Livestock Matters Summer 2019

Livestock Matters Summer 2019 04 Take a holistic approach to preventing coccidiosis in dairy calves Preventing and treating coccidiosis in calves requires a holistic approach which will include reducing the coccidial disease challenge, boosting calf immunity and nutritional health, and if necessary, strategic use of a coccidiostat or coccidiocide. “Last summer we saw coccidiosis breakdowns on several farms,” says vet Lucy Hepworth of Friars Moor Livestock Health. “What’s more these farms had previously had good control of the disease using an in-feed coccidiostat. All the cases occurred after weaning: calves developed bloody diarrhoea, and some died. “By identifying the particular species of coccidiosis on the farms we were able to advise on appropriate medicinal treatment and timing – but attention to good health and environmental hygiene was an essential part of the remedy.” About coccidiosis Coccidiosis is the condition caused by infection with coccidia – a single celled protozoa which is not affected by antibiotics or vaccines. It infects the lining of the intestines, stunting the villi and affecting absorption of nutrients and water. Coccidiosis can occur in calves between 4 weeks and 6 months of age and tends to occur around weaning. Infections can be acute, chronic, or sub-clinical. In acute cases, bloody diarrhoea is seen with animals straining to pass dung and becoming dehydrated. Death can follow. Chronically affected animals have poor coat hair, pasty dung and poor growth. Sub-clinical cases will appear normal, but the infection limits the animal’s growth and future performance potential. Lucy explains: “The only way to kill coccidia is to use a coccidiocidal drench; these are active in the small and large intestine. Alternatively, an in-feed coccidiostat – decoquinate – which is only active in the small intestine can be used to suppress the infection. Step 1: Identify the coccidia “In cattle, there are 13 different species of coccidia, but only three are pathogenic: Eimeria bovis, Eimeria zuernii and Eimeria alabamensis . It is helpful to know which species is present so that prevention measures can be targeted correctly. “Every farm is different, and coccidiosis can strike at different times of calves’ lives,” explains Lucy. “For instance, calves may develop diarrhoea when turned out to pasture. If E.alabamensis is identified then changes to pasture management are needed, but if E.bovis is the cause then this originated in the shed and the disinfection protocol needs improving. “To assess whether coccidia are present, we can carry out faecal oocysts counts. Farmers need to collect faecal samples directly from the rectum of 10 animals. These should be kept cool and ideally submitted to the vet practice on the same day where they will be pooled. “Scouring can happen before coccidial oocysts are shed, and also continue after shedding has ceased. By pooling samples taken from scouring and non- scouring animals, there is more chance of finding the evidence. “We carry out faecal oocyst counts in our lab here at Friars Moor, and then send samples away for speciation. From this information we will know the length of its lifecycle and hence be able to target preventative measures.” Lucy Hepworth Friars Moor Livestock Health Faecal oocyst counting Coccidiosis John Walsh Friars Moor Livestock Health