University of Missouri Extension

G3270, Reviewed October 1993

Whole Soybeans for Dairy Cattle

Ron Belyea and Barry Steevens
Department of Animal Sciences

Whole soybeans (WSB) can be used in dairy cow rations; they are palatable and have excellent feed value. WSB have lower protein content than soybean meal, but because of higher fat, have higher net energy content (Table 1).

Table 1
Comparison of whole soybeans to soybean meal

  As fed basis
WSB Soybean meal
Protein, percent 39 44
ADF, percent 9 10
NDF, percent 10 12
Crude fiber, percent 6 6
Fat, percent 18 1.4
Ca, percent 0.28 0.36
P, percent 0.66 0.75
Net Energy Mcal per pound 0.88 0.79

How much WSB should I feed?

You can feed limited amounts of WSB. We generally consider the maximum to be six to seven pounds per day or up to 20 percent of the concentrate. The amount depends upon other feed ingredients in the ration and their fat content (Table 2).

Table 2
Fat content of feeds (dry basis)

Feeds Percent fat
Barley 4.3
Corn 2.3
Whole cottonseed 25.0
Dried distiller grains 9.4
Hominy 8.3
Milo 3.2
Oats 4.4
Whole SB 20.0
SB meal 1.4
Wheat 2.0
Alfalfa hay 2.0
Corn silage 1.0

Some examples

Ration 1

Ration 2

Ration 3

Ration 4

The point is that the other ingredients add fat to the diet and this must be taken into account. The more fat there is in the other grains, the less WSB you should feed.

How much fat can I allow?

Most research indicates that if the total diet contains more than about 5 percent fat, digestibility, milk yield and milk composition may decline. For the average cow eating 40 to 50 pounds of DM daily, 5 percent fat amounts to 2 to 2.5 pounds of fat (Table 2).

What if fat content is too high?

Too much fat may often depress digestibility, particularly that of fiber. This may be because fatty acids, hydrolyzed from fat in the rumen, attach to bacteria and inhibit their action. This effect, however, is minimized by increased calcium and magnesium in the diet.

In a study at Ohio State, researchers fed cows diets containing various proportions of corn, oats, wheat bran, soybean meal, alfalfa meal, corn silage and alfalfa pellets. Fat percent in the diet varied from 3.2 to 10.8 percent. The data are summarized in Table 3.

Table 3
Effect of feeding diets varying in fat percent (Ohio State study.)

Diet Experiment 1 Experiment 2
11 12 13 21 22
Protein, percent 16.6 17.5 17.5 15.9 16.3
ADF, percent 18.2 18.5 19.7 19.3 21.3
Fat, percent 3.2 5.7 10.8 2.9 6.8
Calcium, percent 0.7 0.8 0.8 0.6 6.8
Concentrate, percent diet 42 42 42 50 33
Digestibility, percent DM 62.5 67.3 66.7 63.1 59.3
Digestibility, percent ADF 35.6 44.3 44.0 31.3 35.3
Digestibility, percent protein 64.0 67.6 70.6 63.7 66.7
DMI pounds per day 44.4 46.6 40.4 42.5 44.4
FCM pounds per day 62.3 66.7 59.8 53.2 60.9
Milk fat, percent 3.51 3.42 3.25 2.71 3.44
Milk protein, percent 3.06 3.04 3.12 3.38 3.23

In this study, increasing dietary fat had little effect on intake. Milk yield (FCM) was highest for the 5.7 percent fat group; milk fat percent decreased as fat increased. Digestibility was increased in the 5.1 percent fat diet (Diet 12) but not in the 10.8 percent fat diet (Diet 13). Milk protein percent, sometimes depressed by high dietary fat, was unaffected in this study. Milk fat percent was lower in diet 21, probably because more concentrate was fed.

WSB feeding studies

WSB were fed to lactating cows in several studies. They are summarized in Tables 4 and 5.

Table 4
Feeding whole soybeans to dairy cows (Wisconsin-Marshfield study)

  Ensiled shelled corn + dry WSB Ensiled ear corn + ensiled WSB Dry conventional concentrate
Concentrate, pounds DM per day 9.8 11.0 9.2
Forage1, pounds DM per day 23.6 23.8 25.4
FCM, pounds per day 39.9 40.1 38.5
Milk fat, percent 4.11 4.16 4.23
Number of cows 17 17 17
1Legume — grass haylage and corn silage.

Table 5
Feeding whole soybeans to dairy cows (California study)

    Whole cotton seed
Control WSB 15 percent1 30 percent1
DMI, pounds per day 41.4 42.8 40.7 42.0
Test feed, pounds per day2 – 3.4 6.8 14.0
Milk, pounds per day 71 77 67 70
Milk fat, percent 3.7 3.74 4.0 4.18
Milk protein, percent 3.14 3.06 2.99 3.01
1Percent of diet.
2WSB, 15 percent WCS or 30 percent WCS

These studies suggest that reasonable amounts of WSB don't cause detrimental effects and can be substituted in typical diets. Some other concerns and considerations are:

G3270, reviewed October 1993

G3270 Whole Soybeans for Dairy Cattle | University of Missouri Extension

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