Feeding By-Products to Dairy Cows

By-products are leftovers from food, fiber and fuel industries that cows can turn into milk. Used well, they can lower feed costs. Used carelessly, they can cause problems.

Key points

By-products can cut feed cost but vary from batch to batch
Ask for analyses and check supply, storage and spoilage
Introduce gradually and balance the whole ration
Check feed rules and buyer or certification limits
Keep records of sources, loads and amounts fed

What by-products are

By-product feeds come from making other products, such as grain processing, brewing, baking, oilseed pressing, food manufacturing and ethanol production. Many are rich in fiber, protein or energy and fit naturally into dairy rations.

They vary a great deal from one source and batch to the next, so each one needs to be understood before it is added. Do not assume that two loads from the same plant are alike, since the process that makes the by-product can change. Always confirm the exact product name and source before it goes into the ration.

Why dairies use them

The main reason is cost and availability. A nearby by-product can replace purchased grain or protein at a lower price per unit of nutrition, depending on the market. Some also offer useful fiber or help improve palatability.

Prices and supplies change, so ask your nutritionist to compare options based on current numbers and not on what worked last year. Ask the supplier how they handle changes in their process and whether they will tell you when something shifts. Talk with your milk buyer if you are unsure whether a by-product could affect milk flavor or quality.

What to check before buying

Ask for a nutrient analysis and ask how consistent the product is. Find out how it is delivered, how fast it spoils and how much storage you need. Check the supplier's reputation for consistency and for handling.

Ask whether the product is approved for dairy feed, and check with the U.S. Food and Drug Administration and your state feed control office if you are unsure. A good nutritionist will also compare by-products to what you grow on your own farm, so you do not pay for something you can produce more cheaply.

What are its main nutrients, and how variable are they?
How quickly does it spoil, and how must it be stored?
How reliable is the supply?
Is it allowed for dairy under feed rules and buyer programs?
What does it cost per unit of nutrition delivered?

Storage and handling

Wet by-products can spoil fast, especially in warm weather. Plan how much you can use before the quality drops and keep it covered and packed or sealed as recommended. Dry products need protection from moisture and pests.

Keep different loads separate when you can, since quality may differ, and test regularly so the ration reflects what is really in the pile. Watch for sorting, since some by-products are fine or wet and can clump or separate in the mix. Ask whether the product could carry contaminants from the source process, and request documentation from the supplier.

Fitting them into the ration

Add new by-products gradually and balance the whole ration with your nutritionist. Some are high in certain minerals or fats, and the total amount in the diet must stay within safe limits for the cow. Do not guess at amounts.

Watch the herd after a change. Look at intake, manure, milk components and cow behavior, and report anything unusual to your nutritionist. Keep a small sample of each load for a short time so you can test it if the herd responds oddly.

Records and rules

Keep supplier names, load dates, analyses and amounts fed. Organic and other certification programs have their own rules on what feeds are allowed, so check with them and with your milk buyer before bringing in something new.

Make sure the supplier can document the source, and keep that paperwork on file. Think about manure handling too, because some by-products change the nutrient content of manure that you spread on your fields. Plan an exit option in case supply fails or quality drops, so you are not forced into a hurried ration change.

Common mistakes

Buying on price alone, not testing and feeding too much of one by-product are all common. Others include letting wet feed sit too long and failing to track changes in the herd.

Treat each by-product like a new ingredient with its own limits.

When to get help: Ask your dairy nutritionist to balance rations whenever a new by-product is added. Call your veterinarian if cows go off feed or show illness after a feed change, and follow label and vet-set withdrawal times exactly for any treated animal.

Sources and further reading

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

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