Scour in sheep Flashcards
What are the different causes of scour in neonates, lambs and adults?
Neonates
- incorrect mixing of milk replacer
- E. coli
- clostridium perfringens type B
- salmonella
- rotavirus
- cryptosporidium
Lambs
- rumen acidosis (crop feeding)
- coccidiosis
- nematodirus
- parasitic gastroenteritis
Adults
- rumen acidosis/lush pasture
- salmonella
- (Johnes)
What clinical signs are associated to E. coli infections in young lambs? What makes them predisposed? How can it be prevented? How are lambs treated?
- Lambs are pyrexic, lethargic and may scour. Mortality rates are high.
- Watery mouth’ – lambs hypersalivate.
- ‘Rattle belly’ – lambs get a pot belly.
Predisposition
* Associated with poor hygiene and failure of passive transfer
Prevention
- good hygiene - clean dry bedding
- colostrum management - 50ml/kg coostrum ASAP after birth and ewe nutrition and BCS
Treatment
- spectam scour halt antibiotic in lambs with scour
- not to be used routinely
What clinical signs are associated with C. perfrigens type B? Describe the pathogenesis of the infection. How can it be prevented?
- Sudden death +/- bloody diarrhoea
- Lambs may appear dull/listless before death
- Affects young lambs (usually <3w).
Pathogenesis
* Gram positive anaerobic bacteria, ubiquitous in environment and commensal in GIT
* Rapid onset disease caused by toxins released when bacteria have opportunity to multiply.
Prevention
* Control is by vaccination of ewes (lambs can be vaccinated from 2-3w)
What lambs are most at risk from coccidiosis infection?
- Lambs 3-12 weeks old are most at risk from infection.
- Typically lambs born in the first half of the lambing period exposed to a low level of challenge and develop immunity.
- However, these early lambs multiply up the oocysts in the shed or field whilst they develop immunity and the later born, youngest lambs then encounter a high challenge of infectious oocysts and suffer with clinical disease (scouring, dehydration) before they develop immunity.
What 2 eimeria protozoal species are pathogenic in sheep?
Eimeria ovinoidalis and Eimeria crandallis
What are risk factors for coccidiosis? What is its life cycle? Describe pathogenesis? What clinical signs are associted? How can it be prevented?
Risk factors:
* Mixing age groups of lambs
* Moving young lambs to shed/pasture where older lambs were kept
* Intensively stocked systems
* Faecal contamination in/around feed/water troughs
Pathogenesis and clinical signs:
* Damage to gut lining causes straining, abdominal pain and diarrhoea +/- mucus and blood. Leads to dehydration and death in severe cases (young lambs exposed to high challenge).
* Affected animals may also show ill thrift and poor growth rates.
* Concurrent infection with Nematodirus or Cryptosporidium can exacerbate clinical signs.
Control measures:
* Ensure adequate colostrum intake, maintain good hygiene and prevent faecao-oral transmission (e.g. raise feed and water troughs or move frequently)
How is cryptosporidium parvum transmitted? Describe pathogenesis. What clinical signs are associated? How is it diagnosed?
Protozoal parasite that can cause disease in young lambs (usually <10d old) and calves
Faeco-oral transmission
Oocysts persist in environment and resistant to many disinfectants = infection levels build up over time.
Causes diarrhoea, inappetence, abdominal pain and mild pyrexia. In mild infections may see reduced growth rates and general poor performance.
May get mixed infections with E.coli/Nematodirus = severe clinical signs.
Diagnosis by faecal sample/PM
How can cryptosporidium parvum be prevented?
- Ensure adequate colostrum intake, maintaining good hygiene and preventing faecao-oral transmission (e.g. raising feed and water troughs)
- Can be transmitted in water courses so could consider fencing these off.
- Older animals tend to shed the parasite which then causes disease in younger animals, so mixing animals of different ages should be avoided where possible.
- Check that any disinfectants used are effective against Cryptosporidium.
