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Feed refusals: How low can you go?

According to the University of Minnesota Center for Farm Financial Management, the average daily feed cost per cow in 2021 was $7 in the upper Midwest; it was up to about $7.50 in 2022. Continually rising feed prices have tightened margins for dairy farms. In fact, over the last decade, total feed costs of a dairy herd are a better predictor of profitability than milk production. Reducing wasted feed is critical to farm success.

One of the greatest opportunities to reduce lost feed is by limiting refusals at the feed bunk. The beef feedlot industry has developed approaches to feed cattle to their exact requirements with practically no refusals. But the differences in management and physiology of dairy cows prevent implementing the “slick bunk” strategy used on feedlots.

Factors that affect dairy cow intake, such as lactation stage, age, body weight and milk production, make it more difficult for dairy producers to predict intake on a group of cows.

Milk, and particularly milk fat production, is much less resilient to short term periods of underfeeding, so we must be more risk averse when feeding to an expected feed intake. Even short-term periods of limited milk production, especially in early lactation, can lead to reduced lifetime milk production.

Still, there are opportunities for dairy producers to target intakes of cows more precisely. Here are a few recommended strategies for reducing the need for feed refusals.

Reduce and account for the variation in TMR dry matter

Variations in dry matter of forages, and subsequently the total mixed ration, are easily the largest factor contributing to differences between expected feed intake and actual feed intake.

Corn silage can vary by over 10% from one day to the next, which, if not accounted for, results in overfeeding or underfeeding the diet of cows by over 5% assuming corn silage makes up approximately half of ration dry matter.

To account for these variations, dry matter of silages should be taken as often as possible and used to adjust the ration. At a minimum, dry matter should be determined once per week and after weather events such as heavy rainfall.

Make sure feeding time is consistent

Cows are creatures of habit and become accustomed to eating at the same times each day. Research has shown that altering feeding time of cows leads to slug feeding, which reduces daily feed intake.

Keep in mind that 15 minutes of time equates to 1% of the day, so even small delays in feeding time can have large impacts on refusals due to reduced time available for cows to eat.

Group cows based on expected intake and nutrient requirements

When you or your nutritionist are formulating a ration for a group of cows, you are generally trying to meet the requirements of the average cow within that group. The larger the variation you have in the nutrient requirements within a pen, the greater number of cows in that pen will end up being overfed or underfed.

To some extent, creating a low-producing cow pen can create low-producing cows. But even if you are not dramatically lowering the energy content for the low-producing cow group, creating a separate group of lower production, later lactation cows will allow you to better predict the DM intake of this group.

It is also valuable to have a separate fresh group fed to a higher refusal rate (4 to 5%) to prevent limiting feed intake of these cows. Intake of fresh cows will generally be less predictable as they begin to approach peak milk production.

Ensure ingredient loading accuracy

It is easy for small errors in feed loading to add up and impact the accuracy of feed offered to cows. Calibrate TMR mixer scales regularly.

Batching can also help reduce the variation in dry feed ingredients at low quantities within a total mixed ration. Using feed management software easily allows you to adjust a diet based on the number of cows in a pen and the dry matter of feeds and helps track the variability in load weights.

Increase frequency of feeding and feed push-ups

Research suggests that increasing feeding frequency from once a day to twice a day reduces sorting and increases dry matter intake, milk production and milk fat.

Delivery of fresh feed stimulates cows to visit the feed bunk and it limits the amount of time for cows to sort feed from each feeding. Frequent feed push-ups reduce the amount of time cows do not have access to feed. Pushing up feed more often reduces the variability in feed refusals.

Approximate cost of feed lost per year at a feed cost of $7.50 per cow per day

Herd size 10% refusal 5% refusal 2% refusal 1% refusal
1 $274 $137 $55 $27
100 $27,375 $13,688 $5,475 $2,738
250 $68,438 $34,219 $13,688 $6,844
750 $205,313 $102,657 $41,063 $20,531
2000 $547,500 $273,750 $109,500 $54,750

Author: Isaac J. Salfer, assistant professor of dairy nutrition

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