Do not do a consistent job of cutting forage to a uniform length. This does not create a Total Mixed Ration (TMR) when stem length varies to this degree.
Cost, these are very expensive machines to purchase and maintain.
If feeding a high hay ration, it can take as long as 20 to 30 minutes per round bale to chop it fine enough to feed out of their unloader system.
Using slow moving knives, blades, and augers to process baled forages requires very high torques. They work reasonably well when everything is new and sharp but cause much strain on the machine as it wears.
If the operator mixes too long, most of the forage length gets smashed and too small for most feeding application, especially for dairy TMR feeding.
They work best for mixing and feeding with low hay rations. For high hay rations, cutting and mixing takes a long time and chop length is very inconsistent (not a true TMR ).
Wear and maintenance is much higher when using a mixer machine to process hay.
Pre-grinding your forage to the length you want and then mixing it with your feed ration extends the life of your expensive mixer by 4 to 5 times.
If your bales weigh 1200 lbs. and you require 400 lbs. per batch, you have to put the bale into the mixer and wait for it to shred enough to unload the extra hay that you do not need. This process wastes a lot of time. Most operators need to be able to mix different weights and batches several times a day. This is very difficult when your bales vary in weight and you cannot adjust your ration to include a whole bale.
Many feeders who have used these types of mixers are not satisfied with the quality of mix, consistency of the mix, forage lengths, the time it takes to mix and process hay, the cost of these machines, and expense of repairs. They are now realizing that they should pre-process their forages to the length they want to be more efficient at quality mixing and accurate weights per batch while also reducing labor, fuel costs and feeding – mixing time. Using our Roto Grind for a few hours per week solves all of these problems.

Rotogrind Start Up - Instructions Manual