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Pol Llonch presents Poster 65 during the poster sessions in the Aula.
Session theme 6: Free topics
137
Poster 65
AVERSION TO THE INHALATION OF NITROGEN AND CARBON
DIOXIDE MIXTURES USED FOR STUNNING IN PIGS
P. Llonch 1 , A. Dalmau 1 , P. Rodríguez 1 , J.L. Ruiz de la Torre 2 , X. Manteca 2 , A. Velarde 1
1 Finca Camps i Armet s/n. 17121 Monells, Girona, Spain
2 School of Veterinary Science, Edifici V, Campus Unisersitari UAB, 08193, Cerdanyola del Vallès,
Barcelona, Spain
In the CO2 stunning system, pigs are loaded into a crate which is then lowered into a pit prefilled
with high concentration of CO2. However, the inhalation of concentrations above 30% CO2 by
volume in atmospheric air causes aversion in pigs. The objective of the study was to assess the
aversiveness of alternative N2 and CO2 (up to 30% by volume in atmospheric air) mixtures to stun
pigs
The aversion to the inhalation of 85% nitrogen and 15% CO2 (85N15C), 80% nitrogen and
20%CO2 (80N20C), or 70% nitrogen and 30% CO2 (70N30C) were assessed in 3 different trials of
10 pigs each, using aversion learning test and behavioural studies. Pigs entered the crate
individually and descended into the pit during 6 consecutive sessions. During the first 3 sessions the
pit contained atmospheric air and the following 3 sessions it contained the gas mixture. The
following behavioural parameters were recorded: time to cross the raceway and enter the crate,
presence and time taken to perform the first retreat attempt, escape attempts, gasping as sign of
breathlessness and loss of posture as sign of unconsciousness. Proc MIXED and Proc GENMOD
statements of SAS were used for the variable “time to cross the raceway and enter the crate” and for
the ordinal data, respectively.
After the training sessions, pigs were well adapted to the facilities. For 85N15C and 70N30C
groups, the time taken to cross the raceway and enter the crate increased after the first exposure to
the gas (p0.05) were found between treatments on
the aversive behaviour into the crate, pigs took less time (p