Mixer Wagon or Grass: How to Decide Between TMR and Pasture

People argue about drylots like they argue about trucks. The truth is neither one wins everywhere. Grass is the cheapest feed there is when it grows. A mixer wagon and a pen are worth the money when it does not, or when land costs more than you can stand. Here is how I would sort it out for a working Angus herd, using extension guidance. None of it gives one national answer, so you have to run your own numbers.

When drylot starts to pay

South Dakota State Extension says drylotting pairs fits when drought cuts forage or grazing acres are hard to get. It says the total cost per day for drylotting pairs can be similar to or lower than pasture costs in some rent markets. When feed is short, a drylot can beat hauling hay or hunting for rented grass.

Nebraska's drylotting article lists the side benefits: pastures rest and recover, you see the cows every day, calves learn the bunk before weaning, and weaning stress is lower. It also says drylotting can keep older cows with broken mouths going. It gives no cost comparison, so the numbers depend on local hay and feed. It did say that with hay above $200 a ton, limiting forage in the diet paid.

What the mixer does for you

SDSU says low-quality roughage works best in a TMR with supplements, byproducts or silage to help palatability and intake. The mixer keeps cows from picking out the good stuff and leaving the rest. You can test the ration and balance it. Nebraska says to test the forages and the mix so you meet needs without wasting feed. For a number to aim at, SDSU says a 1,400-pound cow giving 30 pounds of milk at peak needs about 10 percent crude protein and 58 percent TDN.

Build it right

• Keep forage at least 0.5 percent of body weight on a dry matter basis so the rumen works, per Nebraska.
• If you limit feed, give cows at least about 1.75 percent of body weight or they get ornery from an empty gut.
• Plan roughly 500 to 800 square feet and 28 to 36 inches of bunk per pair.
• Sort young cows and heifers from mature cows in good flesh.
• Do not build a pen too big for a dry climate. Dust brings pneumonia to calves.

Herd size

A mixer, bunks and a pen cost the same whether you feed 50 cows or 500. A big herd spreads that cost. A small one may do better with a sacrifice lot, hay rings and a supplement for dry spells, or with a neighbor who has the equipment. If you use a custom lot, SDSU says to get the agreement in writing. Our piece on rotational grazing shows how to get more from grass before you decide you need a mixer.

Geography

• Long grazing season and rain: stay on grass and stockpile.
• Long winters: more feeding days, so feed cost dominates. A Tennessee fescue-belt survey, reported in a 2020 paper on Cambridge Core, put average winter hay feeding near 82 days. That is one state and one year, so treat it as an example.
• Drought country: a drylot is your insurance.
• Near grain or byproduct supply: TMR gets cheaper.
• High land rent: drylot looks better.

Questions before you buy a mixer

1. What does my grass cost per cow per day, counting rent, fertilizer and fence?
2. What would the drylot cost per cow per day, counting equipment, fuel, labor and manure?
3. Where does the manure go, and is it worth anything on my fields?
4. Do my cows handle confinement? Feet and temperament matter.
5. Can I run it in a wet spring and a hard freeze?

Do the whole budget

People leave things out when they compare. Put the loan payment and fuel for the mixer on one side, and fence, rent, fertilizer and your hours moving cattle on the other. Count the manure as a cost if you have to haul it and as a credit if your fields need it. Count the extra death loss or sickness risk if you pack cows into a small pen in a wet spring. Count what happens to the pasture you rest, because grass that recovers can carry more cattle later. Then figure it per cow per day for each system and compare. A rough number done honestly beats a good guess done in a hurry.

If the answer comes out close, start small. Try a drylot for a dry fall with a few groups before you build a full system. You learn the problems on a small scale.

My take

Use grass when it is cheap and plentiful. Use a drylot when forage is short, land is dear, or you need control. Plenty of ranches use both, one in summer and the other in a drought. Farm.fm's page on managing grazing patterns covers the pasture side, and agriculture.directory can help you find your extension office. Prices change and so do conditions, so talk to a nutritionist before you spend on equipment.