Economic benefits of prophylaxis with diclazuril against subclinical coccidiosis in lambs reared indoors

One hundred and twenty weaned male lambs, naturally infected with Eimeria s pecies, were used to assess the economic benefits of the prophylactic admin istration of diclazuril. They were randomly divided into four groups of 30 lambs on the basis of their bodyweight and output of oocysts. The groups we re either left untreated (group 1), treated orally with a simple dose of di clazuril at 1 mg/kg (group 2), with two doses two weeks apart (group 3), or with sulphadimethoxine at 50 mg/kg for five consecutive days (group 4). No clinical signs of coccidiosis were observed in any of the groups. The outp ut of oocysts was significantly reduced on day 7 after treatment in group 2 , on days 7 14 and 28 in group 3 and on days 7 and 14 in group 4. No signif icant differences were found between the treated and untreated groups for b odyweight, carcase weight and carcase classification. The mean fattening pe riod was shorter for the treated lambs (52 and 55 days) than for the untrea ted controls (60 days). The average growth rate of the lambs treated twice with diclazuril and with sulphadimethoxine was improved and the feed conver sion rates of the lambs treated once or twice with diclazuril were 7 per ce nt and 16 per cent better than that of the untreated lambs.