The author is the founder of DNMCmilk, which works with dairy producers and heifer growers in several regions of the U.S. and around the world.

It seems no two dairies have the exact same plan of how to manage bunks and what to do with the feed refusals. With a likely new normal for feed cost levels, it is a good time to re-evaluate how feed refusals can be best used because they also carry a higher monetary value these days.

The range of uses for feed refusals might include spreading it with manure, giving it to the neighbor to feed beef cows, or putting it back into another milk cow ration. The most common use is including the pushed-out feed as an ingredient in non-lactating rations for dry cows or heifers.

Most on-farm feeding software is set up to handle refusals in various ways. Techniques can be employed to track refusals and to subsequently calculate accurate lactating cow intakes. Lastly, this also includes getting the material loaded back up and staged for the next use.

Keeping it as feed

There are some basic guidelines to be sure the refusals are maintained as “feedable” feed. Chief among these is to be sure that when pushing out the bunks and accumulating yesterday’s feed, never push it across manure. In many freestall and dry lot arrangements, this is no small feat. Remember that manure areas include not only flush lanes and scrape alleys, but it also involves places where manure vacuums or tractors exit pens and turn around as well as cow traffic lanes. Mixing manure and feed is never good.

Assuming manure contamination can be avoided, the next question is how often bunks should be cleaned so that the leftover material is still considered good feed. The gold standard is to clean all milk cow bunks daily. This is a basic recommendation, not only for strong intakes but also to reduce the negative impacts of sorting and mold growth in the bunk.

We should quickly touch on how much leftover feed is appropriate for the milk cows. They are of primary importance in this conversation.

It is not good business to excessively over-feed cows just to be sure they have enough. There are many resources to guide us on how much extra feed a pen needs to be sure there is truly enough for cows to reach their genetic milk production levels. It is likely that each dairy has a different correct level for what percent overfeeding is right.

A few of the factors determining the right amount are pen density, number of times cows are fed per day, and how many hours between the last feeding of today and the first feeding tomorrow. Several other factors, particular to each farm, are likely to have an influence on the best level of leftover feed.

What’s the right number?

I remember back in the financial stress of 2009, many dairies found out that good intakes can be achieved with less refusals than were the standard in those days. Since then, we often see between 3% and 5% refusals as a good level. As a point of reference, in the academic publishing world, between 5% and 10% feed refusals are common to determine true ad libitum (free choice) feed intake.

It seems that 3% to 5% is a pretty small number, but on a large dairy, this can be a large pile of material. It is literally a pile of money in need of reinvestment.

Based on the experience of many, an overly loose way of feeding refusals to heifers will result in over-conditioned animals. It is a real problem and seems to be a common mistake.

A similar risk is having a good plan for a smart use of refusals but poor follow-up to be sure the quantity available matches the amount called for in the feeding software. This will never be perfect, but care should be taken to verify the plan for actual pounds available versus the amount needed.

I must say, even in situations where care is taken to be sure the available and required amounts are close, problems can occur. Surprisingly, most days, it seems to work out about right. Hmm. This should tell us that the feeders are making some decisions in real-time to use what is provided or use alternate rations or substitutes to get the animals fed. There are a lot of moving parts here, and digging into the details is probably warranted.

What’s in it?

Since refusals will change over time for various reasons, it is important to send feed refusal samples to the lab, similar to how you might send silage or other forage samples. Differences in formulation, amount of bunk sorting, ration changes, and season of the year can impact the true nutrient content of the leftovers. This information is critical when using refusals to formulate other rations.

Similarly, it is advisable to separate lactating from nonlactating ration refusals. This may be difficult, but care should be taken to avoid feeding refusals from close-up (prefresh) rations that may contain anions that could be problematic if used in a milk cow ration.

On-farm moisture testing is also necessary since ration changes, weather events, and use of bunk-line soakers can have a significant impact on the actual dry matter percent of the refusals. If you never change the dry matter percent in the feeding software like you do your silages, this could be a problem. Also, refusals from nonlactating rations will likely be dryer than that from the milk cow pens.

The last factor is related to value. It is common for dairies to have a set cost for refusals created in milk cow, dry cow, or heifer pens. There are numerous ways to estimate this value, but one thing to avoid is double charging.

If you count the total cost fed out to the milk cows, perhaps it is logical to feed it to the heifers for free. If you calculate the amount of refusals and your feeding software deducts the pounds and cost from the milk cows, I suggest using a slightly discounted value of the original cost per pound of dry matter when considered in a nonlactation ration. When doing this, it is likely that including this material in a heifer diet will not actually reduce the cost of that diet. Each dairy will have to sort this out and decide on the best approach. And, as feed cost changes, the refusals cost should be flexible as well.

One last point on the economic value is related to the small contribution of minerals, vitamins, and other additives in the milk cow ration. These nutrients should still be of value in the ration in which refusals are an ingredient.

Despite varied opinions, feed refusals can be successfully refed to milk cows, too. It requires a careful effort to follow all of the previously detailed rules. It is the best economic leveraging of the value of the refusals.

Does it make the milk cow ration a little less perfect to support high levels of milk production and cow health, though? Maybe. Perhaps this is more successful during cool weather months and maybe better targeted for later lactation rations, avoiding fresh cow diets. This approach should be handled with great care, but it can and is being done successfully.

It’s a business decision

Throwing away or misusing a valuable feed ingredient is just bad business! However, at times, refusals are compromised from rain, snow, or blowing dirt. Never, ever feed bad feed!

A feed refusal plan should be an integral part of every dairy’s feeding program. It contains too much value to handle in a loose fashion. Make a good plan and then audit the follow-through, making adjustments as necessary. It is likely that the plan needs to be changed seasonally and frequently evaluated. Giving the responsibility of closely managed refusals to a highly trusted feed employee may be the key to success.