Reversible protocols of chemical containment and impact of oxygen supplementation on free-living capybaras (Hydrochoerus hydrochaeris)

Author(s)

Jefferson Farias Cordeiro

• Document type: Doctoral Thesis
• Press: Pirassununga.
• Institution: Universidade de São Paulo (USP). Faculdade de Zootecnica e Engenharia de Alimentos (FZE/BT)
• Defense date: 2020-02-10

Examining board members

Adriano Bonfim Carregaro; Silvia Renata Gaido Cortopassi; José Maurício Barbanti Duarte; Natache Arouca Garofalo; Martielo Ivan Gehrcke

• Advisor: Adriano Bonfim Carregaro

Abstract

Capybara (Hydrochoerus hydrochaeris) is considered an important amplifier of spotted fever in the wild, making its population control necessary. Therefore, they should generally be chemically contained. The present study aimed to compare different chemical containment protocols, the impact on lung capacity and other arterial parameters, the effect of different oxygen supplementation flows and the total or partial reversal of the protocols on free-living capybaras. Thirty-six animals were chemically contained with 5 µg/kg dexmedetomidine, 0.1 mg/kg midazolam and 0.2 mg/kg butorphanol (DMB) or 0.1 mg/kg methadone (DMM), IM. After 30 minutes, 1/3 of the animals remained breathing ambient air (DMB-Air and DMM-Air), 1/3 was supplemented with 2L / min flow of 100% O2 with an intrasal probe (DMB-2L and DMM-2L) and 1/3 with 5L/min flow (DMB-5L and DMM-5L After 60 minutes of application, 1/2 of the animals received 2 µg / kg of flumazenil 5 µg / kg of atipamezole and the other 1/2 the same protocol associated with 4 µg / kg of naloxone. Thus, 12 groups were obtained (n = 3). Latency and recovery were assessed using a behavioral scale. During containment, clinical parameters and reflexes were monitored every 10 minutes after initial application and the gases, ions, glucose and arterial lactate were analyzed at 30 and 60 minutes after initial application. The protocols promoted excellent restraint, without falls or excitement. The animals allowed manipulation after 9.3 ± 3 minutes, with no difference in duration and quality of latency between DMB and DMM. Once contained, all showed excellent muscle relaxation and allowed the handling and collection of blood. Although DMM has higher values than DMB in FC (80 [66; 104] and 75 [54; 92] hr, respectively) and ƒ (36 [18; 56] and 28 [15; 53] rr), they were not great differences were observed between opioids during containment. At 30 minutes, all animals showed considerable hypoxemia (PaO2 = 44 [30; 73] mmHg, SaO2 = 81 [62; 93]%), reversed only in the 5L group (PaO2 = 188 [146; 414] mmHg, SaO2 = 100 [99; 100]%). The recovery time (8.3 [3.5; 21.2] minutes) did not differ between groups and, despite the animals that received methadone score better than those that received butorphanol, no clinical difference was observed. There was no difference in the recovery of the groups with or without O2 supplementation, as well as between the groups of total or partial reversion. It is concluded that the protocols provided excellent chemical containment and smooth recovery of capybaras, but because they promote hypoxemia, they should be supplemented with 5L / min of 100% O2. (AU)

• FAPESP's process: 16/21121-9 - Reversible protocols of chemical restraint in wild capybaras (Hydrochoerus hydrochaeris)
• Grantee: Jefferson Farias Cordeiro
• Support Opportunities: Scholarships in Brazil - Doctorate