News 2562 views last update:Feb 25, 2016

Nitrogen gas foam for humane culling of pigs

The use of nitrogen gas foam as a humane way to cull animals that are in pain is being tested at the Swine Research Centre of Wageningen University.

With this method the pigs will be unconscious quickly due to too much nitrogen and also die in a short time. The research follows the new European council regulation No 1099/2009, stating that pigs or poultry (and other animals) that are in severe pain or that suffer severely have to be euthanised, if there is no practical and economical way to alleviate this pain or suffering.

Nitrogen foam
The method of nitrogen foam uses a barrel, filled up with a layer of high expansion foam (big bubbles) completely filled with pure nitrogen. The animal will be placed into the foam and covered with a layer of foam of at least 60 cm. The animal will breathe 98% nitrogen. Blood oxygen diminishes very quickly and the animal will very soon become unconscious. Because of the extreme oxygen deficiency (anoxia) the animal dies within 1.5-2 minutes.

The animal will not regain consciousness and will be unaware of breathing in pure nitrogen. It will not be harmful or painful for the animal because the normal air an animal breathes consists already of 80% nitrogen. Inhalation of nitrogen is therefore not stressful, whereas for example with high concentrations of carbon dioxide the animal will try not to breathe.

The method of nitrogen foam is also not physically demanding on the farmer and his employees. The animal almost instantly loses consciousness after being dipped through the foam. Fixation of the animal to avoid them to hurt themselves during stunning is not needed.

Capture nitrogen
The advantage of the use of high expansion foam is that the nitrogen gas is captured in the bubbles. Nitrogen is lighter than the surrounding air and would normally mix quickly with ambient air. The method therefore is safe to use for the operator.

Working with nitrogen gas foam is also hygienic. The animals will stay in the barrel were they are euthanised. No body fluids will be released.

Extensive research with the method of nitrogen foam with piglets started in January 2013 at the Swine Research Centre of Wageningen University, located in Sterksel.

This research has to prove that the animals are unconscious in a short time and die without stress because of the lack of oxygen.

Apart from the effects on the animals the reliability of the equipment will be tested, and a standard operating procedure will be developed. By the second half of 2013 the method will become available commercially.

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