MAMMARY IMMUNE SYSTEM Lactation Biology Animal Science 337 Leo Timms Iowa State University
ANATOMY AND PHYSIOLOGY OF THE UDDER
Mammary Defense Mechanisms skin Teat Shape * * heritable Teat * placement
* * * heritable
The Mammary Gland Streak Canal Keratin epithelial cells, fatty acids & cationic proteins
The 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: % PMN: % 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 cells/ml 10 6 >10 6 >10 6 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
Results Quarter Closure: Variable between herds
Results 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 SCC GET TOO LOW?