- Introduction
- Components of Food Material
- Classification of Animal Feeds
- Compounded Feeds
- Digestion and Digestive Systems
Introduction
- Animals are fed for the purpose of production and body maintenance.
- The edible material given to animals is called food.
- It is digested, absorbed and· utilized in the body.
- Nutrients are organic and inorganic substances contained in the food materials.
Components of Food Material
- Water,
- Protein,
- Carbohydrates,
- Fats and oils,
- Vitamins
- Mineral salts.
Water
Sources
- Free water (through drinking)
- Bound water (contained in feeds).
- Metabolic water (obtained from oxidation of food).
Functions
- Regulates body temperature.
- Transport agent in the body.
- Universal solvent in the body.
- Gives shape to the cells (turgidity).
- Acts as a lubricant.
- Acts as constituent of body fluids.
Factors Determining the Requirements of Water by Livestock
- Production level.
- Amount of dry matter eaten.
- Temperature of the surrounding area.
- Type of animal.
- Type of food eaten.
Protein
Sources:
- Groundnut cakes,
- cotton seed cakes,
- fish meal,
- meat meal.
Functions:
- Growth of new tissues.
- Repair of worn out tissues (body building).
- Synthesis of antibodies.
- Synthesis of hormones and enzymes.
- Production of energy during starvation.
Digestion of Proteins
- In non-ruminants, protein digestion takes placed in the stomach.
- Food is subjected to mechanical breakdown through chewing into small particles.
- Protein is acted on by enzymes to turn into amino acid which is assimilated into the bloodstream.
- In ruminants, protein digestion initially takes place in the rumen.
- Food is acted on by micro-organisms into microbial protein.
- Later, enzymatic action takes place in the "true stomach" or abomasum where proteins are broken down into amino acids which are then assimilated into the bloodstream.
Carbohydrates
Sources:
- Cereals,
- tubers
- commercially mixed feeds.
Functions:
- Supply energy and heat to the body.
- Excess is stored in form of fat for insulation of the body.
Digestion of Carbohydrates
- In non-ruminants;
- carbohydrate feeds are broken down by chewing into small particles.
- Then enzymatic action further breaks down carbohydrates into glucose, fructose and galactose which are then assimilated into the bloodstrea
- In ruminants;
- mechanical breakdown of carbohydrate feeds is followed by microbial activities which break down cellulose into volatile fatty acids.
- These are absorbed through the rumen walls.
- Some carbohydrates are broken down by enzymatic action in the "true stomach" or abomasum.
Fats and Oils
Sources:
- Cotton seeds,
- soya beans
- groundnuts.
Functions:
- Supply energy and heat to the body.
- Excess is stored as fat adipose tissues.
- Source of metabolic water in the body.
- Required for the development of neural system.
- Insulator in the body.
Digestion of Lipids in Ruminants
- Fats are hydrolysed in the rumen into fatty acids and glycerol.
- Others are fermented into propionic acid,
- The shorter chains are passed to the true stomach where enzymatic action takes place.
Vitamins
Sources:
- Green materials,
- dried grass
- fish liver oil.
Functions:
- Protects the body against diseases.
- Regulate the functions of all parts of the body.
- It acts as a co-enzyme in the body.
Examples:
- Vitamin A,
- vitamin B2
- vitamin C,
- vitamin E
- vitamin K.
Minerals
Sources:
- Salt licks,
- bone meal,
- legumes
- cerea
Functions:
- Form part of the tissues such as bones and teeth.
- Work together with the enzymes.
- Act as acid -base balances.
- Act as electrolyte in the body.
- Regulate osmotic balance in the body.
Examples:
- Calcium,
- phosphorus,
- magnesium,
- iron,
- iodine,
- sodium
- chlorine.
Calcium and phosphorus -
- Needed for teeth and bone formation.
- Lack of these minerals leads to rickets, osteomalacia.
- Lack of iron leads to anaemia.
Classification of Animal Feeds
- This is based on nutrient composition:
- Roughages.
- Concentrates.
- Feed additives.
Roughages
- Are feeds of low available nutrients per unit weight and high fibre content.
Examples:
- Dry roughages,
- succulent roughages,
- residues from agricultural by products and conserved materials.
Characteristics
- Low level of available nutrients.
- Have high level of calcium especially legumes.
- Good source of vitamin A.
- Have high fibre content.
Concentrates
- Are feeds of high available nutrients per unit weight.
Examples:
- Maize germ and bran,
- malt extract,
- milk products,
- soyabeans,
- oil seed cakes,
- meat meal,
- bonemeal
- bloodmeal.
Characteristics
- Low fibre content.
- Feed content is consistently high.
- High digestibility of the feed.
- High in nutrient content.
Feed Additives
- These are substances added to the feed to increase;
- palatability,
- medication
- or hormones to make animals produce more.
- There are two types:
- Nutritive additives, such as mineral licks (maclick).
- Non-nutritives additives, such as;
- medicants (coccidiostats),
- Stilboestrol (used in beef animals)
- oxytocin (to increase milk let down).
Functions
- Stimulate growth and production.
- Improve feed efficiency.
- Prevent disease causing organisms.
Compounded Feeds
- These are the feeds prepared and mixed by use of machines.
- These feeds can be round, pelleted, pencils, cubes or mash.
Classification of Poultry Feeds
- Chick mash having 20% D.C. given to chicks.
- Growers mash having 16% D.C. given to growers.
- Layers mash having 12-15% D.C.P. given to layers.
Terms used to Express Feed Values
- Nutritive ratio (NR):
- Is the proportion of protein to carbohydrates and fats.
- In young animals 1:3:6
- In old animals 1:8.
- Crude protein (C.P): Is the total amount of protein contained in a feed.
- Digestible Crude Protein (D.C.P): Is the portion of crude protein which an animal is capable of digesting.
- Crude Fibre (C.F.):
- Is the total amount of fibre contained in a feed.
- It is mainly lignin and cellulose.
- Digestible Fibre (D.F.): Is the portion of the total fibre contained in a feed which an animal is capable of digesting.
- Dry Matter (D.M.): Is the material left in a feed after water has been removed.
- Starch equivalent (S.E.): Is the amount of pure starch which has the same energy as 100kg of that feed.
- Total Digestible Nutrients (T.D.N.): Is the sum of all the digestible organic nutrients such as fats, proteins, carbohydrates and fibre.
Computation of Livestock Rations
- Ration:
- Is the amount of food that will provide essential nutrients to an animal in a 24 hour period to enable that animal to meet its maintenance and production requirements.
- Balanced ration:
- Is the ration that contains all the essential nutrients in required amounts and in the right proportion.
- Maintenance ration:
- is the portion of a feed required by an animal to continue with the vital body processes with no loss or gain in weight.
- Production ration:
- Is the feed required by animals over and above maintenance ration to enable the animal to produce;
- for example; milk, eggs, wool, grow in size, perform work, reproduce and fatten.
Steps in Ration Formulation
- Finding out the animal's feed requirement based on body weight.
- List all the available feeds, with their nutrient composition and their prices.
- Calculate the amount of ingredients required in the ration to meet the animals needs.
Methods used in Ration Formulation
- Trial and error method
- Pearson’s square method
- Graphical method
- Linear programming(use of computers)
Examples;
Mix a Pigs ration 22% protein using soya bean meal 40% DCP and maize meal containing 8%DCP.
Soya bean meal (14 × 100) = 43.75kg
32
Maize meal (18 × 100) = 56.25kg
32
Digestion and Digestive Systems
- Digestion is the process through which food is broken down into small particles in the alimentary canal ready for absorption into the blood stream.
- Digestion of food in livestock takes place in three stages;
- Mechanical breakdown and chewing
- Microbial breakdown by bacteria and protozoa in the rumen of ruminants
- Chemical breakdown by enzymes.
Digestive System of a Ruminant
Rumen
- Breakdown of food by micro-organisms and also stores food.
- Synthesis of vitamin B-complex.
- Synthesis of amino acids from ammonia gas.
- Proteins are broken to peptides and amino acids.
- Carbohydrates are broken to volatile fatty acids.
Reticulum:
- Separates large food particles from the small particles.
- Retains foreign materials such as stones, hard wood and sand.
Omasum:
- Breaks up food by grindin
- Reduction of water content from the feed stuff.
Abomasum:
- Enzymatic digestion takes place here ..
- Contains some microbes which digest cellulose.
- Breaks up food by grinding.
- It is also found in non-ruminants.
Digestive System of a Non-Ruminant
Comparison Between Digestion in Ruminant and Non-ruminants
Differences
Ruminants | Non-ruminants |
|
|
Similarities Between Digestion In Ruminants and Non-Ruminants
- Digestion in young ruminants is similar to that in non-ruminants as they do not have a developed rumen-reticulum complex.
- Final protein digestion takes place in the small intestines in both cases.
- Water absorption takes place in the colon in both ruminants and non ruminants
Digestion System of Poultry
Functions of the Parts of Poultry
Crop:
- Storage of food.
- Softening of food by secretions from small glands in the walls.
Proventriculus: Enzymes start the breakdown of food.
Gizzard:-Crushes and grinds the coarse food (has small grit and gravel).
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