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Ag Animal Test 3 > Passive Transfer of Immunity > Flashcards

Passive Transfer of Immunity Flashcards

1
Q

Again, placentation of ruminants? What is the significance of this?

A
  • Synepitheliochorial

- Hypogammaglobulinemic

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2
Q

Describe the neonatal immune system again

A
  • Immunocompetent but naive
  • Immature system
  • Time delay for response
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3
Q

What is the implication of the neonatal immune system being immunocompetent but naive?

A
  • Maternal immunologic assistance is necessary
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4
Q

Does ingestion of colostrum = successful passive transfer?

A
  • NO
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5
Q

What is successful passive transfer of immunity?

A
  • TIMELY INGESTION and ABSORPTION of an adequate MASS of Ig (and other factors) by the neonate
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6
Q

What non-Ig components are in colostrum - specifically leukocytes?

A
  • Leukocytes (1x 10^6 cells /mL)
  • T lymphocytes (alpha and Beta)
  • B lymphocytes
  • PMNs (primarily udder defense)
  • MACs (cytokines and APCs)
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7
Q

What non-Ig components are in colostrum - specifically cytokines?

A
  • IL-2, TNF, IGF-1, TGF

- Limited data

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8
Q

Function of colostral leukocytes

A
  • Overall helpful but not required
  • Freezing, pasteurization
  • Traffic to lymph nodes and mucosal lymphoid structures
  • Enhances both innate and adaptive immunity
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9
Q

Failure of passive transfer defined by serum IgG (Bovine)

A

<1000 mg/dL @ 48 hours

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10
Q

Failure of passive transfer defined by serum IgG (Camelid)

A

<800 mg/dL @ 36-48 hours of age

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11
Q

What are the immediate and long-term risks associated with FPT?

A
  • Increased risk of death in the first 3 months

- In the future, decreased weight gain, future milk production, and survival past 1st lactation

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12
Q

What is responsible for 50% of dairy calf deaths?

A
  • FPT
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13
Q

Clinical signs of FPT?

A
  • NONE
  • They can look healthy or sick
  • You cannot detect this on physical exam
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14
Q

What are calves who have FPT at increased risk for?

A
  • Septicemia
  • Diarrhea
  • Enteritis
  • Omphalitis
  • Respiratory disease
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15
Q

Are the Ig levels for FPT set in stone?

A
  • No, they are ONLY GUIDELINES for Ig needed for protection
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16
Q

Other factors that play into protection of calves

A
  • Management
  • Environment
  • Infection pressure
  • Virulence
  • Antibody specificity, etc.
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17
Q

What are three factors that can help determine infection vs disease?

A
  • Animal
  • pathogen
  • Environment
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18
Q

What are the three mechanisms by which colostral Ig protect calves?

A
  • Lactogenic
  • Systemic
  • Enteric
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19
Q

Lactogenic protection

A
  • Ig binds and neutralizes pathogens in the gut

- This is independent of gut closure or absorption

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20
Q

Systemic protection by IgG

A
  • Must be absorbed

- Goes into circulation

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21
Q

Enteric protection by IgG

A
  • IgG secreted back into the gut
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22
Q

What are the two mechanisms that must occur for passive transfer to take place?

A
  1. Transfer of IgG from maternal serum to colostrum

2. Transfer of colostral IgG from neonate’s gut to ECF

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23
Q

How does IgG get from the maternal serum to colostrum?

A
  • Active
  • Selective
  • Receptor mediated
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24
Q

Which Ig is selected to be moved from maternal serum into colostrum?

A
  • IgG1 > IgG2, IgM, IgA
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25
Q

When do maternal antibodies go from the serum to the colostrum?

A
  • 4-6 weeks prepartum
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26
Q

Features of absorption process of IgG to the calf

A
  • Non-selective
  • Saturable (you can screw up)
  • Non-receptor mediated
  • “Closure”
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27
Q

What is absorbed from the calf gut when it’s open?

A
  • IgG1
  • Also IgG2, IgM, IgA, albumin
  • And whatever else
  • You can screw this up
28
Q

Factors associated with successful passive transfer

A
  1. Formation of colostrum with adequate IgG concentration by the dam
  2. Ingestion of an adequate mass of IgG by the neonate
  3. Timely absorption of IgG by the neonate
29
Q

Colostral immunoglobulin concentration - what can cause variation?

A
  • Dairy vs beef (dairy is much less concentrated)
  • Breed (jersey and Holstein > Brown Swiss, Ayrshire)
  • Individual
  • Parity
  • Nutrition, environmental factors, etc.
30
Q

Colostral IgG1 in Beef vs dairy

A
  • Dairy heifers have the lowest concentration

- Even crappy beef cow colostrum is usually better than dairy cow colostrum

31
Q

What is the goal for ingestion of adequate mass of IgG1?

A
  • 150-200g x 1gG1

Mass = concentration x volume

32
Q

What can lead to a failure to ingest colostrum?

A
  • Mothering (or lack thereof); heifers and maidens at risk
  • Teat conformation
  • Hard milkers
  • Weak, stressed neonate
  • Dummy
  • Multiple neonates
33
Q

When does the gut close in the neonate?

A
  • around 24 hours
  • Linear closure
  • The longer you wait, the worse it is
34
Q

Why does gut closure timing matter?

A
  • Age at first feeding is crucial
35
Q

What other things are transferred along with IgG?

A
  • Cytokines, proteins, growth factors, enzymes, cofactors, other cells
36
Q

Who tends to get FPT: beef or dairy?

A
  • In beef, it’s 5% FPT

- In dairy, it’s up to 39%

37
Q

What is the best way to measure passive transfer in bovine?

A
  • Serum refractometry
38
Q

Other ways to measure FPT

A
  • SRID
  • Zn sulfate
  • Na sulfite
  • Glutaraldehyde coagulation
  • Serum refractometry
  • Serum GGT
  • Latex agglutination
  • Enzyme immunoassay
39
Q

What is often underlying cause of FPT in dairy?

A
  • Low IgG concentration in colostrum
40
Q

What is the best way to perform FPT assessment, and what’s the predictive value?

A
  • REFRACTOMETRY

- Reasonable predictive value

41
Q

What values of refractometry are normal? Which suggest FPT?

A
  • > 5.2-5.5 suggests adequate PT
  • <4.5 ish suggests FPT
  • Birth = 4.5-4.9 g/dL
42
Q

Sample type for measuring FPT

A
  • Blood off the baby in the first 24-48 hours
43
Q

Limitations of refractometry as a measure of FPT

A
  • Dehydration or illness

- Acute phase proteins

44
Q

Refractometry in camelids?

A
  • CANNOT DO TO ASSESS FPT
45
Q

Can you assess colostrum based on appearance?

A
  • NO
46
Q

Immunoassays to measure colostrum quality

A
  • Good sensitivity and specificity
  • Not very available
  • Increased cost
47
Q

Colostrometer/hydrometer for colostrum quality

  • Sensitivity and specificity
A
  • 43% of dairies use this
  • Measures SG
  • Low sensitivity for poor colostrum (2/3 deemed okay)
  • Temperature sensitive and fragile
48
Q

Optical refractometry for colostrum quality

A
  • Decent sensitivity and specificity
  • Not temperature sensitive
  • Not fragile
  • Frozen or fresh colostrum
49
Q

What % on a Brix (optical) refractometer is adequate?

A

> 22% Brix = 50 g/L

50
Q

Best way to measure colostrum quality in dairy cattle?

A
  • Brix refractometer
51
Q

Best colostrum practices in dairy

A
  • Milk the cows ASAP (decreased IgG every hour)
  • Measure colostrum quality
  • Feed 150 g IgG1 in the first 4 hours or feed 7.5% body weight
  • Feed additional 5-7.5% body weight by 12 hours
  • Pasteurize if Johne’s, Salmonella, Mycoplasma, or BLV
  • Avoid pooling (or pool similar quality)
  • Monitor for FPT
52
Q

Beef best colostrum practices

A
  • Avoid severe dietary intake precalving 9decreases colostrum volume and increased viscosity)
  • Minimize disruption of calving
  • Monitor and ensure suckling within 6 hours
  • Intervene if dystocia or dummy calf
53
Q

What is best intervention if dystocia or dummy calf?

A
  • Restrain dam

- Milk dam and bottle (best) or tube if needed

54
Q

Which is better: bottle or tube feeding for colostruM?

A

Bottle

55
Q

What should you do to get colostrum in an animal if its unable to nurse?

A
  • Milk out dam or other female
  • Bottle/tube 3-4 quarts in the first 2 hours, repeat in 12 hours
  • Frozen colostrum (diseases to consider are Johnes, CAE, etc.)
56
Q

Commercial colostrum products

A
  • Read the label
  • Substitutes vs replacers
  • if they contain IgG, they are regulated by the USDA
57
Q

Colostrum supplements

A
  • Provide exogenous IgG to supplement poor quality colostrum
  • Provide 25-60 g IgG
  • 1 dose is inadequate
  • Inadequate nutrients
58
Q

Colostrum replacers

A
  • Fed instead of maternal colostrum
  • Provide minimum of 100g IgG
  • Adequate nutrients
  • Expensive
59
Q

Which is better: colostrum supplement or colostrum replacer?

A
  • Colostrum replacer in general
60
Q

Which is better: colostrum origin or serum origin colostrum replacers?

A
  • Colostrum origin (similar nutrients, hormones, growth factors; lack cell wall components)
  • By contrast, serum origin has a different process and is only approximately 20% Ig
61
Q

Canadian CR and CS

A
  • All CR prouducts licensed through CFIA

- Plasma derived CR or CS not permitted

62
Q

USA CR and CS - licensed

A
  • Only some manufacturers licensed through USDA, CVB

- Potency, purity, efficacy, regulated

63
Q

Non-licensed CR and CS

A
  • Can’t legally claim to supply IgG or purport to be used as a CR or CS, or prevent FPT
  • But often used for this purpose
64
Q

How should you select CS/CR?

A
  • Select those that undergo independent evaluation for efficacy in field studies
  • Consider PT of IgG, nutritional support, health, and performance
  • Consider dose of IgG
  • Consider apparent efficacy of absorption
65
Q

Apparent efficacy of absorption

A
  • % fed compared to amount absorbed systemically
  • IgG mass (dose)
  • Manufacture methods
  • Other nutrients and additives
66
Q

Colostrum supplements and substitutes summary of effects and when to use

A
  • Generally don’t raise the IgG adequately
  • Insufficient quantities of Ig
  • Ingredients vary
  • Often labeled as colostrum replacers
  • Maybe could give pre-emptively
67
Q

How to treat suspected FPT

A
  • Plasma or whole blood (20-40 ml/kg IV or IP)

Oral colostrum??? (Lactogenic but not systemic immunity)

  • Supportive care (Antibiotics, NSAIDs, nutrition, environment)

Ag Animal Test 3 (7 decks)

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