The history of decoquinate in the control of coccidial infections in ruminants.

Decoquinate is a quinolone derivative that has been used for over 20 years in the control of coccidiosis in domestic ruminants. Decoquinate treats coccidiosis in lambs and calves and prevents coccidiosis in lambs when administered in feed at a dosage of 1 mg decoquinate/kg bodyweight (b.w.) daily for at least 28 days. It prevents coccidiosis in calves and aids in the prevention of coccidiosis in lambs when administered in calf and ewe feed, respectively, at a dosage of 0.5 mg/kg b.w. daily for at least 28 days. Decoquinate also aids in the prevention of abortions and perinatal losses owing to toxoplasmosis by medication of ewe feed at a dosage of 2 mg/kg b.w. daily, fed continuously for 14 weeks prior to lambing. Several field studies have reported reductions in cryptosporidial oocyst shedding. Decoquinate acts early in the life cycle of Eimeria on sporozoites, released from ingested oocysts, and on first-generation meronts, arresting development and release of merozoites and thus preventing further damage to the intestines owing to the gametocyte stages. Production benefits associated with the use of decoquinate are due mainly to its action as a coccidiostat rather than any effects on diet utilization or ruminal fermentation.