Management and Clinical Examination of Neonatal Ruminants (not done)

T/F all livestock species are born hypogammaglobulinemic?

True

What is the significance of all livestock species being hypogammaglobulinemic at birth?

They are immunocompetent, but are immunologically naive

For the first 3-6 weeks, what protects neonates?

Immunoglobulin from colostrum

When does colostrogenesis begin?

5 weeks prior to parturition

What % of whey protein in colostrum is immunoglobulins?

>95%

What does transport of IgG into colostrum cause in cows?

Decrease in serum total protein, globulin, and IgG (cannot give dams plasma to neonate because they are deficient)

What are the components of colostrum?

Nonspecific antimicrobial factors, vitamins, minerals, IgG, growth factors, hormones, colostral fat

What helps develop the microbiome of a calf?

Colostrum

What are the Ig in colostrum?

IgG, IgM, IgA

What is the largest Ig in colostrum?

IgG (specifically IgG1)

What are the nonimmunological benefits of colostrum?

Improved daily weight gain and feed conversion

Decreased preweaning morbidity and mortality

Increased milk production in 1st and 2nd lactation

Enhanced development of GI tract

What is transfer of passive immunity?

Timely ingestion and absorption of an adequate mass of IgG

How long do enterocytes non-selectively absorb immunoglobulins?

24 hours (enteric absorption is time sensitive)

What is an adequate amount of passive immunity in dairy calves?

10g/L IgG in serum

How do we get enough passive immunity in dairy calves?

High quality colostrum at dose of 10% of BW

Provide minimum of 150g of IgG within 2 hours of birth

What is an excellent amount of passive transfer?

300g

What is the definition of failure of transfer of passive immunity?

Calf serum IgG < 10 g/L at 24-48 hours of age

What are the goals of passive immunity in beef calves?

1.4-2L of colostrum in 4 hours

2-3 more liters if they do not start nursing their dam

>10g/L of IgG

Excellent if >24 g/L of IgG

What is target serum IgG in beef claves?

16-27 g/L

Whare the goals of passive immunity in small ruminants?

Much less known but aim for 15 g/L of IgG and need 35g IgG to do so

How do you determine failure of passive transfer in calves

There is no best standard way, but radial immunodiffusion is “most accurate" but takes 24 hours to get results

Other methods are ELISA, GGT, TP, brix refractometry, zinc sulfate turbidity

When does sampling for detection of failure of passive immunity need to occur?

24 hours - 7 days old

A serum TP of < 5.1 means what?

FTPI (failure of passive transfer)

A serum TP of 5.1-5.7 means what?

Marginal passive transfer

A serum TP of 5.8-6.3 means what?

Good-excellent passive transfer

What is the goal in a dairy herd for immunity as a whole using serum TP?

>80% of calves with a serum TP of >5.5 g/dL at 24 hours old

What are some factors associated with failure of passive transfer?

Failure to produce, ingest, or absorb

What is a reason a calf fails to absorb?

In the winter, it can be sold cold the calf is not able to absorb much IgG

How is the volume of colostrum needed determined?

Depends on IgG concentration of maternal colostrum

What factors affect IgG concentration in colostrum?

Breed, parity (increases with previous calves), pooling of colostrum, time of collection, genetics

What are some methods to evaluate colostrum quality?

Radial immunodiffusion

Brix refractometry

Colostrometer

What is the problem with a colostromter?

Affected by TS, fat, and temperature

Easy to break

When should colostrum be kept using a Brix refractometery?

>18% (>50g/L of IgG

T/F brix refractometry is high sensitivity and high specificity?

True

When is the colostrometer line in the green?

50g/L IgG

How does the colostrometer tend to be wrong?

Overestimate IgG level

How do we ensure adequate colostrum consumption by the calf?

Calf should receive 300g of IGG in first 2-4 hours of life

What factors can affect calf absorption?

Delayed feeding of colostrum

Hypothermia

Poor storage and handling of colostrum

Bacterial contamination of colostrum