1. A pilot study on the value of fallen stock necropsy to sheep farmers, with an emphasis on ewe mortality
F. M. Lovatt & B. Strugnell
Flock Health Ltd

3. Background
In the UK, the Animal Health & Veterinary Laboratories Agency (AHVLA) provides:
Disease surveillance
Diagnostic service
Currently this situation is being reviewed by consultation with the aim of
Improving surveillance
Reducing government budgets
How can industry benefit more from disease surveillance and diagnosis?

4. Fallen Stock Do these carcases have diagnostic value?
In UK all fallen stock must be collected by a licensed collector and disposed of according to Animal-By-Products legislation.
Carcases are taken to a central location (cost met by farmer)
Do these carcases have diagnostic value?

5. Aims of Project
Establish the diagnostic potential of material collected by fallen stock collectors
Identify risks and constraints, such as autolysis and cross-contamination
Collect pilot information on the approximate prevalence of certain ovine diseases (e.g. Johnes, OPA)
Propose how information gained may be used in the longer term

6. Why adult ewes? 15 million breeding ewes in UK
Annual ewe mortality rates estimated at ~5% (0.75 million)
Causes can be estimated from a few sources but not known at flock or national level
Losses usually not investigated because of low economic value of animals
Area probably under-represented by current surveillance arrangements

7. Total ewe necropsies by AHVLA 2006-2011 (England & Wales)
Most was ~750/ year in total (2009). Deaths (5% of 10 million)= ~500,000/ year.
i.e. ~0.15% of total

8. Materials & methods 11 sessions at a fallen stock collection
Average of 10 necropsies per session
Sessions staggered through the year.
Breed, estimated age, body condition and degree of autolysis, gross findings recorded
No clinical history collected for carcases
Further testing commissioned as appropriate
Data collated to be reported

9. Sample details

10. Results
Diagnosis in 70% of ewes. Results for 106 ewes included.

11. Mastitis (11%)
Most common diagnosis in this study (mainly in May & June)
Only 0.3% of all diagnosable submissions to AHVLA (VIDA 2012)
Farmer diagnosis hence national data currently lost to surveillance

12. Acute fasciolosis (7%)
Acute fluke was a common diagnosis from October onwards
Emphasised how valuable fallen stock necropsy could promptly alert farmers to the need to take action
Useful at a farm or regional level
Can treat after first ewe dies, not after tenth

13. Ovine Pulmonary Adenocarcinoma (6%)
No useful test in the live animal & likely to be underdiagnosed
Average of 28 diagnoses per year by AHVLA
Probably a large cost on high prevalence flocks
Is there a place for an accreditation scheme for flocks selling breeding sheep – based on routine PM of fallen stock?

14. Johnes Disease (6%)
Also probably underdiagnosed and a major cost on endemic flocks
Average of 40 cases per year by AHVLA from
Likely to be a significant ‘iceberg disease’ responsible for much premature culling, poor milk yields/ lamb growth rates.
Some approaches for control. .

15. Chronic suppurative pneumonia (6%)
Pasteurella bronchopneumonia (7%)
Chronic suppurative pneumonia (6%)
Caseous
Endocarditis (1%) Neoplasia (6%) Lymphadenitis (1%)

16. Constraints
Despite searing all surfaces prior to bacterial swabbing, and using charcoal transport swabs, bacterial culture results were sometimes overgrown with Proteus and/ or coliforms
Contaminated environment.
Lack of clinical history (might have been treated with antimicrobials)
Attention to minimise this required.

17. The need for further testing

18. Further Applications to the sheep Industry
Where are the health-related losses?
Infectious Abortion
Perinatal Mortality
Lamb losses turnout-slaughter
Ewe losses (mortality and morbidity)
All of these should be relatively cheap to diagnose (with proper application of existing knowledge).

19. Infectious Abortion
Three major causes of infectious ovine abortion account for ~80% of cases:
EAE (Chlamyophila) (~£12 million)
Toxoplasma gondii
Campylobacter
The diagnosis is easy to make in all three cases.

20. Perinatal Mortality
Disease-related causes of perinatal lamb mortality:
Watery mouth
Lamb dysentery
Rotavirus
Poor colostral intake
Joint Ill

21. Diseases of Neonatal Lambs: Diagnosis
Diagnostic critera
Treatment/ control
Poor colostral intake
Visual + Refractometer
Management/ Nutrition
Watery mouth
Visual + culture
Appropriate antibiosis
Rotavirus
Visual + PCR/ PAGE
Supportive
Joint Ill
Necrobacillosis
Visual +/- culture
Management/ Nutrition/
Lamb Dysentery
Visual +/- CP toxin detection
Vaccination of ewes

22. Growing Lambs Worms Clostridial Disease (pulpy kidney etc.)
Coccidiosis
Pasteurellosis
Acute/ Chronic Fluke
…probably together account for 80% of losses
(and are NOT hard to diagnose)

23. 7.3. Diseases of growing lambs: Diagnosis
Diagnostic critera
Treatment/ control
PGE
Visual +WEC+ TWC
Worm & manage
Nematodirus
Visual + SI TWC
Worm (promptly!)
Clostridial disease
Visual +/- glucosuria +/- cp toxins
Vaccinate
Pasteurella
Visual +/- culture
Treat & vaccinate
Coccidiosis
Visual + WEC
Treat & manage
Fluke
visual

24. Diseases of adult ewes Mastitis Johnes Disease OPA Fluke
Haemonchosis (PGE)

25. Diseases of adult ewes: Diagnosis
Diagnostic critera
Treatment/ control
Johnes
Visual +/-PCR or ZN smear
Manage/ vaccinate
OPA
Visual + Histopathology
Manage/age stratify
Fluke
Visual
Treat promptly
Haemonchosis
Visual +/- Abo wash
Treat

26. The importance of early diagnosis and intervention
Most sheep farmers will wait until a few have died before wondering whether to investigate.
In some cases this is OK but in some cases further preventable losses ensue.
Fluke and nematodirosis highlight the potential effectiveness of intervening early and with minimal cost and effort to the farmer.

27. Conclusions: Fallen Stock Survey
Material CERTAINLY diagnostic
Can provide useful flock data to inform interventions
Can provide useful national data to inform useful areas of future research

28. Conclusions: Further application of principles.
It is more likely that losses will be pursued if to do so is EASY and CHEAP
Sheep farmers are lucky in that the diseases responsible for most of their (disease related) losses are EASY and CHEAP to diagnose.
This knowledge just needs to be applied in the correct situation (i.e. promptly when disease occurs).
The proposed approach is one way to achieve this.

29. Acknowledgements
Flock Health Ltd

30. QUESTIONS/ DISCUSSION