Instructions:

Table 1 presents ration ingredients, nutrient composition, and intake for four dairy replacement rations. Unfortunately, the table contains missing cells. Using the information presented in the reading and your nutrition-related critical thinking skills, answer the 9 multiple-choice questions listed here. Some of the questions may be ambiguous Your explanation is really what counts!

Ration Composition	D	C	A	B
Ration Ingredients, % of ration dry matter
Corn silage	32.0	28.0	28.0	31.0
Legume silage, bud	66.0	71.0	48.0	61.0
Shelled corn	...	...	14.4	7.3
Soybean meal	...	...	...	...
Expeller soybean meal	1.3	...	8.9	...
Salt	0.3	0.3	0.3	0.3
Mineral & Vitamin premix	0.5	0.5	0.5	0.5
Total	100	100	100	100
Ration Nutrient Composition, % ration DM (unless noted otherwise)
Crude Protein (CP)	13.0	13.5	16.5	15.0
Rumen undegraded protein (RUP)	3.0	3.0	5.9	3.5
Total Digestible Nutrient (TDN)	59.0	60.0	67.0	62
Metabolizable Energy (ME), Mcal/lb	1.0	1.0	1.1	1.0
Neutral Detergent Fiber (NDF)	48.0	48.4	39.2
Non-Fiber Carbohydrate (NFC)	30.4	29.8	35.8	31.2
Dry Matter Intake
DMI, lb/day	26.5	21.2	8.5	14.7

Question 1: TDN of ration D is about:
a. 55%
b. 60%
c. 65%
Explain: Correct answer is b. 60%; TDN of D must be almost the same as for diet C because NDF and NFC are almost identical.

Question 2: CP of ration A is about:
a. 14.5%
b. 15.5%
c. 16.5%
Explain: Correct answer is c. 16.5%; Much greater than ration B (15%) because t includes 9% expeller soybean meal (which would more than make-up for the lower afalfa (the two sources of protein in the diet).

Question 3: NDF of ration A is about:
a. The lowest compared to the other rations
b. About equal to ration B
c. More than in ration D
Explain: Correct answer is a. The lowest compared to the other rations; Most NDF comes from forage (corn silage and alfalfa silage), all rations other than ration A includes more than 90% forage (and more than 45% NDF. Thus with only=78% forage, ration A must have a lower NDF than any other ration.

Question 4: What is the percent of RDP in ration B?
a. Unknown
b. 11.5%
c. 12.5%
d. 13.5%
Explain: Correct answer is b. 11.5%; CP - RUP = RDP. Thus, 15.0 - 3.5% = 11.5%

Question 5: Which of the rations would be appropriate to feed a 900-lb heifer:
a. Ration A or B
b. Ration B or C
c. Ration C or D
d. Ration D or A
Explain: Correct answer is c. Ration C or D; An 18 month old 900 lbs heifer should be fed the highest forage diets.

Question 6: Ration A is most likely the best ration for:
a. 300-kb heifer
b. 600-kb heifer
c. 900-kb heifer
d. 1200-kb heifer
Explain: Correct answer is a. 300-kb heifer; Ration A is the highest energy diet, which should be fed to the youngest heifers.

Question 7: Which of the rations would be appropriate to feed a 600-kb heifer?
a. Ration A
b. Ration B
c. Ration C
d. Ration D
Explain: Correct answer is b. Ration B; Ration C and D must be forolder, heavier heifers (> 1 yr) because of their low CP. Ration A is to high in CP for a 600-lb heifer.

Question 8: Assuming the same dry matter intake, which of the rations would result in the least amount of manure excretion per day?
a. Ration A
b. Ration B
c. Ration C
d. Ration D
Explain: Correct answer is a. Ration A; The ration with the highest TDN would yield the least manure.

Question 9: Assuming the same dry matter intake, which of the ration would contribute least to global warming through enteric methane production
a. Ration A
b. Ration B
c. Ration C
d. Ration D
Explain: Correct answer is a. Ration A; CH₄ production is closely associated with NDF fermentation in the rumen. Ration A with the least NDF will yield the least CH₄.