The purpose of this study was to evaluate disposition of butorphanol (BUT) in goats after intravenous (IV) and intramuscular (IM) administration and to relate behavioral changes with plasma concentrations of BUT. Each of six healthy 3-year-old neutered goats (one male, five females) (46.5 ± 0.5 kg) were given BUT (0.1 mg kg−1, IV or IM) using a randomized crossover design with a one week wash out period. Plasma BUT concentrations were determined for 14 hours after drug administration (IV: 0, 2, 5, 10, 15, 30, 45, 60, 90, 120, 180, 240, 360, 480, 600, 720 and 840 minutes; IM: 0, 5, 10, 15, 30, 45, 60, 90, 120, 150, 180, 240, 360, 480, 720 and 840 minutes). Pharmacokinetic values were calculated using a computerized model. Behavior was scored subjectively (3 = fractious; 2 = fidgety; 1 = quiet with heightened alertness; 0 = normal) at 0, 15, 30, 60, 120 and 240 minutes after butorphanol administration. Estimated peak plasma concentration of BUT after IM administration was 54.98 ± 14.60 ng mL−1; time to maximum concentration was 16.2 ± 5.2 minutes; bioavailability was 82 ± 41%. Volume of distribution at steady state after IV BUT was 1.27 ± 0.73 L kg−1; systemic clearance was 9.6 ± 2.4 mL kg−1 minute−1. Elimination half-life after IV BUT was 112.4 ± 89.4 minutes and after IM administration was 165.1 ± 115.9 minutes. Plasma BUT concentrations were greater than 10 ng mL−1 for 240 minutes. Behavioral scores for goats at 15 and 30 minutes were significantly different from baseline and 240 minutes after IM BUT. With IV BUT, baseline behavioral scores were different from those at 15 minutes; those at 15 minutes were different from scores at 120 and 240 minutes. Both time and plasma BUT concentration predicted behavior. Every 15 minutes that passed lowered the behavior score by 13% after IV BUT, and by 10% after IM BUT; each ng increase in plasma concentration increased the behavior score by 4% after IV BUT and by 7% after IM BUT. Behavioral scores had returned to baseline by 120 minutes after IV BUT and by 240 minutes after IM BUT. The dose of BUT that we use clinically to treat postoperative pain in goats results in an acceptable half-life for ease of dosing; plasma concentrations meet or exceed target plasma concentration (10 ng mL−1) for 4 hours. Behavioral changes occur after IV and IM BUT in goats without pain. Further investigation is needed to validate the efficacy of BUT as an analgesic in goats.