12 - Neonatal Immunity and Colostrum

Question 1

When does the immune system develop?

Answer 1

in the fetus and/or early neonatal life
- pocket pets w/ a short gestation period like mice (21d) and rats, considerable development of immune system after birth
- Lger pets with long gestation periods like K9 (63d), cow (274d), horse (340d), the immune system is nearly fully developed at birth

Question 2

Are neonates of common domestic species at a special risk of infectious disease? T or F

Answer 2

Yes, because the adaptive immune system is naive

Question 3

What does naive mean in regards to the immune system?

Answer 3

no memory T cells to give rapid, major, response
no preformed antibody at birth

Question 4

What cells are present in a neonate’s immune system?

Answer 4

lymphocytes, macrophages, dendritic cells
for many antigens, primary response is sim to adults

Question 5

Do neonates have innate immunity?

Answer 5

Yes, innate means born with it. So it its similar to that of an adult
They have well developed adaptive immune system but it is inexperienced and will need exposure to pathogens to develop memory and production of circulating antibody

Question 6

What is passive immunity?

Answer 6

neonates are protected in early life by transfer of antibodies from dam to neonate

Question 7

What is passive transfer of antibodies?

Answer 7

the dam provides protective Ig’s to keep the neonate healthy while its immune system develops.
Passive because immunity is not made by neonate and transferred bc via colostrum or placenta

Question 8

Explain how placentation and transfer of Ig’s are in farm animals, k9’s and feels, and humans

Answer 8

Farm Animals (Ruminants, pigs, horses) - maternal blood cells separated by vascular endothelium, CT and uterine epithelium, no placental Ig transfer,need colostrum
Fel/K9 - some Ig transfer (10% of adult concentrations), colostrum very important
Humans - most newborns IG is from placenta, colostrum only sm effect on neonatal dz incidence

Question 9

What is colostrum?

Answer 9

the first secretion prod by mammary gland of common domestic species.
takes weeks to produce
ig, especially IgG, is transported from serum into colostrum
colostrum is rish in variety of nutrients, lymphocytes, and immune regulator proteins
colostrum is thicker + stickier + yellower than milk and has higher specific gravity. A basis of a test for colostrum quality

Question 10

At what point does colostrum go to milk? What are the differences?

Answer 10

1st 2 milkings are rich in Ig - true colostrum. Lactation begins at parturition
As neonate suckles, colostrum replaces with milk and residual colostrum is diluted
milk is then produced for 1st few days as change from true colostrum to true milk
milk has lower conc of Ig, most are synthesized in mammary gland

Question 11

What are the differences between colostrum and milk?

Answer 11

Colostrum - more Ig’s, nutrients, lymphocytes, immune regulator proeins, IgGs, higher specific gravity, thicker, stickier, more yellow, high in glucose
Milk - less Ig’s, pale white,

Question 12

What is failure of passive transfer?

Answer 12

colostral antibody is absorbed by neonate = passive transfer of immunity to provide protection for first weeks of life
FPT refers to lack of significant absorption of colostral Ig by the neonate

Question 13

What are the consequences of not recieveing colostrum or FPT?

Answer 13

More prone to infectious diseases, death(from hypothermia and hypoglycemia), delayed growth, better response to vx’s

Question 14

What is the morbidity and mortality of FPT?

Answer 14

about 40% of dairy calves fail to obtain adequate colostral antibody and are more likely to suffer from serious disease and more likely to die

Question 15

What is the incidence IPT %, Mortality in IPT group % and overall mortality % in bovine - dairy calves

Answer 15

40% incidence IPT
10% mortality in a group
7% overall mortalitiy

Question 15

What is the incidence IPT %, Mortality in IPT group % and overall mortality % in bovine - beef calves

Answer 15

6% incidence IPT
5% mortality in IPT group
5% overall mortality

Question 16

What is the incidence IPT %, Mortality in IPT group % and overall mortality % in foals (0-12)

Answer 16

3% incidence IPT
0% mortality in IPT group
5% overall mortality

Question 17

List calves,f oals, puppies and kittens from most to least important in getting colostrum

Answer 17

calves>foals>puppies> and kittens

Question 18

In regards to FPT and dz, does environment play a role?

Answer 18

Colostrum is very important if the neonate is in a contaminated environment
some farming practices reduceexposure of calves, lambs, piglets to infection by washing rear end of cows, digging ewes, and clean bedding
Colostrum is less important if the environment is very clean, such as solitary pet on clean bedding and no other animal contact

Question 19

What is adequate Ig concentration? What do we need to be aware of and keep in mind?

Answer 19

Con declines rapidly with milking in all species (only feest 1st or 2nd milking colostrum)
very high prod dairy cows prod dilute colostrum (do not feed to calf at birth, use from another cow)
Some cows (and mares) leak colostrum b4 parturition (feed colostrum from alt source)
heigers have lower Ig lvls than cows - calves have more dz, sometimes calves fed supplemental colostrum
cattle req colostral IgG conc of >60 g/L - sufficient Ig within constraints of calf’s normal intake

Question 20

What are some factors that may lead to failure of a strong suckle reflex?

Answer 20

being born to a heifer *
assisted calving, poor mothering, born in a stanchion or a twin, and premature birth
calves not sucking vigorously are normally tube fed colostrum

Question 21

How does the bodily process of absorbing Ig’s and colostrum work?

Answer 21

Ig not digested due to reduced digestive enzymes in calves and enzyme inhibitors in colostrum
mucosa of neonate is lined by specialized cells that are strong pinocytotic and absorb antibody intact
starting at birth, these cells are gradually replaced by normal epithelia cells - delaying feeding only affects this in piglets, also leads to loss of Ig absorption ability and called CLOSURE

Question 22

What is the timing of closure?

Answer 22

In general, good absorption falls within 6h of birth, little by 24h after birth (common in all domestic species)

may be a slight delay in closure if not fed colostrum and complete closure by 36hrs

Question 23

For colostrum management, what is the best practice for calves, foals, lambs and kids

Answer 23

Feed/suck within 6hrs of birth - earlier the better, closure @24hr but can range from 6-36h
Only the first 2 nurses are useful source of high lvls of Ig but the first is best

Question 24

How can we check colostrum quality prior to feeding?

Answer 24

We can asses quality of colostrum with a colostrometer
these measure the SG of the colostrum (a guide to Ig content)
is commercially available but must follow instructions, perform at room temperature. Results can be questionable if a lot of colostrum (>10L at first milking)
used in dairies and vet clinics to check quality of colostrum

Question 25

What are some alternative colostrum

Answer 25

Frozen colostrum
commercialc olostrum
plasma transfusions

Question 26

What is frozen colostrum? Benefits? Side effects? How to use?

Answer 26

frozen colostrum - it is inexpensive, collected from other dams on farm, dairy cows often have surplus colostrum, mares can be milked out (abut 250L) after foal has sucked once, stable for 1yr in freezer, can feed bovine colostrum to lambs but there is a risk of occasional hemolytic anemia

Question 27

What is commercial colostrum-replacers? Benefits? Cons? Use?

Answer 27

Better if made from colostrum than blood, some products contain very little Ig despite the name on the label
a good source : Stoon colostrum company - products for calves, Headstar, Calf’s Choice Total, Colostrum 200, need at least 8-G Ig, also products for lambs, kids and pets

Question 28

What is plasma transfers in regards to alternative colostrum methods?

Answer 28

used in foals as a source of Ig

Question 29

What amount of calves need daily, what about if they are tube fed< beef calves? foals?

Answer 29

Most hand fed dairy calves allowed to nurse for ~2L
Reluctant calves are tube fed about 3-4L by esophageal feeder (45Kg calf)
either way, additional @L about 8hr later
beef calves, at least 1L by orogastric tube or bottle, they are less bc beef colostrum is more concentrated
in foals, aim for 2-3L colostrum divided btw 3 or 4 feeds at hrly intervals, by bottle or nasog tube

Question 30

How can we check for a successful transfer?

Answer 30

performed around 24hrs of age - Ig absorption mostly completed
refractometry (calves, does not work in foals) - measures total protein like Albumin and globulins, no transfer TP is <50g/L, successful transfer TP is .60g/L
test by precipitation tests like zinc sulfate turbidity, sodium sulfite turbidity, more turbid the better
and by glutaraldehyde agglutination

Question 31

What are immunoassays?

Answer 31

Ways to check for successful transfer in foals
by ELISA: antibody combined w/ an enzyme that produces a color change or a SNAP test
Divide serum into 3 groups

Question 32

What are the rates of incomplete, partial failure and successful transfer of antibodies? FPT

Answer 32

<400 mg/dl (4g/L) of IgG: complete FPT, give plasma transfusion if >16hr
400-800 mg/dL (4-8)g/L of IgG: partial FPT, action depends on value of foal and perceived risk
>800mg/dL (>8g/L) of IgG : successful PT

Question 33

What questions might arise when FPT is present and we might need to intervene?

Answer 33

Value of offspring and lvl of risk
Foals (and very valuable calves) older than 16hr will need plasma transfusion, typically 1-3L and may need commercial IG supplements IV
Puppies (though rate) will ned SC serum - about 25ml/kg

Question 34

The immune system of neonates of common domestic species at birth is?

Answer 34

immunologically naive at birth - the immune system has not been primed, some minor reduction in efficiency of immune system
colostrum is the cure