Module 4- Immunity-Development in the Fetus and Newborn

T or F: In domestic animals- the immune system is fully developed before birth

True

What are newborns susceptible to?

Microbial infection

What type of response do newborns mount every time a microbe invades

Primary response

What is the fetus’ first organ to develop?

Thymus

What are the secondary lymphoid organs to develop in a fetus?

Spleen, lymph nodes, bone marrow

When are most species capable of an immune species

2nd trimester

What is passive immunity?

Transfer of antibodies from actively immunized host (mom) to a non immune host (baby)

Why should a pregnant animal should be housed where they give birth for at least two weeks prior to parturition?

What are the 2 ways passive immunity is done through?

• colostrum

• Placenta

What % of transfer do carnivores get in utero

5-10%

What species have NO placental transfer?

• Equine

• Ruminants

*colostrum is critical immediately

What types of antibodies are found in colostrum?

• IgG

• IgA

• IgE

• IgM

When is permeability of colostrum highest

First 6 hours after birth

Shuts down after 24 hours

What does it mean that passive immunity is transitory?

Protects the young until its own immune system can kick in and build its own response

What do bottle fed babies suffer more from than nursing babies?

Stomach upsets & diarrhea

(Because antibody secretions in milk provide local immunity in gastrointestinal system)

If a new born doesn’t receive enough _____ they are most likely to get sick and die

Antibodies

List 7 reasons why insufficient ingestion of colostrum can happen. (Baby didn’t receive enough antibodies)

• Low concentration of Ab in colostrum

• Young mother

• Non vaccinated mother

• Baby didn’t eat enough

• Poor udder conformation

• Weak newborn

What are 3 reasons for insufficient absorption of colostrum

• delay in receiving colstrum (more than 6 hrs)

• Interference in efficiency of absorption (stress)

• Pre/post mature babies less able to absorb

What is the time window that we should test for failure of passive transfer

24-48hours after birth

How do we diagnose failure of psssive transfer?

Measure serum antibody levels using refractometer to check total protein

• zinc or sodium sulfate turbidity test

• Serum electrophoresis

What are the antibody level meanings when testing with serum electrophoresis (what # is good and bad)

Less than 200 mg/dl = TREAT

200 - 400 mg/dl = WATCH CLOSELY

Over 400 mg/dl = GOOD PASSIVE TRANSFER

How many g/dl means antibody levels are good in calf serum on refractometer and how many g/dl means it should be treated w plasma

>6.0 g/dl = GOOD

<5.0 g/dl = TREAT W PLASMA

What % of body weight in colostrum should calves get within the first 6 hours of birth

5-10% body weight in colostrum within 6hr of birth

How long is frozen colostrum good for

1 year

If calf isn’t sucking colostrum, what do we do?

Tube feed

How long does the refractory period last (development of immune response in neonatals)

Many months

True or False: During refractory period, maternal antibodies will not protect the animal from getting a disease

True

If mother was exposed to disease, she will given her offspring “neutralizing antibodies”. Makes it so they cannot mount immune response to fight off disease

How are maternal antibodies passed to chicks?

Yolk

How long do chicks absorb antibodies after hatching

24hr

What is Infectious Bursal Disease?

Infects Bursa of Fabricius

• destroys B-lymphocytes resulting in immunosuppression