Chemical Restraining and Electroejaculation Protocols for Semen Collection in White-Lipped Peccary (Tayassu pecari)

Abstract

Background: In order to reverse the White-lipped peccary decline, besides protecting its habitat and controlling hunting, it is necessary a captive breeding program. There are reports, however, on the low fertility of white-lipped peccary, making it difficult its reproduction in captivity, making artificial insemination one of the main tools to prevent the loss of genetic diversity of species kept in captivity. Information on safe methods of anesthesia and the collection of semen should be investigated. Therefore, we aimed to compare the effects of the anesthetic protocols acepromazine/ketamine and xylazine/ketamine, as well as electroejaculation protocols, for semen collection in white-lipped peccary (Tayassu pecari).

Materials, Methods & Results: Twelve adult male white-lipped peccaries were submitted both to the xylazine/ketamine and acepromazine/ketamine anesthetic protocols. The anesthetic induction time and duration, the degree of muscle relaxation, the time for anesthetic recovery and the quality of the animals’ recovery were evaluated. Additionally, the quality of the sedation was evaluated based on the animal’s behavior. We also evaluated the effect of drugs on erectile functions as well as the efficiency of three electroejaculation protocols with increasing or fixed voltages (2 to 4 V; 5 to 12 V; 12 V). The acepromazine/ketamine combination promotes shorter induction time, duration and recovery from anesthesia than the xylazine/ketamine association. There were no differences, however, between the tested anesthetic protocols in relation to heart rate, respiratory rate and temperature. Ejaculate was obtained from only 2 animals when using the xylazine/ketamine protocol and adoption of stimuli between 5 and 12 V, with 10 stimuli at each voltage. In turn, ejaculate was obtained from four animals submitted to the acepromazine/ketamine protocol, three of them with the adoption of stimuli between 5 and 12 V and one with the adoption of fixed 12 V stimuli, with 45 stimuli at this single voltage.

Discussion: The animals presented less deep anesthesia and, consequently, worse indicators of well-being during and after the collection procedures when submitted to the xylazine/ketamine protocol compared to the acepromazine/ketamine protocol. When submitted to the acepromazine/ketamine protocol, the animals allowed the observer to approach and handle them, facilitating handling and collection of semen, in addition to promoting better indicators of animal welfare. Also, with this aforementioned protocol, the animals showed better anesthetic return. For both anesthetic protocols, the protocol of increasing stimuli from 5 to 12 V, with 10 stimuli at each voltage, resulted in penile erection and in obtaining ejaculate in a greater number of animals in relation to the other electroejaculation protocols. In turn, the use of the growing protocol 2 V to 4 V did not even cause an erection in any of the 12 animals. From the ejaculates collected from the white-lipped peccary, volumes (0.2 to 1.0 mL) and average sperm concentration (379.1 x 106 sperm/mL) were comparatively higher than those from Pecari tajacu. The white-lipped peccary (Tayassu pecari) is considered an aggressive animal, and this characteristic can explain the relatively low success in obtaining ejaculates, as aggressiveness is directly related to stress, which is an antagonist of ejaculation. Thus, we proposed to test chemical restraint with the aid of a blowgun in future studies.