Soybeans in dairy nutrition

Soybeans in Dairy Rations: The Whole Story

Soybeans in Dairy NutritionSoybeans in Dairy Nutrition

Feeding soybeans to dairy cows has garnered the attention of dairy cattle producers for decades.

As a field nutritionist the question that I get asked most frequently from clients is: “What is the best way to utilize soybeans in a dairy ration, raw or

heat treated?” The answer is both ways. Confused? Let’s take a closer look.

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Dry Matter % CP% UIP %NElcal/kg)

Raw Beans 87 41.4 20 2.11

Roasted Beans 92 41.3 49 2.17

48% SB Meal 90 53.3 28 1.99

Soybeans in Dairy Nutrition

“Full fat” beans as a protein for dairy cattle makes a great deal of sense for two major

reasons: economics and the high-energy value of full fat beans.

Roasting adds an additional cost but roasted beans still break even economically compared

to commercial protein supplements.


On dairy farms with enough acreage to justify growing beans, growing a protein/energy

supplement for the herd certainly looks more attractive than other cropping options.


The high fat content of soybeans impacts on the dairy ration in two positive ways: fat has

2.25 times the energy value of starch and therefore has a higher energy density.

Because of this the cow requires slightly less grain and supplement, allowing her to eat

slightly more forage; with more energy coming from fat there is less starch in the diet.


With more fibre and less starch, diets that contain soybeans usually result in a higher

butterfat test in early lactation.

With more energy available, many cows also respond with a slight increase in milk

production or maintenance of body condition.


The decision to feed raw or roasted beans will be dictated by the additional cost of heat-treating and the quality of heat treatment

available. Roasted beans should exit the roaster at 140 to

150 C and steep for 30 to 40 minutes. Over cooking beans denatures the protein making it unavailable and reduces specific

amino acid availability.


Heat-processed beans should be uniform in colour, show no evidence of burning and have a pleasant nutty taste; beans that taste bitter

have not been roasted properly.

Over the years I have seen far too many poorly roasted beans that have resulted in on-farm

disasters.


Under-cooked beans have the same properties as raw beans but are fed out as roasted,

presenting inherent problems. Burnt beans render the protein unavailable.

Many “back yard” roasters have both “hot” and “cold” spots in them resulting in both

burnt and under cooked beans. I would much rather work with quality raw beans that roasted beans of an unknown quality!


To use raw soybeans effectively, certain precautions must be taken.

Raw beans contain the enzyme urease that breaks down urea to ammonia making diets that include raw beans and urea unpalatable

and potentially dangerous. In hot weather ground or rolled beans become rancid quickly and should not be stored after

processing.


Also in raw beans exists the anti-nutrient “trypsin inhibitor” which interferes with

protein digestion.

Therefore, raw beans should not be fed to animals less than 6 months of age; in mature ruminant the toxin is destroyed in the rumen.

Nutritionally

When too much fat is introduced into the diet or it is introduced too quickly both milk

production and butterfat can be depressed.

To avoid this situation all high fat feeds should be introduced to the rumen slowly; in

addition extra calcium (1 – 1.1% DM) and magnesium (0.35 – 0.4% DM) should be

added to the diets.

Nutritionally

These minerals, in combination with fat, form soaps that do not coat the feed particles.

There is some research that also recommends feeding higher levels of selenium and

vitamin E because unsaturated fats reduce vitamin E activity.


Store raw and processed beans whole; crack or roll them as you use them to avoid rancidity,

this is especially true in warm weather.

Ration fat level must not exceed 7 to 8%.This includes 2-3% from natural sources, 2-3%

from vegetable oil or tallow, 2-3% from by-pass fat.

Quick tips for utilizing raw or heat-treated soybeans in

your herd:

Raw soybeans are an excellent feed ingredient for lactating dairy cows.

Feed a maximum of 2.5 kg as fed/ head/day of raw beans.

Feed a maximum of 3.0 kg as fed/ head/day of heat-treated beans.

Raw soybeans should never be fed with urea or supplements that contain non-proteinnitrogen.


your herd:

Use only heat-treated beans in young ruminants less than 6 months old.

Store beans whole to prevent rancidity. Beans should be rolled or cracked beforeincluding in a ration.

Heated treated beans are more palatable and contain more bypass protein than raw beans.


your herd:

In addition, heat-treating destroys anti-nutrient factors such as urease and trypsin inhibitor. However, heat treatment MUST be done properly and be cost effective.

Watch that the total fat levels in the diet do not exceed 7 to 8% and unprotected, added fat must not exceed 2% to 3% of the dry matter intake.


your herd:

Increase ration levels of calcium to 1% to 1.1% and magnesium to 0.35% to 0.40% (total ration dry matter).

Added dietary fat can increase the risk of oxidized milk; vitamin E levels in the total ration DM should be between 1000 to 4000 IU/cow/day to help prevent oxidized milk.

Health & Medicine

Soybeans in dairy nutrition