Coccidiosis generally occurs where lambs become infected orally from faecal contamination, with areas such as dirty bedding, contaminated feed and water troughs and pastures the main entry routes due to higher numbers of oocysts (coccidial eggs) present.
The greatest risk is in lambs aged between three and eight weeks, with clinical symptoms most evident in lambs aged six to eight weeks. Lambs develop resistance to coccidia with age (10 weeks of age and older), but at this stage, great harm can be done with lambs finding it difficult to recover.
Clinical symptoms
The characteristic symptoms of coccidiosis is a bad scour, which can be blood-stained and, as such, black in colour.
Lambs can be seen straining and performance will quickly suffer, with high mortality levels common during an outbreak.
This is not to be confused with nematodirus, which is also currently a risk and is covered in this week’s management notes. Nematodirus will also give rise to a bad scour, but this will be green in colour.
Prevention
Therefore, the focus must be on prevention. Where lambing is in the final stages, it is important to maintain high standards of hygiene until the last ewe has lambed.
Bedding should be kept dry and feed and water troughs should be raised to limit contamination.
Where ewes are being supplemented outdoors, it is important to keep troughs moved regularly and to avoid placing troughs where animals are naturally congregating. Keeping lambs of a similar age in batches will also help.
Treatment is via oral coccidiostats, with a number available on the market. The full list is shown in Table 1 below.
It should be noted some of these treatments have a residual period of cover and this is another reason for keeping lambs of a similar age grouped together.