Moreau, E. 2010. To squeeze or not to squeeze? A Discussion on LAREF, September, 2009. Laboratory Primate Newsletter 49(2), 3-4.
The discussion was started by the following questions: "Is the squeeze-back mechanism more or less stressful than the pole and collar system for removing a macaque from his cage for an IM (intramuscular) injection?" and "How are stress levels being measured when using either system or both?" Trust and communication between animal and human through positive reinforcement training (PRT) were mentioned several times as the best means to reduce and eliminate the stress of either restraint system. Both the squeeze-back and the pole and collar have been well established in the field of laboratory animal science. Variants have also been developed in agriculture (squeeze chute) and for household pets (e.g., collars for dogs and cats). As with any tool for animal restraint, developing a sense of trust and communication between the animal and person will lessen the anxiety and stress level of both parties. One of the most powerful modes of communication with animals is through PRT. Trust comes when communication is established. Strengthening both communication and trust develops a cooperative working relationship. Communication and trust are most effectively built through desensitization. Desensitization is the process of gradually exposing the animal to a novel or fearful stimulus and pairing it with a neutral or pleasant stimulus. Reinhardt (2003) documents a training protocol in which PRT is used to train macaques for cage-side femoral blood collection while using the squeeze-back mechanism as a tool. Donelly has incorporated the squeeze-back as a means of guiding the animals into proper position for pole and collar training. Rubino makes use of the squeeze-back cage as a matter of health and safety when giving IM injection in the cage. Sorrells, on the other hand, does not make use of the squeeze-back to aid in training. By using PRT only, she has been able to train her macaques to present for injection. Each discussion participant has also stated the importance of a good desensitization to the squeeze-back in order for its use to be minimally stressful while still effective. By not using the squeeze-back mechanism, Sorrells has been successful in decreasing stress levels. In facilities such as a contract research organization, time is of the essence. Boehle and Klein & Murray (1995) point out that staff experienced with the squeeze-back and comfortable with its proper use help to lower the perceived stress level of this restraint technique. Fear and anxiety are sources of stress for a restrained nonhuman primate (NHP). Kerwin makes use of the squeeze-back in a dedicated cage, reserving the homecage as a safe haven. Use of a separate cage for a dedicated purpose cues the animal to what will happen next, resulting in less anxiety of the unknown. Boehle has found that NHPs have been less likely to cooperate entering the chair when past experience was unpleasant, such as restraint for an injection. NHPs have the capacity to remember unpleasant experiences and are usually deceived only once (Fowler, 2008). The use of a ruse and the health and safety of personnel need to be measured carefully. The health and safety of staff have made the squeeze-back the safest option for administering IM injections to NHPs, Rubino believes. Sainsbury (1989) and Klein & Murray (1995) both weigh-in in favor of the health of safety of personnel. The health and safety of staff and animals can be established by the efforts of collecting good data and conducting good science. The focus is to lessen the stress of the restraint technique by the use of the squeeze-back and pole and collar. Klein & Murray (1995) warn of the possible exaggeration of a medical condition due to the stress of restraint. Rubino also reminds us that the primary concern when working with research animals is to ensure that biological factors are not affected. A summary of possible physiological parameters affected can be found in Reinhardt (2003). In scientific research, variables such as stress can lead to the need to repeat an experiment, which leads to the use of more animals. Training by PRT leads to gaining the trust of the animal (Reinhardt, 1995, 2003, Klein & Murray, 1995). Gaining the trust of the animal is best achieved by desensitization because it minimizes the stress of a new procedure (Boehle, Klein & Murray, 1995; Sainsbury, 1989).The NHPs that we work with are sentient and capable of learning and communicating with us. By listening to and working with the animals during common and routine restraint procedures, we will minimize the stress that the animals may experience.