A comparison of methods for exposing chickens to Coccidiosis in floor-pen trials.

Three floor-pen trials were conducted for the purpose of evaluating 4 methods of exposing broiler chickens to coccidiosis. The methods were compared on the basis of their effect on weight, feed efficiency, histological lesions, and mortality. In each of the individual trials, birds exposed to coccidiosis via the feed had significantly (P is less than 0.5) higher incidence of light to severe histological lesions that those exposed via "seeder birds" or contaminated litter. On the basis of pooled data from the three trials, birds exposed via the feed had lower feed efficiency, higher mortality, and significantly (P is less than 0.5) lower weight at 8 weeks than those exposed via the other techniques. However, the feed method of exposure resulted in a significantly higher variability (P is less than 0.1) in mortality among pens. For uniformity of infection, it was concluded that the most satisfactory method of exposing birds to coccidiosis in floor pen trials was to spread laboratory sportulated oocysts over the litter.

Efficacy of arprinocid (MK-302) against Eimeria species in broilers.

Eight floor pen trials were conducted to determine the effect of arprinocid on the weight, feed efficiency, and histological lesions of broiler chickens exposed to coccidiosis. In three trials, the levels of arprinocid were 0, 40, 60, 70, 80, and 90 ppm, and in the other five trials, 0, 50, 75, and 100 ppm. Histological lesions were significantly (P less than .05) reduced in the medicated birds. Weights were not significantly (P less than .05) different between birds given 40, 60, or 70 ppm in the first series of trials no 50 and 75 ppm drug in the second and third series, although in both series the treated birds were significantly (P less than .05) heavier than the control birds. Feed efficiency was improved by all levels of arprinocid in the first and third series of trials and by 75 ppm in the second series.