abortion work-up in the cow Flashcards
Why does legislation require that all cattle abortions are reported to APHA?
This is part of the Brucellosis surveillance strategy
When abortion samples are submitted, why are diagnostic rates low in cattle?
There are lots of non-infectious causes of abortion that are difficult to definitively diagnose. There is also often a time delay between death and expulsion (due to CL dependent pregnancy), when autolysis can occur.
Why are most diagnoses made in foetuses aborted during the last trimester?
Earlier abortions may be missed due to the small size of the fetus. Later abortions are more likely to be expelled with less autolysis.
What factors are considered in herd history when investigating abortion?
Is it likely to be infectious or non-infectious? (and is it zoonotic?)
Number of animals affected and time span.
Recent management changes or stressors (e.g., movements, diet changes).
Are they housed or at grass?
Herd vaccination and previous testing history.
Herd biosecurity status – any recent animal purchases?
What should be examined in an abortion case clinical exam?
The cow: Systemic illness, age, homebred or bought-in, other clinical signs.
The fetus and placenta: Any abnormalities, mycotic lesions, dystocia signs.
Gestation stage: Can be estimated using the formula:
2.5 × (21 + crown-rump length) = gestation in days.
What are the key diagnostic steps in an abortion investigation?
Determine if a Brucellosis enquiry is required.
If the fetus and placenta are available, collect samples:
- Lung
- Liver
- Fetal fluids (abdominal/thoracic)
- Stomach contents
- Placenta (multiple cotyledons)
- +/- thymus, kidney, brain, heart, spleen
If the fetus and placenta are NOT available:
Perform serology on the dam and other herd mates.
A heifer aborted at 7 months gestation but is systemically well. What should you do next?
Report to APHA if required.
Conduct a thorough examination of the fetus and placenta.
Collect appropriate diagnostic samples.
Monitor the herd for further cases.
A closed spring-calving herd has 3 abortions in 48 hours. The cows are pyrexic with elevated heart rates and reduced rumen turnover. What should you do next?
Conduct immediate infectious disease testing.
Collect samples from affected cows and aborted fetuses.
Investigate environmental and management risk factors.
Implement biosecurity and control measures.
A dairy herd has a 6% abortion rate over the past year, with more abortions in heifers. The farmer is unconcerned. What should you do next?
Investigate potential chronic infectious or environmental causes.
Review vaccination and biosecurity protocols.
Conduct herd-wide serological testing.
Assess nutrition, stress levels, and housing conditions.
