Vitamins & Minerals Functions in livestock feeding - PowerPoint Presentation

Slide1

Vitamins & Minerals

Functions in livestock feedingSlide2

Vitamin Facts

Vitamins are essential organic nutrients, required in small amounts.They cannot be synthesized by the body. Must be obtained by outside sources like diet, rumen bacteria & sun.

Required for growth, maintenance, reproduction and lactation.Slide3

Classes of Vitamins

Fat Soluble Vitamins:

stored in tissues

Examples

A

DEK

Water Soluble Vitamins:

not stored in tissues, must have constant supply

Examples

B, B1, B2, B6 & B12

Niacin

Folic Acid

CSlide4

Vitamin A

Active forms are retinol,

retinaldehyde

, and retinoic acid

Plants synthesize the more complex carotenoids which are cleaved to retinol by most animals and stored in the liver as retinyl palmitate

N retinol plasma values: 15-30 mcg/dl in infants & 30-90 mcg/dl in adultsSlide5

Function, Deficiency Signs & Sources

Vitamin A

Function:

development healthy skin and nerve tissue. Aids in building up resistance to infection. Functions in eyesight and bone formation. ALL ANIMALS require a source of Vitamin A. It is important in the ration of pregnant females.

Deficiency signs:

retarded growth in the young, the development of a peculiar condition around the eyes known as

Xerophthalmia

, night blindness and reproductive disorders.

Sources:

whole milk, carotene, animal body oils (cod fish and tuna), legume forages and can be synthetically produced.

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Hypovitaminosis ASlide8

Vitamin E

Function:

normal reproduction.

Deficiency signs:

poor growth, "crazy chick" disease, Muscular Dystrophy, "white muscle" disease in ruminants and swine and "stiff lamb" disease (affects the nerves and muscles).

Sources:

synthetic for poultry and swine, cereal grains and wheat germ oil, green forages, protein concentrates, oil seeds (peanut and soybean oil).

Vitamin E rapidly destroyed in rancid or spoiled fats. That is why these may cause white muscle disease. Utilization of Vitamin E is dependent on adequate selenium.Slide9
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Vitamin D

The animal form is vitamin D3 (

cholecalciferol

) and the plant form is vitamin D2 (

ergocalciferol

). Vitamin D2 and D3 are not biologically active; they must be modified in the body to have any effect.

The active form of vitamin D is indeed a hormone and is known as 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] or calcitriol. (Feel free to use that as a conversation starter the next time you’re picking up a hot date.) Both vitamin D2 and D3 have been commercially synthesized and both forms seem to be effective at maintaining blood levels of vitamin D in the body.Slide11
Slide12

Vitamin D

Function:

is essential for the proper utilization of calcium and phosphorus to produce normal, healthy bones.

Deficiency signs:

retarded growth, misshapen bones (rickets), lameness and osteoporosis.

Sources:

Whole milk, sun-cured hays, forage crops, fish liver oils, irradiated yeast. Slide13

Osteomalacia

A young male w/ osteomalacia. Note a pseudofracture in the medial edge of the upper femoral shaft (arrow).

Xray showing a pseudofracture (red arrow) from an adult who has x-linked hypophosphatemic rickets. This sign is seen only in osteomalacia, but not in many of the cases.

AP pelvis in a patient w/ osteomalacia. The film shows diffuse osteopenia, & a Looser zone (arrow) in the superior ramus of the right obturator ring. Slide14

RicketsSlide15
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Vitamin K

Vitamin K

1

,

naturally occurring vitamin K, is abundant in pork, liver, soybeans & green leafy vegetables

Intestinal microorganisms synthesize

Required for normal clotting of blood

Vitamin K-dependent clotting factors made in the liver: prothrombin, proconvertin (Factor VII), plasma thromboplastin component or PTC (Factor IX) & Stuart-Prower factor (Factor X)Slide17

Vitamin K

Function:

necessary for the maintenance of normal blood coagulation.

Deficiency signs:

blood loses its power to clot or the time needed for clotting is longer and serious hemorrhages can result from slight wounds or bruises. Sources:

green leafy forages, fish meal, liver, soybeans, rumen and intestinal synthesis, and the synthetic compounds.

Slide18
Slide19

Vitamin K Deficiency (Hypoprothrombinemia)Slide20

RELAX !!!Slide21

Second LectureSlide22

Vitamin Classification

Fat soluble vitamins A, D, E, KWater soluble vitaminsVitamin C

B-complex vitamins

Thiamine (B1), Riboflavin (B2), Niacin(B3), B6 Pyridoxine, B12

Cyanocobalamin

, Folic Acid,

Choline, Pantothenic Acid(B5), BiotinSlide23

Vitamin C (Ascorbic acid)

Function:

has an effect on the metabolism of calcium in the body (Not required in rations of farm

animals except in poultry .).

Important role in various oxidation-reduction mechanisms in living cells, electrontransport,

Impt for normal collagen metabolism, imprtance to convert of hydroxyproline

from

proline

&

hydroxylysine

from lysine

Deficiency

signs:

none demonstrated in livestock. Human deficiency: scurvy (swollen and painful joints and bleeding gums) and brittleness of bones.

Sources:

citrus fruits, tomatoes, leafy vegetables and potatoes.

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Vitamin B

1

(Thiamin)

Function:

required for the normal metabolism of carbohydrates.

Deficiency signs:

loss of appetite, muscular weakness, severe nervous disorders, general weakness and wasting (

BeriBeri

).

Chicks: polyneuritis (nerve degeneration and paralysis)

Sources:

raw, whole grains and especially their seed coats and embryos; fresh green forage; and yeast, milk and rumen synthesis

.

Some feeds (bracken, raw fish) contain

thiaminase

which destroys thiamin.Slide26
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Slide28

Vitamin B

2

(Riboflavin)

Function:

necessary for normal embryo development, important in the metabolism of amino acids and carbohydrates.

Deficiency signs: poor reproduction characterized by small litters and deformed young (cleft palate and club-footedness) curly toe paralysis in chicks, digestive disturbances, general weakness and eye abnormalities.

Sources:

milk and dairy by-products, yeast, green forages, well cured hay (especially alfalfa), whole grains, wheat bran and synthetic riboflavin rumen synthesis

.

Cereals are a poor sourceSlide29
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Niacin(B3) Nicotinic acid )Slide31

Niacin Deficiency

Pellegra in Humans“Black tongue” in dogsPigs and chicken

– poor growth, enteritis,

dermititisSlide32

High corn diets are a problem because corn contains little niacin OR tryptophanSlide33
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B6 PyridoxineSlide35

B6 Main Functions

Amino Acid Decarboxylation and DeaminationC-COOH -- C COOH

C-NH2 ----- C NH2Slide36

B6 Deficiency

Poor Growth, etc.ANEMIANervous symptoms – convulsionsDemyelinization of peripheral nerves

Other degenerative changes

Reduced antibody response

Needed for normal reproductionSlide37

Pantothenic AcidSlide38

Pantothenic Acid(B5)

Function :-Component

of Coenzyme A

Fatty Acid breakdown

CHO oxidation

Therefore – to use energy

!!!Deficiency:- Goose Stepping in pigsNervous incoordinationDiarrheaLoss of hair, skin problems

Poor growth, etc.

Sources:-

widely distributed in plants and not a serious problemSlide39

Choline

Function :- component of fats and nerve tissues

Deficiency:-

Slow Growth, Fatty Liver, PEROSIS (also

Mn

), Reduced litter size in pigs

Therefore add extra to sow’s diets and poultrySouces:- soy bean and meal Slide40

B12 Cyanocobalamine

Function:-

Synthesis of RNA and DNA

Chemistry of Methyl Groups

Deficiency :-

Pernicious AnemiaPernicious means “leading to death”All the symptoms of starvationSources:- animal protein , fermintation product,Slide41

Mineral Facts

Essential inorganic nutrients, required in small amounts.As many as 20 minerals may be required!Required for growth, maintenance, reproduction and lactation.Slide42

Who is Cap. KS Naclmg?

The MacromineralsCalcium CaPhosphorous P

Potassium K

Sulfur S

Sodium Na

Chlorine Cl

Magnesium MgSlide43

Calcium (Ca)

Function:

major component of bones and teeth and essential in blood coagulation, nerve and muscle function and milk and egg production.

Deficiency signs:

retarded growth, deformed bones in young animals (rickets), and soft shelled eggs and osteoporosis in older animals.

Sources:

milk, oyster shells and limestone. Slide44

Sodium chloride

Considered together because of a close biochemical relationship and are provided as common salt (NaCl)

Function:

required for the formation and retention, concentration and pH of body fluids, such as protoplasm, blood. Important in the formation of digestive juices and functions in nerve and muscle activity.

Deficiency signs:

poor condition and depressed appetite. Most farm produced feeds are deficient in these two minerals.

Sources:

salt supplements and injectable products. Slide45

Phosphorus (P)

Function:

essential for the formation of bones, teeth, and body fluids. Required for metabolism, cell respiration and normal reproduction.

Deficiency signs:

similar to calcium deficiency, lack of appetite, poor reproduction and unthrifty appearance.

Sources:

dicalcium phosphate, bone meal, and low fluorine phosphates.

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Potassium (K)

Function:

retention and formation of body fluids, pH concentration of body fluid and rumen digestion.

Deficiency signs:

nonspecific and unlikely under most conditions but may have decreased feed consumption and efficiency.

Sources:

roughages. Grains are less than roughages .Slide47

Manganese

(

Mn

)

Function:

Fetal development, udder development, milk production and skeleton development.

Deficiency signs:

Abortions, reduced fertility, deformed young and poor growth.

Sources:

Most use trace mineralized salt.Slide48

I Cu FeSe Mn Mozn!

What’s that supposed to mean?

The Microminerals

Iodine (I)

Copper (Cu)

Iron (Fe)

Selenium (Se)

Manganese (Mn)

Molybedenum (Mo)

Zinc (Zn)Slide49

Copper (Cu)

Function:

should be present in animal tissues for iron to be properly utilized, hemoglobin formation and synthesis of keratin for fair and wool growth.

Deficiency signs:

poor pigmentation of feathers, stringy wool, sway back lambs, lack of muscle coordination and anemia.

Sources:

forages and copper salts. Slide50

Iron (Fe):

Function:

essential for the function of every organ and tissue of the body (Hemoglobin).

Deficiency signs:

seldom occurs in older animals, nutritional anemia, labored breathing and pale eyelids, ears and nose.

Sources:

forages and copper or trace mineral salts.

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Cobalt (Co)

Function:

required as a nutrient for the microorganisms in ruminants and thereby aids in rumen synthesis of Vitamin B

12

. Because swine cannot manufacture B

12 from cobalt, the diets are supplemental with vitamin B12 instead.

Deficiency signs:

lack of appetite, loss of weight, rough hair coat, anemia, decreased milk and wool production and death in extreme cases.

Sources:

legume forages and salt containing cobalt. Slide52

Magnesium (Mg)

Function:

similar to calcium and phosphorus.

Deficiency signs:

Animals are irritable, their heart beat is irregular and there is severe kidney damage.

Sources:

mineral supplements and ordinary feeds.

Slide53

Poor posture?

Ca & P

Which nutrient deficiencies

does Cap. KS have?

Childless/ reproductive dysfunction?

B

2

& A

Bleeding gums & Scurvy?

C

Lameness?

D & E

Night blindness?

A

Blood won’t clot?

KSlide54

Vocabulary Review

Nutrients:

chemical substances in food that are used by the body to produce energy and tissues.

Vitamins:

essential organic nutrients, required in small amounts, that cannot be synthesized by the body. Required for growth, maintenance, reproduction and lactation.

Vitamin deficiency:

decline in health due to the lack of a vitamin in a ration.Slide55

Vocabulary Review

Fat soluble vitamin:

a vitamin that can be stored and accumulated in the liver and other fatty tissues.

Water soluble vitamin:

a vitamin that cannot be stored in the tissues. Must be provided regularly as deficiencies can develop in a short time.

Minerals:

essential inorganic compounds, required in small amounts. Required for growth, maintenance, reproduction and lactation.

Macrominerals

:

required in large amounts.

Microminerals

required in small amounts.Slide56
Slide57

Evaluation

of

foods

Animal uses its feeds for:-

Maintance

:-food required by animal to keep good bodily health .

production :-food required by animals in addition to the

maintance

, to supply nutrients needed for form of production

e,g

. Growth , fattening , milking 00000.Slide58

There are prime consideration

Protein supply:-

Each animal requires

adefinite

amount of Pr. Daily for Maintenance and production .

For these reasons it is necessary to be able to measure the

ammount

of Pr.

In food .

So the animal can be rationed to meet its protein requirement s

.

Energy supply-The system of expressing the energy value of feeds are :-

Starch Equivalent

Total digestible nutrients(TDN)

Net energy

Digestible energy

Metabolizable

energy Slide59

Evaluation of foods: digestibility

the quantities in which nutrients are supplied by foods, and the quantities in which they are required by different classes of farm animal.

The digestibility of a food is most accurately defined as the proportion that is not excreted in the

faeces

and that is, therefore, assumed to be absorbed by the animal.

It is commonly expressed in terms of dry matter and as a coefficient or a percentage.

Digestibility coefficient are calculated for dry

matter,crude

protein , crude fiber ,

Ether extract , nitrogen free extract Slide60

Nutrients intake – nutrient in

faece Digestability

rate=-----------------------------------------*100

Nutrient intakeSlide61

Factors influencing Digestibility

Species of animal

Cattle and

buffaloe

is better than non ruminant.

Age of animal

Digest increases as age increases.Level of feeding The Digest. Is dependent upon the rate of passage of

digesta

from GIT.

If the food stay for

alonger

time in the GIT then it is more

more

exposed to enzyme.

If the level of feeding per unit

Bwis

increased , the

Dig.of

feed is decreased

dueto

inceased

rate of passage of

digestaSlide62

Processing of feed and fodder

Grinding of roughage (straw) reduces the

digestibilitysince

increases the rate of passage

Alkali lead to increases of digest. Because

breakedown

of lignocellulose complexof cell wallThe Digest. Of cereal grains is higher when they are given crushed to cattle and ground to the pig .Slide63

Feed composition

Elder plant convert fiber to lignin( pure cellulose is highly digestible by the ruminants, but with association of

ligninwith

the cellulose , the crude fiber digestibility is very much decreased.

Nutrient Digest. As Cp

The digest. Is reduced when molasses is added to the diet of ruminant. Slide64

Measure of Pr.

All Pr. Contain approximately 16% Nitrogen .

Cude

protein = nitrogen in food * 100/16

CP= N* 0.25.

This a convenient method of measuring protein

It is not absolutely accurate for:-

All Pr.

Doesnot

contain 16%N .

All Nin food is not necessarily combined as Pr.

CP= True Pr. +amides Slide65

Supply of Energy

The 3 constituents that a food its energy value are:-

-CHO.

Fat

Protein

That CHO (Sugar , Starch ) and the fat are energy foods.

Also Pr. Is giving the food its value e,g (tigger). Slide66

Measurement of Energy Value

Inorder

to know

howmuch

energy food is supplied and so these must be some way of measuring :-

Starch equivalent :-

Kellener (Chemist) considered all food consistuents that provided the animal with and decided that starch was the one which he would base his calculation .

This substances is common to most fattening food stuffs.

It can be digested by all class of stock

It has

aconcentrated

supply of energy .Slide67

Kellener

is able to calculate the fattening value of starch

He then substituted other food

inplace

of the starch and he was able to compare them for fattening value .

Next step was to substitute the starch with the individual food constituents such as Pr. , Oil and fiber and compare them with starch for fattening value .

Starch Equivalent :- No. of pound of starch that has the same E. value as 100 Ib of the food . Slide68

Evaluation of foods: energy content of foods and energy partition within the animal

An animal requires energy for both maintenance and production.

The energy requirement for maintenance

represents

the energy required for the vital body processes that are essential for life, for example the work associated with essential muscular activity (beating of the heart), the work associated with active transport (movement of dissolved substances against the concentration gradient), and the energy associated with the synthesis of essential body constituents such as enzymes and hormones.Slide69

Measures of Feedstuff Energy

Total Digestible Nutrients (TDN) : The feed and faeces

are subjected to the proximate analysis (CP, -CF, Ether extract-

General, calculated amount

Does not account for important losses of digestion

Can be expressed as lbs., %, or kg

Can be extremely variable/inaccurate (usually overestimate)

1lb. TDN from 1.2 lbs. corn = 1.2

Mcal

NE

1lb. TDN from 2.1 lbs. hay = 1.0

Mcal

NE

1lb. TDN from 2.4 lbs. poor hay = .8

Mcal

NESlide70

Nutrient Partitioning in Digestion & Metabolism

Gross Energy (GE)

Total potential energy of a feedstuff consumed

Determined in a bomb calorimeter

Fecal Energy (FE)

Undigested residue that passes through the GI

Can be collected and tested same method as above

Digestible Energy (DE)

DE = GE – FE

Takes account of some losses during digestion

Gasseous

Products of Digestion (GPD)

Combustible gasses that escape the body during digestion & absorption

Mostly methane; some H, CO, acetone, etc.

Most common in ruminants

Hard to measure accuratelySlide71

Urinary Energy (UE)

Includes materials that result directly from the digestion/absorption/enzymatic processes

Many

endogenous

sources as well

Metabolizable

Energy (ME)ME = DE – UE – GPDMore accurate measure of nutritive value than DE and TDN

Easy to determine in

nonruminants

because of the lack of GPDSlide72

SUPPLY OF ENERGY

Gross energy (GE):-

Energy is stored in the chemical components of food as chemical energy.

The amount of chemical energy in a food is measured by converting it to heat and determining the heat production

Energy Units

Calorie

= amount of heat needed to raise 1g water 1

ºC

Kilocalorie

= 1000 calories

Megacalorie

= 1000 kcal, or 1,000,000 calories (a.k.a.

therm

)

One

Joul

=4 caloriesSlide73

Heat Increment (HI)

Increase in heat production following feed consumption

Caused by the heats of fermentation, and heats of nutrient metabolism

Energy is wasted unless the environmental temperature is below the animal’s critical temperature zone

If it is used for temperature regulation, becomes part of

NEm

Net Energy (NE)

NE = ME – HI

Amount of energy used for maintenance only, or for maintenance and production purposes

Function should be stated clearly when reporting/evaluating NESlide74

NEm

(NE for Maintenance)Part of total NE needed to keep animal in energy equilibrium

No gain/loss of energy in body tissue

Basal Metabolism :– energy needed to maintain basic vital cellular activity

Energy of Voluntary Activity :– energy needed for basic movement to obtain food, water, lying down, etc.

Heat to keep body warm :– additional heat needed when environmental temp < animal’s critical temperature

Heat to keep body cool – extra energy expended when environmental temp > animal’s thermo neutral zoneSlide75

NEp

(NE Production)Additional energy required above

NEm

What would be considered production?

NEl

,

NEgSlide76
Slide77
Slide78

Feeds and Feed Consumption

Silages Energy Feeds >18% CF, <20%CP

Protein supplements >20% CP

Mineral supplements

Vitamin supplements

Nonnutritive additives

Antibiotics

Coloring

Flavors

Medicants

Etc.Slide79

FEED EVALUATION AND EXPRESSION OF VALUE

The total value of a feedstuff in practical nutrition depends on the following factors:

1. Energy content → carbohydrates, fats, proteins & digestibility

2. Protein content → including NPN and aspects of degradability

3. Nutrient density (digestibility) and structure value

4. Digestibility

5. Vitamin/mineral contents

6. Special aspects → like keeping quality, taste, toxins, influence on milk

colour

/taste, availability, handling etc.

7. Physical aspects

8. PriceSlide80

What is the mean of

Dry matter

The feed value (nutritive value) of food is contained in DM, the remainder of food being water. The DM is expressed as a percentage (%) or as gram per kg of food. For instance, the DM of grass is 15% equals 150 gram DM/kg grass.

DM is very important to an animal as it is used to measure hunger or appetite (the amount of food an animal can eat per day).

The daily amount of DM eaten per day is called Dry Matter Intake (DMI).

The total composition of the daily ration should include all nutrients required necessary for maintenance and production purposes within the quantity of DM. Slide81

The value of protein is usually expressed as crude protein (CP) or digestible crude protein (DCP).

The DCP and/or CP values are indicated:

Sometimes as → %/gram CP/DCP per kg food on a wet/fresh basis,

or sometimes as → the same values on a DM basis!

Protein Content

Slide82
Slide83

Maintenance

Nutrients are used to keep the body in good health and to maintain its temperature without bodyweight gain/loss. Majority of nutrients are used by muscles to:

pump hundred of

litres

of blood each day + breath

squeeze hundreds of kilograms food and water in the digestive system (eating, swallowing, ruminating, contractions, and digestion)

moving in order to collect the food

continuously repair of worn-out tissue Slide84

Feeding standards for maintenance and growth

Feeding standards may be expressed either as quantities of nutrients or in dietary proportions.

Thus, the phosphorus requirement of a 50 kg pig might be stated as 11 g P/day or as 5 g P/kg of the diet.

Various units are used for feeding standards.

For example, the energy requirements of ruminants may be stated in terms of net energy (NE),

metabolisable

energy (ME), digestible energy (DE) or feed units,

and their protein requirements in terms of crude protein (CP), digestible crude protein (DCP) or

metabolisable

protein (MP).

The requirements of cattle and sheep are often given separately for maintenance and for milk production, but those for growing chickens are for maintenance and growth combined.

In some cases, the requirements for single processes are not known; this is particularly true for vitamin and trace element requirements.Slide85

NUTRIENT REQUIREMENTS FOR MAINTENANCE

An animal is in a state of maintenance when its body composition remains constant, when it does not give rise to any product such as milk, and when it does not perform any work on its environment.

As animals are rarely kept in this non-productive state, it might seem of academic interest to determine nutrient requirements for maintenance; however, the total requirements of many classes of animal, particularly ruminants, are calculated

factorially

by summation of the requirements for maintenance and production.

Consequently, knowledge of the maintenance requirements of animals is of practical as well as theoretical significance.Slide86

Animals

deprived of food are forced to draw on their body reserves to meet their nutrient requirements for maintenance.

We have seen already that fasted animals must

catabolise

body reserves to provide the energy required for essential body processes such as respiration and circulation of blood.

As the energy so utilized leaves the body as heat, the animal is then in a state of negative energy balance.

The same is also true of other nutrients; for example, an animal fed on a protein-free diet will continue to lose nitrogen in its faeces and urine and is therefore in negative nitrogen balance.

The purpose of a maintenance diet is to prevent this drain on body reserves,

and the maintenance requirement for a nutrient can be defined as the quantity required to ensure that the animal experiences neither a gain nor a loss of that nutrient.

The requirement for maintenance is thus the

minimum quantity promoting zero balance (the qualification ‘minimum’ is necessary, because if the animal is unable to store the nutrient in question, then increasing the quantity supplied above that required for maintenance will still result in zero balance).Slide87
Slide88

Energy requirements for maintenance

Energy requirements for maintenance are generally estimated from fasting heat production (i.e. basal or fasting metabolism) or feeding trials.

Fasting metabolism is proportional to the metabolic live weight of the animal (typically W0.75).

An average value for mammals is 0.27 MJ/kg W

0.75

, but this will vary depending on the age and sex of the animal and the plane of nutrition.

Protein requirements for maintenance are estimated from endogenous urinary nitrogen and metabolic

faecal

nitrogen excretion.

There are also small losses of nitrogen in hair and scurf.

In ruminants the protein requirement for maintenance can generally be met by microbial protein synthesis.Slide89

Feeding

standards for growth (energy

Ruminants

EVg

= (4.1 + 0.0332W - 0.000009W 2)\(1 - 0.1475 LWG)

where

EVg

= energy value of live weight gain (MJ/kg), W =

liveweight

(kg) and LWG=

liveweight

gain (kg/day).

The first bracketed term in the equation describes the increasing energy content of gain as cattle increase in size, and the second term describes the correction for the increasing energy content of gain associated with higher

liveweight

gains.

Thus, the energy value of the gain (

EVg

) in a 100 kg animal gaining at 0.5 kg/day is predicted to be 7.9 MJ/kg,

whereas the

EVg

in a 500 kg animal gaining at the same rate would be 19.9 MJ/kg. The corresponding values for animals gaining at 1.0 kg/day are predicted to be 8.6 MJ/kg and 21.6 MJ/kg, respectively.

Feeding

standards for growth (energySlide90

Poultry

With the exception of birds reared for breeding ,

growing poultry are normally fed to appetite, and nutrient requirements are therefore expressed not as quantities required per day but as the nutrient concentrations in the diet.

By poultry are inversely related to the concentration of energy in their diets.

This means that if the energy concentration of a diet is increased without a corresponding change in the concentration of, for example, protein, then the birds will begin to eat less of the diet.

Consequently, although their energy intake may remain approximately the same, their protein intake will fall and the birds may be deficient in protein.

For chicks up to 6 weeks of age are appropriate to diets containing 11.5 MJ ME/kg and would need to be adjusted for diets containing more or less energy.Slide91

Horses

The energy requirements of growing horses (DE, MJ/kg gain) published by NRC (2007) are derived from published studies in which the energy intake and growth rate of horses were recorded.

The DE requirement for gain was estimated by subtracting the DE requirement for maintenance from the DE intake and dividing by the daily gain.

Using these data the DE requirement for gain (MJ/kg gain) can be predicted from the age of the animal in months (x) as:

DE (MJ/kg gain) = 8.33 + 5.06x - 0.088x2.Slide92

Feeding standards for growth (protein)

Ruminants

In cattle, the net protein requirement for growth (

NPg

, g/day) is predicted from the animal

’

s

liveweight

and its rate of gain (LWG, kg/day) as follows:

NPg

= LWG * (168.07 - 0.16869W + 0.0001633W2)

* (1.12 - 0.1223 LWG)Slide93

poultry

In addition to a general requirement for protein, non-ruminant animals have a specific dietary requirement for the ten or so essential (or indispensable) amino acids.

Shows the outcome of an experiment to determine the lysine requirement of chicks in which a diet low in lysine was supplemented to give diets ranging from 7g/kg to 14 g/kg lysine. From this experiment, it was concluded that the lysine requirement was 11 g/kg.Slide94

MINERAL AND VITAMIN REQUIREMENTS FOR MAINTENANCE AND GROWTH

The net requirement of a mineral element for maintenance plus growth is calculated as the sum of the endogenous losses and the quantity retained.

To determine the dietary requirement, the net requirement is divided by an average value for availability. For example, a 300 kg heifer gaining 0.5 kg/day might have an endogenous calcium loss of 5.0 g/day and be retaining 6.0 g/day. Its net calcium requirement would therefore be 11.0 g/day.

For an animal of this type, the availability of calcium is predicted to be about 0.68 and the daily calcium requirement would be calculated as 11.00.68 = 16.0 g/day.

Recent information has been incorporated into more contemporary feeding standards.

For example, the mineral requirements of growing cattle and sheep are published by NRC (2000), NRC (2006) and CSIRO (2007).

Similarly, the mineral requirements of horses are published by NRC (2007), and the mineral requirements of pigs are published by NRC (1998).Slide95

Vitamins

There are no estimates of endogenous losses on which to base vitamin requirements.

Therefore, standards must be based on feeding trials.

As with the assessment of mineral requirements, the main problem associated with the assessment of vitamin requirements is establishing appropriate criteria for adequacy.

Until recently, the main criteria have been growth rate and freedom from signs of deficiency, as assessed by visual examination of the animal or physiological tests, such as vitamin levels in the blood.

Vitamin storage can also be assessed, either by tissue analysis or from indirect evidence of tissue saturation provided by vitamin excretion in urine.