The Response of Commercial Egg Production Stocks to Experimental Infection With Eimeria tenella and its Relation to Field Mortality

INTRODUCTION MUCH information has been accumulated concerning the performance of commercial egg production stocks with respect to a variety of economic traits. A particularly valuable source of information has been the various Random Sample egg production tests. Although variation between stocks in the occurrence of mortality has been observed, there is by the nature of the tests little information concerning response to specific pathogens. The Random Sample tests do not provide a highly sensitive means of detecting differences in survivability since the incidence of mortality due to pathogens is dependent upon natural exposure. In addition, more or less strenuous control measures are directed at certain diseases. These factors have evidently led to a large amount of stock × environment interaction which has contributed to the very low repeatability estimates for mortality data (A.R.S., U.S.D.A., 1961–1966). This study was designed to measure the response of a series of Random Sample . . .