Relation between tonic immobility and production estimated by factorial correspondence analysis in Japanese quail

Station de Recherches Avicoles, INRA, 37380 Nouzilly, France.

Duration of tonic immobility (TI) is a well-established criterion of fearfulness in birds, but its relation to production traits has been little studied. TI and 27 variables related to egg production and quality, feed consumption, and body condition were collected for 355 female Japanese quail. Experimental birds were the F2 generation from a reciprocal cross between a line selected for long TI and a line from a different origin and selected for early egg production. TI and several other variables had very asymetrical distributions so all variables were categorized, and the association between traits was studied by factorial correspondence analysis (FCA). Attributes of good versus poor layers were well separated by the FCA, but no association was obtained between TI and other traits on the primary axes of the FCA. Fearfulness, as measured by TI, was not related to levels of performance of egg laying quail. Secondary negative associations between TI and body temperature and between TI and residual feed consumption were obtained; however, they were marginal and need to be confirmed.