Feed Bunk Management and Cow Sorting

Cows are good at picking out the parts of a ration they like best. When they sort, the cow at the end of the line gets a different diet than the formulated one.

Key points

Sorting means cows are not eating the ration you designed
Dry mixes, long forage and long gaps between feedings encourage it
Check refusals and use a particle separator as your nutritionist advises
Fresh feed, steady timing and enough bunk space reduce sorting
Change one variable at a time

What sorting is and why it matters

Sorting means cows select the finer, sweeter or more palatable particles and leave longer, stemmier ones. Over a day, the early eaters take the best of it and the later eaters take what is left.

The result is uneven intake of fiber, starch and minerals. Some cows run a higher risk of rumen upset, while others may fall short on energy. Milk fat can swing, and manure consistency can change from one group of cows to the next.

Why cows sort

Several things push cows toward sorting. A ration that is too dry, with long forage standing apart from fine grain, makes it easy. Long, unprocessed forage can be separated from the mix. Hunger after a long gap since the last feed makes cows pick faster and more aggressively.

Crowded bunks and competition add stress. Cows that cannot get to feed calmly tend to grab and run.

Keep a short written log of what you changed and the date. When a result shows up a week later, you will be able to link it to the right change instead of guessing.

Dry mixes with distinct fines and long stems
Forage chopped too long for the mixer or too inconsistent
Long gaps without fresh feed
Not enough bunk space for the group

How to check for sorting

Look at the bunk through the day. If the feed left late in the day looks coarser than what you delivered, cows are sorting. Look at the pattern of refusals as well as the amount.

Many farms use a particle separator on the delivered feed and on refusals and compare them. Ask your nutritionist or extension specialist how to use one and what targets suit your ration. Do not copy numbers from another farm.

Practical fixes

Work through the ration with your nutritionist. Adding a little moisture, chopping forage to a consistent length, mixing in the right order and avoiding over-mixing or under-mixing can all help. Some farms change the form of a fine ingredient so it clings to the rest of the mix.

Management matters as much as formulation. Deliver fresh feed on a steady schedule, push up feed so it stays within reach, and avoid long periods when the bunk is empty.

Revisit the bunk after weather swings, new forage cuttings or any change in feed delivery. Sorting often shows up just after something shifts, and catching it early keeps the whole group on a more even diet.

Mix long enough to blend the ration but not so long it grinds forage down
Keep delivery times steady from day to day
Give every cow room at the bunk
Watch freshly calved and first-calf animals, which are often pushed aside

Bunk space and cow behavior

Heifers and low-ranking cows often eat less and sort more under pressure. If your first-calf heifers are mixed with older cows, ask whether a separate group would help.

Spend time at the bunk when cows are eating. Watch for pushing, displacement and cows that eat in a hurry then walk away. Behavior tells you what the bunk is doing to cows.

Reading manure and milk for clues

Cows that sort leave signs. Manure that varies a lot from cow to cow in the same group, cows that seem to chew less cud, or fat tests that wander without a clear reason all deserve a look at the bunk.

Compare what you see with your records. Note the time of day, the weather, any change in forage and any change in who is doing the feeding. Patterns appear faster when the notes are written down.

Share your observations with your nutritionist and veterinarian. They can help tell sorting from other causes of the same signs, and suggest what to adjust first.

Common mistakes

Treating every drop in milk fat as a ration problem without checking sorting is common. So is assuming a mix that looked fine at the mixer is the mix the cows are eating. Another mistake is changing several things at once, which makes it hard to know what worked.

Change one thing, give cows time to adjust, and check the bunk again.

When to get help: Ask your nutritionist to review the ration texture if sorting is visible. Call your veterinarian if you see loose manure, off-feed cows or drops in milk fat that do not match changes you have made.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

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