Scour in sheep

Question 1

Causes of scour in lambs

Answer 1

Nutritional
- Rumen acidosis (creep feeding i.e. grain overload))

Parasitic
- Coccidiosis
- Nematodirus
- Parasitic gastroenteritis (PGE)

Question 2

Causes of scour in neonates

Answer 2

Nutritional
- Incorrect mixing of milk replacer (if bottle fed)

Bacterial
- E.Coli (watery mouth)
- Clostridium perfringens type B (lamb dysentery)
- Salmonella

Viral
- Rotavirus

Parasitic
- Cryptosporidium

Question 3

Causes of scour in adults

Answer 3

Nutritional
- Rumen acidosis / lush pasture

Bacterial
- Salmonella
- (Johnes) (doesn’t tend to present with scour in sheep but keep on differentials for scouring adults)

Question 4

Salmonella

Answer 4

• Can cause sudden death +/- diarrhoea in neonates, or outbreaks in adults
• May also be associated with abortion
• High up on ddx for very sick lambs and/or adults with pyrexia and abortions

Question 5

Rotavirus

Answer 5

• Can cause diarrhoea in lambs <2w
• Less common than in calves

Question 6

E.Coli

Answer 6

• E.coli infection in young lambs (<4d old)
• Lambs are pyrexic, lethargic and may scour
• Mortality rates are high
• ‘Watery mouth’ – lambs hypersalivate
• ‘Rattle belly’ – lambs get a pot belly
• Associated with poor hygiene and failure of passive transfer
• May just present as sudden death
• High stocking densities

Question 7

E. coli control

Answer 7

Control measures include good hygiene and colostrum management

Good hygiene
- Clean dry bedding in pens, changed between ewes if in individual pens.
- Hospital pens for sick lambs/ewes.

Colostrum management:
- 50ml/kg colostrum ASAP after birth (definitely by 6 hours) 5kg lamb = 250ml.
- 200ml/kg in first 24hrs (5kg lamb = 1litre)
- Ewe nutrition and BCS – check forage/do metabolic profiling of ewes pre-lambing (~6w pre-lambing).

Question 8

Using Brix what should ewe colostrum be?

Answer 8

• above 26.5%

Question 9

Clostridial dz in sheep

Answer 9

• Gram positive anaerobic bacteria, ubiquitous in environment and commensal in GIT
• Rapid onset disease caused by toxins released when bacteria have opportunity to multiply

Question 10

C perfringens control & tx

Answer 10

• Control is by vaccination of ewes and ensuring adequate colostral transfer of antibodies
• Lambs can be vaccinated from 2-3w
• Variety of vaccines available, all cover different clostridial strains, some protect against Pasteurella too
• Treatment is usually unsuccessful and mortality rates are high

Question 11

C.perfringens type B: Lamb dysentery

Answer 11

• Sudden death +/- diarrhoea
• Lambs may appear dull/listless before death
• Affects young lambs (usually <3w)
• Youngest animals tend to be affected first
• risk factors: wounds, navel that hasn’t dried up properly