Abstract
The efficacy of toltrazuril (Bay Vi 9142) in preventing ovine coccidiosis due to an infection acquired immediately after turnout on pasture was evaluated by comparing the faecal consistency, weight gain, and oocyst output of treated and untreated lambs in 3 trials. The lambs were either given a single treatment with toltrazuril at 15 or 20 mg/kg, or they were given a dose of 10 mg/kg on 2 separate days. A single treatment with toltrazuril at 20 mg/kg on day 10 after turnout on pasture almost completely prevented coccidiosis in 2 trials. In a third trial the acute phase of a severe Nematodirus battus infection coincided with the outbreak of coccidiosis, and thus partly masked the clinical effect of the anticoccidial treatment. In lambs treated with toltrazuril at 15 mg/kg on day 10 after turnout, the coccidial infection caused a softening of the faeces, but the lambs were not severely affected by the coccidia. In lambs given a dose of 10 mg/kg of toltrazuril twice, either on days 10 and 11 after turnout, or on days 10 and 20, the coccidial infection caused a softening af the faeces, including some cases of diarrhoea. Oocyst production due to the initial coccidial infection on pasture was markedly reduced by all treatments with toltrazuril. The reduction was most pronounced after a dose of 20 mg/kg. Lambs treated with single doses of 15 or 20 mg/kg of toltrazuril had a better weight gain than the untreated controls in 2 of the trials. Lambs treated with toltrazuril on day 10 after turnout were partially resistant to the coccidial reinfection acquired immediately after treatment, and they had a similar level of immunity as the untreated controls to the subsequent reinfection on pasture.
Sammendrag
Ulike dosar av toltrazuril (Bay Vi 9142) vart gitt profylaktisk til lam som hadde vorte naturleg infiserte med koksidiar like etter utslepp på beite. Effekten av middelet vart vurdert ved å samanlikna feceskonsistens, oocystetal og tilvekst hos handsama og uhandsama lam. Ein einskild dose på 20 mg/kg av toltrazuril gitt på dag 10 etter beiteslepp hindra nesten fullstendig utbrot av koksidiose i 2 forsøk. I eit tredje forsøk var lamma samstundes infiserte med Nematodirus battus, slik at den kliniske effekten av toltrazuril delvis vart maskert. Lam som fekk ein einskild dose på 15 mg/kg på dag 10 etter beiteslepp, synte berre milde symptom på koksidiose. To dosar på 10 mg/ kg, gjevne anten på dag 10 og 11, eller på dag 10 og 20 etter beiteslepp, var ikkje så effektive til å førebyggja diaré som ein einskild dose på 20 mg/kg på dag 10. Alle dei nemnde dosane av toltrazuril førte til ein drastisk reduksjon i produksjonen av oocyster, med størst reduksjon for dosen på 20 mg/kg. Lam handsama med toltrazuril på dag 10 etter beiteslepp var delvis immune mot den naturlege reinfeksjonen med koksidiar like etter handsaminga, og hadde, som dei uhandsama lamma, ein sterk nok immunitet til å motstå den kontinuerlege reinfeksjonen med koksidiar seinare i beiteperioden.
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Acknowledgments
The authors thank Dr. A. Haberkorn, Bayer AG, Wuppertal, for helpful suggestions during the planning of the trials and for providing us with toltrazuril (Bay Vi 9142). Sincere thanks are due to J. J. Nedkvitne, Agricultural University of Norway, Ás, for his co-operation in Trial 3. Further, we would like to thank B. A. 0ien and S. L. Rolstad for technical assistance.
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Gjerde, B., Helle, O. Efficacy of toltrazuril in the prevention of coccidiosis in naturally infected lambs on pasture. Acta Vet Scand 27, 124–137 (1986). https://doi.org/10.1186/BF03548565
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DOI: https://doi.org/10.1186/BF03548565