Parasites are one of the main causes of diarrhoea in calves and lambs, the responsible parasites being predominantly coccidia and cryptosporidia. Plant extracts have a general anti-inflammatory effect and can protect the overall health of the digestive tract in young ruminants.
Coccidia are frequently found on cattle and sheep farms. Parasite’s damage epithelial cells in the gut, thereby disturbing the normal absorption of nutrients and seriously impair the retention of fluids. This has long-term negative effects on growth. Coccidiosis is caused by eukaryote parasites of the genus Eimeria. Infections start with oral intake of Eimerian oocysts that then release sporozoites into the intestine. These invade cells in the gut wall where they multiply and finally release new oocysts with the faeces. Coccidia are transmitted from one animal to another mainly through faecal contamination. The parasite infection causes diarrhoea and fluid loss, and the infected animals usually show reduced appetite and poor growth.
Various prevention strategies have been proposed for coccidiosis and cryptosporidiosis. The most frequently used strategies are management programmes, aimed at limiting the spread of parasites between animals. Firstly, animals should be born into a clean environment. Contact between animals should be minimized. All hutches should be thoroughly cleaned and dried, and preferably also left empty for a period between animals. Ensuring an adequate amount of high-quality colostrum within six hours after birth has also been observed to reduce the severity of coccidiosis infections. During stressful periods, e.g. when young animals are bought and collected from different herds, measures for strengthening the immune response are recommended.
Nutritional programmes that are used when diarrhoea is observed include supplying extra electrolytes, vitamins and carbohydrates in a solution to prevent dehydration. Coccidiosis often occurs in subclinical form, suggesting that for every treated animal in a group, there are several other animals that are infected but not showing any symptoms. The biggest economic cost of parasite infections is impaired growth. The weight gain lost due to subclinical infections can therefore become a large hidden cost.
