The Greek definition of euthanasia is “good death.” Some call euthanasia “the kindest act” because its objective is a death which causes no pain or distress to an animal. However it’s defined, the food animal veterinarian often faces the situation of euthanasia with an animal that is injured, ill or debilitated.

“It is one of the paradoxes of being a veterinarian,” says Jan Shearer, DVM, MS, University of Florida. “We enter this profession with the hope of treating disease and saving lives, not ending them. But at some point we realize that being a veterinarian requires us to serve not only as a healer, but also as an executioner. It’s never easy, and just because it’s a cow doesn’t mean that we don’t struggle internally when called upon to end its life. But, as veterinarians, we understand the difference between prolonging life and prolonging death. We are morally obligated to end suffering by inducing a quick and painless death.”

In some cases, animals may suffer because owners don’t fully understand what they are enduring, Shearer explains. Cattle in severe pain may exhibit very vague signs of discomfort (see Pain Management, Bovine Veterinarian, November 2007).

“As veterinarians, we have a responsibility for the animal’s sake to interpret these signs for their owners so that they can make the proper decisions on ‘when to say when,’” Shearer notes. “By virtue of our understanding of disease conditions and their prognosis, we have a vital role to play in advising our clients about the likelihood of a successful outcome, or misery that may accompany attempts to affect recovery. There is a natural inertia that we all feel when faced with these situations, but when we think about our moral responsibility and the oath we’ve taken as veterinarians to relieve animal suffering, we’re empowered to do the right thing.”

The loss of productive function in an animal offers at least two options: slaughter or euthanasia. Slaughter should be reserved for animals that are not in severe pain, are freely able to stand or walk, capable of being transported and free of disease or treatment that might constitute a significant public health risk. Euthanasia is the appropriate option when these conditions cannot be met.

Selection and training of employees

While veterinarians recognize that euthanasia is an important responsibility of the role they play in promoting animal welfare, it is easy to forget that clients and their employees need direction and assistance in implementing these procedures. “We sometimes fail to see that euthanasia is a particularly difficult decision for some, if not most, livestock owners,” Shearer says.

Some people simply can’t do it. In small operations where producers share a very close relationship with their animals, they may find it particularly difficult to make the decision to euthanize an animal. Instead of intervening with euthanasia, people will choose to displace themselves from the area and hope that nature will take its course and life will be ended naturally. “Unfortunately, in many cases this just doesn’t happen,” Shearer says. “It is in these situations we are obligated to assist and thus provide a very real service to both the animal as well as the owner.”

Avoiding pain and distress when euthanizing an animal requires that the techniques used cause immediate loss of consciousness, which is followed by cardiac or respiratory arrest that ultimately results in loss of brain function. Persons who perform this task must be technically proficient and have a basic understanding of the anatomical landmarks and equipment used for humane euthanasia.

The difference between some owners or their employees and veterinarians, in most circumstances, is that veterinarians possess the knowledge, skills and necessary equipment for performance of these procedures with minimum pain and distress to the animal. However, every operation needs to have someone trained to conduct this procedure. In large operations, Shearer suggests it is necessary to train several people to perform euthanasia procedures so that these duties may be spread among several people. This will more likely assure round-the-clock coverage of these duties and someone to fill in on holidays or weekends.

“It is important to remember that not all persons are mentally or emotionally capable of performing euthanasia procedures,” Shearer notes. “In fact, studies of persons required to perform these procedures on a repetitive basis show that some people develop work-related dissatisfaction. And still others may develop a greater tendency toward callous handling of animals. It is important to carefully select the people who will perform these procedures.”

Veterinarians are the ideal persons to provide the training of personnel in euthanasia procedures. Additionally, they can discuss related issues such as animal welfare and appropriate animal handling and care. Since the opportunities to provide such information and training are sometimes few, seizing the chance to discuss these issues in relation to euthanasia techniques should not be missed.

Experienced persons should assist in the training of inexperienced persons and utilize cadavers to demonstrate anatomical landmarks and application of the various techniques, Shearer suggests. Cadavers should be used for practice by trainees until they become proficient with the procedures.

Methods of euthanasia

Persons conducting euthanasia procedures should attempt to minimize animal distress. Cattle should be approached quietly and restrained only if necessary to properly conduct the procedure. If the animal is ambulatory and able to be moved without causing distress, discomfort or pain, it may be moved to an area where the carcass may be more easily reached by removal equipment. Dragging of non-ambulatory animals is unacceptable. In cases where movement may increase distress or animal suffering, the animal should be euthanized first, then moved following confirmation of death.

Properly applied, euthanasia by either gunshot or captive bolt causes less fear and anxiety and induces a more rapid, painless and humane death than can be achieved by most other methods. However, both methods may involve human risk and, therefore, require skill and experience. Neither method should be attempted by untrained or inexperienced persons.

Gunshot

Euthanasia by gunshot is the most practical method under farm or ranch conditions. A .22 caliber long rifle bullet is sufficient for most young animals as long as one uses a solid-point bullet. Shearer stresses that hollow-point bullets should never be used since there is always a possibility that they will not penetrate the skull. Only solid-point bullets will provide consistent results to traverse the skull, enter the brain and cause massive brain destruction. For mature animals or bulls, use a 9 mm, .357 or similar caliber with a solid-point bullet.

For people who have not handled firearms, a quick course in the handling and care of firearms is advised. These are available in most local areas through hunter safety programs. This is particularly important since ricochet is not uncommon and, depending upon location of by-standers, may be very dangerous. People should also be aware that it is possible for a bullet to pass through an animal and exit with sufficient energy to hit a by-stander. Proper positioning of all nearby personnel is important to avoiding injury. 

Advantages: When properly positioned, the bullet causes massive brain destruction and immediate unconsciousness. Gunshot is inexpensive and does not require close contact with the animal.

Disadvantages: Gunshot is dangerous. Ricochet of the bullet is possible and, therefore, the operator and by-standers must use extreme care in positioning themselves and others when the procedure is performed. Another disadvantage is that in cases involving fractious animals, it may be difficult to hit the vital target area.

Whereas most animals for which euthanasia by gunshot is indicated are either debilitated or down, opportunity for proper placement of the bullet is less difficult. For animals on their feet and mobile or potentially dangerous, it may be necessary to shoot from a distance. In such cases, the preferred target areas are the head or neck.

Captive bolt

Captive bolt followed by immediate exsanguination (bleeding out) is the preferred method for euthanasia of cattle in abattoirs. Captive bolt guns cause concussion and trauma to the brain. Because placement and positioning of the captive bolt projectile is critical, some degree of restraint is required for the proper use of this device.

There are two types of captive bolt: penetrating and non-penetrating. Both are discharged by gunpowder or compressed air. A non-penetrating captive bolt works by concussion and only stuns the animal. It should never be used as the sole method of euthanasia. Exsanguination or chemically assisted euthanasia is required whenever a non-penetrating captive bolt is used. A penetrating captive bolt works by concussion and trauma to the brain. It causes immediate unconsciousness and destruction of brain tissue as a result of penetration of the discharged bolt.

While the destruction of brain tissue with the penetrating captive bolt may be sufficient to result in death, operators are strongly advised to ensure death by exsanguination or chemically assisted means, such as by the rapid intravenous injection of 120 ml of a concentrated potassium chloride (KCl) solution which will cause cardiac arrest.

Advantages: Although not without risk, captive bolt is generally safer for the operator and by-standers. Beyond the initial investment of a captive bolt, continued use is inexpensive.

Disadvantages: Death may not occur unless followed by exsanguination or chemical assistance. The operator must be close to the animal and have it adequately restrained in order to get proper placement of the captive bolt. The captive bolt should not be fired when the animal is moving its head.

The most consistent mistake in conducting euthanasia is failure to direct the projectile (whether a bullet or bolt from a penetrating captive bolt) into the proper location in the skull, Shearer says. “Many people tend to shoot animals between the eyes, but this misses the brain completely.” The proper location may be determined by drawing an imaginary or real X (with a marking crayon, for example) from the inside corner of each eye to the base of the opposite horn (or top of the ear in hornless cattle). This places the recommended point of entry in the center of the forehead somewhat above a line drawn between the eyes.

When euthanasia is performed by gunshot, the firearm should be held approximately 2–10 inches from the intended target. Ricochet may be prevented if the barrel of the firearm is positioned perpendicular to the skull.

Exsanguination/chemical assistance

Once the animal has been rendered unconscious, exsanguination or the intravenous injection of KCl solution should be initiated to ensure death. Shearer stresses that KCl should never be used in conscious animals.

Exsanguination should be performed with a pointed, very sharp knife with a rigid blade at least 6 inches in length. The knife should be fully inserted through the skin just behind the point of the jaw and below the neck bones. From this position the knife is drawn forward, severing the jugular vein, carotid artery and windpipe. Properly performed, blood should flow freely with death occurring within several minutes. Exsanguination is more rapidly achieved if the knife is directed deeper toward the thorax to incise the vena cava.  

Alternatively, one may sever the brachial vasculature by lifting a front leg and inserting the knife deeply into the axillary area at the point of the elbow and cutting the skin, blood vessels and surrounding tissue until the limb can be laid back against the thorax of the animal. Regardless of the method used, great care should be exercised in performing exsanguination procedures. Although unconscious, animals in this state are capable of violent involuntary movement that may cause personal injury. The same is true when making intravenous injections of chemical euthanasia agents. The operator must position himself/herself properly to avoid injury associated with involuntary movement.

No matter which method is used, confirmation of death is important and includes evaluation of the following parameters:

  • Lack of a heartbeat
  • Lack of respiration
  • Lack of a corneal reflex
  • Lack of movement over a period of several hours
  • Rigor mortis

Shearer adds that unacceptable methods for euthanasia of cattle include:

  • Manually applied blunt trauma to the head.
  • Injection of any chemical substance not labeled for use as a euthanasia agent.
  • Injection of air into a vein.
  • Electrocution, as with a 120- or 220-volt electrical cord.