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Unit notes and practice questions

Grade 11 Agriculture unit 5: Animal Feeds and Feeding Practices

Everything here is for unit 5 of the Grade 11 Agriculture textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.

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4
Cards
10
Practice questions on unit 5
68–90
The textbook pages for unit 5

What unit 5 covers

  1. 1.Feed resources in Ethiopia
  2. 2.Classification of feed resources
  3. 3.Nutrient requirement of farm animals
  4. 4.Feed formulation practices
  5. 5.Feed conservation and compound feed

Short notes for unit 5

The cards filed under this chapter on the Grade 11 Agriculture page. Open one at a time.

Feed ClassCrude FiberTDNCrude Protein
Roughages>18%> 18\%<60%< 60\%Variable
Energy-rich concentrates<18%< 18\%>60%> 60\%<18%< 18\%
Protein-rich concentrates<18%< 18\%>60%> 60\%>18%> 18\%

When you use it

Use when categorizing feedstuffs into roughages or concentrates based on Crude Fiber, TDN, and Crude Protein contents.

Watch out

Roughages have high fiber above 18 percent and low TDN below 60 percent. Concentrates reverse this with fiber below 18 percent and TDN above 60 percent.

Drafted from Grade 11 Agriculture, pages 69-93, then checked twice before it went up

FeatureHaySilage
Preservation processDrying (curing)Anaerobic fermentation
Preserving agentSun and windLactic acid (pH≤4pH \le 4)
Final moisture content15%−20%15\% - 20\%60%−70%60\% - 70\%
Storage structureBales or tripod standAirtight silo pit or bag

When you use it

Use when comparing hay making and silage making processes, storage conditions, and final moisture targets.

Watch out

Hay relies on aerobic moisture removal down to 15 to 20 percent, whereas silage requires strictly anaerobic fermentation to lower pH below 4.

Drafted from Grade 11 Agriculture, pages 69-93, then checked twice before it went up

WA=∣CPB−CPtarget∣∣CPA−CPtarget∣+∣CPB−CPtarget∣×WtotalW_A = \frac{|CP_B - CP_{\text{target}}|}{|CP_A - CP_{\text{target}}| + |CP_B - CP_{\text{target}}|} \times W_{\text{total}}
WAW_A
Mass of Feed A required in the rationkg\text{kg}
CPACP_A
Crude protein percentage of Feed A%\%
CPBCP_B
Crude protein percentage of Feed B%\%
CPtargetCP_{\text{target}}
Desired crude protein percentage of the final ration%\%
WtotalW_{\text{total}}
Total mass of the formulated ration to preparekg\text{kg}

When you use it

Use when calculating the exact masses of two feed ingredients needed to obtain a balanced ration of a target crude protein level.

Watch out

One feed must have a nutrient percentage above the target and the other below it. Subtract diagonally across the square and ignore negative signs.

Drafted from Grade 11 Agriculture, pages 69-93, then checked twice before it went up

When you use it

Use when identifying restricted livestock groups for silage and improper silo opening practices.

Watch out

Silage must never be fed to monogastric animals, calves under 6 months, or cows in late pregnancy. Never open the entire silo at once because air ingress spoils the remaining silage.

Drafted from Grade 11 Agriculture, pages 69-93, then checked twice before it went up

Practice questions on unit 5

10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.

Question 1

In livestock production enterprises, what percentage of the total operating cost is typically spent on animal feed?

  1. A.10% to 25%
  2. B.30% to 45%
  3. C.50% to 80%
  4. D.85% to 95%
Show the answer and why

Answer: C 50% to 80%

Why

The textbook states that feed is the largest operating cost in livestock production, varying from 50% to 80% depending on the operating area.

Question 2

Which of the following elements is classified as a macro-mineral in animal nutrition?

  1. A.Calcium (Ca)
  2. B.Copper (Cu)
  3. C.Iodine (I)
  4. D.Zinc (Zn)
Show the answer and why

Answer: A Calcium (Ca)

Why

Macro-minerals are required in larger amounts by the animal body and include calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K), and sodium (Na). Copper, iodine, and zinc are micro or trace minerals.

Question 3

What is the Pearson Square method used for in livestock feeding?

  1. A.Determining the soil fertility of grazing lands
  2. B.Calculating the portion of two feeds needed to balance a ration
  3. C.Measuring moisture loss in hay bales
  4. D.Counting the bacterial population during silage fermentation
Show the answer and why

Answer: B Calculating the portion of two feeds needed to balance a ration

Why

The Pearson Square method is a well-known method used to calculate the proportions of two feeds needed to meet either the protein or energy requirements of an animal.

Question 4

What is the primary purpose of the curing process in hay making?

  1. A.To increase the crude fiber content above 50%
  2. B.To reduce the moisture content of green crops from 70-90% to 15-20%
  3. C.To raise the pH level of the forage to 8 or higher
  4. D.To promote anaerobic bacterial growth under sealed plastic
Show the answer and why

Answer: B To reduce the moisture content of green crops from 70-90% to 15-20%

Why

Curing is the drying process in hay making that reduces the moisture content of green crops from 70-90% down to 15-20% using energy from the sun and wind.

Question 5

According to the classification of animal feeds, a feedstuff is defined as a roughage when it contains:

  1. A.Less than 18% crude fiber and more than 60% Total Digestible Nutrients (TDN)
  2. B.More than 18% crude fiber and less than 60% Total Digestible Nutrients (TDN)
  3. C.More than 18% crude protein and less than 10% moisture
  4. D.Less than 18% crude protein and more than 80% dry matter
Show the answer and why

Answer: B More than 18% crude fiber and less than 60% Total Digestible Nutrients (TDN)

Why

Roughages are bulky feeds containing more than 18% crude fiber and less than 60% Total Digestible Nutrients (TDN). Concentrates contain less than 18% crude fiber and more than 60% TDN.

Question 6

Which agro-industrial by-product contains about 54% TDN and 3% protein, and is used as an appetizer and dust settler?

  1. A.Wheat bran
  2. B.Soybean meal
  3. C.Molasses
  4. D.Brewer's spent grain
Show the answer and why

Answer: C Molasses

Why

Molasses is a sugar industry by-product that provides high energy (54% TDN) and low protein (3%). It serves as an appetizer and stops dry feed from becoming dusty.

Question 7

During the packing and sealing stage of silage making, which chemical change lowers the pH to 4 or below?

  1. A.Aerobic respiration converting fats into amino acids
  2. B.Carbohydrates breaking down into organic acids such as lactic acid
  3. C.Proteins transforming directly into urea and mineral salts
  4. D.Vitamins absorbing excess water from the compacted forage
Show the answer and why

Answer: B Carbohydrates breaking down into organic acids such as lactic acid

Why

Under anaerobic conditions in a sealed silo, carbohydrates (sugars) break down into organic acids (especially lactic acid), which reduces the pH to 4 or lower and preserves the feed.

Question 8

A farmer near Debre Zeit observes cattle chewing on wood and metal objects, showing stiff joints and producing less milk. Which nutrient deficiency causes these specific signs?

  1. A.Carbohydrates
  2. B.Fats
  3. C.Minerals
  4. D.Water
Show the answer and why

Answer: C Minerals

Why

Chewing and suckling of wood and metal, stiff joints, weakened bones and teeth, and drop in milk production are textbook signs of mineral deficiencies in livestock.

Question 9

A farmer wants to prepare 200 kg of feed containing 16% crude protein (CP) using maize grain (9.5% CP) and soybean meal (42% CP). Using the Pearson Square method, how many kilograms of maize and soybean meal are needed?

  1. A.160 kg maize and 40 kg soybean meal
  2. B.100 kg maize and 100 kg soybean meal
  3. C.140 kg maize and 60 kg soybean meal
  4. D.180 kg maize and 20 kg soybean meal
Show the answer and why

Answer: A 160 kg maize and 40 kg soybean meal

Why

Using the Pearson Square: parts of maize = |42 - 16| = 26; parts of soybean meal = |9.5 - 16| = 6.5; total parts = 32.5. For 100 kg, maize is (26 / 32.5) * 100 = 80 kg and soybean meal is (6.5 / 32.5) * 100 = 20 kg. Therefore, for 200 kg, the farmer needs 160 kg of maize and 40 kg of soybean meal.

Question 10

According to the management checklist for feeding silage, which animals must NOT be fed silage?

  1. A.Mature oxen used for plowing
  2. B.Cows in late pregnancy and calves under 6 months old
  3. C.Dairy cows during the first stage of lactation
  4. D.Fattening steers fed in a commercial feedlot
Show the answer and why

Answer: B Cows in late pregnancy and calves under 6 months old

Why

The textbook silage feeding checklist specifies: do not feed cows that are in late pregnancy, calves that are less than 6 months old, or animals that are sick, hungry, and weak.

The app holds 12 questions on this unit, marked as you go. These are the first 10.

The textbook pages for unit 5

Unit 5 runs from page 68 to page 90 of the Ministry of Education edition.

Ministry of Education edition, English, 270 pages

Download the PDF

All Grade 11 Agriculture short notes

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