Animal Nutrition and Digestion – Agricultural Sciences Grade 12 Questions and Answers
QUESTIONS
- Answer the questions below. Check your answers afterwards and do corrections.
- Give yourself one hour.
- Marks: 100
- State the three types of digestive processes that take place in ruminants. (3)
- Describe the function of saliva in the digestive process. (3)
- The bovine stomach consists of four compartments.
3.1 Name the compartments. (4)
3.2 Explain the role of each one briefly. (8) - All ruminants regurgitate their feed.
4.1 Outline the process of regurgitation in a ruminant. (4)
4.2 Explain the importance of regurgitation in the digestive process of a ruminant. (3) - Which components of feed can animals use for energy? (3)
- Give ONE word/term/phrase for each of the following descriptions:
6.1 Roughage with a high moisture content which is mostly used as a feed source for dairy cattle
6.2 A nutrient supplement that is placed in a pasture field to provide the grazing animals with additional nutrients (2) - Name five main categories of nutrients in feed. (5)
- The______ is responsible for the grinding of food by means of small stones found in it. 8.1 crop
8.2 ventriculus
8.3 proventriculus
8.4 caecum (2) - Trace elements are important for the production of healthy red blood cells.
9.1 Name these trace elements. (2)
9.2 What condition results from a deficiency in these elements? (1) - What nutrient deficiency causes each condition below?
10.1 parakeratosis;
10.2 curled toe paralysis;
10.3 night blindness;
10.4 milk fever;
10.5 white muscle disease (5) - Name five essential functions of proteins in the body. (5)
- Food supplies animals with energy for metabolic processes and to grow and reproduce.
12.1 What kind of energy does food contain? (1)
12.2 What other kinds of energy can it be converted into by animals? (2) - Cellulase is an enzyme that is found in the rumen of a______.
13.1 horse.
13.2 fowl.
13.3 pig.
13.4 goat. (2) - Name FOUR methods of processing that can be used to improve the digestibility of feed. (4)
- Name three main characteristics of concentrates. (3)
- Give four examples of feed concentrates. (4)
- Non-protein nitrogen sources can be used to supplement protein in the ruminant diet.
17.1 Briefly explain why. (2)
17.2 Briefly explain how this is achieved. (3) - What is the single Pearson Square method? (1)
- Explain the difference between a maintenance and production ration. (4)
- Examine the table below and answer the questions that follow.
Feed Crude protein (%) Crude fibre (%) Metabolisable energy (MJ/kg) Lucerne pasture 22,5 25,8 9,4 Wheat pasture 12,3 15,5 10,5 Veld grass (summer) 7,0 36,0 8,0 Lucerne hay 14,1 30,1 7,5 Groundnut hay 9,2 24,1 8,7 Maize stover 5,8 27,1 6,8 Oat hay 8,2 28,1 7,1 Soybean meal 45,8 5,8 11,6 Milk powder (skim) 33,5 0,0 12,0 Maize meal 8,9 2,0 12,0 Blood meal 82,2 0,0 9,1 Fishmeal 60,9 0,0 10,6 Ground nut oilcake 45,3 12,6 11,4 Sorghum grain 11,0 1,7 12,2 20.1 Name the four feeds with the highest crude protein content. (4)
20.2 Which feeds identified above are examples of protein-rich animal concentrates? (2)
20.3 Which of the feeds named above are examples of legumes? (2)
20.4 Which feed has the highest crude fibre content? (1)
20.5 Is the feed you named above usually eaten by non-ruminants? Why or why not? (3)
20.6 Which four feeds have the highest ME content? (5)
20.7 Classify the feeds you identified above as roughage or concentrates. (3)
20.8 For each feed that you identified above, name the feed component that gives it a high metabolisable energy. (4)
ANSWERS
- Chewing, enzymatic action and microbial digestion. (3)
- Saliva has these functions: softening, lubricating and digestion with amylase. (3)
- Bovine stomach compartments:
3.1 Rumen; reticulum; omasum; abomasum. (4)
3.2 Rumen: mixing and absorption; reticulum: regurgitation; omasum: removing water; abomasum: enzyme digestion. (8) - Ruminant regurgitation:
4.1 Feed is chewed, swallowed and then comes up into the mouth from the rumen; after being thoroughly chewed it passes into the reticulum and then the omasum. (4)
4.2 Allows ruminants to eat large quantities of roughage at once, then chew it for digestion later. (3) - Fat, carbohydtaes and proteins. (3)
- Word or phrase:
6.1 Silage/green feeds
6.2 Mineral licks/Lick (2) - Fat, protein, carbs, minerals and vitamins. (5)
- Ventriculus.
- Trace elements:
9.1 Iron and copper. (2)
9.2 Anaemia. (1) - Nutrient deficiencies:
10.1 Zinc
10.2 Vitamin B2;
10.3 Vitamin A
10.4 Calcium
10.5 Selenium (5) - Strength, oxygen, transport, muscle, enzymes. (5)
- Energy for metabolic processes and to grow and reproduce:
12.1 Chemical (1)
12.2 Mechanical and heat energy. (2) - Goat
- Mechanical breaking, heating, additives, pelleting (4)
- High weight to volume ratio, high nutrient levels, low fibre percentage. (3)
- maize meal, sorghum meal, animal meals, milk powder, soy bean meal, oil seed cake (any four) (4)
- Supplement protein in the ruminant diet:
17.1 Because rumen microbes can use them to synthesise amino acids. (2)
17.2 Ruminants can use NPN because rumen microbes can use them to synthesise amino acids which can be used by the animal. (3) - It is a method to calculate the amounts of two different feeds which can be mixed to give a chosen percentage of nutrients. (1)
- Maintenance rations keep the animal body in the same state while production rations are higher in nutrients supplying enough to produce product or offspring. (4)
- Table:
20.1 Blood meal, fish meal, soy and ground nut meal. (4)
20.2 Fish and blood meal. (2)
20.3 Soy and ground nut. (2)
20.4 Veld grass. (1)
20.5 No; they can’t utilise the fibre for energy. (3)
20.6 Sorghum, maize, milk powder, soy meal. (5)
20.7 They are all concentrates. (3)
20.8 Sorghum and maize (starch), milk and soy (protein). (4)