Effect of brushing on heart rate variability in Malayan tapirs: Does brushing contribute toward alleviating puncture stress?

Abstract

Many zoos conduct husbandry training with positive reinforcement to improve the care and welfare of wild animals. However, few studies have quantitatively examined whether stress occurs during invasive procedures. Brushing is known to encourage Malayan tapirs Tapirus indicus to lie down, helping with veterinary care, including preventive care. This study aimed to assess stress in Malayan tapirs during veterinary procedures using heart rate variability (HRV) analysis. In Experiment 1, the HRV index was tested by puncturing the tapirs without brushing and behavioural stress indicators were examined. Experiment 2 involved HRV measurement during husbandry training, including blood collection and brushing, to compare HRV changes before and after puncture. Experiment 3 examined the impact of brushing by comparing HRV across different postures, including during nighttime rest. The results showed that in Experiment 1, heart rate (HR) increased during and after puncture, matching the behavioural stress index, suggesting HRV analysis may be a useful stress evaluation tool. In Experiment 2, HR, HF, and LF/HF varied widely among individuals and days, with no clear negative impact of of puncture. Experiment 3 showed significant differences in HRV parameters (HR, HF, and LF/HF) across postures, suggesting that brushing may have a rewarding effect on the tapirs. This study allowed us to conduct the first HRV analysis of Malayan tapirs. In addition, the potential of reducing the stressful effects of invasive procedures by brushing was suggested.