MAMMARY IMMUNE SYSTEM Lactation Biology

Animal Science 337

Leo Timms

Iowa State University

ANATOMY AND PHYSIOLOGY

OF THE UDDER

Mammary Defense Mechanisms

skinTeat Shape * * heritable

Teat *placement

*** heritable

The Mammary GlandThe Mammary Gland

Streak Canal

Keratinepithelial cells, fatty

acids & cationic proteins

The Mammary GlandThe Mammary Gland

Furstenburg’s Rosette

Leukocyte Influx to Teat Cistern

MAMMARY GLAND IMMUNE SYSTEM

• Depends on mammary gland status

Lactating vs. Dry (involuted)

Normal (uninfected) vs. inflamed

NORMAL LACTATING GLAND (milk)

Cellular:• < 100,000 cells/ml (WBC or SCC)

• MǾ: 60-80%• PMN: 10-30%

• Lymphocytes: ~ 10 % (T and B) (some local Ig synthesis)

Humoral:• Low levels of Ig, complement, lactoferrin

INFECTED LACTATING GLAND (milk)

Cellular:• > 200,000 cells/ml (WBC or SCC)

• MǾ: 10 - 40%%• PMN: 50 - 90%

• Lymphocytes: ~ 10 % (T and B) (some local Ig synthesis)

Humoral:• Higher levels of Ig, complement, lactoferrin

NORMAL DRY GLAND

Cellular: Day in dry period . 50 d dry 1 2+3 10 10-25 25-45 45-50 cells/ml < 5 X 105 >106 >106 >106

Cell type MǾ PMN PMN/ MǾ Lym/ MǾ MǾ

Humoral: Lactoferrin high Complement low Ig: increase through dry period (colostrum)

• DILUTION? • SUSCEPTIBILITY?

Natural Teat Sealing

‘Open’ teats observed using the same method in NZ and Canada

7 14 21 28 35 42 49 63 77 9305

101520253035404550

NZ StudyCanadian Study

days dry

% 'o

pen

' tea

ts

0 1 2 3 4 5 60

20

40

60

80

100

Herd 1 Herd 2 Herd 3 Herd 4 Herd 5

Week of Dry Period

Pro

port

ion

Op

en T

eats

Results

Quarter Closure: Variable between herds

Results

Dry 1 2 3 4 5 60

10

20

30

40

50

60

70

80

90

100

< 21

> 21

Week of Dry Period

% O

pen

Qu

art

ers

Hazard Ratio = 0.56 P < 0.01

> 20% of heifer teats are open

prior to calving!!!

#’s or levels don’t tell whole story

1. Poor Ig transport across blood-milk membrane

• selective: colostrum (specific!)• Non specific: leakage

(not specific for Ag)• Immunize: IM, IP, IMM(local vs. systemic Ig)

#’s or levels don’t tell whole story

1. Cells in milk poorer than blood

• Lack of energy (glucose)• Lose 40% of granules

crossing membrane• Cells phagocytize fat and protein

CAN SCCGET

TOO LOW?