Neonatal immunity and colostrum Flashcards
Development of the immune system happens when
Develops in the fetus and or early neonatal life
When do pocket pets be considered immune system developed
Pocket pets with short gestation periods
Mice (21 days), rats
Considerable development of immune system after birth
When are larger animals immune system considered developed
Larger pets with long gestation periods
Dog (63 days), cow (274 days), horse (340 days)
Immune system nearly fully developed at birth
are the neonates of the common domestic species at special risk of infectious disease
Yes because the adaptive immune system is naive
What does naive mean?
No memory cells to grove a rapid, major, response
No preformed antibody at birth
What is in a naive immune system
The potential is present
Lymphocytes, macrophages, dendritic cells
For many antigens, the primary response is similar to that of adults.
Do neonates have innate immunity?
Similar to that in adults
What does the neonatal immune system need to be affective
They have a well developed adaptive immune system but is inexperienced
Needs exposure to pathogens to develop.
Memory
Production of circulating antibody
Passive immunity of neonatal
Neonates are protected in early life by transfer of antibodies from dam to neonate
Passive transfer of in neonates is and happens by
Dam provides protective Ig to keep the neonate healthy while its immune system develops
Passive because immunity is not made by neonate
Transferred via colostrum or placenta
Farm animals (all ruminants, pigs, horses) placenta transfer what
Maternal blood cells separated by vascular endothelium, connective tissue and uterine epithelium
No placental Ig transfer
Colostrum is essential
Cat and dog placental transfer of Ig
Some Ig transfer (10% of adult concentrations)
Colostrum is very important
Placental transfer of Ig from humans
Most of newborn’s Ig is from placenta, colostrum has only a small effect on neonatal disease incidence
Colostrum is
The first secretion of the mammary glands
Takes weeks to produce
Colostrum is rich in
Ig, especially IgG, is transported from serum into colostrum
Very rich in a variety of nutrients, lymphocytes, and immune regulator proteins
High in glucose
Colostrum looks like and is this way because
Colostrum is thicker and stickier (and yellower) than milk
Has a higher specific gravity
Basis of a test for colostrum quality
High in glucose
Colostrum vs milk
The first 2 milkings (and probably suckings in SA) are rich in Ig – true colostrum
Lactation begins at parturition
As the neonate sucks, colostrum is replaced with milk and residual colostrum is diluted
So, transition milk, produced for the first few days as change from true colostrum to true milk
Milk has much lower concentrations of Ig, most are synthesized in the mammary gland
Failure of passive transfer is
Colostral antibody is absorbed by neonate resulting in passive transfer of immunity.
The Ig provides protection in the first weeks of life
Failure of passive transfer refers to lack of significant absorption of cholesterol Ig by the neonate
Consequences of failure passive transfer
More infectious disease
More likely to die
Slower growth
Better response to vaccination
Most likely will die from hypothermia or hypoglycaemia
What percent of dairy calves have FPT
About 40% of dairy calves fail to obtain adequate colostral antibody.
Suffer more serious disease
More likely to die
What percent of calves will die when FPT
7% overall
10% of those that have FPT
How many beef calves will get FPT
6%
Overall mortality of beef calves with FPT
5%
How many foals get FPT
3%
Overall mortality of FPT in foals
5%
Importance of colostrum by species
Calves>foals>puppies and kittens
Due to environmental pressure
Colostrum is most important when
Colostrum is most important if neonate in a contaminated environment
Farm animals
Some farming practices reduce exposure of calves, lambs, piglets to infection
Washing rear end of cows
Dagging ewes also called cribbing
Lots of clean bedding
When is colostrum not as important
Very clean environment
solitary pet on clean bedding
No other animal contact
Factors Important in Preventing FPT/ Ensuring Adequate Transfer
Adequate antibody of colostrum
Adequate antibody concentration
Young must suck dam vigorously
Adequate absorption of Ig
Timing of closure
Adequate volume of colostrum is important for
Adequate nutrition
Heifer produce less volume then cows
Dairy cows is thinner
Adequate antibody concentration is affected by
Concentration declines rapidly with milking in all species
-Only feed first or second milking colostrum
Very high producing dairy cows produce dilute colostrum
-Do not feed to calf at birth, use colostrum from another cow
Some cows (and mares) leak colostrum before parturition
-Feed colostrum from an alternative source
Heifers lower Ig levels than cows
-Calves have more disease
-Occasionally calves are fed supplemental colostrum
Cattle require colostral IgG concentration > 60 g/L
-Sufficient antibody within constraints of calf’s normal intake
What can cause failure of calf to suck
Being born to a heifer
Assisted calving
Poor mothering
Being born in a stanchion
Premature birth
Being born a twin
Calves that are not sucking vigorously are usually tube fed colostrum
How does adequate absorption of Ig through colostrum work
Antibody is not digested due to reduced digestive enzymes in calf and enzyme inhibitors in colostrum
Mucosa of neonate is lined by specialized cells that are strongly pinocytotic and absorb antibody intact
When does gut closure start and what is it
Starting at birth these cells are gradually replaced by normal epithelial cells
Delaying feeding only affects this in the piglet
Leads to loss of Ig absorptive ability
Called CLOSURE
Timing of closure
In general, good absorption within 6 h of birth, little by 24 h after birth (all common domestic species). May be a slight delay in closure if not fed colostrum. Complete closure by 36 hours.
What to do with dams with multiple offspring for colostrum
Check that sufficient working teats
At least 1 per offspring
Can rotate newborns on teats
Best practice to get adequate colostrum in calves, foals, lambs and kids
Feed/suck within 6 hours of birth
The earlier the better
Closure occurs at 24h
Range is 6 to 36h
Only the first 2 milkings/suckings are a useful source of high levels of Ig
The first is the best
How to check colostrum quality and how it works
Can assess quality of colostrum with a colostrometer
These measure the SG (IgG) of the colostrum
A guid to Ig content
Commercially available
Follow instructions
Must be performed at room temp
Results are questionable if a lot of colostrum (>10L at first milking)
Used in dairies and vet clinics to check quality of colostrum
Frozen colostrum
Inexpensive
Collected form other dams on farm
Dairy cows often have surplus colostrum
Mares can be milked out (250 mL) after foal has sucked once
Stable for at least a year in freezer
Can feed bovine colostrum to lambs
Risk of occasional hemolytic anemia
Commercial colostrum replacer products are and benefits
Better if made from colostrum than blood
Some products contain very little Ig despite the name on the label
A good source: Saskatoon Colostrum Company
Products for calves
Headstart, Calf’s Choice Total, Colostrum 200
Need at least 80g Ig (read package fro quantity)
Also, products for lambs, kids, pets
Plasma transfusions are sued instead of colostrum when
Used in foals as a source of Ig
How much colostrum does a hand fed dairy calve that sucks get
Most hand fed dairy calves are allowed to suck
Aim for 2L(normal voluntary intake)
Either way, additional 2L about 8 hours later
Reluctant dairy calves are give
Reluctant dairy calves are tube fed
3 to 4L by esophageal feeder (45 kg calf)
Either way, additional 2L about 8 hours later
Beef calves are given how much colostrum
Beef calves, at least 1L by orogastric tube or bottle. Why less?
Colostrum (beef) is more concentrated
Foals are given how much colostrum
Aim for 2 to 3L colostrum divided between 3 or 4 feeds at hourly intervals
Bottle or nasogastric tube
When do you test for adequate colostrum intake
Performed around 24 hours of age
Antibody absorption mostly completed
Refractometry is and used for
calves, does not work in foals)
Measures total protein
Albumin plus globulins
No transfer TP <50g/L
Successful transfer TP>60 g/L
Use plasma or serum
Immunoassays is
ELISA : Antibody combined with an enzyme that produces a color change e.g. SNAP test
Immunoassays typically divide serum into 3 groups
Immunoassays complete failure of passive transfer
<400 mg/dl (4 g/L) of IgG
Complete failure of passive transfer
Give a plasma transfusion if > 16 h
Immunoassays partial failure of passive transfer
400-800 mg/dl (4-8 g/L) of IgG
Partial failure of passive transfer
Action depends on value of foal and perceived risk
Immunoassays succesful passive transfer
> 800 mg/dl (>8 g/L) of IgG
Types of immunoassays test
Precipitation tests
Zinc Sulfate Turbidity
Sodium Sulfite Turbidity
More turbid the better
Only done in clinic or lab
Glutaraldehyde agglutination
Only done in clinic or lab
Is it worth intervention of FPT?
Depends on value of offspring and level of risk
Foals (and very valuable calves) older than 16h need what if FTP
Plasma transfusion, typically 1-3L
Commercial Ig Supplements IV
Puppies get what if FTP
Serum- about 25ml/kg
The immune system of neonates of common domestic species at birth is?
Immunologically naive at birth
i.e. The immune system has not been primed
Some (minor) reduction in efficiency of immune system
A tube fed dairy calf should get how much colostrum and when?
3 to 4L (better) of colostrum within 4-6 hours of birth
