Neonatal calf disorders Flashcards
top two calf disorders < 30 days of age, for dairy and beef? how common?
- Calf diarrhea
- Respiratory disease
> Over 23% of calves treated for diarrhea (highly variable)
Almost 22% of calves treated at least once for BRD Overall mortality was 3.5% (birth to 3 months)
general problems caused by calf diarrhea and resp disease?
-Cost (money, personnel, inefficient use of space etc)
-Delayed growth
-Reduced overall performance
what is colostrum? what does it contain?
- Colostrum is the first mammary secretion produced after calving
- Colostrum is a rich blend of nutrients, growth factors/hormones, and antimicrobial factors (immunoglobulins!)
immune function of colostrum; what is passive transfer of immunity?
- Calves are born devoid of circulating immunoglobulins (Ig)…“Immunocompetent, but naïve”
- The uptake of immunoglobulins from colostrum by the calf = Passive Transfer of maternal immunity
what is failure of passive transfer? what is its significance and threshold?
- Failure to acquire maternal antibodies via colostrum (“Failure of Passive Transfer”, FPT) is a significant risk factor for development of sepsis
- Calves with serum IgG levels < 1000 mg/dL (10 g/L) are at high risk for disease, and this level can be used as a definition for Failure of Passive Transfer (FPT).
- FPT is the most important cause of morbidity and mortality in calves (Dairy and Beef) and probably also in crias (and foals!).
long term production impacts of failure of passive transfer?
- Fewer calves with IgG <10g/L will survive
- Diminished long-term performance is demonstrated by
> decreased weaning weights in beef calves
> decreased growth and milk production in dairy heifers
rule for calf colostrum consumption
Calves must ingest and absorb an adequate volume of good quality colostrum within the 1st 24 hrs of life.
newborn’s minimum requirement for colostrum immunoglobulin is:
80 – 150 g (fed <2h after birth)
* small birth weight calves require: 80–120g
* high birth weight calves require: 120–150g
Colostrum immunoglobulin concentrations of _______ required to achieve serum IgG concentration of ~10 g/L
Colostrum immunoglobulin concentrations of > 60 g/L are required to achieve serum IgG concentration of ~10 g/L
how many liters of colostrum does a holstein calf need? higher volumes given how?
- ≥ 3-4 litres of colostrum (40-50 kg BWt Holstein calf)
- Higher volumes given by esophageal tube via “spill over” into abomasum (calf rumen volume ≈ 400 ml)
Colostral Quality can be measured quickly via
Brix refractometry
how does serum IgG level change depending on how long it takes to feed the calf its colostrum?
- impact of feeding on serum IgG drops off quickly over time
> need to feed calf within first 6h to achieve serum IgG conc of 10g/L
> The Earlier The Better!
Risk Factors for FPT; calf factors
- Timing of colostrum intake
> Inability to stand
> Inability to nurse - Malabsorption
Risk Factors for FPT; cow factors
Poor IgG in colostrum
* Parity
* Concentration of immunoglobulin in the colostrum is negatively correlated with the volume of milk produced
* Dripping prior to calving
- Pooling colostrum from multiple sources
- If nursing from dam:
> Poor teat conformation
> Rejection by cow
do cows or heifers pass on more IgG in colostrum?
cows
why can pooling colostrum from multiple sources be problematic? how do we prevent issues?
Colostrum immunoglobulin concentrations of > 60 g/L are required for best passive transfer
- most cows do not meet this threshold (maybe 15-20%?) so we would rather just take from the best
>we need to measure antibodies and only bank good quality
methods of assessing passive transfer
1) Serum/plasma protein
2) Zinc sulfate turbidity
3) Sodium sulfite turbidity
4) Glutaraldehyde coagulation
5) Gamma-glutamyltransferase (GGT) level
6) Radial immunodiffusion
why can we measure serum/ plasma protein to assess IgG? what points to an adequate threshold? things to watch out for?
- IgG levels reflected in total protein TP >52 – 55 g/L = likely adequate passive
transfer
if:
* Not dehydrated
* No in utero infection
is protein determination a good test for passive transfer? advantages?
- Overall, good test if clinical condition of calf is considered during interpretation.
Advantages:
* Cheap, easy, quick
* Can adjust cut-off based on risk management (ie. high genetic value… increase cut-off)
Zinc sulfate turbidity pros and cons for passive transfer assessment
- Semi-quantitative
- Cheap, easy, quick
- Generally underestimates Ig level
- No advantage over total protein
Sodium sulfite turbidity/ Glutaraldehyde coagulation pros and cons for passive transfer assessment
- Cheap, easy
- Underestimates Ig
> Over-identification of FPT
GGT Level pros and cons for passive transfer assessment
- GGT present at high levels in colostrum
> High GGT = colostral absorption - Included on routine biochemistry profile
- More expensive, time consuming, longer turn-around time
Radial Immunodiffusion pros and cons for passive transfer assessment
- Direct quantification of immunoglobulins = “The Gold Standard”
- Slow, expensive
Treatment of FPT
Less than 18 hours (6hrs?) of age:
* Oral colostrum (fresh or frozen)
* Oral plasma
* IV plasma or whole blood
* (Oral Ig supplements = marginally effective)
- If calf has nursed, ‘gut closure’ may occur earlier…therefore oral supplementation may be ineffective
