mammary immune system lactation biology animal science 337 leo timms iowa state university
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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?