal mixer may fit a lower feed room and can handle a wide range of chopped forages, moist materials and concentrates. Horizontal designs differ internally: some use augers, others use paddles or combinations. Compare their feed movement and unloading performance with the ingredients actually used on the farm.
Where a horizontal machine is supplied as part of a centralized feeding setup, confirm its loading height, outlet position, conveyor interface, maintenance access and final assembly dimensions. These details often influence the purchase as much as the advertised mixing volume.
4. Trailed, Stationary or Self-Propelled?
The words vertical and horizontal describe the mixing mechanism. Trailed, stationary and self-propelled describe the machine's installation or movement. A farm may compare different combinations of these features.
| Format | Typical use | What must be available on site |
|---|---|---|
| Trailed PTO mixer | A tractor powers and tows the mixer; a loader supplies feed, and the wagon distributes it | Suitable tractor PTO power/speed, hydraulic connections, turning room and stable alleys |
| Stationary electric mixer | Central feed preparation with separate feed distribution | Electrical supply, loading system, suitable foundation, conveyor or feed wagon |
| Self-propelled mixer | Integrated loading/mixing/delivery where the layout and budget justify it | Access routes, operator skills, machine maintenance and service plan |
NexAgri supplies vertical and horizontal TMR mixers, including 5–20 m³ trailed units and stationary configurations up to around 30 m³. Self-propelled systems can also be sourced and configured for projects that require integrated loading and feed delivery.
How Much PTO Horsepower Does a Trailed TMR Mixer Need?
Actual commercial mixer specifications provide a useful reference when checking a tractor already owned by the farm. Selected single-auger vertical mixers on the market carry these minimum PTO ratings:
| Nominal mixer capacity | Published minimum PTO power |
|---|---|
| 7.6 m³ | 50 HP (37 kW) |
| 9.9 m³ | 75 HP (56 kW) |
| 12 m³ | 90 HP (67 kW) |
| 16 m³ | 100 HP (75 kW) |
These model examples show why a fixed horsepower-per-cubic-metre formula can be misleading: the auger, knives, gearbox and drive arrangement change the demand. The figures are useful for preliminary planning; NexAgri's final quotation identifies the PTO requirement of the selected model.
Can a 90 HP tractor run a 12 m³ mixer? First check whether 90 HP is the tractor's engine rating or its available PTO rating. A 90-engine-HP tractor may have less than 90 HP at the PTO and may fall short of a mixer specified for 90 PTO HP. If the tractor provides 90 PTO HP, the next checks are PTO speed (often 540 or 1,000 rpm, depending on the mixer), hydraulic flow and pressure, available reserve for the proposed forage, trailer weight and safe towing. A loaded startup with long forage may be more demanding than a light, chopped ration.
What Motor Power Does a Stationary TMR Mixer Need?
Commercial stationary models provide another practical comparison: some 6–8 m³ units use 15–22 kW motors, while published 10–12 m³ configurations include 30–37 kW motors. A 10 m³ mixer can have a larger motor than a differently designed 12 m³ unit because auger geometry, mixing speed, feed preparation and gearbox ratios differ.
For an electric mixer, request the main mixing motor kW, voltage, frequency, starting method and rated current, plus separate loads for conveyors, pumps and loading systems. For high-inertia or loaded-start applications, the manufacturer can assess an appropriate soft starter or variable-frequency drive (VFD), together with motor cooling and overload protection. The factory's wiring and motor data are then used for the local power and cable design.
5. Check Barn Access, Loading and Discharge Before Ordering
A mixer sized correctly on paper can still be unusable if it cannot enter the barn or meet the feed bunk. These are the measurements worth putting on the site plan:
- Door and roof clearance: overall machine height, including tires, weighing display, safety railing and any raised discharge components.
- Feed alley width: running clearance, parked equipment and whether another vehicle must pass.
- Turning and reversing: tractor-plus-trailer swept path, not simply the mixer length.
- Loading point: loader reach over the tub, safe approach, bale or bucket size and loading surface.
- Discharge: side of discharge, outlet height, conveyor reach, feed-bunk edge and space for material flow.
- Floor and foundation: loaded axle weights for mobile equipment; foundation and anchor requirements for stationary units.
- Expansion: feed storage location, future mixing position, electrical capacity and a second feed-delivery route where needed.
For an existing barn, a dimensioned drawing and a few photos of the tightest door, bend and feed lane make the first equipment discussion much more useful. For a new feed center, position the mixer, loader and distribution equipment together before fixing the building layout.
6. What Equipment Specifications Should a Buyer Compare?
Capacity is the first filter. Daily reliability depends on the drive and the parts that contact feed.
| Equipment area | Information to request |
|---|---|
| Tub and auger | Rated volume, usable load range, steel grades, tub wall and auger plate thickness |
| Knives | Quantity, mounting positions, edge material, replacement method and spare-part reference |
| Drive | Gearbox model, required PTO speed/horsepower or motor electrical rating |
| Weighing | Load-cell configuration, display features, calibration and recipe storage options |
| Discharge | Door/conveyor layout, direction, rate control and remaining feed after unloading |
| Controls and safety | Emergency stop, guards, overload protection, hydraulic interlocks and manuals |
| Service | Access to bearings, seals, hydraulic components, gearbox oil and replacement knives |
NexAgri's heavy-duty vertical configurations include Q345B structural steel and 14–16 mm auger flighting. Q345B is a higher-yield-strength structural grade than Q235: for plate up to 16 mm in the commonly referenced specification, their nominal minimum yield strengths are 345 MPa and 235 MPa, respectively. This helps explain the choice of a stronger structural material for the tub and auger assembly.
For abrasive TMR containing sand, soil or mineral particles, the practical service features are replaceable cutting knives, accessible wear areas, robust fasteners and the correct auger-to-tub clearance. Structural strength, wear resistance and corrosion resistance are separate material properties. Ask for the steel grade, thickness and replaceable parts of the actual model on the quotation.
Weighing Accuracy and Recipe Loading
Load cells help the operator deliver the intended ingredient weights. For a multi-ration farm, useful functions include a clear display from the loader, recipe storage, component targets and a practical calibration procedure.
A ±1% scale-reading target is a practical procurement benchmark used in some commercial mixer-scale guidance. At a known 500 kg test load, that target would permit an indicated error of ±5 kg. The exact target for an order should be agreed with the weighing-system specification.
During FAT, check zero, repeatability and known weights at low, middle and high operating loads. Record the reference weight, display reading and deviation at each point. Farms using several recipes should also test recipe switching and the display visibility during loading. See the University of Minnesota TMR feeding guidance for an on-farm scale-calibration approach.
How to Check Mixing Quality
Mixing performance comes from a combination of ingredient order, actual load size, time, knife condition and ration moisture. Test with representative forage, then inspect feed from the beginning, middle and end of discharge.
A Penn State Particle Separator (PSPS) can compare the proportions of long, medium and fine particles at the beginning, middle and end of feed discharge. In an example test, upper-screen retention of 6%, 7% and 14% across three samples suggests more long particles in the final discharge sample and calls for further investigation. Use the same sampling and shaking procedure at each location. See the Penn State Particle Separator guidance.
For mixing uniformity expressed as CV, use a defined tracer or laboratory nutrient assay. Canada's feed mixer performance procedure provides a CV limit of 15% for complete feeds and TMR under its prescribed testing approach; stricter contractual targets can be agreed when the sample method and ration support them. See the Canadian Food Inspection Agency's mixer testing guidance. PSPS particle-size distributions and tracer-based CV measure different aspects of the ration, so both results should be named separately in the test report.
7. What Should a TMR Mixer Factory Acceptance Test Include?
For equipment purchasing, an agreed inspection sheet is more useful than a generic promise of "high mixing efficiency." NexAgri can coordinate factory inspection, equipment documents and testing arrangements around the ordered mixer.
| Test item | Result to record |
|---|---|
| Configuration check | Model, tub size, auger/knife quantity, drive, discharge and accessories |
| Empty run | Rotation direction, sound, vibration, guards and basic controls |
| Representative load | Ingredient description, batch weight, mixing time, motor or hydraulic operating data |
| Scale calibration | Known low/mid/high test weights, zero, repeatability and measured error; agreed target (for example ±1% of reading) |
| Mix and discharge | Representative samples at discharge start/middle/end, PSPS particle distribution and any separately specified tracer-based CV, discharge time and residue |
| Safety functions | Emergency stop, guarding, overloading and applicable interlocks |
| Handover | Drawings, electrical/hydraulic diagrams, spare parts, manual and inspection record |
When the factory and buyer cannot use the exact feed ingredients during FAT, record the substitute materials. The receiving farm can then check the real ration, mix time, particle size and discharge behavior during commissioning.
A good test also looks at the minimum practical batch if the farm plans to mix several small specialty rations on a large machine. A trial at full load cannot reveal how a very small batch circulates.
8. Wear Parts, Maintenance and the Real Purchase Cost
For a TMR mixer, the main recurring service items may include cutting knives, auger wear surfaces, gearbox components, seals, bearings, hydraulic hoses and valves, and weighing sensors. Wear rate depends on ration abrasiveness, operating hours, maintenance and the actual part design.
For a fair comparison, ask suppliers to quote the machine and a separate recommended spare-parts kit. The kit should give part names, compatible model numbers, quantities, prices and ordering lead times. Include the ability to obtain a replacement load cell or knife locally when uptime is important.
Compare the equipment's delivered and operating costs: machine price, export packing, freight, tractor or electrical requirements, installation, wear parts and expected service labor. A stationary system may need a separate distribution vehicle or conveyor. A trailed unit uses tractor time and fuel. The farm's existing equipment can change which arrangement costs less to run.
9. NexAgri TMR Mixer Selection and Project Support
NexAgri Solutions supplies vertical and horizontal TMR mixers and can coordinate trailed, stationary and project-specific feeding equipment. The standard range includes 5–20 m³ trailed and up to 30 m³ stationary options, with equipment selection based on forage, batch size, power and site layout.
Our initial support can cover mixer-type recommendations, batch and volume calculations, tractor suitability screening, loading/discharge arrangements, barn-access review and expansion planning. Once a configuration is selected, the manufacturing and technical team can confirm detailed equipment drawings, power requirements, foundations, control connections and test procedures.
For an inquiry, send the largest group size, as-fed kg/head/day, ration ingredients, batches per day, measured or estimated density, available tractor/PTO or electricity, and a layout showing access and discharge points. We can prepare an equipment configuration and spare-parts list for discussion.
Explore our TMR mixer product range or contact NexAgri with the farm details and destination country. For detailed feeding routines and ration management, see our TMR Feeding Guide for Dairy Cows.
Frequently Asked Questions
What size TMR mixer do I need for 100 cattle?
For a planning example of 100 cattle consuming 18 kg/head/day as fed, the farm needs 1,800 kg/day. At 260 kg/m³, one batch occupies 6.92 m³. Using 75% fill for the calculation gives an estimated 9.23 m³ rated mixer volume. Two equal batches reduce that estimate to 4.62 m³. Confirm the real ration density and the machine's working-load range before selecting a model.
How big a cattle feed mixer is needed for 300 beef cattle?
For 300 × 25 kg/day = 7,500 kg/day, with a density of 350 kg/m³, two equal batches contain 3,750 kg or 10.71 m³ each. At the example 75% fill fraction, this corresponds to roughly 14.29 m³ nominal volume. Different ration groups, longer forage or an uneven feeding schedule can change the largest batch.
Should I choose a vertical or horizontal mixer for long hay?
A vertical auger mixer with suitable cutting knives is a common starting choice for long hay and large bales. A horizontal mixer may also work where the forage has been pre-cut and the internal mechanism suits the recipe. Check the largest bale or forage particle size and the discharged mix before deciding.
What tractor power does a trailed TMR mixer need?
As a market reference, published single-auger vertical mixers include 7.6 m³ at 50 PTO HP, 12 m³ at 90 PTO HP and 16 m³ at 100 PTO HP. For a 12 m³ purchase, a tractor rated at 90 engine HP may be insufficient if its available PTO output is lower. Check the proposed mixer's PTO-speed requirement, hydraulics, towing weight and loading conditions against the tractor's actual specifications.
Is a 75% fill level right for every mixer?
It is a useful illustration for the calculator on this page. For the purchased equipment, check the manufacturer's minimum and maximum working loads, the actual bulk density and a representative mixing test. Both overly small and overly large batches may give poor circulation.
What motor size is typical for a stationary TMR mixer?
Commercial stationary mixers around 6–8 m³ may use 15–22 kW, and selected 10–12 m³ designs use 30–37 kW. The ordered unit's auger, gear reduction and duty determine the actual requirement. Include conveyor and loading-system motors in the site electrical calculation.
What tests should I request before shipping a TMR mixer?
Request a configuration check, empty run, scale testing at known loads, representative-load mixing and discharge, safety checks, and the equipment/spare-parts documents. For a mixing-uniformity claim, agree on the sampling method and whether it measures particle size, a tracer or a chemical component.
Conclusion
Begin with the largest batch the farm needs to prepare. Its as-fed weight and bulk density give the feed volume; the selected mixer's working-load range determines the nominal size to buy. Then check forage handling, power, loading height, barn access, discharge, weighing and spare parts.
For a distributor or commercial farm, this sequence produces a clearer equipment specification and a more useful quotation than choosing a mixer from cow numbers or advertised cubic metres alone.
