| Popis: |
THERE seems to be some feeling that young chickens are less susceptible than older chickens to infections with Eimeria necatrix. This evidently stems from the studies of Tyzzer, Theiler and Jones (1932) in which they report an experiment in which 7 of 8 birds 35 days old died of experimental infections while only 1 of 7 birds 8 days old died of the infection. The extended discussion of possible factors involved in this matter is excellent and complete and will not be repeated here. In this experiment the birds of different ages were permitted to eat uniformly infected feed for four hours after fasting overnight. This would seem to regulate the oocyst dosage by the size (volume) of the digestive tract. Obviously, the older or larger chickens ingested a larger number of oocysts than the smaller chickens, which may account for the results obtained. Since, as Tyzzer et al. (1932) . . . |
