Broiler chicken with a duplicated lower intestinal tract.

A case is described of a duplicated lower intestinal tract in a broiler chicken. The ileum branched to form two lower intestinal tracts. The ileum of the malformed branch was swollen and attached to paired ceca that were grossly enlarged, and the rectum was a swollen blind sac, disconnected from the exterior of the bird.

Sensitivity of field isolates of Eimeria from two broiler complexes to anticoccidial drugs in the chicken.

The spectrum of resistance to seven currently used anticoccidial drugs in isolates of Eimeria obtained from farms two broiler complexes was examined. All isolates were resistant to monensin, salinomycin, and narasin. Lasalocid was more effective in controlling coccidiosis than the other ionophores, although most isolates were classified as resistant to the drug. The majority of isolates were sensitive or showed reduced sensitivity to robenidine, clopidol, and decoquinate. It was concluded that for drugs that have been used extensively (e.g., monensin and salinomycin), examination of isolates from one or two farms may give results applicable to the entire complex. For drugs that have been used infrequently, however (such as robenidine, clopidol, and decoquinate), examination of isolates from at least five farms would be desirable to establish the spectrum of drug sensitivity.

The effects of shuttle programs upon the growth of broilers and the development of immunity to eimeria species.

A floor-pen trial was conducted to investigate the effects of different shuttle programs upon the growth of broilers to 8 wk of age. Nicarbazin, halofuginone, and robenidine, when included in the starter feed for 3 wk, were effective in preventing lesions due to Eimeria. The effects of medication upon performance were apparent, medicated groups gaining more weight by 6 wk and having a lower feed conversion at 6, 7, and 8 wk than the unmedicated controls. There were no significant differences in body weight at 6, 7, or 8 wk or feed conversion at 6 or 7 wk among the medicated groups, whether medication was withdrawn for 7 or 14 days. A decrease in the number of small and medium oocysts in the litter was observed as the trial progressed. Few large oocysts (Eimeria maxima) were seen in the medicated groups. Numbers of oocysts did not increase following withdrawal of medication. Birds from all medicated groups were challenged at 6 wk with oocysts of Eimeria acervulina, Eimeria maxima, or Eimeria tenella. Weight gains were similar to that of the unchallenged controls, indicating that they had acquired immunity to these species of Eimeria.