Breaux, S. D., Breaux, M. B., Fontenot, M. B. 2013. Positive reinforcement training effects on hemogram and chemistry parameters in chimpanzees. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 669 (Abstract #175).
Positive reinforcement training (PRT) is used at various biomedical research facilities and zoos in order to facilitate animal husbandry activities as well as veterinary procedures. Previous research suggests that the use of PRT helps alleviate stress during potentially distressing events, such as anesthesia for physical examination, as indicated by changes in certain hematology values including white blood cell (WBC) counts, neutrophils (NEU), hematocrit (HCT), and glucose (GLU) levels. However, decreases in these values resulted from trained subjects who cooperated with sedation procedures rather than involuntarily receiving a darted intramuscular injection. Here we consider more fully the effects of PRT by comparing hematology levels of untrained subjects compared with trained subjects both prior to and following PRT for voluntary injection. The subjects were chimpanzees that had no prior experience with PRT (injection only (Inj); n = 11, 11F; 12.67 to 26.83 y; mean = 18.71) or had experience with PRT for urine collection (urine and injection (U&I); n = 35, 14F, 21M; 3.5 to 15.17 y; mean = 8.33) and were then trained to present a thigh for voluntary IM injection, while others remained naïve to PRT (untrained (Unt); n = 27, 10F, 17M; 3.33 to 19.08 y; mean = 14.22). Data analyzed were obtained from two annual physical examinations for each subject. For trained subjects, one data point was collected prior to onset of voluntary injection training while the other was collected after the subject had reached training criteria. Analysis of covariance, covarying age and preinjection training baseline blood values, indicated that among trained subjects WBC levels were significantly lower (U&I<Unt, P < 0.05), as were NEU levels (U&I<Unt, P < 0.05; Inj<Unt, P < 0.05), while GLU (Inj>Unt, P < 0.05; U&I<Inj, P < 0.05) and HCT (U&I>Unt, P < 0.05) were significantly higher. No effect of cooperation with injection was observed. These results suggest that the use of PRT for voluntary injection lowers the stress responses of chimpanzees to sedation procedures, whether or not the subjects voluntarily present for injection.