Unit 5 Animal Nutrition

Unit 5

 Nutrient Requirements and Ration Formulation

1. Balanced Ration and Its Characteristics

2. Nutrient Requirements and Methods

3. Feeding Practices for Cattle and Buffalo

4. Feeding Practices for Sheep and Goat

5. Use of NPN compounds in livestock feeding  

1. Balanced Ration and Its Characteristics

Ration: feed offered to an animal for 24 hours.

• Diet: feed eaten at a time

• Balanced ration: nutrients in proper proportion & proper amount according to physiological requirement for 24 hours.

1.1 Characteristics of a balanced ration:

1.  properly balanced. 

2. The Food must be Palatable

3. Variety of Feed in the Ration: A better and balanced mixture of proteins, vitamins and other nutrients. Variety of feed in the ration makes it more palatable.

4. The Ration should contain enough mineral matter. 

5. The Ration should be fairly laxative. 

6. The Ration should be fairly bulky. 

7.  Allow much of Green Fodder: because of their cooling and slightly laxative action.

8.  Avoid sudden changes in the Diet: SARA, LDA etc.

9.  Maintain Regularity in Feeding

10. The Feed must be Properly Prepared: should be grounded, Soaking, chopping  before feeding 

1.2 Methods of ration formulation

1.  Hit and trial/ trial and error method – ruminants and poultry

2.  Pearson square method – ruminants and poultry

3.   Algebraic method – ruminants and poultry

4.   Linear programming/ computer method/ least cost- ruminants and poultry

5.    In hand calculation – ruminants

 Computer-Formulated Rations: ‘Least cost’ ration/ Linear Programming:

‘Least cost’ ration: 

• If a ration is balanced using a combination of ingredients with the lowest possible total cost, the resulting mixture is called a “least cost” ration.
• Formulating a ration to fulfill the nutrient needs of the animal at the lowest possible cost is difficult by hand. Therefore, computer based models called linear programming are used to formulate the ration with least possible cost. 
• Linear Programming is the technique employed to calculate least- cost and profit-maximizing rations is called linear programming. 
• In the case of livestock rations, it is the minimizing of the cost of a ration or maximizing the income above feed cost.
• Computer programmes have been developed that allowed the calculation of optimum and least- cost rations in a matter of seconds. 
• With the use of computerized linear programming models, the prices of available feed ingredients as well as their nutrient contents can be considered when formulating rations. 
• Accuracy and speed of calculation are the major advantages of computer formulation.

Limitations of Computer method:

1.  Nutrient density within the mix

2.  The ‘Associative effects’ of feeds are not considered.

In-hand calculation method for Ration formulation: ruminants

Computation steps:

1. DMI calculation
2. Nutrient requirement calculation
3. Balance with available ingredient

1.  Dry matter intake (DMI) calculation:

Calculate DMI of the desired animal according to body weight @ 2.5% of BW for indigenous cow and 3% of BW for crossbred cow and buffalo.

Partitioning of dry matter intake:

Roughages:   2/3 of the total dry matter intake.

Dry roughage:           2/3 of roughage dry matter if non-legume green fodder is available OR

¾ of roughage dry matter when legume green fodder is available Green roughage:  1/3 of roughage dry matter for non-legume green fodder OR

¼ of roughage dry matter for legume green fodder Concentrate mixture: 1/3 of Total dry matter intake.

Milking animals’ DMI: 2.5% BW + 10% MY

• DMI from NDF  DMI %BW = 120/ ndf%

• NDF intake: 1.1-1.2% BW

• Maintenance requirement of milch animals is 10-15% higher than dry animals

2.  TDN requirement calculation:

For maintenance: 34g TDN/kg W^0.75

For production: 330 g TDN/kg fat corrected milk (FCM)

Where, FCM (kg) = (0.4 MY + 0.15F), where MY is kg of milk yield and F is kg of milk fat produced.

3.  DCP requirement calculation:

For maintenance: 2.84 g DCP/kg W^0.75

For production: The protein content of milk can be calculated by using the following formula. Percentage of protein = 1.9 + 0.4F, where F is percentage of fat.

Then, DCP requirement is calculated by assuming the BV of microbial protein in Cattle as 70. 

For example: The DCP requirement of 1 kg of milk with 5% fat

Percentage of protein = 1.9 + (0.4 x 5) = 3.9% or 39 g in 1 kg. Quantity of DCP required is (39/70) x 100 = 55.7 or 56 g of DCP.

2. Nutrient Requirements and Methods

A. Energy Requirement For Maintenance

1. BMR = By Direct or Indirect calorimetry

2. Feeding trial: amount of feed energy sufficient to maintain constant weight

• Basal Metabolic Rate: Non-ruminants = number of calories required to keep your body just functioning under

following conditions:

1. Good nutritive conditions: Poor state tends to decrease basal heat production.

2. Environmental temperature: Thermo-neutral zone/ temperature of about 25oC.

3. Complete Rest: minimum muscular activity,

4. Post-absorptive state –to make sure that heat increment due to digestion and assimilation has been dissipated.

• Resting metabolism: ruminants (because minimum muscular activity is very difficult for animals).

• Activity increment: 50% of basal metabolism in poultry and 20-30% in case of sheep/goat/swine/cattle.

• Fasting Metabolism: ruminants (very hard to achieve Post-absorptive state) – so, heat production at specific times after last feeding.

Confirmation of Post-absorptive state:

• Measurement of heat production to a point of a constant minimum level.

• A Respiratory Quotient (RQ) of 0.7 (fat).

• Ruminants: a decline in methane excretion to a minimum level.

• For example, from 30 L of methane to 0.5 L in sheep and from 200 L to 2 L in cattle by 3rd day of fasting.

Unit of Reference in Fasting/Basal Metabolism:

• Rubner: BMR varies with body size = metabolic body size = surface area law

• BMR = 70W 0.75 Kg

For dairy cattle and buffalo:

• NEm = 80 W0.75 (Kcal/day)

• MEm = 133 W0.75 (Kcal/day)

• TDNm = 35.2 W0.75 (g/day)

B. Protein Requirement For Maintenance

1. Feeding trial = minimum dietary protein to maintain body weight

2. Nitrogen balance method- equilibrium = minimum constant N-output

3. Factorial method = EUN+MFN

• Endogenous urinary nitrogen = EUN mg/day = 146 W0.72 kg = Function of Body size

• Indian cattle = 0.020 g/kg BW

• Bos taurus = 0.289 g/kg BW

• Metabolic fecal nitrogen = MFN = Function of DMI

• Indian cattle = 0.35 g/100 g DMI

• Buffaloes = 0.34 g/100 g DMI

Note:

Total or basal endogenous nitrogen excretion of ruminants:- 350mg N/kgW0.75 /day

Dermal losses of nitrogen= 2.2g N/day

• Maintenance requirements of breeds with high milk potential are 20% higher than those with low milk potential

• Maintenance requirements of Bos indicus breeds are 10% lower than Bos Taurus

• Maintenance / NEm requirement of male/ bull is 15% higher than female/cow

C. Energy Requirement For Growth

1. Feeding Trials: different levels of feed energy for optimum/ normal growth

2. Factorial Method: BMR + activity increment + Weight gain (slaughter)

D. Protein Requirement For Growth

1. Feeding trial = minimum dietary protein required to give the maximum growth

2. Nitrogen balance method- minimum dietary protein which provides maximum retention

3. Factorial method = EUN + MFN + Weight Gain (slaughter)

E. Energy  and Protein Requirement For Reproduction

• Significant only during last trimester of pregnancy

F. Energy Requirement For lactation

• Depend upon composition of milk, milk yield and efficiency of conversion of

dietary energy to milk energy.

1. Bomb calorimeter – total energy

2. Gaines formula: Fat corrected milk (FCM), kg : 0.4 (Milk yield, kg) + 15 (Total

fat yield, kg)

• Example: 750 Kcal of NE is required for one kg of FCM.

• Efficiency of conversion of ME to NE of milk = 62%

• Efficiency of conversion of DE to ME = 82% (ME= DE x 0.82)

• DE requirement for one kg of FCM = 1460 Kcal DE

• The amount of TDN required per kg of FCM = 0.330 kg

G. Protein Requirement For lactation

• Depends upon protein content of milk and efficiency of utilization of digestible

protein for making milk protein (generally 60-70%).

• Milk = 3.5% protein = 35 g protein per kg milk

• Dietary Digestible protein required: 50-55 g protein

Energy and protein requirement for egg production

• Energy requirement: maintenance + energy content of egg + efficiency of utilization (68%)

• Daily energy requirement = 314 kcal

• Protein requirement: maintenance + protein content of egg + efficiency of utilization (46-57%) + loss

• Daily protein required:

• Maintenance = 3 g/d

• One egg = 6 g/d

• Feathers = 0.1 g/d

• Total = 9.1 g protein/d

• 46% efficiency = 9.1+ 0.54×9.1= 14g protein.

• From Feeding experiment : 16 g protein /day

Topic 2 MCQs

1. Read the following statements :  MPSC – 2019

a. Energy is the most important nutrient to produce milk.

b. The energy needed depends upon the composition of milk.

Now state whether :

(1) Both the statements are correct

(2) Statement a is correct, but statement b is not correct

(3) Statement b is correct, but statement a is not correct

(4) Neither of the statements is correct

2. Dry matter intake of dairy animals should be Uppsc 2022

(a)      1% of body weight per day

(b)      0.5% of body weight per day

(c)       4% of body weight per day

(d)      10% of body weight per day                                                            

3. The dry matter requirement for cattle per 100 kg body weight is   Kerala PSC – June 2023

a) 1.5 – 2.0 kg

b) 2.5 – 3.0 kg

c) 2.0 – 2.5 kg

d) 3.0 – 4.0 kg

4. Dry matter requirement for a cow weighing 400 kg, giving 10 liters of milk having 4-5% fat is       MPPSC 2023

[A] 2 kg

[B] 4 kg

[C] 10 kg

[D] 20 kg

5. Maintenance D. M. total requirement of 400 kg crossed breed cows require: OPSC 2018-2019

(A) 5-7 kg

(B) 8-10 kg

(C) 11-13 kg

(D) 13-15 kg

3.  Feeding Practices for Cattle and Buffalo

Thumb rule

Feed stuffs	Zebu / indigenous cow	Crossbred cow/ buffaloes
Straw	4.00 kg	4.00-6.00 kg
Concentrates mix
Maintenance	1.25 kg	2.00 kg
Pregnancy (last trimester)	1.25 kg	1.75 kg
Lactation	1.00 kg/ 2.5 kg MY	1.00 kg/ 2.0 kg MY

⮚     1 kg Concentrate mix = 10 kg green fodder

⮚     Concentrate mixture = 20% CP, 65% TDN, 0.5-0.7% Ca and 0.3-04% P

3.1 Feeding of calves

Best feeding practice for rearing a calf is to start feeding from the last trimester of pregnancy then in the pre-ruminant period and post ruminant period.

Extra nutrients should be given during the last trimester of gestation to dam with 15- 20 kg green fodder daily to make colostrum rich in vitamin A.

Pre-ruminant period-0-3 month Feeding during pre-ruminant stage can be divided into following steps

1. Colostrum feeding
2.  Whole milk feeding
3.  Skim milk
4. Calf starter
5. Milk replacer 
6. Roughase–hay

•  Colostrum: within 2 hours @ 1/10th BW (17% protein, IgM, IgA, IgG)
• Milk replacer: 
• Calf starter- Offer fresh lush green fodder free of choice for proper rumen development.

Importance of Colostrum feeding

• Provide passive immunity so calf fed colostrum remain quite healthy Laxative effect hence avoid constipation
• Excellent source of Vit A, D, & E
• Contain antibacterial substances-lactoferrin, lactoperoxidase & lysozyme

FEEDING SCHEDULE OF COW CALVES (0-3 months): WHOLE MILK+ SKIM MILK+ CALF STARTER

Age(days)	Colostrum (lit)	Milk(lit)	Skim milk(lit)	Calf starter(g)
1-3	1/10th B.wt	–	–	–
4-7		1/10th B.wt		–
8-14		1/10th B.wt		–
15-21		1/10th B.wt		Little
22-35	–	1/15th B.wt	–	100
upto 60 days		1/20th B.wt	1/25th B.wt	250
61-90		1/25th B.wt	1/15th B.wt	500

Milk replacer is introduced to cut the feeding cost so that rearing of the calf becomes economical. Achieve comparable weight gain to that of whole milk.

Composition:

Dried skim milk	50
Dried whey	30
Dextrose	8
Oat flour	5
Brewer yeast	5.26
Trace minerals	0.04
Vitamin A	1.7
total	100

Calf starter– 

• solid feed consisting of ground grains, oil cakes, animal protein supplement, brans, dried skim milk, soymeal, whey, mineral mix, and butyrate.
•  For accelerated growth and early weaning of the calves.
• It should contain 23-26% CP, 18-19.5% DCP and 75% TDN. 
• Started at 7-10 days (14 days). 
• Calf starter is a crucial link for proper rumen development and reduces the stress of weaning and saves the calf from diarrhea.

Feeding from 3 months to 6 months:

• From 3^rd month onward green forages can be given @ 2Kg/day and gradually raising its quantity to 5-6 kg/day at 6 months. 
• Concentrate mixture the same as fed to adults should be fed 0.75 kg in 4^th, 1kg in 5^th and 1.5 kg in 6^th months of age. 
• After the 6th month, individual feeding of the calf should be stopped. Hay should be fed ad lib to calves.
• For economical raising of calves, they should be maintained on high quality roughage and minimum of concentrate.

3.2 Feeding high yielders:

•       Energy: Feeding bypass fat to ruminants

•       Protein: Feeding bypass protein to ruminants = UDP = 8% of total diet protein%

•       Fiber: 28-32% NDF

•       Mineral mixture: 10g MM/ kg of milk production.

•       Challenge feeding: steaming up (2 weeks prior to calving)

DCAD salt in pre-partum transition period to maintain a negative dietary cation- anion difference (-100 to -140 meq/kg DMI) for stimulation of parathyroid gland. Activation of parathyroid gland prior to calving, maintain Ca homeostasis and help in avoiding milk fever.

Bypass nutrient technology used in high yielder:

✔   Bypass nutrient technology is an important nutritional tool to increase the productivity of animals.

✔   Bypass nutrients (mainly fat and protein) are protected from hydrolysis in rumen, which gets absorbed from the lower digestive tract without altering the rumen environment.

✔   It represents a fraction of the nutrient that is fermented in the rumen to a comparatively low degree.

✔   It also has a function to provide the rumen microbes with a steady supply of nutrients, rather than with sudden bursts from easily soluble nutrients.

Theoretical considerations about slowly degradable nutrients: there are 3 type of nutrients that could bypass rumen fermentation to certain degree:

• protein/amino acids, 
• fats/fatty acids
• starch
• Minerals (Zn, Cn, Mn) can be chelated, but in that form they entirely bypass the rumen, as they are stable at ruminal.

Objective and importance of bypass nutrient:

• The purpose of feeding “bypass” protein is that a large proportion of the protein is available directly at the lower part of the gastro-intestinal tract, where it is digested and then absorbed as amino acids for utilization at tissue level. The bypass protein provides high quality protein rich in essential amino acids directly at the intestine level. 
• Feeding of “bypass” starch reduces excess production of lactic acid in the rumen, which would otherwise result in low rumen pH (acidosis), thereby affecting fibre digestion. 
• Bypass fat is generally fed during the early lactation to avoid disturbance to rumen fermentation that is generally encountered when ration is made energy dense with cereals and fat. 
• Additionally, it meets the energy requirement of high yielding animals to avoid NEB. Thus, Feeding of “bypass” fat (protected fat) is done primarily to avoid ruminal hydrolysis of bio-hydrogenation of unsaturated fatty acids and increasing energy density of feeds. 

Methods of making bypass protein:

1. Natural bypass protein source: Blood meal, Fish meal, Meat meal, cottonseed cake, maize gluten meal, coconut meal, Linseed meal.

2. Formaldehyde treatment: applied @ 1.2 g/100 g CP to reduce the degradability of highly degradable proteins in rumen. However, corrosive nature and carcinogenic effects. Most widely used method.

3.    Treatment with metal ions: ZnCl₂ and ZnSO₄

4.    Coating with insoluble protein

5.    Acid and alkali treatment: NaOH, HCl, propionic acid – denaturation

6.    Heat treatment: groundnut cake and soybean meal at 150°C for 2 hours seems to give sufficient protection.

Note:

✔   During the solvent extraction and expeller method of oil cakes, the temperature reaches only 90- 95 °C and the proteins are only partially protected at this temperature.

Methods of making bypass fat :

1.    Naturally protected: cotton seeds

2.    Prilled fatty acids

3.    Lipids encapsulated by formaldehyde treated protein

4.    Ca- salt of long chain fatty acids/ Fusion Method – commercial method/ less rumen degradable + Ca source (CaOH).

Note:

i.    Maximal milk production efficiency can be achieved when the supplemental dietary fat provides 15-20% of dietary metabolizable energy or dietary fat @ 6-7% of DMI.

ii.    80-90% FA of unprotected fat are bio-hydrogenated in rumen, but in Ca-LCFA it is 30-40% only.

iii.    Unsaturated fat: CLA (conjugated linoleic acid)- health benefits

iv.    Supplementation of RPF has no adverse effects on the rumen fermentation even up to 15% of DMI but, Feeding RPF at or above 9% of DMI has no additional benefits in lactating cows

v.    During early lactation, maximum response can be achieved at 150– 300 g Ca-LCFA/day/animal.

vi.    3% fat from diet (roughages and concentrate mix) + 3% from Bypass fat.

vii.    Bypass fat: 7-8 % Ca, 80 -85 % rumen protected fat.

4.  Feeding Practices for Sheep and Goat

Feeding of Kids

•  Birth weight= 1-5 kg
•  After birth within 1 hour the kids should get colostrum continued for 3 days.
• After the 3rd day up to weaning, feed them with milk at 2 to 3 times a day (1/6^th BW up to 1 month and then 1/8^th of BW in the 2nd month and 1/10th-1/12^th BW during the 3rd month).
•  Milk feeding completely stopped after the 3rd month.
• At about 2 weeks of age: Young ones should be trained to eat green roughages and hay.
•  At 1 month of age: Young ones should be provided with concentrate mixture (starter feed).
• Provided @ 100 ml/per kg live weight

Creep Feeding

• Creep feeding means providing supplemental feed for nursing kids for rapid growth
•  Essential component of an accelerated growth or early weaning management program
•  It is a palatable and easily digestible concentrate mixture
• Also contains antibiotics like oxytetracycline or chlortetracycline @ 15 to 25 mg/kg of feed.
• After one-two weeks, creep feed is given, which contains
•  If grasses and cereal fodder—DCP 18% & TDN 75%
•  If leguminous fodder –DCP 12% and TDN 70%
•  Helps in rapid growth of kid
•  Hasten the rumen development
• Offer feed @ 50-100gm/animal/ day, and as gradually they eat more, reduce the milk allowance.
• Creep feed started from 10^th day up to 90 days of age or pre-weaning period for faster gain

Advantage of creep feeding

• Increases pre-weaning weight gain. Kids will have greater weight gain per day of age as conversion of creep feed to body weight is very efficient process
• Reach target market weight at very young age
• Reduces the stress associated with weaning
• Transition from milk to dry diet will be much smoother

Feeding Schedule for a Kid from Birth to 90 days

Age of kids	Dam’s milk or cow milk (ml)	Creep feed (g)	Forage, green/day (g)
1-3 days	Colostrum 300 ml, 3 feedings	–	–
4-14 days	350 ml, 3 feedings	–	–
15-30 days	350 ml, 3 feedings	A little	A little
31-60 days	400 ml, 2 feedings	100-150	Free choice
61-90 days	200 ml, 2 feedings	200-250	Free choice

Feeding of growing & Finishing:

• Extensive system doesn’t fulfill the requirement
• The concentrate mixture/day should be fed as per the following recommendations

B. Wt. (Kg)	Quantity of concentrate mix* (gm/ day)
	When good quality fodders are available ad. lib. (e.g. green oat,cowpea, maize, Dub and their hays)	When poor quality fodders are available ad. lib. (e.g. mature grasses, straws, stover etc.)

10 to 15	50	300
16 to 25	100	400
26 to 35	150	600

• Under excellent forage condition, lambs may reach slaughter weight early
• Finisher lambs are usually 5-6 month of age and weight 28-40 kg
•  Slaughter or market lamb should have weight between 45-65 kg
• Rate of weight gain per day in growing lamb – 50-200 g/day

Flushing

• 25% more nutrients above the maintenance from 2-3 weeks prior to breeding till breeding season.
• Flushing brings ewes/does into heat earlier in the breeding season, ewes/does exhibit heat at same time and increases the lambing/kidding rate and incidence of multiple births.
• Mostly energy component is increased about one month before introduction of the bucks
• Mainly to increase body weight, ovulation rate and thus litter size
• This process should continue throughout the breeding season and for approx. 30-40 days after removing the bucks
• For increasing the ovulation rate and consequently the lambing rate.

FEEDING OF PREGNANT DOES

• Gestation period of ewes is about 143-151 days, on an average 147 days.
•  During the first half of gestation period the growth of foetus is not so rapid
• Foetal growth in the last two months of pregnancy is rapid and the metabolic rate of the goat rises rapidly.
• During this period increase ration content to the level of production ration (0.2-0.7kg conc./days/ doe).
• Breeding ram and pregnant ewes (last 6 weeks) should be provided with 50% more nutrients than the maintenance needs.
•  Need additional water throughout pregnancy
• Concentrate mixture for pregnant ewe= 150-250 gm/day + 8-9 hrs of grazing
•  During last 6 weeks of gestation

• Excessive energy intake leads to fattening 🡪 birth difficulty
• Low energy intake 🡪 low birth weight, reduced viability & pregnancy toxemia may result in ewes.
• The advantage of extra allowances of feed given during the last half gestation period are as below:

• It increases the birth weight of lambs.
• It reduces the number of weak or crippled lambs.
•  It reduces the chance of lambing paralysis which occurs just before lambing.
• It increases milk of ewes and thereby avoids the tendency for disowning their own lambs.
• For pregnant but lactating goats 300-400 g of concentrate mixture/kg of milk produced should be given in addition to maintenance amount of 150 g/day.

 Feeding of lactating ewes/Does

• Nutritional requirement is 2-3 times greater during lactation
• With twin produce 20-40% more milk than with single
• Peak milk yield in early 2-3 weeks
• After lambing plenty of water and light feed should be offered
• By the 3^rd day, regular ration can be brought up
• Gradually the feeding of ewes should be increased and start diminishing concentrate feeding by 8^th week
• Lactating sheep’s need twice the maintenance requirement during the first 2 months and 1.5 times for the remaining period.
• DMI during 1^st half of lactating goat is 4-5% and 3-4% of body weight during later half
• For an adult in lactation about 400 g of concentrate mixture or 0.5kg hay or 1kg of good quality green fodder must be given for every ltr of milk produced and over and above that 150 g should be added for maintenance.
• A concentrate mixture for lactating goats should contain about 9-10% DCP and 60-65% TDN.
• A goat weighing 50kg and yielding 2 litres of milk (4% fat) requires 400g of conc. and 5kg of berseem or lucerne.

Conc. mixture for goat:- (Add 2% MM+ 2% Salt)

●       1:2:1 part of wheat bran, maize grain and linseed-cake;

●       2:1:2:2 parts of maize grain, barley, mustard-cake and gram husk;

●       1:2:1 part of wheat bran, barley grain, and groundnut-cake;

●       2:1 parts of gram grain and wheat bran.

Feeding of bucks/Rams

●       Breeding males are fed 3-3.5% of total body weight.

●       Ration providing 5-6% DCP and 50-60% TDN

●       Average breeding buck/ram need 500 g to 1 kg concentrate and yearlings about 25g.

●       Avoid excessive weight gain

●       If pasture is unavailable, feed hay and concentrate up to 0.7 kg/day

Imp fact

Sheep

• The sulfur containing amino acid, methionine, is the first limiting amino acid for

growth of wool and weight gain.

• Feeding habit: grazing

• DMI: 3% both for meat and milk

• Digestion: less efficient than goat

• Maintenance:

DCP: 2.73 g per kg metabolic body size

TDN: 27.3 g per kg metabolic body size

ME: 98 kcal per kg met. Body size

• Weaning age- 90 days

• Colostrum- 100 ml/ kg bwt

• The practice of providing supplemental feed to nursing lambs: creep feeding.

• From 10 days of age to weaning at 90 days to promote growth during early age and rumen

development.

• Grower ration: 15% DCP and 72% TDN

• Sheep finisher ration- 13% DCP and 70% TDN

• Reproduction: Breeding rams and pregnant ewes during the last 6 weeks of pregnancy

should be provided with 50% more nutrients than the maintenance needs.

• Breeding season Ram- 250-500 g concentrate mix daily

• Milk Production: Sheep are mainly raised for lamb and wool but not for milk production.

However, for the nutrition of the lamb, lactating sheep need twice the maintenance

requirements during the first 2 months of lactation followed by 1.5 times the maintenance

during the remaining period.

• If good quality pasture is not available: 400 g concentrate mixture

Goat

• Goat: DCP- 3g/ kg metabolic body size

• TDN- 30 g/ kg metabolic body size

• DMI: for meat = 3% BW and milk = 4-6% BW

• Breeding buck- conc. 4-6% DCP, 60% TDN

• Finisher goat, Pregnant and lactating goat- 5-6% DCP and 60% TDN

• Goat grower con. – 12% DCP, 65% TDN

• If good quality pasture not available: 250-500 g concentrate mixture

• Pregnant doe- pasture plus 500 g conc.

5. Use of NPN compounds in Livestock feeding

Importance of NPN Compounds in the Ruminant Diet

• NPN compounds are less expensive and readily available for consumption.  Sometimes, low-protein concentrates do not always meet the nutritional demands of ruminants 
• their protein should be partially substituted with adequate alternatives, like use of non- protein nitrogen (NPN) compounds. 
• A part of the nitrogen in ruminant diets may be in simple nitrogen molecules that are metabolised in the rumen to release ammonia (NH3), which rumen microbes utilize to generate amino acids.

Non-protein Nitrogen Sources for Ruminants

•      Urea (most widely used NPN compound in the ruminant diet)

•      Ammonium acetate

•      Ammonium bicarbonate

•      Biuret

•      Dicyandiamide

•      Glutamine

•      Glycine

•      Oilseed meals

Urea as the Primary Source of NPN for ruminants:

•  Urea is the most common commercial source of NPN for ruminant diets.

•  Urea is a simple molecule (100% degradability in rumen) that contains 46.7% nitrogen.

•  When plant protein feeds are expensive, the protein supplement in ruminant diets is completed by urea.

• Urea is a white crystalline water-soluble powder used as a fertilizer and is the cheapest solid nitrogen source.

•  When urea reaches the rumen, it is quickly absorbed and converted to ammonia by bacterial urease, yielding up to 29.2 kg of protein per 100g of urea.

Feeding guidelines/ Precaution while feeding NPN compounds:

• Microbial urease completely degrades urea in the rumen and can be toxic at higher levels. It should not be supplemented by more than 1% of the concentrate mixture or total DMI of the animal.

• Should not be fed to calves less than 6 months of age. NPN should not be given to monogastric

animals like pigs, poultry and pre-ruminant calves etc.

• While NPN does serve as a cheaper alternative of protein for ruminants, it should also be kept in mind that NPN are not true protein. Especially for high yielder, to meet the requirement of limiting amino acids like methionine, true protein in the form of protein supplements needs to be used.

•Alone NPN feeding cannot replace the whole protein requirement (only 1/3^rd requirement of protein can be spared by urea).

•   Add NPN with high-energy feed such as grains/molasses and mix thoroughly.

•  Introduce NPN ration slowly as 2-3 week period is necessary for rumen bacteria to achieve maximum utilization of NPN.

•   Use NPN only when additional protein is necessary in the ration i.e. the crude protein in the ration is below 13%.

•  Ensure adequate amount of water during NPN feeding.

•  Never cross the limit of 116 grams of urea for adult cattle and 10 g for sheep per day.

•  Uniform mixing of urea is essential to avoid urea toxicity.

Factors affecting efficiency of Urea utilization:

1.  Effect of level of protein: On low protein-ration (less than 12-13%), urea can be utilized as a substitute for dietary protein.

2.  Effect of carbohydrates: Urea is well utilized when it is fed with readily available energy sources like starch, molasses or cereal grains. 1kg starch/ 100g urea is required.

3.  Level of Sulphur and Nitrogen: better urea utilization requires N:S:: 10:1.

4.  Methionine supplementation improves urea utilization.

5.  Low urea level results in better utilization.

6.  NPN level of other feedstuff.

7.  Adaptation period.

8.  Age of the animal.

Urea Toxicity:

✔   Symptoms:

✔   Bloat

✔   Excessive salivation

✔   Respiratory difficulty

✔   Bellowing

✔   Convulsion

Treatment:

•        Drenching of 20-40 liters cold water (inhibit ureolytic activity)

•        Drenching of 4-5 liters of 10% acetic acid (binds ammonia).

Glacial Acetic acid is given to lower the rumen PH

Methods of urea feeding/ Application of NPN containing feed supplements for ruminants

1.  Urea in concentrate mixture: 1.0% of total conc. mix.

2.  Urea treatment of wheat straw

3.  Uromol:

It is prepared by boiling urea with Molasses in the ratio of 1:3 for 30 minutes. It contains 36% DCP and 70% TDN.

4.  UMMB:

UMMB stands for Urea Molasses Mineral Block. UMMB is a method for slow releasing urea, which checks the proper amount of urea given per day. In this method, the urea is fed in the form of lick blocks to the cattle. The primary objective of UMMB licks is to provide supplementary nutrition to the dairy animals kept in the village on straw and crop residue.

The recommended proportions of the ingredients in UMMB:

Molasses                   – 45 percent

Urea                           – 15 percent

Mineral mixture        – 15 percent

Common salt             – 8 percent

Calcite powder          – 4 percent

Bentonite                   – 3 percent

Protein meal              – 10 percent

5.  Urea-molasses liquid feed:

Liquid molasses containing 2-3% uniformly mixed urea fortified with minerals and vitamin is called Urea-molasses liquid feed.

Urea – 2.5%

Water – 2.5%

Mineral mix. – 2.0%

Salt – 1.0%

Molasses – 92%

Vit. Mix – 25g