LIVESTOCK PRODUCTION II (NUTRITION)
LIVESTOCK PRODUCTION II (NUTRITION).COMPONENTS OF FOOD.
Water.
Accounts for 50% in mature animals.
Functions of water in an animal.
- Component of body cells and many body fluids such as blood.
- Responsible for transportation of nutrients from one part of the body to another.
- Makes cells turgid maintaining the shape of body cells.
- Used in biochemical reactions in the body e.g. digestion of food.
- Helps to regulate body temperatures through sweating and evaporation.
- Helps in excretion of waste products from the body.
- Forms part of animal’s product e.g. milk 83% water and an egg 55% water.
Sources of water.
- From drinking. Known as free water. Available in rivers, wells etc.
- From food. Known as bound water. Released from the food during digestion. Succulent feeds contains more of this water.
- From metabolism. Known as metabolic water. Produced when food is oxidised in the body cells during respiration.
Factors determining amount of water required by an animal.
- Ambient temperature. Animals need more water when it is hot due to high rate of sweating.
- Type of feed eaten by an animal. Animals drink a lot of water when it eat dry feeds
e.g. Hay than when they eat succulent feeds.
- Level of production/amount of work done. Animals producing milk or eggs require more water because it is a constituent of those products. Draught animals lose a lot of water hence need to drink more.
- Weight of the animal/body size. Fat and heavy animals requires more water than lean and light animals because metabolic rate is higher in heavy animals.
- Species of the animal. Under same environmental conditions , cattle requires more water than camel as the camels physiological make up makes it able to resist drought. Camel has tissues tolerant to dehydration.
LIVESTOCK PRODUCTION II (NUTRITION)
Carbohydrates.
Organic compounds that contains carbon, hydrogen and oxygen. Are the chief source of energy.
C6 H12O6 + 6O2 Energy + 6 CO2 + 6H2O
Glucose Oxygen carbon iv oxide water.
- Monosaccharides
Simple sugars such as galactose, glucose and fructose. Contained in small quantities in ripe fruits, honey and blood meal.
- Disaccharides
Formed by the combination of two simple sugars. Naturally occur as sucrose and lactose.
- Polysaccharides
Consists of many simple sugars molecules that form a complex molecular structure.
Examples include: glycogen, starch, cellulose, and lignin. They forms the bulk of CHO in animal feeds.
Sources of carbohydrates
- Grains of cereals and their by-products.
- Roots of crops such as sweet potato and cassava.
- Tubers such as Irish potatoes.
- Molasses- a by- product of sugar manufacturing industry.
- Pastures(grains and legumes) Functions of carbohydrates.
- Supply energy for all body process.
- Used in synthesis of products such as milk, meat, wool and eggs.
- Excess CHO are converted into fats and stored for later production of energy.
Fats and oils.
Organic compounds containing carbon, hydrogen and oxygen.
Sources of fats and oils.
- Oil seeds by-products such as cotton seed cake, sun flower seed cake, groundnut seed cake, coconut seed cake.
- Animal products and by-products such as milk, bone, meat and fish, meal.
- Pasture foliage.
Functions of fats and oils.
- Supply energy to animals after being oxidised in body tissues.
- Excess fat is stored in the body under the skin, hump etc.
- Excess fat is metabolised into energy and metabolic water.
LIVESTOCK PRODUCTION II (NUTRITION)
Proteins.
Organic compounds containing carbon, hydrogen, oxygen, nitrogen, sulphur and phosphorous.
Broken up during digestion into amino acids. Makes up 20% of animals tissues.
Types of amino acids.
- Essential amino acids. Amino acids that cannot be manufactured/synthesised in the body and must be supplied in the diet.
- Non-Essential amino acids. Amino acids that can be manufactured/synthesised in the body thus no need of supplying them in the diet.
Sources of proteins.
- Seed cake from sun flower, groundnut, cotton, simsim etc.
- Foliage from leguminous plants such as Desmodium , Lucerne, clovers etc.
- Animal products and their by-products e.g. milk, meat and blood meal, liver and fish meal.
- Young green grass.
Functions of proteins (amino acids)
- Growth, repair and replacement of worn out body tissues.
- Production of antibodies that protect the animal from diseases.
- Production of digestive enzymes to break food particles.
- Production of certain hormones in the body.
- Production of products such as meat, milk, eggs and wool.
Insufficient protein causes:
- Retarded growth.
- Low production.
- Low fertility.
- Poor resistance to diseases.
- Wearing out of body tissues.
Vitamins.
Organic compounds needed in the body in small amounts.
Fat soluble vitamins. (ADEK) vitamin A, D, E and K. Water soluble vitamin. Vitamin C, B complex (B1, B2 and B12) Sources of vitamins.
Grass ,grains.
Vitamin A.
Common in fresh grass, milk and cod liver oil.
Helps in prevention of disease and needed for proper growth.
Deficiency.
- Retarded growth.
- Poor eye sight.
- Reduced resistance to diseases.
Vitamin B complex.
Found in whole grains and their by-products. Synthesised by micro-organisms in the rumen of ruminant animals.
Include:
- B1(thiamine)
- B2(riboflavin/lactoflavin)
- B6 (Pyridoxine) Ø B12 (Cyanocobalamin) Ø Folic acid.
- Ø Biotin.
Deficiency.
- Retraded growth.
- Slow heartbeat.
- Reduced resistance to disease attack.
- Poor reproduction.
- Vitamin B2 deficiency causes curled toe paralysis in poultry.
LIVESTOCK PRODUCTION II (NUTRITION)
Vitamin C (Ascorbic acid) Increases resistance against diseases.
Source: green seeds and fruits.
Deficiency.
- Defective bones and teeth.
- Continuous bleeding of fresh wounds. Ø Sore gums.
Vitamin D.
Sources: sunlight, milk and green grass.
Helps in bone formation.
Deficiency.
- Rickets, softness of bones, weak teeth.
- Production of soft shelled eggs. Ø Enlarged joints.
Vitamin E.
Found in whole grains and green vegetation.
Helps in reproduction.
Deficiency.
- Sterility
- Premature birth(abortion) Vitamin K.
Helps in blood clotting.
Sources.
- Green feeds e.g. fresh grass and Lucerne. Ø Synthesised by intestinal bacteria.
Deficiency.
Excessive bleeding of open wounds.
FUNCTIONS OF VITAMINS.
- Promote growth.
- Helps in blood clotting.
- Helps in bone formation.
- Helps in muscular contraction.
- Prevent diseases in animals.
- Acts as organic catalysts in various metabolic and physiological reactions.
MINERALS.
Needed in small amounts. Livestock under grazing system do not get sufficient minerals thus need to be supplemented.
Mineral requirements vary with age and level of production.
Young animals requires more calcium and phosphorous for milk synthesis.
Mineral in excess is detrimental thus need to be supplied in proper amounts.
Include:
Essential:
Calcium, phosphorus, potassium, magnesium, iron, sodium, manganese, sulphur, iodine, copper, cobalt, molybdenum, selenium, zinc and chlorine.
Calcium and phosphorus.
Needed in formation of strong bones and teeth.
Deficiency.
- Deficiency in lactating cows leads to milk fever.
- Oesteomalacia and rickets. Characterised by: softness of bones, loss of weight and muscular weakness.
- Calcium deficiency in poultry leads to soft shelled eggs or eggs without shells.
- Pica: depraved appetite when phosphorous is missing in the animal’s diet. Characterised by the animal chewing wood, bones and rocks. Bones are brittle and can easily fracture.
Sources.
Milk, meat, bone meal.
Ground limestone and oyster shell in poultry diet.
Magnesium.
Important for healthy bones and teeth.
Activates metabolic enzymes.
Important for proper functioning of the nervous system.
Sources.
- Leafy vegetables.
- Cereal grains.
Deficiency.
Grass tetany/grass staggers/hypomagnicemia. Characterised by dizziness and staggering.
Animals on lush grass are more vulnerable than those on older pastures.
LIVESTOCK PRODUCTION II (NUTRITION)
Iron.
Found in haemoglobin in RBC.
Deficiency results in anaemia. Common in piglets as they are born without iron and the sow’s milk has inadequate supply of iron.
Sources.
Cereal grains, green vegetables, fish and liver meal.
Copper.
Important in blood formation.
Improves the feed conversion rate in calves and piglets.
Improves uptake of iron in the body.
Deficiency.
Enzootic neonatal ataxia/swayback in lambs.
Sources.
Grain legumes, cereals and green herbage.
Iodine.
Helps in formation of thyroxine that regulates metabolic rate in the body.
Deficiency.
Causes goitre.
Source.
Salt licks.
Sulphur.
Necessary in the manufacture of sulphur containing amino acids.
Deficiency.
Loss of wool in sheep and feathers in poultry.
Sources.
Proteinous feedstuffs.
Zinc.
Helps the enzymes to function.
Deficiency.
Parakeratosis. Characterised by:
Unhealthy appearance, rough coat, stiffness of joints, dry scaly skins on the ears, cracking of skin around the nostrils.
Sources.
Green herbage, liver meal, mineral licks, cereal grains and meat meal.
Cobalt.
Used in the synthesis of vitamin B 12.
Increases the appetite of ruminants.
Deficiency.
- Reduced growth rates.
- Premature births. Ø Scaly skins.
- Low milk yields.
Manganese.
Activates enzymes used in metabolism of carbohydrates, proteins and fats.
Deficiency.
- Delay of sexual maturity in females.
- Irregular ovulation.
- Reduced hatchability in birds, reduced shell thickness and head retraction in chicks.
Sodium, potassium and chlorine.
Functions.
- To maintain osmotic pressure and acid-base equilibrium.
- Control movement of nutrients in cells. Ø To regulate water metabolism.
Deficiency.
- Reduced appetite.
- Loss of weight.
- Decreased production of eggs, meat and wool.
Sodium is important in muscular contraction.
Deficiency.
Low egg production.
Cannibalism.
LIVESTOCK PRODUCTION II (NUTRITION)
FEEDS AND FEEDSTUFFS.
Feedstuff.
Food material that’s contain one or more nutrients.
Feed.
Mixture of several feedstuffs which supply the required nutrients to animals.
Feedstuff classification.
Based on nutrient contained or bulkiness of the feedstuff.
Include:
Roughages.
Concentrates.
Roughages.
- Feedstuff with a high fibre and CHO content.
- Low in protein content.
- Low digestibility.
- Originates from plant.
Facilitates digestion.
Types of Roughages.
Ø Succulent roughages. Ø Dry roughages.
Succulent roughages.
Includes: fresh grass, silage, napier grass.
Characteristics.
- High fibre content.
- High moisture content.
- Low protein content.
- High CHO content.
Dry roughages.
Plant materials which contains very little moisture.
Includes: straw, hay and maize stalks.
Have low feed value.
Concentrates.
Feedstuff with high amount of proteins or energy (CHO) and low in crude fibre.
Form the main part of diet for no-ruminants animals such as poultry and pigs.
Supplement diet of ruminants’ animals especially when in production or being fattened.
Types of concentrates.
- Energy concentrates. 2. Protein concentrates.
Energy concentrates.
Contains high percentage of carbohydrates. Supply animals with energy.
Sources.
- By-products of flour mills such as: bran, germ meal and pollard.
- By-products of breweries such as: dried grain sprouts and malt extract.
- By-products of sugar industries e.g. molasses.
- Whole grains such as: wheat, barley, oats, sorghum and maize.
Protein concentrates.
Have a high protein percentage in their dry matter.
Sources.
Plant origin.
Oil seed cake such as: cotton, groundnuts, sunflower and simsim.
Animal origin.
Meat meal, bone meal, fish meal, milk and milk products such as whey, skim milk.
Minerals and vitamin supplements.
It is recommended that mineral supplements be provided in form of mineral licks such as maclick in lactating animals.
Feed additives.
Special substances which are added to the livestock feeds in small quantities.
Includes: hormones such as stilbestorl, antibiotics e.g. tetramycine, and medicants such as coccidiostats.
Feeding of livestock.
Concept of rationing.
Ration. Daily amount of food given to an animal to cater for both maintenance and production requirements.
Maintenance ration. Daily feed allowance per animal containing all the nutrients in right proportions to sustain all the body process without losing or gaining weight.
LIVESTOCK PRODUCTION II (NUTRITION)
FACTORS AFFECTING MAINTENANCE REQUIREMENTS.
- Body size/weight of the animal.
A large animal uses more energy to sustain essential body process.
- Age of the animal.
Minimum energy required for maintenance of a young animal is more than for an older animal.
- Animal’s activities.
Active animals need more energy for maintenance since their body mechanisms are always active.
- Level of production.
High producers need more for maintenance requirements.
Production ration.
Daily amount of feed given to an animal over and above the maintenance requirement and contains all the nutrients in the proper proportion for the purpose of production.
Balanced ration.
Daily feed allowance per animal inn correct amounts and contains all the nutrients in the right proportion.
The amount of feed given to an animal depends on:
Body size or weight of the animal.
Environmental condition within which the animal is.
Physiological condition of the animal.
Level of production.
Purpose for which the animal is kept.
Rationing.
Practice of giving known amount of feed to livestock. E.g. sow 2.5kgs of sow and weaner plus an extra 0.25kgs per piglet per day.
Terms used to express feed values.
Digestibility.
Portion of food retained in an animal’s body after taking care of losses through urine, faeces and gases. It is measured as a percentage.
Percentage digestibility= (feed retained/feed intake) X 100.
Apparent digestibility= (feed intake-waste products (faeces+ urine)/dry matter in feed Factors affecting digestibility.
- Chemical composition of the feed. g. %age of lignin or cellulose influence digestibility.
- The form in which the food is offered to the animal. For example crushed maize is more digestible than whole maize.
- The species of the animal. g. digestibility of grass is higher in sheep than in pigs.
- The ratio of energy: protein. The higher the ratio the lower the digestibility.
- The quantity of feed already present in the digestive system of an animal.
Dry matter.
Actual percentage of proteins, CHO, and minerals in a feed.
The higher the dry matter content in a feed, the higher the nutritive value (depending on the digestibility of the dry matter.) Calorific value.
Calorie. Amount of energy required to raise the temperature of one gram of water through 1 degree Celsius.
Calorific value. Measure of energy used to express the energy of foods.
Bomb calorimeter. Apparatus for determining the gross energy of a feedstuff.
Starch equivalent.
Energy value of a feed that is equivalent to the net energy of a certain amount of pure starch.
For example, a feed with 70% starch equivalent means that 100kgs of the feed produce a net energy equivalent to energy produced by 70kgs of pure starch.
Total Digestible Nutrients. (TDN)
Sum total of all the digestible nutrients in a feed. That is sum total of digestible proteins, CHO and fats.
N/B: Energy value of fat is 2,25 times that CHO and proteins thus during feed computation, the energy value of fat should be multiplied by 2.25.
Crude protein. (CP)
Sum total of all nitrogenous compounds in a feed.
Digestible crude protein. (DCP)
Express the percentage of the proteins absorbed from a feed by an animal’s body.
Crude fibre. (CF)
Includes cellulose and other CHO that are so resistant and insoluble that they are not dissolved by weak acids and alkalis. Feeds with a high crude fibre are less digestible.
Computation of livestock feeds.
Ways of computing rations:
- Trial and error method.
- Pearson’s square method.
- Graphical method.
LIVESTOCK PRODUCTION II (NUTRITION)
Trial and error method.
A farmer may mix feeds in various proportion, give them to the animal and watch the animals response thus gain experience on the right proportion of various animals’ feeds to use when computing rations.
Pearson’s square method.
Used when two feedstuffs are available for mixing to get the desired feeds.
Conditions for its use.
- Percentage of nutrient to be obtained must be specified.
- Values of the nutrients contained in the two feedstuff must be known in percentage form.
- One of the feedstuff must have a lower nutrient percentage than the desired nutrient.
Procedure.
Draw up a square.
Write the percentage of the protein required in the feed at the centre of the square.
Draw the diagonals of the square.
Write the protein values of the feedstuffs to be used at the left corners of the square.
Substart diagonally across the square the small numbers from the large one regardless of the sign and write the resultant values at the right corners of the square.
The resultant number on the right side of the square gives the parts of each of the feedstuffs needed to make the intended ration.
Add the parts to obtain the base of each feedstuff to be used in the feed
Digestion and digestive systems of farm animals.
Nutrient components in the food eaten by animals are in form of complex insoluble molecules.
Digestion.
Process of breaking down food materials into simple substances.
Absorption.
Movement of digested food substances across the intestinal wall to the blood stream.
Food is mechanically digested through masticatory activities and the muscular contraction of the walls of the alimentary canal.
Chemical action of food is arrived at by enzymes secreted by the animal in various digestive juices.
Microbial digestion of food (also enzymatic) is carried out by the action of bacteria and protozoa in digestive tract. (Mostly in ruminant animals)
The general process of digestion
Digestion in the mouth.
Food is chewed by the teeth and mixed with saliva.
Saliva is secreted by: parotid, sub-maxillary and sublingual glands.
Saliva contains 99% water, 1% mucin and amylase.
Salivary amylase converts starch to maltose.Digestion in the stomach.
Stores food temporarily before it proceeds to the intestines.
Food is churned and mixed up.
Gastric juice (produced by gastric gland) contains dilute Hcl, enzymes (pepsin and renin) Role of Hcl.
Ø Creates a suitable acidic medium for the action of enzyme pepsin. Ø Kills harmful micro-organisms that may be present in the food.
Pepsin. Breaks proteins into proteases and peptones.
Renin. (Found in young animals) coagulates milk to increase surface area for the action of enzyme pepsin.
Digestion in small intestines.
Divided into three parts.
- Duodenum.
Bile and pancreatic ducts empty their contents in the duodenum.
Role of bile.
Contains sodium and potassium salts that neutralises acidity of food created by Hcl in the stomach.
Emulsifies fats into globules (droplets) increasing surface area for fats and oil digestion. Acts as a catalyst in digestion of fats and oils.
Pancreatic juice contains:
- Pancreatic amylase. Converts starch to maltose.
- Converts fats to glycerol and fatty acids.
- Converts proteins to peptones and peptides.
- Jejunum.
The intestinal juice produced by the gland cells in the jejunum contains the following enzymes:
Erepsin (peptidase). Converts peptones and peptides to amino acids.
Maltase. Converts maltose to glucose.
Lactase. Converts lactose to glucose.
Ileum.
Has villi which increases surface area for absorption. The final products absorbed are shown below.
Food material | Final product. |
Carbohydrates. | Glucose. |
Proteins. | Amino acids. |
Fats &oils | Fatty acids. |
In ruminants, fatty acids and Ammonia gas are absorbed in the rumen.
Digestion in large intestines.
Consist of caecum, colon and rectum.
Cellulose is broken through microbial activity in caecum and the volatile fatty acids released are absorbed through the caecum. Water absorption is mainly done in large intestines.
The anus.
Waste materials from large intestines are got rid of through the anus.
LIVESTOCK PRODUCTION II (NUTRITION)
Digestion in monogastric animals (Non-ruminants )
Do not chew cud and have one simple stomach. Include: pigs, poultry camels, donkeys and horses.
Digestion in pigs.
Food is chewed, ground and mixed thoroughly with saliva. Saliva softens food to make it easy to swallow.
Salivary amylase converts starch to maltose. In the stomach food is acted upon by the various enzymes that break down proteins. It then enters the small intestines via the pyloric sphincter.
Digestion in rabbits.
Rabbits, horses and camel are monogastric though they can handle a large amount of roughage. They have a large caecum which contains micro-organisms that break down cellulose in roughages.
Digestion in poultry.
Has no teeth and the mouth is modified into a beak that pecks food.
Food is swallowed whole to the crop which is an enlargement of the oesophagus.
Functions of the crop.
- Stores food temporarily.
- Moistens food with water.
Food then proceeds to the proventriculus (acts as true stomach)
Pepsin is produced in the proventriculus but the food passes quickly to the gizzard.
Gizzard.
Equipped with tough muscles on each side. The sliding movements of the muscles crush and grind food into paste.
Modification of the gizzard.
- Has grit (sand) which helps in the grinding of food.
- Has, muscular walls whose movement helps to grind food.
It is therefore important to provide grit to housed birds for efficient digestion of food in the gizzard. E.g. oyster shells which also supply calcium in the diet.
Food then proceeds to duodenum (refer to general digestion mechanism)
Poultry have a large caecae that has micro-organisms to digest cellulose. It also absorbs water and by-products of microbial digestion.
Poultry produce solid urine attached to the faecal matter. The solid urine (uric acid) seen as white patches on the faecal matter makes the droppings more rich in nitrogen compared to other animals.
Digestion in polygastric (ruminant) animals
They chew cud. Include: cattle, goats and sheep.
The stomach is divided into four compartments namely: rumen, reticulum, omasum and obomasum.
No enzymatic digestion take place in the mouth as they do not have ptyalin in their saliva.
Rumen.
Also known as pauch. Large and is the first stomach compartment.
Acts as a temporal store of food before being regurgitated to the mouth for further chewing.
Digestion is microbial.
Food is fermented; a condition necessary for microbial digestion.
Microbial activities in the rumen.
- Fermentation of food.
- Synthesis of vitamin B complex (Thiamine, Lactoflavin, Pyridoxine. And vitamin K.
- Synthesis of amino acids from ammonia gas.
- Breakdown of proteins to peptides, amino acids and ammonia.
- Breakdown of carbohydrates and cellulose to CO2 , and volatile acids such as acetic, butyric, propionic and formic acids.
- Ammonia gas and volatile fatty acids are absorbed through the wall of the rumen.
- Ammonia is recycled through the liver to saliva making saliva alkaline.
- Gases like methane, CO2 ,and hydrogen are released through bleaching.
Reticulum/honey comb.
Has a comb-like structure. Receives food from the mouth after regurgitation.
Oesophageal groove. Skin fold at the entrance of the rumen which closes to let food into the reticulum.
Functions of reticulum.
- Sieving and separating fine from coarse food materials.
- Retaining foreign and indigestible materials such as polyethene papers, wires which might have been swallowed accidentally.
Omasum (many piles/book)
Contains many suspended parallel rough-surfaced leaves that lie on top of each other like pages of a book.
Functions.
- Absorbs water and to grind and sieve food particles. Ø Temporal storage of food.
Abomasum/true stomach.
Known as true stomach because enzymatic digestion of proteins takes place here like in nonruminants.
COMPARISON BETWEEN DIGESTION IN RUMINANTS AND NON-RUMINANTS.
Ruminants. | Non-ruminants. |
1. Chew cud. | 1. Do not chew cud. |
2. Has four stomach chambers thus polygastric. | 2. Has one stomach chamber thus monogastric. |
3. Regurgitate food. | 3. Cannot regurgitate food once swallowed. |
4. Can digest cellulose. Have microorganisms in the rumen that digest cellulose. | 4. Have no micro-organisms in the stomach hence cannot digest cellulose expect those animals with micro-organisms in the caecum. |
5. Have no ptyalin in saliva hence no enzymatic digestion in the mouth. | 5. Have ptyalin in saliva hence enzyme digestion start in the mouth. |
6. Most digestion and absorption takes place in the rumen. | 6. Most digestion and absorption takes place in small intestines. |
7. Have alkaline saliva due to presence of ammonia. | 7. The saliva is neutral in pH. |
Similarities.
- Digestion in young ruminant is similar to that of monogastric as they don’t have a developed rumen-reticulum complex.
- The final protein digestion takes place in the small intestines.
- Water absorption takes place in the colon in both ruminant and non-ruminants.
LIVESTOCK PRODUCTION II (NUTRITION)
ALL AGRICULTURENOTES FORM 1-4 WITH TOPICAL QUESTIONS & ANSWERS
PRIMARY NOTES, SCHEMES OF WORK AND EXAMINATIONS