Solutions to Chapter 4 Problems - Use these to check you answers and help you learn how to do the problems.  Make sure you understand these because you will be tested over them.

1.

Corn (9% CP) = X

SBM (44% CP) = Y

X +Y = 2000 LB

.09X + .44Y = 320 LB (16% X 2000 LB)

- .09Y = 180

.35Y = 140

Y = 400 lb SBM

 

2. X + Y = 2000 lb

.09X + .44y = 360 LB

- .09y = 180

.35Y =180

Y= 514 lb SBM

X = 1486 lb corn

3. X= grd. Milo

y= CSM

X + Y = 1000 KG

.11X +.41y = 180 KG

- .11Y = 11O KG

.30Y = 70 KG

Y = 233 kg CSM; X = 767 KG MILO

4. X = lime

Y = DICAL

X + Y = 500 LB

.36X+.23Y=135 LB Ca (500 X 27%)

- .36Y =180 lb

-.13Y=-45

Y = 346 LB DICAL; X = 154 LB LIMESTONE

346 X18% P = 62 LB P CONTAINED IN THE 500-LB MIXTURE

% P = 62 lb/500 lb X 100% = 12% P

5. Refer to page 237, part B

X = LB GRAIN MIX

Y = LB SBM (46% CP)

Step 1. Calculate the % CP in the grain mixture:

3 parts corn (9% CP)

1 part oats (11% CP)

4 parts total


So: 75% of the mixture is corn; 25% oats

     75 X 9% = 6.75%

+ 25 X 11% =2.75%

                       9.5% is the CP in the corn-oat mixture

Step 2. X + Y= 1500 LB

.095X + .46y = 225 LB

             .095Y= 143

           .365 Y = 82 LB

Y = 225 LB SBM

X = 1275 LB GRAIN MIX

Step 3. Break out the grains

1275 X 75% = 956 LB CORN

1275 X 25% - 319 LB OATS

Step 4. List ingredients.

956 lb corn

319 lb oats

225 lb SBM

1500 lb

6.     60 lb fixed ingrediets

X = lb dical

Y = lb rock phosphate

X + Y = 40 lb

.22X +.15Y = 7 lb P

        -   .22Y = 8.8

            -.07Y=-1.8

Y = 26 lb Rock P

X= 14 lb Dical

7. See part E on page 250.

Req. forage supplies still need

28 Mcal NEl - 12 Mcal NEl = 16 Mcal NEl

         6 lb CP - 2.25 lb CP = 3.75 lb CP

set up:

X = lb corn Y = lb CSM

protein equation: .09 x + .40 Y = 3.75 CP

energy equation      .8 X + .7 Y = 16 Mcal

                                     - 3.6 Y = 33.3

                                     -2.9 Y = -17.3

Y = 6 lb SBM

Plug in Y in one of the original equations and solve.

X = 15 lb corn

 

15 lb corn

6 lb SBM

21 lb total

8. A. determine fixed ingredients = 10% of diet

B. determine CP in fixed (if necessary, here it is)

5% alfalfa meal X .20 CP = 1% CP

1% vit./antibiotic X.50 CP = .5% CP

Total 1.5% CP or 30 lb CP per ton.

 

C. set up X = lb milo

Y = lb SBM

       X + Y = 1800 lb (not 2000 because 10% is fixed)

.11X+.48Y = 270 lb (300 lb - 30 lb from fixed)

        .11Y =198

        .31Y = 72 lb

Y = 196 lb SBM

X = 1800-196= 1604 lb milo

D. list the all ingredients and pounds of each per ton to total 2000 lb.

9 and 10. Optional, can be turned in for bonus points!