Total mixed rations

With a Total Mixed Ration (TMR), every mouthful that a cow eats should be a balanced ration. The benefits of a TMR include less feed selection by the cow, synchronization of carbohydrate and protein availability in the rumen, and lower rumen acidity. A TMR may save labor and facilitate feeding commodity feeds. The main disadvantage of a TMR is the inability to feed cows as individuals. Larger farms with more groups of cows are able to minimize this problem. Forages and other wet ingredients should be fed on a dry matter basis. Increase or decrease the TMR ingredients in constant proportion. Beware of overmixing and sorting problems that can result in acidosis.

With a Total Mixed Ration (TMR) every mouthful of feed that the cow eats is a balanced ration. A ration is not a TMR if: hay is fed separately, a computer feeder is used for added grain, grain is fed in the milking parlor, grain is just spread on top of a forage in a feed bunk and not really mixed in, or cows are out on pasture at some time during the day.

Benefits of a TMR for the Cow

1. Cows Can't Pick and Choose What They Eat

  • You can hide less palatable feed ingredients within a TMR.
  • You don’t have some cows that eat mostly hay and others eating mostly grain.

2. Synchronization of Carbohydrate and Protein Availability in the Rumen

  • Rather than having protein fed at one hour, energy fed an hour later, and hay crop silage fed two hours after that, with a TMR, protein, energy, and fiber are supplied to the rumen microbes at the same time. The rumen microbes reproduce very rapidly and require nutrients in a specific ratio throughout the day. Microbial growth and microbial protein synthesis can increase by feeding a TMR rather than feeding ingredients individually because of a more uniform supply of nutrients.

3. Less Acid Build-Up in the Rumen

  • Acidosis is caused by the accumulation of acid and the reduction in pH of the rumen contents. Grain generates large amounts of acid and fiber is needed to stimulate saliva production. Saliva buffers the rumen. It reduces rumen acidity (increases rumen pH). With a TMR, grain is consumed in many small meals throughout the day rather than in 2-4 larger meals as is the case with component feeding. Fiber is also consumed in many smaller meals. TMR’s help to increase the average rumen pH throughout the day, especially minimizing dramatic variation in rumen pH during the day.

Disadvantage of a TMR for the Cow

Cows Are Not Fed as Individuals

  • With a TMR, all cows in a group get the same ration. Often, with component feeding, high producers are supplemented with extra grain and cows that are off-feed are given less grain and perhaps some extra hay. This individual attention is eliminated with a TMR.
  • Unfortunately, on farms without the facilities for many groups, cows are often too fat or too thin. This is evidence that some cows got too much grain and others didn’t get enough. This is especially true on farms with only one milking ration (one-group TMR). This situation not only compromises production but it is also inefficient and costly, especially for lower production herds (less than 80 pounds (36 kg) /cow/day) that are not milking three or four times per day and are not using bST.
  • On farms with only 2 or 3 milking rations, cows sometimes drop in milk production when they are moved from a group balanced for a higher level of milk production to a lower production group. This is a nutritional problem as well as a social problem. Social problems can be minimized. Move groups of cows instead of moving one cow at a time. Move cows at a time of day when social interactions will be minimized (i.e. after evening milking rather than after morning milking). Nutritional problems can be reduced by having no more than a 20-pound (9 kg) spread in the milk production support between rations and by keeping the protein content a little higher than that needed to support the level of production in the lower group.

Advantages for the Dairy Farmer

  1. A TMR may save labor because there will be less trips to make around the barn (in the case of a tie-stall barn). A TMR will save time spent in the parlor if the cows don’t need to be fed grain there.
  2. TMR’s may facilitate the use of commodity feeds such as wet brewer’s grains and whole cottonseed that are more difficult to handle. This may reduce feed cost.

Development of a TMR for a Group of Cows

  1. Determine average body weight, milk production, and fat test of the group. Determine the realistic, desired amount of milk production to balance the ration for.
  2. Evaluate body condition of the cows in the group. If necessary, increase or decrease the energy content of the ration according to body condition needs.
  3. Estimate dry matter intake and forage NDF intake. Determine the amounts of individual forages to be fed on a dry matter basis (based on quality and inventory). Remember that cows eat pounds of nutrients, not percentages of nutrients. The nutrients must be provided in a package size that the cow can eat.
  4. Formulate the grain and mineral supplements to meet the nutrient needs of the cow beyond the nutrients supplied by forages.

Day to Day TMR Feeding

  1. Feed forages and wet ingredients on a dry matter basis. Monitor changes in dry matter content of silage and wet by-product ingredients. A moisture tester is a good investment and should be used at least weekly and when there is an obvious change in the forage being fed. A TMR should supply a consistent amount of dry matter from forages in a balanced diet. So, if the moisture content of forage increases, more pounds of As-Fed forage should be fed but the pounds of forage dry matter should remain the same. A change in the size of a mixer load or a change in TMR refusals by the cows should alert feeders to a change in forage dry matter, but it is preferable to correct weights before feeding an incorrect ration for a few days and suffering milk production losses. During vvariable weather conditions, some farmers will feed a consistent volume of each silage and rely less on silage weight.
  2. Keep track of the number of cows in the group and adjust the amount fed according to the number of cows in the group.
  3. Increase or decrease the total mix fed according to daily intake levels --- Move all feeds up or down in proportion. The easiest way to figure this is to feed for more or less numbers of cows in a group. If intake is consistently more than 5% higher or lower from that predicted (and that balanced for), work with your nutritionist to adjust the ration accordingly.
  4. Keep the TMR fresh. Don't let the TMR sit around before feeding, especially during hot weather.

Grouping Strategy

Pre-Fresh Cows: (2-3 weeks before calving up to calving day)

  • These cows have low dry matter intakes (about 23 pounds (10.5 kg) /day for large breeds) but increased protein and energy requirements because of the impending lactation as well as the large calf growing inside. This ration should be used as a transition to the fresh cow ration. The goal is to supply the needed nutrients and to adjust the rumen microbes and the rumen papillae (which absorb acids from the rumen) to a diet that contains more grain while at the same time maintaining rumen function during a time of low and fluctuating daily dry matter intake. The diet should contain 32-34% NFC (usually 7-8 pounds (3-3.5 kg) of grain) plus long, effective fiber. Five pounds (2.25 kg) of hay included in the ration is very helpful. The mineral balance of this ration is also critical for avoiding milk fever. Close attention should also be paid to ration palatability.

Fresh Cows: (0-30 DIM)

  • These cows have lower intakes but high nutrient requirements. A primary goal is to provide the nutrients needed to drive the cow towards high peak milk production while maintaining rumen function and preventing metabolic disorders (D.A.'s, ketosis, acidosis).
  • Often fresh cow rations are formulated with a slightly higher level of forage NDF than the high group ration. The inclusion of long hay (4-5 pounds (2 kg)) is also very helpful. Additives such as calcium propionate, niacin and rumen protected choline are often added to fresh cow rations to help cows experiencing some degree of ketosis. Money is well spent in this group because it should pay off for the entire lactation.

High Cows: (30-150 DIM)

  • Most of these cows should be near peak feed intake and peak milk production. The goal is to maintain high milk production and to get cows bred back at this time. Close attention should be paid to maintain adequate effective fiber in this ration that is balanced for high milk production.

First-Calf Heifers:

  • First-calf heifers generally respond in milk production if they are in their own group. This is due to social as well as nutritional reasons. Rations for first-calf heifer groups are balanced for less dry matter intake and support slightly less milk production than the high group ration. If first-calf heifers are smaller than mature cows and they are grouped separately, expect 5-10% more milk over the lactation. The ultimate goal in today’s high-producing herds, however, should be to grow large, well-framed heifers so that there is less need for a first-calf heifer group.

Medium Cows: (150-210 DIM)

  • These cows should be bred and milk production will be declining. Underfeeding these cows will lead to irrecoverable milk losses. Overfeeding will be a waste of money and result in overconditioning which will be a problem when cows begin their next lactation. The goal with this group should be to maintain milk production as economically as possible. Often, if farms have a first-calf heifer group, they used the medium group for tail-end first-calf heifers.

Tail End Cows: (210-305 DIM)

  • These cows have low nutrient requirements that can mostly be supplied by forages. A primary goal is to avoid overconditioning at this time.

Dry Cows:

  • The goal of the dry period should be to prepare the cow for the next lactation. Avoid overconditioning (using medium quality forages) and rejuvenate the rumen preferably through the provision of long hay. Adequate protein and a proper mineral balance should be supplied.

The number of groups used on a particular farm will depend on factors such as, the size and configuration of barn, the number of cows on farm, milking parlor and holding area constraints, milk production level of herd, and labor constraints.

Other Factors To Keep In Mind With a TMR

Scale Calibration
Check mixer wagon scales routinely. Scales should be calibrated when there is a lot of weight in the mixer as well as when it is empty. Many people find it easiest to place a known weight, such as a 50-pound bag of feed, on the corners of the wagon to test each load cell. Consult the mixer wagon manual for manufacturer’s recommendations.

Add TMR Ingredients in the Proper Order and Don’t Overmix
It is important to maintain length of forage fiber in your TMR. Generally, it is recommended that the haycrop silage, long hay, or other long fiber sources be added last, unless the mixer is equipped with at hay processor (then the hay must be added first). With auger mixers, a mixing time of 5 minutes should be enough. Fifteen to twenty minutes is too much. Again, consult the mixer wagon manual for manufacturer’s recommendations. If you are wondering how much your long fiber is reduced in the mixer wagon, mix a small TMR in the proper proportions by hand and compare it (visually or better yet with a Penn State Particle Size Separator) to what is coming out of the mixer wagon.

Don't feed to an empty bunk
The feed that is swept out should look like the feed that was put in. A bunk with only corn cobs and long, fibrous particles is an empty bunk! Feeding to an empty bunk will result in slug feeding and acidosis.

Maintain adequate feed bunk space and push feed up often
At least 18-24 inches (46-61 cm) of feed bunk space per cow is recommended. The ration should be pushed up to the cows often (at least 6-8 times per day), especially if bunk space is marginal.

Timing of Feeding
Feed when cows want fresh feed (i.e. after milking). Many farmers only feed their TMR once per day. With adequate feed access (plenty of push ups) this strategy can work O.K. Most nutritionists, however, would agree that more feedings per day encourages cows to eat.

Watch Out For Sorting
Cows will take their noses and wiggle down through a TMR to sort out the grain from the forage. This process provides the rumen microbes with a few mainly grain meals and a few mainly forage meals per day, just like component feeding without a TMR. The result is acidosis. Ration dry matter can dramatically affect the incidence of sorting. The drier the ration, the more sorting. Sorting has been reduced when water was added to rations containing more than 50% dry matter to bring ration dry matter down to 43%. Also, if the ration is too coarse (especially with coarse-cut dry corn silage), cows will sort. Feeding cows more frequently will also help reduce problems with sorting.


Chase, L.E. and C.J. Sniffen. 1987. Feeding management considerations – Total Mixed Rations. In: Proceedings of the Advanced Dairy Nutrition Seminars for Agribusiness, September 1987. Cornell Cooperative Extension Service.

de Ondarza, M.B. 2000. Feed sorting leads to acidosis, other problems. Hoard’s Dairyman, April 10, 2000, p. 286.

Shaver, R.D. 1995. Look in the bunk when there are feeding problems. Hoard’s Dairyman, December 1995, p. 798.

Shaver, R.D. 1996. Careful weighing and mixing a must for TMR’s. Hoard’s Dairyman, May 25, 1996, p. 401.

Related Links:

Total Mixed Dairy Rations on Your Farm?
M. Bennett et al., University of Missouri

Using a Total Mixed Ration for Dairy Cows
J.W. Schroeder and C.S. Park, North Dakota State University

Feeding Systems In: Feeding the Dairy Herd North Central Regional Extension Publication
J.G. Linn et al.

Total Mixed Ration Mixer Sizing and Costs
D. Kammel, University of Wisconsin


Mary Beth de Ondarza

Mary Beth de Ondarza
45 articles

Nutritional consultant for the dairy feed industry at Paradox Nutrition, LLC.

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Dr. de Ondarza received her Ph. D. from Michigan State University and her Masters Degree from Cornell University, both in the field of Dairy Nutrition.

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Paradox Nutrition

Paradox Nutrition

Paradox Nutrition, LLC is a nutritional consultation business for the dairy feed industry. Mary Beth de Ondarza, Ph.D. is the sole proprietor.

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