Physiological and biochemical responses to repeated anaesthesia and electroejaculation in adult and yearling pampas deer (Ozotoceros bezoarticus) males

As pampas deer (Ozotoceros bezoarticus) is an endangered species, gamete preservation is a useful tool for preservation and maintenance of genetic diversity. However, semen should be collected by electroejaculation (EE) under general anaesthesia, for which the animals should be captured with darts. We previously reported that EE induces pain and stress in this species, even under general anaesthesia. The objective of this study was to determine if the repetition of captures, anesthesia and EE affects heart rate (HR), pulse rate (PR), respiratory rate (RR), rectal temperature (RT), oximetry (SpO2), cortisol, alkaline phosphatase (AP), and creatinekinase (CK) responses in adult and yearlings pampas deer (Ozotoceros bezoarticus) males. The study was conducted from June to March of the following year at the Estacion de Cria de Fauna Autoctona Cerro Pan de Azucar, Maldonado, Uruguay with 11males. From these, 6 were adults [4-7 years old; 29.6 ± 2.7 kg (mean ± SEM)] and 5 yearlings (1.5-2 years old; 25.0 ± 2.2 kg), each group allocated in a 0.5 ha enclosure. The animals were captured with darts flowed from a blowpipe containing 2mg/kg of xylazine, 1.6 mg/kg of ketamine, and 0.013 mg/kg of atropine every ~3 months (June-July, September-October, January, late March). Once asleep, EE was performed applying series of 1v lasting 4-5 s each, with rest intervals of 2-3 s, increasing 1v every 10 pulses, until achieving ejaculation or a maximum of 6 v. After the process ended, yohimbine hydrochloride (0.26 mg/kg) was administered iv to reverse the anesthesia. Heart rate (HR), PR, RR and SpO2 were measured before EE (BEE), in each voltage serie, and after EE (AEE), and cortisol, AP, CK, and RT were measured BEE and AEE. All animals survived at least for 6 months after the last manipulation. Adult and yearling animals had similar induction times (11.4 ± 6.8 min vs. 11.3 ± 8.4 min, ns) and remained anesthetized 80.0 ± 5.0 min and 75.8 ± 3.2 min (ns). The erection occurred at 4.2 ± 0.9 v and 4.5 ± 1.0 v in adults and yearlings (ns). Semen was collected from all animals in all the procedures, beginning when 3.0 ± 1.5 v and 3.8 ± 1.8 v were applied in adult and yearling males, respectively (P = 0.06). Heart rate, PR, RR, CK, and cortisol concentration increased AEE. Heart rate increased from 52 ± 8 to 151 ± 2 bpm (P <0.0001); PR from 64 ± 5 to 109 ± 4 bpm (P <0.0001); RR from 24 ± 4 to 31 ± 3 bpm (P <0.001); CK concentration from 303 ± 25 to 788 ± 112 UI/L (P <0.001) and cortisol concentration from 0.21 ± 0.01 to 0.99 ± 0.45 µg/dl (P = 0.003). On the other hand, RT decreased AEE from 37.5 ± 0.2 to 36.7 ± 0.2 oC (P = 0.004). Heart rate was maximum in the first 118 ± 5 bpm and third collections 122 ± 6 bpm (P < 0.01), RR in the fourth 44 ± 3 bpm (P < 0.001), and RT in the third 38.1 ± 0.1 oC and fourth 38.3 ± 0.2 oC (P < 0.0001) procedures. Creatinekinase was maximum in the first 405.1 ± 48.1 UI/l (P = 0.02), and AP in the second 741.1 ± 193.7 UI/l (P < 0.0001) procedures. We concluded that EE under general anesthesia in pampas deer males is stressful, although the procedures can be repeated with the intervals used in this study without accumulated negative effects.