Sheep farming

‘Cocci’: a common suspect in lamb diarrhoea

What is it?

Coccidiosis is caused by a very small parasite called Protozoa. A Protozoa is only made of a single cell. There are lots of different types of Protozoa; the one which causes Coccidiosis in sheep is called Eimeria. You may find up to 15 different species of Eimeria in lambs.

Why does it cause diarrhoea?

The Eimeria lifecycle begins with a lamb consuming the eggs of the parasite. These may come from the surface of the udder, pasture, feeders, water troughs, or anything which could have faecal contamination from other lambs or ewes. Once the eggs have been swallowed, they hatch in the small intestine. The newly hatched parasite then finds a cell on the lining of the gut to enter and hijack. The hijacked cell becomes a factory making multiple copies of the parasite. The hijacked cell then bursts open and the new parasites are released into the gut lumen, these new parasites then sexually replicate inside another gut cell and create eggs. The eggs are shed in vast numbers in the faeces which contaminate the environment and infect other lambs, repeating the cycle.

When the gut cells are damaged four things happen that contribute to diarrhoea:

  1. The damaged cells can’t absorb any nutrients
  2. Undigested feed sits in the gut lumen:
    1. Causes fluid to flow from the lamb into the gut lumen (osmosis)
    2. Makes a good growth medium for secondary bacterial problems
  3. The damaged areas of the gut leak fluid from the lamb into the lumen of the gut
  4. The lamb makes an immune response causing the guts to become further inflamed

What do you see on farm?

Problems are commonly seen in lambs around 1-2 months of age. Their faeces will have a foetid smell and may contain mucus and/or blood. Severely affected lambs will lose condition quickly. Mildly affected lambs may show no signs of diarrhoea and appear healthy, but they will still be experiencing gut damage and won’t be absorbing nutrients properly. You may not see actual loss of condition, but you can’t see the potential growth that they have missed!

How can it be controlled and treated?

Unfortunately the eggs of the parasite are very stable in the environment and can persist from months to years. Complete eradication is unlikely, but Coccidia burden in the environment can be reduced by physically removing or chemically inactivating eggs. There are 5 ways you can do this:

    1. Ensure all buildings are thoroughly cleaned and disinfected
    2. Regularly change bedding of sheep and lambs
    3. Ensure feeders, troughs, equipment etc. are as clean as possible at all times
    4. Move feeders/troughs regularly to avoid faecal contamination accumulating in their vicinity
    5. Treat ewes to reduce the amount of parasite they might be shedding

Lambs can be treated in response to disease or before the risk period starts. Medication can be included in the feed to aid prevention and provide treatment for coccidiosis in lambs and can also be used to reduce burden in Ewes, with the added benefit that it aids in toxoplasmosis prevention when given during pregnancy. It can also be administered via compound feed or nutrient tubs.

For further information please contact Zoetis UK Limited, Walton Oaks, Dorking Road, Tadworth, Surrey KT20 7NS. www.zoetis.co.uk Customer Support: 0845 300 8034. Use medicines responsibly (www.noah.co.uk/responsible). Date of preparation: January 2018. AH862/17