| Popis: |
WITH expansion of hatchery operations for broiler chicks and resulting economic demands for increased efficiency, the causes of poor hatchability and early chick mortality are becoming more significant to the poultry industry. These hatcheryassociated losses have frequently been ascribed (Jungherr, 1935; Bierer, 1950; Watts and Rac, 1958) to so-called “nonspecific” bacterial infections. Mortality patterns similar to field outbreaks are readily induced in newly hatched chicks by yolk sac or subcutaneous inoculations of pure or mixed bacterial cultures (Harry, 1957; and Reid and Kleckner, 1958). Lorenz et al. (1952) experimentally infected market eggs using a dipping and chilling technique to study “Pseudomonas spoilage.” Shell penetration by Salmonella organisms has been demonstrated with turkey hatching eggs by Pomeroy and Fenstermacher (1941) and Gregory (1948). The importance of shell penetration in producing so-called nonspecific bacterial infections in commercial hatchery operations has not been extensively evaluated. In this report field outbreaks have been studied… |
