Silage Quality and Milk Production

Silage is the backbone of many dairy diets, and cows are quick to show when it is not right. Quality is built at harvest and protected through storage and feed out.

Key points

Silage quality is made at harvest and protected through packing, sealing and feed out.
Look for good smell, clean face and steady intake.
Treat mold, heating and off odors as warning signs.
Follow safety rules for equipment and confined spaces.
Share fermentation results with your nutritionist.

Why silage quality shows up in the milk tank

Cows eat more of feed that smells and tastes good, and they digest well-preserved feed more completely. Poor silage lowers intake, wastes nutrients, and can leave the herd flat in production even when the ration is balanced on paper.

Silage problems also tend to be herd-wide. If milk, intake or manure change across several groups, check the silage before looking elsewhere.

Harvest decisions that set the stage

Crop maturity, moisture and chop length at harvest affect how well the crop packs and ferments. Too dry and it is hard to pack and prone to heating. Too wet and fermentation can go wrong and nutrients can be lost.

Work with your agronomist and nutritionist on timing. Have equipment checked ahead of harvest so chopping, kernel processing where used, and packing are consistent.

Harvest at the right maturity and moisture for the crop
Check chop length and kernel processing
Fill quickly
Pack well in thin layers

Packing and sealing

Oxygen is the enemy in a silo, bunker or pile. The tighter the pack and the faster it is covered, the less spoilage. Cover promptly, seal edges, and keep the cover weighted and free of holes.

Safety comes first. Packing tractors on bunker walls and pile slopes carry real rollover risk, and silo gases can be deadly in enclosed spaces. Follow manufacturer, OSHA and extension safety guidance, and never enter a silo or confined space without proper procedures.

Reading fermentation and herd signs

A fermentation analysis shows the acids and pH in a sample and gives a clue to how well the crop ensiled. A silage that fermented well usually smells sharp and sweet-sour. Silage that smells of butter-like, rancid, or ammonia odors, or that feels slimy, signals trouble.

Visible mold, heating, and a hot face are signs of spoilage. Do not feed moldy silage without talking to your nutritionist or veterinarian, since mold and mycotoxins can affect cow health and performance.

Watch for lower intake, sorting, feed refusals, loose manure, drops in milk or components, and reduced cud chewing. Several of these together after a silage change point toward feed quality. Record the date of any change in bunker face, new bag, or new field, so patterns become visible.

Feed out management

Many losses happen after the cover comes off. A smooth, clean face that is removed steadily limits air getting into the pile. Ragged faces and slow feed out let heat and mold move in.

Remove feed at a rate that keeps the face fresh, and avoid leaving loose silage sitting in the open. Store only what you need for the day near the feed bunk.

Mycotoxins and spoiled feed

Moldy or heated silage may carry toxins that reduce intake, hurt performance and affect cow health and fertility. You cannot tell by sight alone whether a feed is safe. Discard clearly spoiled feed, and talk to your nutritionist and veterinarian about testing and about how to handle questionable feed.

Spoiled silage should be kept away from calves and young stock too. Do not mix it into the ration in the hope that it will be diluted away.

Planning and questions for your nutritionist

Ask what fermentation results look like for your feed, how long silage should ferment before feeding, and what supplements or ration changes fit this year's crop. Ask what to do if the pile shows spoilage.

Plan ahead for lean years too. A forage shortage can push feeding toward lower-quality feeds, and your nutritionist can help you protect milk and cow health.

Before harvest, write down how much feed you need, where it will be stored, what equipment you will use, and who will do what. Include safety steps for packing and covering, and a plan for rain. After feeding begins, review how it went. Note which bunkers or bags performed well, what the cows ate readily, and what you would change. A short written review each year builds into a useful guide for the next season.

When to get help: Talk to your nutritionist when silage changes or intake drops. Call your veterinarian if cows show illness, drops in milk across the herd, or you suspect moldy feed.

Sources and further reading

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

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