233 EFFECTS OF A LONG-ACTING TRANQUILIZER ON SPERM MOTILITY OF NORTH AMERICAN BISON BULLS

Abstract

Handling induces stress in North American bison that can lead to injuries for both handlers and animals. Moreover, this induced stress may result in variations in collection and quality of the semen. The objective of this study was to investigate if a long-acting neuroleptic (LAN) can lower the stress on bison bulls, allowing for safer handling and improvement in the quantity and quality of the collected semen. For this study, 6 mature bison bulls (3 Bison bison bison and 3 Bison bison athabascae) housed at the Native Hoofstock Centre, near Saskatoon, SK, Canada, were used. For each trial, bison bulls were randomly separated into 2 groups: LAN-treated (n = 3) and nontreated control (n = 3). In the treatment group, each bull was injected with 100 mg of Piportil L4^® (piperodine phenothiazine, a LAN with antipsychotic properties and weak sedative activity that has a prolonged duration of action ≈2 wk). After injection, both groups were given a 5-day rest period before semen collection. All bison were collected by electroejaculation, twice a week for 2 wk with a minimum 48 h of rest between collections (total of 3 trials; 4 collections per trial). Between each trial, a rest period of 1 wk was given to the bulls. To evaluate the stress level of the animal, the bull’s heart and respiration rates were recorded before and after each collection. Electroejaculated semen was kept at 37°C and transported to the laboratory for further semen analysis (≈2 h). Semen was analysed using computer assisted sperm analyzer. Several parameters including volume, concentration, total motility, progressive motility, velocity curvilinear (VCL), velocity average path (VAP), and velocity straight line (VSL) were recorded. The data were analysed using two-way ANOVA (SAS 9.2; SAS Institute, inc., Cary, NC, USA). Data are presented as mean ± SD and P < 0.05 level of significance. Results for the stress level revealed that the heart rate (beats/min) before semen collection (control: 65.8 ± 14.6, treated: 65.3 ± 9.4) and heart rate after semen collection (control: 67. 9 ± 14.4, treated: 62.9 ± 9.1) showed no differences between control and treatment. Both respiration rates (breaths/min) before and after collection did not show difference due to treatment (control: 44.1 ± 17.5 and 36.6 ± 15.1, and treated: 41.6 ± 22.0 and 35.3 ± 14.3, respectively). Results of the semen analysis showed no significant effect of treatment on the volume of ejaculate between control (5.3 ± 2.0 mL) and treated (4.6 ± 2.4 mL). Both total and progressive motility of the semen showed no difference between control (70.5 ± 18.1% and 64.6 ± 19.4%) and treated (64.6 ± 22.7% and 58.6 ± 23.2%), respectively. No significant effects were seen in any of the sperm velocity parameters (μm s^–1): VCL, 123.5 ± 31.5 in control and 121.7 ± 28.9 in treated; VAP, 75.4 ± 18.7 in control and 71.8 ± 17.2 in treated; and VSL, 62.3 ± 16.9 in control, and 59.3 ± 15.3 in treated groups. It can be concluded that 100 mg of Piportil has no discernible effect on stress levels, sperm count, or motility in bison bulls.