TMR and Ration Basics: Mixing, Sorting and Working With a Nutritionist

A dairy cow eating a lot of grain and too little fiber can get sick, and a cow eating too much fiber and too little energy cannot produce milk at her potential. Feeding a high-producing Holstein is a balancing act, and the tool most larger herds use to manage it is the total mixed ration, or TMR. A TMR blends forages, grains, protein feeds, minerals and vitamins into one feed so that every mouthful has the same nutrient mix.

This guide explains how a TMR works and what farms do to make it work well. It does not give formulas, because rations must be built for each herd's feeds, cows and goals by a qualified nutritionist. If you want to find dairy nutrition workshops near you, agriculture.directory can help you find agriculture events in your area.

Why a TMR

If grain is fed separately from forage, cows may eat the grain fast and the forage slowly, which can upset the rumen. The TMR is designed to prevent that by delivering a consistent balance of nutrients in every bite and letting the cow eat throughout the day. It also lets a farm use a wide range of ingredients, including byproduct feeds, in a controlled way. The system is only as good as the mixing, the forage quality and the feeding routine, and it is easy to let any of those slip.

The Building Blocks

• Forages. Corn silage, haylage, hay and other fibrous feeds that supply fiber and much of the energy. Quality varies year to year, which is why testing matters. See the forage quality guide.
• Energy feeds. Corn grain, barley and similar starch sources, and fats.
• Protein feeds. Soybean meal, canola meal, distillers grains and others.
• Minerals and vitamins. Added to meet needs for calcium, phosphorus, trace minerals and vitamins, with special attention to cows around calving.
• Additives. Buffers, yeasts or other products when a nutritionist recommends them.

Different Groups, Different Rations

A herd usually runs several rations: fresh cows, high producers, lower producers late in lactation, far-off dry cows, close-up cows and heifers. Each group has different needs, and mixing a ration for a group that is too varied wastes feed or limits production. Transition cows have special needs, covered in the transition cow guide. Grouping and moving cows takes management and has a cost in stress, so work out the best compromise for your herd with your adviser.

Mixing

A mixer wagon or stationary mixer blends the ingredients. Mixing details matter:

• Load order. Equipment makers and nutritionists recommend an order, often long hay or other dry, bulky ingredients first, then grains and supplements, then wet feeds. Follow the recommendation for your mixer.
• Accurate weighing. Scales must work and be calibrated, and operators must load the right amounts. Small errors multiply over hundreds of cows.
• Mixing time. Too short leaves clumps and uneven mixes, and too long chops fibers too fine and reduces effective fiber. Use the manufacturer's guidance and check the result.
• Equipment condition. Worn knives and augers change how the feed mixes and how long particles are.

Particle Size and Sorting

Fiber length matters because it stimulates chewing, saliva and a healthy rumen. A well-known on-farm tool, the Penn State Particle Separator, sorts a sample of feed through stacked screens so you can see how much is long, medium and fine. Your nutritionist can set a target distribution. Cows sometimes sort a TMR, picking out the grain and fine particles and leaving the long fiber. Sorting defeats the purpose of mixing. Signs include a pile of long stems in the bunk after cows have eaten, and cows at the end of the day eating a different ration from those at the start. Keeping the mix moist enough, controlling the length of the forage and pushing up feed can help reduce sorting.

Feeding Routine

• Feed on a consistent schedule. Cows are creatures of habit.
• Keep feed in front of the cows. Push it up regularly so cows can reach it.
• Manage refusals. Many farms aim to leave a small amount of feed in the bunk at the next feeding, so cows are never short. Remove and weigh leftovers, and adjust the amount mixed.
• Provide enough bunk space and clean water. Competition in a crowded bunk lowers intake of timid cows.
• Keep the bunk clean. Remove spoiled feed, which can sicken cows.

Cow comfort affects eating as well as resting, and the cow comfort guide explains the link.

Signs the Ration Is Off

• Falling milk or butterfat. Can point to too little effective fiber or rumen upset.
• Loose manure or undigested feed in manure. Check particle size and starch.
• Cows not chewing cud. A normal cow spends hours a day chewing cud, so many cows not chewing suggests a problem.
• Weight loss or gain beyond plan. Body condition scoring tracks it.
• Metabolic problems. Ketosis, displaced abomasum and acidosis can be linked to feeding.
• Lameness. Rumen acidosis can contribute, as the lameness guide notes.

Working With a Nutritionist

A good nutritionist knows the cows, the feeds and the economics. Share forage test results, milk records, body condition scores, manure observations and your goals. Ask how the ration was formulated, what changes you should watch for and how to measure results. Compare cost per cow per day with milk income, a measure often called income over feed cost, so you can judge whether a change pays. The enterprise budget guide shows where feed fits in total costs. University extension dairy programs, including University of Minnesota Extension dairy and Penn State Extension dairy, publish nutrition and feeding management resources.

Keep Records

Record feed amounts, refusals, forage changes, milk yield and any health problems. Changes in forage lots, such as a new silo, can change the ration's effect overnight, so keep notes and ask for a retest.

Common Mistakes

• Not testing forages. Nutrient content changes.
• Loading the mixer carelessly. Errors affect every cow.
• Over-mixing. Fiber gets too short.
• Letting cows sort. Cows eat different rations.
• Changing feed suddenly. Rumen microbes need time to adjust.

Farm.fm's page on dairy covers dairy news and background, and for a laugh, see farm.fm's piece on a dairy nutrition expert who gives a cow a personalized diet while the farmer eats a gas station burrito.