title: The effect of a metaphylactic treatment with diclazuril (Vecoxan) on the oocyst excretion and growth performance of calves exposed to a natural Eimeria infection.
abstract: A multicenter field efficacy study was performed in six farms located in Belgium, France and Germany with a history of suspected coccidiosis outbreaks and the proven presence of Eimeria bovis and/or Eimeria zuernii. At each of these trial sites the calves were randomly allocated to two groups (T, treated; C, control) of similar size. In total, 231 calves were included in the study. Group T calves (n=116) were drenched with a single dose of diclazuril (Vecoxan, 1mg/kg body weight) close to the time of expected outbreak of coccidiosis (day 1 of the study period), group C calves (n=115) served as placebo-treated controls. Although E. bovis and/or E. zuernii were identified at all trial sites, clinical coccidiosis was only noted in 16% of the group C calves. At day 5 of the study period (4 days after treatment), faecal oocyst counts (opg, oocysts per gram) were substantially lower in group T ("short-term effect") compared to group C. At four trial sites, the respective values of groups T and C were significantly different (P=0.0132 to P=0.0001) in favour of group T. For the pooled data of all trial sites, this effect was highly significant (P<0.0001). The overall faecal oocyst counts from day 3 until day 21 of the study period ("Area Under the Curve") was significantly reduced in group T by 87.2-99.5% ("long-term effect") at five trial sites (P=0.0139 to P<0.0001). The pooled data revealed a highly significant effect of treatment on oocyst excretion over the observation period (P<0.0001). On five of the six trial sites, the average weight gain was higher in group T than in group C. On those trial sites, the average weight gain of group T calves exceeded that of the controls by 95-268g/day and by 2.0-6.0kg over the study period. This effect was statistically significant (P<0.01) at one trial site. Altogether the calves of group T gained on average 129g more weight daily than the controls (+2.7kg over the study period). For these pooled data, statistical analysis confirmed the positive effect of treatment of calves exposed to coccidiosis on growth performance (P=0.003). In conclusion, metaphylactic treatment with diclazuril efficiently controls coccidiosis in calves thus reducing environmental contamination with oocysts and preventing negative effects of natural exposure to coccidiosis on growth performance of calves.
authors.affiliation: Institute of Parasitology, Faculty of Veterinary Medicine, University of Leipzig, An den Tierkliniken 35, D-04103 Leipzig, Germany. daugschi@vmf.uni-leipzig.de
authors.forename: A
authors.initials: A
authors.lastname: Daugschies
authors.forename: J
authors.initials: J
authors.lastname: Agneessens
authors.forename: L
authors.initials: L
authors.lastname: Goossens
authors.forename: H
authors.initials: H
authors.lastname: Mengel
authors.forename: P
authors.initials: P
authors.lastname: Veys
mesh_terms: D000818:Animals; D002417:Cattle / Q000254:growth & development*; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology*; D003048:Coccidiosis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D003049:Coccidiostats / Q000627:therapeutic use*; D004539:Eimeria / Q000502:physiology*; D005243:Feces / Q000469:parasitology; D005260:Female; D008297:Male; D009570:Nitriles / Q000627:therapeutic use*; D033661:Oocysts / Q000187:drug effects* / Q000502:physiology; D014227:Triazines / Q000627:therapeutic use*
chemical_list: D003049:Coccidiostats; D009570:Nitriles; D014227:Triazines; C057884:diclazuril