Ask around any feed alley and you’ll hear it: ration doesn’t look right? Mix it longer. It’s one of the most stubborn beliefs about TMR mixing time out there, and most of the time it’s wrong. Past a certain point, extra minutes don’t help. They grind down the fibre cows need, burn fuel and wear the machine out faster.
I’ve watched this play out on a lot of farms. Worn knives and long mix times almost always show up together. As herds move onto winter rations across the US, it’s a good time to check the clock.
What Mixing Is Actually Supposed to Do
A TMR mixer has two jobs. Blend every ingredient so each bite matches the formula. And cut long forage to a length cows can’t easily sort. Once both are done, the mixing is done. Everything after that is just processing, and processing costs you.
The Myth: Longer Mixing Always Means a Better Ration
Over-mixing does a few things, and none of them are good:
- It kills effective fibre. Keep cutting and tumbling and particle length keeps dropping. A ration that started with plenty of effective fibre can come out too fine, and now you’re flirting with low rumen pH and sub-acute acidosis.
- Balling and separation. In some rations, long mixing makes wet ingredients clump or lets the fines settle out. That hurts uniformity instead of helping.
- Wasted fuel and labour. A few extra minutes on every batch, every day, all year. Do the math.
- Faster wear. Knives, augers, liners and drivelines wear by the hour. More hours, more wear.
The Truth About TMR Mixing Time: It’s Your Ration, Not a Rule
There’s no one right mixing time. It depends on the mixer, the knives, batch size, ingredient moisture, forage length and load order. Manufacturers give general guidance, and that’s fine as a starting point. The right answer for your farm comes from testing it.
Shake It Out With a Particle Separator
A particle separator box, like the common Penn State design, is the easiest way to see what your mixer is really putting out:
- Pull samples at the start, middle and end of the bunk.
- Shake each one and write down the percentage on each screen.
- Compare them. Big differences along the bunk mean the mix isn’t uniform.
- Hold the results up against your nutritionist’s long-particle targets.
- Try mix times a few minutes shorter and longer, and find where uniformity is good and particle size is still on target.
Shake the refusals too. If cows are leaving mostly long stems, the ration may need more processing or a different loading approach.
Load Order Beats Total Minutes
A lot of mixing problems that get blamed on time are really sequence problems. A typical order, adjusted for your mixer and ration:
- Dry hay or straw first, so it gets processed before the tub fills.
- Grains, concentrates and minerals next.
- Silages and wet by-products after that.
- Liquids last, spread across the load.
Then set one mix time that starts after the last ingredient goes in. Don’t run the mixer the whole time you’re loading and then add minutes on top. Hay that’s been tumbling through a long loading session can be over-processed before you even start the timer.
Maintenance Shortens the Clock
Dull knives are one of the biggest reasons guys feel they need more time. A worn knife tears instead of cuts. It takes longer and eats more power. Check knives and kicker plates on a schedule, along with auger flighting and any restrictor or counter-knife settings. A mixer that’s kept up usually gets to a good mix quicker.
Don’t Overfill
An overfilled mixer can’t move feed. Whatever’s on top stays on top, and the operator makes up for it with more time. Keep batches inside the mixer’s practical working volume for that ration’s density. With bulky, light rations, that can be well below the maximum weight rating.
Mixer Design Changes How Fast You Get There
Different mixers get to a uniform ration in different ways. Single-auger verticals use one auger to lift and fold the feed. Twin-auger machines pass material between two augers, which on a lot of rations speeds up blending and breaks down long forage more evenly. Horizontal reel and auger mixers work differently again. None of them is automatically right or wrong, but knowing how your machine moves feed helps explain your separator results. Twin vertical-auger mixers like our LEO VT Series, with counter-rotating augers, are designed so the ration keeps folding over itself. On those machines, the right mix time after the last ingredient is often shorter than operators expect. Test it before you assume longer is better.
Write the Standard Down and Train to It
Once you’ve found the right mix time and load order, write it down. Post the sequence, target weights and mix time next to the mixer, or put it in the scale’s recipe system, and train everybody who feeds. Three operators with three different habits is one of the most common reasons a ration changes day to day. No amount of extra mixing fixes that.
Test Again When Anything Changes
New-crop silage, a new hay supplier, a different by-product or a new ration from the nutritionist can all move the right mix time. Shake out the ration whenever a major ingredient changes, and at least once a month otherwise.
Final Truth
Longer isn’t better. The right mixing time is the shortest one that gives you a uniform ration at the particle size your nutritionist wants. Check it with a separator box, load in the same order every time, keep the knives sharp and don’t overfill. Your cows get a more consistent ration, and your fuel bill and wear parts get a break. That’s a win you can actually see in the milk check.
Related reading: The load order crews keep when silage arrives · Third-cut stem length your vertical mixer still has to cut · Corn silage face order keeps batches on weight
