Postmortem examinations of livestock offer valuable information about underlying diseases that might be present on farms which together with further testing, can implement control strategies including effective vaccination programmes, parasite control and proactive health planning, increasing livestock health with economic and welfare benefits.

Centrally subsidised postmortem services in the UK in recent years have been reduced due to budget cuts, with the number of Veterinary Investigation Centres and SRUC facilities offering full postmortem by veterinary pathologists now more difficult to access for many farms.

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Fallen stock on farm hold valuable information about underlying diseases, it can be a massive waste throwing away this surveillance in the back of a fallen-stock lorry, particularly when looking at diseases which might be easily preventable.

Postmortems on farm offer a cost effective and convenient way to get quick answers to deaths or underlying ill-thrift. Many diagnoses can be made straight away, for example liver fluke or OPA but samples for further testing can also be taken. Sending samples to veterinary laboratories for culture or histopathology allows more specific diagnoses like salmonella or mycoplasma. SRUC veterinary pathologists offer invaluable advice and support.

Abortion diagnosis

In both cattle and sheep, abortions can be a frustrating and costly occurrence. If abortions levels reach 2%, it is highly recommended to carry out further testing, as there may well be underlying infectious and preventable causes. Laboratory diagnosis is key, but this starts with a postmortem of the foetus and collecting samples from the placenta and blood samples from the dam. The more samples available, increases the chance of definitive diagnosis.

Lab samples will also be tested for zoonitic infections like salmonella, brucellosis and Q-Fever. It can be frustrating when a definitive diagnosis is not made and further testing recommended, however, during the process many significant causes will have been ruled out, which in itself is valuable knowledge.

Parasite surveillance

Postmortems can be valuable, quick ways to understand parasite burdens on farms. They can be an early indicator of liver fluke and haemonchus infections in sheep and underlying lung worm infections in cattle. Testing gut contents back at the laboratory will also allow worm egg counts for other parasites. Negative results are also useful, indicating whole herd treatments are not necessary.

Pneumonia outbreaks

Respiratory disease in cattle is a complex condition with many risk factors and underlying causes. Fresh postmortems of both acute and chronic cases gives us valuable information about primary causes and also allows us to do further diagnosis testing. Sensitive and specific PCR testing is now available for swabs taken from live animals but also postmortem material. The significance of IBR is important to understand, as there are effective live vaccines that can be used in the face of an outbreak. Testing for other viruses and bacteria allows us to choose the most effective vaccine protocol in the future.

Iceberg diseases in sheep

Postmortems of dead or lean ewes is a great way to understand the significance of our flock iceberg diseases. OPA and Johnes can be diagnosed from changes in the lungs and bowel but further lab testing from samples is likely needed for definitive diagnoses including border disease, MV and CLA. It is also a useful time to check parasite burdens, take liver samples for underlying trace element deficiencies and check dental condition.

Sudden death

There is a long list of potential causes of sudden death in cattle and sheep. From poisonings, electrocution, calcium and magnesium deficiencies, acute infections like pasteurellosis and clostridial diseases. Unexplained sudden deaths should be reported to APHA through your veterinary practice. Anthrax is a notifiable zoonotic disease and should be suspected in any carcase where the animal died suddenly and there is no reasonable alternative diagnosis or explanation. A risk assessment will be carried out and may involve anthrax testing by an OV vet before the carcass can be moved or postmortemed.

Clostridial diseases are common acute infections affecting cattle and sheep, where clostridial spores are present in the environment/pasture/diet. These may be dormant for long periods of time, causing disease after stress triggers. If clostridial disease has been suspected or diagnosed, highly effective vaccines are available against the many types of clostridal disease. These vaccines require two initial doses followed by annual boosters for effective immunity.

Sudden death in store lambs is common, where pasteurellosis and clostridial disease are often found. Making an early diagnosis allows whole flock treatments or vaccination possible to limit losses. These postmortems are also useful to determine liver fluke status and parasite burdens.

Abattoir feedback

Understanding the causes of organ and carcase rejection at slaughterhouses offers important feedback from livestock going direct to slaughter. Liver damage caused by fluke is common and valuable information when treating the rest of the flock/herd. Care must be taken interpreting this information, as liver damage might be historic and not active.

With livestock values high at the moment, any losses are significant. Think of the value in deadstock for disease investigation. Disease surveillance could be much improved if material is used for a diagnosis before it goes on the fallen-stock lorry. Good quality validated diagnosistics are available through all our vet practices, supported by the SRUC, VLA and private veterinary laboratories.