Neonatal Immunity And Colostrum Flashcards
Describe the development of the immune system in pocket Pete with short gestation periods
Mice(21 days), rats
Considerable development of the immune system AFTER birth
Describe the development of the immune system in larger pets/farm animals with long gestation periods
Dogs (63 days), cow (274 days), horse (340 days)
Immune system is nearly fully developed AT birth (still at high risk of disease since the adaptive immune system is naive-no memory, has had no exposure to pathogens so there is no memory cells to give a rapid response or preformed antibody in the blood at birth) but they have the frame work (lymphocytes, macrophages and dendritic cells (innate))
Response to antigens will be the same as in adults just no memory
Because a neonates adaptive immune system is developed by inexperienced, how does passive transfer aid in the first while of life
Dam provides protective antibody to keep the neonate healthy while the immune system develops
Passive because the immunity comes from the dam, and is not made by the neonates own immune system
Transferred via the colostrum or placenta
Describe the placental route of passive transfer in farm animals (all ruminants, pigs and horses)
Maternal blood cells separated by vascular endothelium, connective tissue and uterine epithelium, this results in NO placental antibody transfer
This makes colostrum essential for these animals
Describe the placental route of passive transfer in cats and dogs
There is SOME placental antibody transfer (10% of adult concentrations)
This makes colostrum very important to these animals
Describe the placental route of passive transfer in humans
Most of the newborns antibody is from the placenta, colostrum has only a small effect on the neonatal disease incidence
Describe the production of colostrum
Colostrum is the first secretion produced by the mammary glands of the common domestics species
It takes weeks to produce (not hours) in prep for birth (milk after wards is produced fast)
Antibody (especially IgG) is transported from serum into colostrum
The first 2 milking (suckings) are rich with antibody (true colostrum)
Describe the composition of colostrum
Rich in a variety of nutrients, lymphocytes and immune regulatory proteins
Colostrum is thicker and stickier and yellower than milk (has a higher specific gravity which is the basis for testing for colostrum quality)
What does having a high specific gravity mean
More “stuff” or solutes suspended in the liquid or solvent
Lactation beings
At parturition
As the neonate continues to suck from the dam, what happens to colostrum
Colostrum is replaced with milk and residual colostrum becomes diluted (transitions to milk for the first few days)
True colostrum changes to true milk
Milk has a much lower concentration of antibody, most are synthesized
In the mammary gland
Colostrum antibody is absorbed by the neonate resulting in passive transfer of immunity, what does this antibody do
Provides protection in the first weeks of life (until it is replaced or dies off)
What is failure of passive transfer?
Refers to the lack of significant absorption of colostrum antibody by the neonate
Neonatal digestive tract is undeveloped at birth, how does this aid in passive transfer
The undeveloped digestive tract allows large antibody proteins to be absorbed without being broken down
In what animals is failure of passive transfer most significant in
Farm animals since immunity depends completely on colostrum (no placental transfer)
True or false
If the mom is vaccinated, the colostrum will have those antibodies to give to the neonate
True
Without colostrum, what can occur
Slower growth
More infectious disease prevalence
More deaths
More deaths from hypothermia/hypoglycemia
True or false
Without receiving colostrum, neonates have a better response to vaccines?
True
Because there is no circulating antibody from colostrum to fight off the vaccine antigens (this is why the first serious of vaccinations is done with 3 successive rounds, to ensure it was not broken down by passive transfer immunity)
About ___% of dairy calves fair to attain adequate colostrum antibody
40%
These suffer more serious disease and are more likely to die
Put the follow animals in order of highest to lowest need for colostrum
Kittens, foals, calves, puppies
Calves > foals > puppies and kittens
Difference in disease and death of neonates are due to
Environmental pressure and the neonates circumstances (cleanliness of environment)
Dirt environments (farms) result in a greater need for colostrum
What are some ways farming practices reduce exposure of calves, lambs and piglets to infection
Washing the rear end of the dam before parturition
Dagging (clipping hair of the hind end, udder and vagina) especially in ewes (wool is a huge contaminant and it makes it easier for neonate to nurse)
Lost if clean bedding
When would environmental situations result in a lesser need for colostrum
Solitary animals on clean bedding
No other animal contact
What are the 4 general factors in preventing failure of passive transfer and ensuring adequate transfer of colostrum immunity
Ensuring Adequate volume of colostrum
Ensuring and equate antibody concentration in colostrum
Ensuring good sucking by the neonate
Ensuring adequate absorption of the antibody
describe how you can ensure adequate volume of colostrum is provided
Adequate nutrition of the dam
Heifers produce less volume than cows
Describe how you can ensure adequate antibody concentration of colostrum
Concentrations decline with milking in all species (only feed first it second milking of colostrum)
Very high producing dairy cows produce very dilute colostrum (do not feed to calf at birth, use colostrum from another cow)
Some cows/mares leak colostrum before parturition (may have to feed colostrum from another source)
Heifers have lower antibody concentrations that cows (younger/exposed to less) (calves may be fed supplemental colostrum)
Cattle require colostrum antibody concentration of
> 60g/L
Sufficient antibody Within constraints of calf’s normal intake
Neonates much suck dam vigorously (good sucking reflex), what are the risk factors for FAILURE) To suck strongly in calves
Being born to a heifer Assisted calving (not natural birth) Poor mothering Being born in a stanchion (not natural) Premature birth Being born a twin
Why would being born a twin result in failure of passive transfer?
Dam still produces the same amount of colostrum they would for single neonate
Calves that are not sucking vigorously are usually
Tube fed colostrum
Describe what happens in the neonates stomach that results in adequate absorption of antibody
Antibody is not digested due to reduced digestive enzymes in the calf and enzyme inhibitors in colostrum
Mucosa of a neonate is lined with specialized cells that are strongly pinocytotic (cell drinking) and absorb antibodies intact
Starting at birth these cells are gradually replaced by normal epithelial cells (delaying feeding only affects this in piglets) -leads to loss of antibody absorption. This is called CLOSURE
When should colostrum be ingested? What happens if this does not occur?
In general, good absorption within 4 hours of birth, little by 24 hours after birth (tapering absorptive abilities) (all domestic species)
Closure will begin (completes by 36 hours) so colostrum must be fed before this
Describe colostrum management in dams with multiple offspring (dogs, cats and pigs)
Check that there are sufficient working teats (at least 1 per offspring)
Can rotate newborns on teats (especially is some are poor functioning)
Describe colostrum management in dams that typically have one or two offspring (cows, foals, lambs, humans)
Feed/suck within 4 hours of birth -the earlier the better (closure at 24 hours but range is 6-36h -stretching it)
Only the first 2 milkings/suckings are a useful source of high levels of antibody (first is the best)
How can you check the quality of colostrum prior to feeding
Can assess quality of colostrum with a colostrometer
These measure the specific gravity of colostrum (a guide to the antibody content)
Commercially available (follow instructions, must be performed at room temp, results are questionable if there is a lot of colostrum >10L at first milking)
Used in dairies and vet clinics
If the need for an alternative source of colostrum is needed, what are the two most common sources?
1) frozen colostrum
2) commercial colostrum replacer products made from colostrum or blood
Describe frozen colostrum
inexpensive
Can be collected from other dams on the farm
Dairy cows often have surplus colostrum
mares can be milked out (250ml) after foal has sucked once
stable for at least 1 year in freezer
can feed bovine colostrum to lambs (risk of hemolytic anemia)
Describe commercial colostrum replacer products
Better is made from colostrum than blood. Blood antibody is only moderately absorbed
Some products contain very little antibody despite the name on the label (These often have a name like COS… followed by milk supplement or nothing)
A good source: Saskatoon colostrum company
These are often sold by veterinary practices because they are convenient and there is no risk of farm to farm transmission of disease
A potential third source of antibodies is to give
IV plasma transfusions (used in foals)
Most hand fed dairy cows are allowed to suck, how much should be ingested
Aim for 2L (normal voluntary intake)
Reluctant dairy calves are usually tube fed, how much are they normally fed?
3-4L by esophageal feeder (45kg calf)
Feed additional 2L about 8 hours later
Beef calves are fed at least 1L by nasogastric tube or bottle, why is this less than a dairy calf?
Antibody in Colostrum from beef cows is much more concentrated because they don’t make as much milk as dairy calves
How much colostrum should foal ingest
Aim for 2-3L of colostrum divided between 3-4 feedings at hourly intervals
By bottle or nasogastric tube
Some neonates are checked to seen if they have achieved adequate passive transfer (valuable or if there is a herd problem), what are the testing methods
Done on SERUM
Refractometry
Immunoassays
Glutaraldehyde agglutination and precipitation tests
Describe refractometry
Works on calves but NOT on foals
Measures total protein (albumin plus globulins)
No transfer: TP <50g/L
Successful transfer: TP >60g/L
Describe immunoassays
Used on foals
Based on ELISA: enzyme-linked immunosorbent assay
Antibody combined with an enzyme that produces a color change (SNAP tests)
Immunoassays typically divide serum into 3 groups
1) <400mg/dL of Ig: complete failure, give plasma transfusion if >16h (too late to give colostrum)
2) 400-800mg/dL of Ig: partial failure, action depends on value of the foal and perceived risk
3) >800mg/dL of Ig: successful
Describe glutaraldehyde agglutination and precipitation tests
Produce turbid (opaque/cloudy) solutions when there is enough antibody
Zinc sulfate turbidity
Sodium sulfite turbidity
The more turbid the better
describe the assistance needed for failure of passive transfer in older neonates
Intervention depends on value of the offspring and the level of risk
foals and valuable calves older than 16h:
- plasma transfusion (1-3L of plasma) - commercial Ig supplements IV
Puppies
- rare since they get most Ig from placental transfer - SQ serum (about 25ml/kg)
A dairy calf should get ___L (tube fed) of colostrum within ___hours of birth
3-4L
4 hours
Bottle fed cakes should get at least __L within ___ hours of birth, and should get another ___L ___ hours later
2L
4 hours
2L
8 hours
