Early T-maze behavior can predict broiler growth.

MARIN, R. H .; SATTERLEE D. G.; S A, CASTILLE; JONES, R. B.

Atlanta, Estados Unidos

Congreso; International Poultry Scientific Forum.; 2003

Poultry Science Asociation

  In laboratory and on-farm studies in Argentina, broiler chicks that showed a short latency to exit a T-maze (LEX) (HP, high performance) gained more weight than slower ones (LP, low performance). The present study re-examined this relationship and evaluated additional T-maze measures using broilers reared in quasi-intensive, environmentally controlled conditions. A mirror at the end of a corridor in the T-maze stimulates the test chick to leave the start box and to move towards its reflection. Upon reaching the mirror it can see other birds and thereby be stimulated to exit the maze. However, if it hesitates or stops at the mirror its performance categorization may be confounded. Herein, the T-maze performance of 3-d-old broiler chicks was assessed using three measures: 1) latency to exit the start box (LEB), 2) latency to reach the mirror (LRM), and 3) LEX. The fastest (upper 25%) and slowest ( lower 25%) of birds within sex and within each T-maze criterion were classified as HP and LP chicks, respectively. Relationships between these measures and body weight within quartiles were examined in 4, 42 and 56-d-old males and females. All HP and LP chicks had similar body weights at 4 d of age but chicks classified as HP according to LEB or LRM measures were heavier than LP ones at 42 and 56 d (P < 0.02 for all comparisons). These differences were apparent in both sexes. However, there were no detectable differences in body weight at the latter ages between chicks categorized as HP or LP according to their LEX scores. Our results suggest that: 1) broiler chicks that exit the T-maze start box and reach the mirror quickly gain more weight than the slower birds, and 2) LEB and LRM are better predictors of growth than the LEX value used in previous studies.