NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665

March 4, 1999

NDSU Dairy Specialist: Make Good Use of Total Mixed Ration

Many of North Dakota's dairy producers are now using a total mixed ration (TMR), but just buying a mixer won't guarantee success, says an animal scientist at North Dakota State University.

"TMR offers the advantage of providing a balance of all the nutrients an animal needs in every mouthful she consumes as a means to increase milk production," says J. W. Schroeder, dairy specialist with the NDSU Extension Service. "But an improperly mixed or fed TMR can actually result in poor animal performance and health."

Schroeder outlines several points dairy producers need to consider to ensure that they're making good use of their TMR.

Weighing Feed
"It's important to check the scales on your mixer," Schroeder says. He suggests placing one 50-pound feed sack on each corner and observing the scale weight. Then, remove the sacks and begin adding feeds to the mixer.

After about a third of the total mix weight has been added, place the sacks back on the corners and check the scale to see if it increased 200 pounds, he says. Repeat this after about two-thirds and again after all the feeds have been added to the mixer.

"Too often, we assume that if the final weight of a TMR is correct, the individual feed weights must be close to the amount listed for the batch recipe. This is not always true," Schroeder stresses. "You could have added 400 pounds too much of one feed and 400 pounds too little of another."

Mixing the TMR
In general, minor ingredients, minerals, protein supplements, and grains should be added to the mixer first and forages last, Schroeder says. However, this formula varies with the type of mixer and feeds being mixed, so follow manufacturer's recommendations.

"A TMR is usually completely mixed after four to five minutes" he says. "If you mix much longer than this, especially with auger mixers, forages and long particles can be ground too fine, resulting in a mushy mix which cows don't particularly relish. To check, particle size your TMR on a particle shaker box. Between 6 and 10 percent of the sample should be on the top screen."

Undermixing a TMR can happen when mixers are overfilled. To get the most efficient mixing, fill only to about 90 percent of the mixer's capacity, Schroeder says. To avoid either overmixing or undermixing, develop guidelines that specify the order of adding ingredients and how long to run the mixer between feed additions and after all feeds are added.

Adding Hay
Baled hay is often added to a TMR to provide the fiber needed for good rumination. Unfortunately, what generally occurs when hay is added is that it gets sorted out in the manger, and cows eat the grain and other finer material, Schroeder says. When this happens, cows develop acidosis symptoms such as sore feet, low fat tests, fluctuating or lowered feed intake, displaced abomasums, or other problems.

"Without grinding or processing hay before adding to most mixers, it is almost impossible to get consistently good mixing of hay into a TMR and prevent cows from sorting," Schroeder says.

Feeding
The first feeding every day should always be to a clean bunk or manger. Clean out refusals each day before fresh feed is delivered, Schroeder says. Evaluate the refusal for quality and amount. Weighbacks should be the same composition as the TMR fed and no more than 2 percent of the TMR fed.

"At least 1 percent weighback is needed to assure cows are being fully fed," Schroeder says. "However, as weighback amounts increase, the opportunity for sorting increases."

TMRs can be fed once a day, but for best performance, twice a day is preferred, he says. Producers who feed once a day need to have adequate bunk space. The average lactating cow will eat 80 to 100 pounds of feed per day.

As cows eat, they push feed away from them, Schroeder says. On flat mangers, push up feed at least four times per day to minimize sorting.

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Source: J.W. Schroeder (701) 231-7663

Editor: Tom Jirik (701) 231-9629