Protecting lambs from Coccidiosis
Finding a successful treatment depends on accurate diagnosis of the disease in the first place
Coccidiosis is a parasite-caused disease that mostly affects young lambs between three and eight weeks of age, although there are exceptions to this. Very often, the disease is incorrectly diagnosed as Nematodirus, as it occurs at the same time in March-born lambs.
Coccidiosis is characterised by a dark, sometimes bloodstained scour and if left untreated, the parasite will quickly cause irreparable damage to the digestive tract of the lamb. Delayed treatment of affected lambs can result in a high rate of mortality and a lot of poor lambs with badly damaged digestive tracts that will never again perform.
Coccidiosis oocytes or eggs are extremely hardy and can over-winter on ground grazed by sheep in a previous year. Wet and mucky conditions, both indoors and outdoors, suit the parasite and help spread the infection.
Lambs have maternal immunity to the parasite for the first few weeks of life but once this wanes, they start picking up the infective parasite and, in general, most lambs will have developed their own immunity to the parasite by the time they are eight to 10 weeks of age.
Some level of control can be achieved by providing the lambs with safe pasture (ie, pasture that was not grazed by lambs in the previous year), and keeping the areas around troughs and feeders dry by moving them frequently.
Indoors, plenty of clean straw should be used to keep the bed dry. Pay attention to leaking water troughs as the area around these are ideal for infection to spread. Avoid grazing younger lambs after an older bunch as they will end up grazing the parasites excreted by the older lambs.
Successful treatment depends on an accurate diagnosis in the first place. There are lots of coccidia species that are found in the digestive tract of sheep but only two species cause disease. For this reason, using faecal egg counts to decide if treatment is necessary is of little value because it is not possible to distinguish between those species that cause disease and those who do not.
Where young lambs start to scour at around four or five weeks of age, they should be first treated with an anthelmintic to rule out Nematodirus infection. If, after treatment, the lambs don't dry up, go in straight away with a treatment that is effective against Coccidiosis.