FEATHER RETENTION FORCE IN BROILERS ANTEMORTEM, PERIMORTEM, AND POSTMORTEM AS INFLUENCED BY ELECTRICAL AND CARBON-DIOXIDE STUNNING

Stunning and slaughter trials were conducted to evaluate the influence of stunning method (electrical 50 V alternating current, CO2 gas: 0 t o 40% for 90 s or 40 to 60% for 30 s) on feather retention force (FRF) in commercial broilers. Feathers from the pectoral, sternal, and femo ral feather tracts were sampled with a force gauge before stunning (an te-mortem) and contralaterally either after stunning (peri-mortem from 0.5 to 4 min) or after stunning and bleeding (post-mortem from 2 to 6 min). Prior to stunning, ante-mortem FRF values varied among assigned stunning methods only for the pectoral (7%) feather tract. After stun ning, peri-mortem FRF values were higher only for the sternal tract (1 1% for 40 to 60% CO2 for 30 s); whereas after stunning and bleeding, p ost-mortem FRF values were lower than ante-or peri-mortem only for the sternal tract (10% lower for 40 to 60% CO2 for 30 s). Peri- and post- mortem FRF values did not differ among stunning methods for the pector al curd femoral feather tracts. Small changes in FRF values occurred f rom ante-mortem to peri-mortem (-1 to +12%), and from ante-mortem to p ost-mortem (-2 to +8%) across stunning methods, A significant increase was determined for only the pectoral tract (7%) from ante-to peri-mor tem across stunning methods. Electrically stunned broilers that were n ot bled gained weight in excess of the 36 feathers removed (0.16%), ap parently due to body surface water pickup during the brine-stunning pr ocess, whereas CO2-stunned broilers lost weight due to excretion of cl oacal contents (-0.31 to -0.98%). The change in body weight among stun ning methods was significant (P < 0.0233). Peri-and post-mortem FRF, i n addition to bleed-out body weight loss, were not substantially influ enced by electrical or CO2 stunning methods, and, therefore, carcass d efeathering efficiency may not differ after scalding.