Week 10- Failure of Passive Transfer Flashcards
Are foals born with a fully functional immune system?
No
What term describes the state of a foal’s immune system at birth?
Immunocompetent but immunologically naïve
What do foals rely on for immune protection early in life?
Colostrum and non-specific defense mechanisms
Which immune cells in neonatal foals have reduced pathogen killing ability?
Phagocytes
What is the effect of colostrum on innate immune factors like complement and lactoferrin?
Increases their levels after transfer
What is the limitation of antigen presentation in neonatal adaptive immunity?
Decreased capacity
When is IgGb detected in foals?
After 63 days
Why can’t foals receive antibodies via the placenta?
Because horses have an epitheliochorial placenta
How do foals absorb immunoglobulins from colostrum?
Through pinocytosis in the gut
How long after birth does passive transfer of immunity occur?
Only in the first 6–12 (up to 36) hours
At what age is immunoglobulin absorption most efficient in foals?
At birth
How much immunoglobulin is absorbed at birth?
50–60%
When is there little absorptive capacity for colostrum left?
After 12 hours
What prevents breakdown of colostral proteins in the GI tract?
Trypsin inhibitor in colostrum
What is the peak timing for IgG levels in foal blood?
18–24 hours
Name three immunoglobulins found in colostrum.
IgG
What percentage of adult complement activity is present at birth?
0.13
What type of immune cells from the mare can be found in the foal’s blood?
T lymphocytes
What IgG level is considered adequate for passive transfer?
> 8 g/L
What is the half-life of colostrally derived antibodies?
20–30 days
When does the antibody trough typically occur?
Between 6–12 weeks of age
Why should mares be kept at the foaling site before foaling?
To ensure local disease-specific antibody development
What are the two main causes of FTPI?
Insufficient intake and poor-quality colostrum
What IgG level defines complete failure of passive transfer?
<4 g/L
What IgG level defines partial failure of passive transfer?
4–8 g/L
What is a common FTPI incidence range in foals?
3–39%
Name one mare factor that reduces colostrum quality.
Milk leakage before foaling
Name one foal factor that causes ingestion failure.
Weakness or illness
What happens when bacterial challenge exceeds the immune response?
Sepsis
What percentage of healthy foals had positive blood cultures in one study?
0.57
How many colostrum-deprived foals fed milk replacer developed sepsis?
7 out of 8
What are possible negative outcomes of FTPI?
Death
How does the management setting affect FTPI outcomes?
Extensively managed foals show stronger FTPI-mortality link
What is the gold standard for IgG testing?
Radial immunodiffusion (RID)
What is a faster quantitative alternative to RID?
Immunoturbidimetric assay
What test is commonly used on farms for IgG?
SNAP ELISA
At what time should foals be tested for IgG?
From 12 hours
What IgG result requires essential treatment?
<4 g/L
What is the treatment for FTPI after gut closure?
IV plasma transfusion
How much plasma typically raises IgG by 2–3 g/L?
1 liter
What should be used to administer plasma?
Blood giving set with filter
What IgG level should donor plasma have?
> 1200 mg/dL
Why is self-harvested plasma riskier?
Risk of neonatal isoerythrolysis and infection
What are signs of plasma transfusion reaction?
Increased RR/HR
What protein may cause anaphylaxis in foals receiving plasma?
Bovine serum albumin (BSA)
How should colostrum substitutes be defrosted?
Slowly in warm water (never microwaved)
What Brix refractometer reading indicates excellent colostrum?
> 30%
How much colostrum should be stored for a bank?
250 ml from good quality source
What is a last-resort colostrum source if equine is unavailable?
Bovine colostrum
What is the primary goal in managing FTPI?
Prevention
How soon should treatment begin if FTPI is suspected?
As early as possible
