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LACTATION PHYSIOLOGYMK. Nutrisi Ternak Perah (NTP333)

Department of Nutrition and Feed TechnologyFaculty of Animal ScienceBogor Agricultural University (IPB)

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Syllabus

In this chapter, student will learn about anatomy of mammary gland, physiology of milk secretion and feeding lactating cow.

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Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Synthesized feed into milk

Feed

Milk

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Milk Composition - FH

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Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Milk Compsition of Other Spesies

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Measurement of Nutrient Intake

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Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Streak Canal

Rosette of FürstenbergTeat Cistern

Gland Cistern

Front Quarter

Glandular Tissue

Abdominal (Milk) Vein

Mammary Vein

Mammary Artery

LymphNode

RearQuarter

LymphVessel

Frandsen, 1981. Anatomy and Physiology of Farm Animals

Udder Anatomi & Blood Flow

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Duct System and Secretory System

Connective tissue Lobules

Blood capillaries Intralobular ducts Alveoli

Myoepithelial cell Secretory cells Milk

Teat cistern (30 - 40 ml)Gland cistern (400 ml)

Major duct

Supportive (connective tissue)

Streak canal

Lobe

Frandsen, 1981. Anatomy and Physiology of Farm Animals

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Myoephitelial cell

CapillaryLumen

Alveoli – Fuctional Milk Synthesizing Unit

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

1 2 3 4

T = Tight Junction

Fat Droplet

M = Mitochondria

M

G

G = Golgi Apparatus

R

R = Rough Endopl.reticulum

S = Smooth Endopl.reticulumS

N N = Nucleus

T

Pathway:

BloodPrecursors:

SaltsLeucocytes

SECRETORYCELLS

MILK

Aminoacids

GlucoseIons

Mi = MicrovilliMi

Sv = Secretoryvesicles

Sv

Fatty acids, Glycerol,Acetate,B-hydroxy-butyrate

Casein micellesLactose, water

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Immuno-globulins

LEGEND:

The Origin of The Component of Milk

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LIVER

Mammary Gland

RUMEN IntestineDietaryNDF & NFC

Propionate

Glucose“Glucose”

Glucose

Galactose

Lactose

Glucose

Propionate

GlucoseAA Glucose

Propionate

Glycerol

Fats

Origin of Lactose

Lactose Biosynthesis

O OH

O

OH OH

CH2

OHOH

OH

O

OH

CH2

OH

Galactose GlucoseLiver Secretory Cell

Glucose Glucose

Blood

CH3 CH2 CO

O -

Propionate

Glucogenic amino-acids(glutamte, aspartateserine, etc.)

Glucose-P

Galactose Galactose

Glucose

A

B

A = galactosyl transferase; B = alpha lactalbumin

LACTOSE

Golgi Apparatus

Water

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Milk Synthesis - Lactose

Origin of Milk Fat

LIVER

Mammary Gland

RUMEN Intestine

NDF & NFCAcetateButyrate

Saturated FA+ MG“Glucose”

NEFA

Glycerol

Milk Fats

Fatty acids

AcetateBOHB

Fatty Acids

AcetateBOHB

AcetateBOHBl

BOHB = B-hydroxybutyrate

VLDL - very low density lipo-proteins

Adiposetissues

TG

NEFA = Non-Esterified Fatty acids

VLDL

Ketones

TG

MG = MonoglyceridesTG = Triglycerides

Fats Saturation + Hydrolysis

FA = Fatty acids

VLDL

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Biosynthesis of Fat

BloodCapillaryWall

BasalMembrane

Secretory Cell

Triglycerides(VLDL)

Non-EsterifiedFatty Acids(NEFA)

Glycerol

Monoglycerides

Free Fatty acids (C16, C18C18:1, C18:2)

Glycerol

Monoglycerides

Glucose

AcetateB-hydroxybutyrate

Glucose

AcetateB-hydroxybutyrate

Fatty acids(C4-C16)

MilkTriglycerides

1LPL

1LPL = Lipoprotein lipase

Free Fatty acids

Glycerol

VLDL = very low density lipoprotein

Milk Syntesis - Protein

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Milk Syntesis - Protein

Origin of Casein

Liver

Urea

Mammary Gland

Rumen IntestineDietary Crude Protein RDP

Bacteria

AminoAcids

RUP

AA

(AA)

AA

Casein

AA

NH3Urea

AAAAProtein

AA

NH3 Glucose

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Secretory Cell

Amino Acids

Amino Acids (AA)

Blood

1: Translation of DNA

GTP + ATP +CTP + UTP

m-RNA

Nucleus

2: Amino-acid Activation+ ATP + t-RNA

RER

AA1~t-RNA

3: Translation

RER =Rough Endoplamic Reticulum.

Ribosome AA~ t-RNA

AA1-AA2-AA3 … AAn

AA2~t-RNAAAn~t-RNA

AA3~t-RNA

Casein micelle

Biosynthesis of Protein

SummaryOrigin of Milk Components

NDF NFCCarbohydrates

RDP RUPCrude ProteinLipidsFEED

RUMENFERMENTATION

40%Milk Protein60%50%

LCFA

Bodyreserve

Milk Sugar(Lactose)

50%UDDER

Milk Fat

30%SCFA

BacterialProtein

AceticButyric Propionic

Lactic

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Milk Volume vs Milk Component:Glucogenic vs Ketogenic Nutrients

Glucose -Hydroxy-butyrateAceto-acetate (Acetone)

Amino AcidsBlood

SugarsPropionate, LactateGlycerolCertain amino acids

Acetate, ButyrateFatty acids (long chain)GlycerolCertain amino acids

Amino acidsPeptides

GI tract

GLUCOGENIC KETOGENICAmino acidsLiver Liver Liver, adipose tissue

Milk proteinMilk lactose Milk fat (short chain)Udder

Amino acids in the Liver and the Udder

AminoAcid

E NE

G K Grp

E = Essential, NE=Non Essential, G= Glucogenic, K = KetogenicGroup = G1: mammary uptake = milk secretion; G2 : mammary uptake > milk secretionG3 : Non-Essential AA, with variable uptake / milk secretion

AminoAcid

E NE

G K Grp

Arginine E G G2Histidine E G G1

LeucineE G K G2

LysineE K G2

MethionineE G K G2

PhenylalanineE G G1

ThreonineE G K G1

TryptophanE G G2

Isoleucine

E G K G1Valine E G G2

Alanine NE G G3Asparagine NE G G3Aspartate NE G G3Cysteine NE G G3Glutamine NE G G3Glutamate NE G G3Glycine NE G G3Hydroxyroline NE G G3Proline NE G G3Serine NE G G3Tyrosine NE G G1

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Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Milk Fat Depression and Forage to Concentrate Ratio

Volatile fatty acids(VFA) produced

in the rumen

Milk productionand composition

Propionic Acid

Milk production(kg/day)

Total VFAproduction(moles/day)

Rumen pH 5.55.0

6.06.5

Acetic Acid

Butyric Acid

Fat in themilk (%)

50

Concentrates20 % ration dry matter80 % ration dry matter

Forages 80 60 4020 40 60

60 %

20

30

40

What is the origin of milk fat?

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Theories Regarding Milk Fat Depression

Acetate deficiency Low acetate: propionate ratio is not due to lower acetate, but rather an

higher amount of propionate. Vitamin B12 deficiency

Ruminal synthesis of vit. B12 is low under high grain diet. Vit B12 is required for propionate metabolism in the liver and elongation of fatty acid chains with acetic acid or -hydroxy-butyrate (BHBA) in milk fat synthesis.

Insulin and suppression of fat mobilization Hormonal messages, with high amount of propionate and possibly

glucose absorption in the lower intestine elicitng an insulin response which tend to inhibit fat mobilization and the availability of ketones for fatty acids synthesis in the udder.

Inhibition of the de novo synthesis of short and medium chain of fatty acids in the mammary gland by trans fatty acids (TFA). TFA are produced during ruminal hydrogenation of polyunsaturated fat

supplements (vegetable oils)

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Origin of Long Chain Fatty Acids (LCFA) and Short Chain Fatty Acids in Milk Fat

Carbohydrates

Acetate-hydroxy-butyrate

Saturated, short chain fatty acids:C4, C6, C8, C10, C12, C14, C16

De Novo synthesis

Lipid

Long chain fatty acids(LCFA ≥ C16)

Saturated or unsaturatedlong chain fatty acids:

C16, C18, C18:1, C18:2, C18:3

“Direct”Incorporation of

LCFA

Diet

Blood/Lymph

Uddersecretory cells

Milk fat

Inhibition

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Role of Trans Fatty Acids (TFA) in Milk Fat Depression

Milk fat depression results from change in rumen hydrogenation (saturation) of fats rather than change in rumen VFA patterns. TFA are produced from incomplete saturation of polyunsaturated

fatty acids (PUFA). TFA in milk fat is high on high grain-fat depressing-diets. Vegetable or marine PUFA depress milk fat% even in diets with

normal amounts of forage. Addition of buffer decreases production of TFA in rumen,

decreases TFA in milk fat and alleviate milk fat depression Lower rumen pH (insufficient effective fiber) favors the production

of TFA with fat-depressing effects. Fat depression does not occur if rumen pH remains > 6.0

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Dietary Induced Milk Fat Depression

Erdman, Tri-State Dairy Conference 1996.

2.5

3.0

3.5

4.0

Milk fat, %

Reduced forageparticle size

High grain diet

High levels ofunsaturatedFatty acids

Milk fatdepression

Effective fiber

Buffer (rumen pHabove 6.0. Ac:pro ratio per se is not

important)Milk Fatrestoration

Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Summary and Implications

Milk biosynthesis - things to remember: Lactose synthesis:

depends on liver gluconeogenesis (glucogenic precursors), determines milk volume.

Protein (casein) synthesis: is regulated by DNA, relies on transamination of amino acids.

Fat synthesis: is the most variable of the main three components, depends upon ketogenic precursors.

Ultimately milk composition depends upon: breed / nutrition / management / environment / health.

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Dairy Nutrition (C) 2016 – Bogor Agricultural University (IPB)

Thank You

Better feed for better milk production and quality