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On-Farm Euthanasia of Swine Recommendationsfor the Producer
It is inevitable that on every swine farm, situations that require pigs to be euthanized will arise. These situations include, but are not limited to, illness and injuries. Since it is usually not possible or practical for the veterinarian to be available for timely euthanasia of pigs on-farm, producers and their employees often need to perform humane euthanasia of pigs.
5 2 The term euthanasia is derived from the Greek terms eu meaning good and thanatos meaning death. Euthanasia is the humane process whereby the pig is rendered insensible, with minimal pain and distress, until death. For the euthanasia process or method to be considered humane, it must be quick, effective and reliable. Key elements for determining if a method is humane include: minimal pain and distress to the pig during administration rapid loss of consciousness, death is achieved quickly and consistently. This brochure provides practical recommendations for the on-farm euthanasia of swine. It also highlights euthanasia methods that have been shown to meet the definition for humane euthanasia based on the available scientific literature. However, this list may not be all inclusive and other options may be used as long as they meet the definition and key elements for euthanasia discussed above. All euthanasia techniques should be discussed with a veterinarian before being implemented. When a pig becomes ill, injured, or otherwise disadvantaged, the initial decision for action may include treatment or euthanasia. In some cases, euthanasia may be the best option for the well-being of the pig. It is important that the decision to euthanize is made in a timely manner so as to minimize the pigs pain or distress. For example, timely or immediate euthanasia is recommended for: Pigs that show inadequate improvement or that have minimal prospect for improvement after two days of intensive care, Severely injured or non-ambulatory pigs with the inability to recover, Any pig that is immobilized and with a body condition score of 1. This brochure is designed to aid producers in making appropriate decisions regarding euthanasia of swine. The Pork Checkoff and the American Association of Swine Veterinarians recommend that pork producers and their employees read this brochure, discuss the options with their veterinarian and fill out the action plan at the end of this brochure. All swine caretakers should be aware of the action plan and be trained on the euthanasia methods selected for the pigs in their care. The action plan should be reviewed as part of new employee training and annually with a veterinarian and all employees.
Table 1: Methods of Euthanasia Appropriate for Pigs of Different Sizes (weights) Suckling pig (up to 12 lbs) Carbon dioxide (CO2) Gunshot Penetrating captive bolt Non-penetrating captive bolt Electrocution, head-to-heart Electrocution, head-only Veterinarian administered anesthetic overdose Blunt trauma
Nursery pig Grower - Finisher pig Mature pig, (up to 70 lbs) (up to market weight) sow or boarYes Yes, but not practical Yes Yes Yes, but not practical Yes Yes
Yes Only for pigs over 10 lbs Only for pigs over 10 lbs
Yes with secondary step Yes
Yes, with secondary step
Yes, with secondary step
Yes, with secondary step
This method is an acceptable form of euthanasia for this size of pig but may not be practical for individual pig euthanasia on-farm due to lack of equipment suitable for this size.
The Process of Euthanasia
Euthanasia of swine may be a one- or two-step process. A one-step process renders the pig permanently insensible and results in death. A two-step process temporarily renders the pig insensible, but requires a secondary step to achieve its death. The second step is typically achieved by exsanguination or pithing (see page 14). It is important to understand the difference between the two processes. It is important to remember that certain methods for euthanasia are more appropriate than others for pigs of certain sizes or weights. Table 1 lists various methods of euthanasia in pigs and the size of pigs they are most appropriate for.
Considerations for Euthanasia
When euthanasia is the most appropriate option for a pig, consider the following to select the suitable method: Humansafety: The method must not put producers or their employees at unnecessary risk. Pigwelfare: Any method should minimize pain or distress of the pig during administration. Practicality/technicalskillrequirements: The method should be easily learned and repeatable with the same expected outcome. The skill required noted in Table 2 assumes the caretaker has been adequately trained to use the method. Caretakercompliance: Producers and their employees must be comfortable with, and willing to perform, the chosen method when needed. Lack of compliance compromises the well-being of the pig.
The method should not be objectionable to the person administering the procedure. Public perception of the method and its application also may be a consideration. Limitations: Some methods are only suitable for certain sizes of pigs or under certain circumstances. The availability of equipment in good working order and carcass disposal options also can be limiting factors for choosing a method. Table 2 lists euthanasia methods and special considerations for each one.
Table 2: Considerations for Specific Euthanasia Methods for Swine Risk to Human Safety Carbon dioxide (CO2)Moderate
Skill RequiredModerate to low, based on equipment design Moderate to high Moderate
AestheticsBloodless, some excitatory movement or vocalization possible in pigs Discharge of blood from wound Discharge of blood from wound
LimitationsCurrently only practical for small pigs Security of firearms; legal restrictions May be a two-step process depending on equipment design; maintenance of equipment May be a two-step process based on size of pig Adequate amperage needed; commercial hog stunner recommended; head only is a two-step process Applicable agents available only to licensed veterinarian; carcass disposal Only applicable to small pigs
Penetrating captive bolt
Non-penetrating captive bolt
Minimal to no blood discharge as a one-step process Muscle contraction
Electrocution head-to-heart and head-only
Low if proper lock out/tag out procedure followed
Veterinarian administered anesthetic overdose Blunt trauma
High, veterinary administration only Moderate
No blood discharge, limited pig movements Some blood discharge; objectionable for some
Details for Each of the Recommended Methods 1. Carbon dioxide (CO2)Gradual filling of the container is done by placing the pigs into the container and filling the container with carbon dioxide at an effective flow rate. For effective euthanasia, pigs require a constant exposure of 80-90 percent carbon dioxide concentration, for at least 5 minutes. The time needed to achieve effective concentration is a function of the flow rate and container volume. Consult with your veterinarian or other trained professional to discuss these variables. Compressed carbon dioxide gas in cylinders is the recommended source of carbon dioxide. Other sources of carbon dioxide, such as dry ice, fire extinguishers, or chemical reactions, are unacceptable. A regulator is required to control the release of gas from the cylinder. Unregulated release or excessive flow rates of carbon dioxide have the potential to freeze the pigs and result in excessive use of carbon dioxide. The use of a flow meter is recommended to monitor the gas exchange rate in the chamber. When unmonitored, an inadequate exchange rate can result in lack of death or can result in the pig suffocating before it becomes anesthetized or loses sensibility. When proper equipment is used and gas is used correctly, carbon dioxide results in loss of consciousness followed by respiratory arrest and death. Euthanasia of swine by carbon dioxide inhalation is safe for farm personnel who have been trained, have access to the proper equipment, use the gas properly, and carry it out in a well-ventilated area. Carbon dioxide is non-flammable and non-explosive.
Carbon dioxide (CO2) replaces oxygen in the body and causes rapid onset of anesthesia with subsequent death due to respiratory arrest. Although unconscious, pigs may experience involuntary vocalizations and movements when carbon dioxide is used correctly. Euthanasia by carbon dioxide inhalation is relatively inexpensive but requires special equipment to work effectively. An enclosed, airtight container that is large enough for the size of pigs being euthanized is required. The container must be equipped with inlet and outlet valves. Because carbon dioxide is heavier than air, the containers outlet valve should be located at the top. This way, the container can be completely filled with carbon dioxide while the air displaced is allowed to escape. Euthanasia by carbon dioxide inhalation can be completed by pre-charging or gradual filling of the container. Pre-charging is done by filling the container with carbon dioxide before the pigs are placed in it. Additional carbon dioxide must be added to maintain effective concentrations within the container after the pigs have been placed in it. The container should be positioned in a way that reduces disturbance of the gas when the container is open or the pigs are placed into