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As nutrition consultants, we know that formulating the nutrition program on a dairy receives a lot of attention, as well it should. Dairy nutrition has become much more complex through the years and requires expertise, experience and constant training to provide nutritional programs that perform well and are profitable for today's dairy operation.
Nutritionists must account for effective fiber, fiber digestibility, carbohydrate type and digestibility, amino acid and fatty acid profiles, commodity prices and efficiencies while keeping an eye on income over feed costs (IOFC). Qualified nutritionists understand these topics and enjoy discussing them; however, they can also cause disagreements among nutritionists on what levels are best.
The results gained from good ration formulations are critical to the profitability and success of dairies. However, a common and often overlooked problem on many dairies can make the best nutritional programs fail, regardless of how well the ration is put together: total mixed ration (TMR) mixing errors.
Improperly mixed rations can cause daily milk fluctuations, lower butterfat content, inconsistent manure and poor foot health. If continued over a long enough time period, they can potentially contribute to increased immune stress and reproduction issues. These can affect overall farm profitability, so it pays to make sure your TMR mixer is doing what it's supposed to do - mix feed properly and put it in front of the cows consistently.
If the mix consistency is too far off, it can force a nutritionist to feed a more conservative diet than is needed, which will lower production. The nutritionist may add costly additives to help alleviate perceived issues, when simply being more consistent and accurate in the feed mixer would help reduce these issues and increase cow performance.
You should regularly evaluate handfuls of feed from several different places down the feed bunk and lay them side by side to see if they appear the same. By examining these handfuls and moving them around slightly, you can get a pretty good idea how well the long fiber is mixed and if there is about the same amount of fines in each pile. While this method is far from scientific, it gives you insight into whether or not you need to look further into a potential mixing error. Be sure to take the samples the same way, by scooping up under the TMR; this way you'll be sure to get all of the fines. Try to sample about the same amount with each handful so the results don't fool you.
A more scientific method is to take each of those handfuls and run them through the Penn State Particle Separator. This will tell you how many fines are in each location and how well the longer particles are being distributed. Most mixing issues seem to be caused by too much extremely long fiber or an excess of fines. Confirming their uniformity will increase your confidence that a good mix is being delivered to the cows.
You can be even more precise and send TMR samples to a forage lab for analysis. Pulling samples from several places in the feed bunk will tell you how close the mix is to its formulated values, as well as how physically consistent the mix is. This is an expensive test, but it shows how well the feed was mixed and how well you took the sample.
With today's TMR, you can change the crude protein by 2 percentage points by either scooping up the TMR (catching more fines) or grabbing a handful from the top (letting the fines filter out). If you remember to take this sampling variability out of the testing process, chemical analysis can give you a good idea how well things are mixed. We recommend that at least three samples be taken per feed bunk: beginning, middle and toward the end. Many farms run a chemical analysis on a monthly or quarterly basis, or after a major feed or forage change. However, a single test does not tell the whole story, and many producers and nutritionists are not willing to go to the extra expense of testing multiple samples to assure good, consistent mixes.
We have been doing the jelly bean test for over a decade with great success. Add 5 pounds of the brightest-colored jelly beans you can find to the TMR. Mix the feed as usual and watch as it is being unloaded. The distribution of these colored markers will indicate how well the feed is mixed. If all the jelly beans show up in a clump, you have a mixing issue.
Any hard, brightly colored candy will work, as long as it stands out in the final TMR and does not quickly dissolve in water. We've tried a certain hard-shelled chocolate candy, but the colors are not as bright, and it seems more of them end up in the "mixee" than in the mixer. One advantage to this test is that it is very visual for the employees doing the mixing and helps illustrate how important consistent mixing is to the dairy farm.
We recommend that producers check their TMR mix regularly. There is just too much money involved if something changes. Furthermore, we recommend checking the TMR with each forage change. Alfalfa and grasses mix very differently. Dry hay can give a lot more issues than well-made haylage. There are several common feed ingredients that can change how the mixer works with their addition or subtraction.
Far too often, we see farms that have added 20 percent more cows, but did not add mixer capacity or mix more frequently with a smaller batch. If you look in your owner's manual, most mixers recommend a specific amount to be used for optimal results, generally two-thirds to three-quarters of total capacity. We commonly see TMR mixers that are filled well in excess of the recommended capacity, to the point that sideboards have been added to keep the feed from overflowing. At one farm, the entire 5 pounds of jelly beans were in a 2-foot space in the feed bunk, because the feed was oozing over the sides and had no chance to be mixed. When the issue was addressed, the cows increased milk production by 5 pounds in 10 days, because they were receiving a consistent and accurate diet.
TMR consistency is critical in maintaining good milk production, healthy cows and profitability. You don't need to spend a lot of money or time to confirm that you're mixing your TMR well. The jelly bean test is a quick, inexpensive way to check on-farm consistency, and the Penn State Particle Separator is a powerful tool to confirm mixes.
The order in which feeds go into the mix, the contents of that mix, the moisture in the TMR, and the amount of time spent mixing all impact TMR consistency and a farm's bottom line. Inspection after any feed change will help minimize mixing errors and keep a uniform mix in front of cows so they can give consistent results. If the results are the same day to day, we can better interpret them and help adjust things accordingly so the herd can be more profitable from year to year.
Steve Massie and David Lloyd are nutrition and farm management consultants for Renaissance Nutrition, Inc.