Keenan Mech Fibre 340 mixer

By: Ian Harwood, Photography by: Ian Harwood

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Keenan Mech Fibre 340 is a mixer wagon that comes with a nutrition package to ensure the machine is utilised to its full potential

Keenan Mech Fibre 340 mixer
Keenan Mech Fibre 340
  • Low PTO horsepower requirement
  • Thorough mixing
  • Robust construction
  • Handles bales easily
  • Automatic oiling operates every time guillotine door used

Keenan New Zealand is part of Mid Canterbury-based Rakaia Engineering, which supplies the dairy industry with grain handling and meal feeding systems for dairy sheds, dairy shed design and construction, as well as cow barns.

I thought that a "paddle" mixer wouldn’t handle bales and take a lot of horsepower to drive, however I was proven incorrect, as the Keenan "consumed" a round baleage bale in about 35-40 seconds with an old 80hp Kubota tractor.

Loading and mixing

With the mixer operating, the different feeds are tipped in and mixed by the paddles, which are offset so as to reduce the power requirement.

The mixing action is different to that of an auger machine, and is similar to the action of a tumble dryer. The paddles bring the feed to the top before it falls off, creating the "tumbling" action.

Bales are easily handled, with the rounds of baleage "digested" by the machine as the paddles take small bites off the bale every time they pass under the steel tines supporting the bale. The paddles push the bites past a stationary knife at the top, beginning the chopping process, which is continued by individual knifes in the body of the mixer.

The mix

The tumbling action of the paddles appears to give a very even mix of the ingredients, meaning the less palatable feed cannot be picked out of the ration.


When the ration is mixed, the feed chute on the left side of the mixer is opened hydraulically over the feed trough. A guillotine type door is lowered, exposing a full-length auger, allowing the paddles to transfer the mix into it. The auger then discharges onto the chute, placing the mix in the trough in a very even row.

The Carter’s feed pad troughs have a pipe rail set at 1.2m to stop cows entering the trough so their mixer has had an optional discharge chute fitted to suit feeding over this rail.

Simple driveline

Most mixer wagons have a driveline through heavy right-angle gearboxes, however the Keenan has a simple chain reduction system with heavy duty roller chain and spring tensioned adjusters.

Automatic oiling is also fitted and operates every time the guillotine door is used. The Keenan "baleblend" is the system that allows the machine to handle baled feed, and even with the 80hp tractor driving, it proved it doesn’t need huge amounts of horsepower to process a bale.


The Carters have fitted their Keenan with the optional "PACE" weighing system, which manages the ingredient loading sequence, showing the operator what quantities of each feed are needed.

The weight required is shown in kilograms and counts down to zero as the feed is loaded. This information can then be transferred to a computer, where performance and production can be analysed.

The verdict

I would guess that a lot of mixers that are used without a nutrition package are not utilised to their full advantage and are, in fact, expensive silage wagons.

Apart from the shear bolt in the driveline as apposed to a slip clutch the Keenan appears to be a robust, well designed machine.

What the owner says

Ross Carter says they purchased the Keenan after trying to feed into the feed pad using a silage wagon but found the mix was inconsistent and the cows picked through the mix, eating the most palatable feed.

Another factor was that the existing Massey 295 was able to drive the mixer, meaning they didn’t have the expense of a bigger tractor on top of the mixer purchase. The 295 has now been replaced with a Massey 6150, which handles the Keenan easily.

Introducing the Keenan system has lifted per cow production from 375kg MS to 485kg MS, with per hectare production lifted from around 1100kg MS to 1530kg MS/Ha.

See Keenan Mixers for sale.

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