Maharashtra Board Class 11 Animal Science And Technology Chapter 6 Feeds And Feeding PDF Download

6. Feeds And Feeding

Can you recall?

1. Which nutrients are present in our food?

2. Role of proteins, carbohydrates, lipids, vitamins and minerals in animal body.

3. What are the common sources of water for farm animals?

6.1 Feed Nutrients

The animal body derives all its required nutrients for various physiological functions of the body from the food it eats. In order to understand the science of livestock feeding, it is necessary to know certain facts about these feed nutrients, their contents in the feed-stuff and requirements, functions and symptoms of deficiencies in the animals. This topic deals with the basic study of the nutrients like water, proteins, carbohydrates, lipids, vitamins and minerals present in the animal feed.

Feed nutrient is a substance or any food constituent that nourishes the body and helps in maintenance, growth, production and reproduction of an animal.

6.1.1 Water

Though not acting as a source of energy, water ranks far above all other nutrients in the body as regards the rate of turnover and is the most important single nutrient for the regulation of life and required in highest amount. Its shortage adversely affects the productive capacity of the animals, particularly in milk producing animals. In summer cool water has beneficial effect.

Remember: In the absence of water an animal would die comparatively in a short time compared to any other nutrients.

Sources Of Water For Animals

1. Drinking water: This is a major source of water and contributes about 75-80 per cent of the total water requirement.

2. Water available from feeds and fodders: The water content in various feeds of plant origin is taken by the animals through their feeding. Green fodders supply 75 – 90 per cent water, while dry fodders and cereal grains and their by-products provide 8-10 percent, and oil cakes 10-12 per cent water. It contributes about 10-15 per cent of the total water requirement of the animal.

3. Metabolic water: Animals also obtain water resulting from the oxidation of food is called metabolic water. It contributes about 5 – 10 per cent of the total water requirement.

Each gram of carbohydrates, protein and fat yields about 0.6, 0.4 and 1.1ml of metabolic water respectively.

Can you tell? Why animals drink water?

Water plays vital role in almost all life processes. It is the simplest, readily available and cheapest feed nutrient. In cattle, water is approximately 75 to 80 per cent at birth, 68 to 72 per cent at 5 months and 50 to 60 per cent of body weight in the mature animals.

Teacher's Note

Water is very important for all animals. Just like we drink water every day to stay healthy, cows and buffalo also need fresh water for milk production.

Exam Trick

Remember: Without water, animals die faster than without food. Water is needed for everything - digestion, blood, milk production.

Points To Remember

Water is the most important nutrient for animals.
Animals get water from drinking, food, and metabolic processes.
In summer, cool water helps keep animals healthy.
Lack of water reduces milk production in cows.
Water makes up 50-80% of an animal's body weight.

6.1.2. Proteins

Can you recall?

1. Who coined the term "Protein"?

2. Deficiency symptoms of proteins in our body.

Proteins are defined as complex organic nitrogenous compounds consisting of various amino acids joined together by peptide linkage. Chemically, all the proteins contain C, H, O, N and generally sulfur and occasionally phosphorous, iron, zinc and copper.

Classification Of Proteins

On the basis of chemical composition, solubility and shape, proteins are classified as:

1. Fibrous Proteins: These insoluble animal proteins are resistant to animal digestive systems and are composed of elongated, filamentous chains joined up by cross linkages. They are Collagens, Elastins and Keratins.

2. Globular Proteins: This group includes all the enzymes, antigens and hormones having proteins. They are Albumins, Globulins, Lacto globulins, Histones and Protamines.

3. Complex Proteins: These are composed of simple proteins combined with nonproteins substances called 'prosthetic' group. They are Phosphoproteins, Glycoproteins, Lipoproteins, Chromoproteins, Nucleoproteins and Metalloproteins

Functions Of Proteins

1. They are structural and functional unit of animal cell.

2. Being constituent of enzymes, they act as catalytic agents in different kinds of chemical reactions.

3. Proteins stored as amino acids act as food nutrient for growing embryo, e.g. ovalbumin of egg white.

4. They are constituent of haemoglobin and myoglobin which help in transport of O₂ in blood and muscle cells, respectively.

5. Blood plasma proteins viz. thrombin and fibrinogen help in clotting of the blood.

6. They are component of antibodies, e.g. lacto-globulin in colostrum.

7. Keratin (Structural protein) is responsible for giving structure to skin, hooves, feathers.

8. They are important constituents of milk (Caesin) and egg (Albumin).

9. They are the components of hormones like insulin and thyroxine.

10. They act as energy source.

Remember: One gram of protein yields about 4.08 Kcal of energy.

Can you recall? The sources of protein required for your body

Amino Acids

Amino acids are the building blocks of protein structure and determine many of the properties of protein. They are produced when proteins are hydrolysed by enzymes, acids or alkalies.

Plants, ruminants and many micro-organisms are able to synthesize the amino acids and consequently the proteins from simple non-protein nitrogenous compounds (NPN) such as nitrates but monogastric animals cannot synthesize the amino acids in sufficient amounts required to build their body proteins, therefore it must be provided through a dietary source referred as essential amino acids. While some are synthesized in their body and hence need not to be supplied through the diet are referred as non-essential amino acids.

In ruminants all the amino acids required are synthesized in required amounts and proportion by the rumen-micro-organisms, thus making this class of animal independent of a dietary source.

The essential amino acids for the poultry birds are: Threonine, Valine, Leucine, Lysine, Histidine, Arginine, Phenylalanine, Tryptophan, Iso-leucine, Methionine and Glycine.

Internet my friend: Functions of essential amino acids.

Teacher's Note

Proteins are like the building materials of the animal body. Just like we need to eat eggs, milk, and dal to grow strong, animals also need proteins for their health and growth.

Exam Trick

Remember: Amino acids = building blocks of proteins. There are essential amino acids (must get from food) and non-essential amino acids (body can make them).

Points To Remember

Proteins are made of amino acids joined together.
Animals need proteins for growth, milk, and blood clotting.
Essential amino acids must come from food for non-ruminants.
Ruminants can make all amino acids from simple nitrogen compounds.
One gram of protein gives 4.08 kilocalories of energy.

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