title: The epizootiology of Eimeria infections in commercial broiler chickens where anticoccidial drug programs were employed in six successive flocks to control coccidiosis.
abstract: The course of natural Eimeria infections in 6 successive broiler flocks at a commercial farm comprising 4 houses, where different anticoccidial drug programs were employed, was studied by counting the number of oocysts in the litter at weekly intervals. The course of infection in all flocks followed a bell shaped curve in which oocyst numbers, initially low, increased to a peak ranging from 36 × 10(3) to 74 × 10(3) oocysts/g (OPG) of litter around 3 to 4 wk of age. Numbers subsequently declined to 3 × 10(3) to 15 × 10(3) OPG. Oocysts could be detected between flocks when birds were not present. Species of Eimeria identified included E. acervulina, E. maxima, and E. tenella Despite the presence of large numbers of oocysts in the litter, coccidial lesions were not observed in the intestines of the birds. The performance of broilers at the study site was comparable to that of other farms in the area where birds from the same settlement were reared to a similar age using the same drug programs. The results indicate the ubiquitous nature of Eimeria spp. infections in commercial broilers despite prophylactic medication.
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA dchapman@uark.edu.
authors.forename: H D
authors.initials: HD
authors.lastname: Chapman
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1 Canada.
authors.forename: J R
authors.initials: JR
authors.lastname: Barta
authors.affiliation: Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1 Canada.
authors.forename: M A
authors.initials: MA
authors.lastname: Hafeez
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA.
authors.forename: P
authors.initials: P
authors.lastname: Matsler
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA.
authors.forename: T
authors.initials: T
authors.lastname: Rathinam
authors.affiliation: Department of Poultry Science, University of Arkansas, Fayetteville, AR 72701 USA.
authors.forename: M
authors.initials: M
authors.lastname: Raccoursier
mesh_terms: D000822:Animal Husbandry; D000818:Animals; D002645:Chickens / Q000469:parasitology*; D003048:Coccidiosis / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D003049:Coccidiostats / Q000627:therapeutic use*; D004539:Eimeria; D011201:Poultry Diseases / Q000188:drug therapy / Q000469:parasitology* / Q000517:prevention & control
chemical_list: D003049:Coccidiostats
keywords: Eimeria; broiler chicken; coccidiosis; oocyst