Natural Resistance to Disease in the Chicken

[摘要] Extensive bacteriological examination of the organs of 61 breeding birds, all survivors of a fowl typhoid infection, showed 21.3 per cent of them to be carriers of S. gallinarum . The ovary was the most frequent seat of localization of the bacterium in the females. Only 1 of 7 males examined proved to be a carrier. Chicks hatching from the carrier hens proved slightly, but not significantly, less resistant than those from non-carrier hens. The mortality among 129 chicks from carrier hens was 44.2 per cent and among 366 chicks from non-carrier hens 40.2 per cent. The non-carrier hens were those from which the organism was not isolated.Data secured from bacteriologic examination of a small number of chicks killed at various intervals after infection suggest that chicks from the selected population are more refractory to the fowl typhoid organism than are chicks from an unselected population. Agglutination tests on the blood serum of these chicks indicate that the young chick lacks the ability to develop agglutinins of high titer, if at all.

[学科分类] 生物科学（综合）