Evaluation of a Fluoroscopic Angiography Protocol in Hispaniolan Amazon Parrots (Amazona ventralis).

Fluoroscopic angiography evaluates the heart and vascular tree in real time and can be recorded for further diagnostic analysis and measurements. Although reports have been published of the use of fluoroscopic angiography in birds, this technique has not been evaluated in any avian species. The purpose of this study was to evaluate a fluoroscopic angiography protocol in 12 adult Hispaniolan Amazon parrots (Amazona ventralis). Under general anesthesia, the birds were positioned in right lateral (LAT) recumbency on a fluoroscopy table. A bolus of nonionic iodinated contrast agent was injected through a catheter inserted into the basilic or medial metatarsal vein during video acquisition. The same bolus was repeated to obtain the ventrodorsal (VD) view with the bird placed in dorsal recumbency. Eleven studies were performed. A total of 19 (10 VD, 9 LAT) continuous, real-time, fluoroscopic angiograms were successfully captured. The brachiocephalic trunk, aorta, pulmonary arteries, pulmonary veins, and caudal vena cava were visualized, and selected intraluminal measurements collected. The intraobserver and interobserver variability for 3 observers was calculated. Intraobserver agreement was found to be near perfect (intraclass correlation coefficient ≥0.95), whereas interobserver agreement was moderate to substantial (intraclass correlation coefficient ≥0.52). Coefficients of variation were excellent (VD 0.99, LAT 0.99) for intraobserver assessments and moderate (VD 0.72, LAT 0.52) for interobserver assessments. For the interobserver assessments, the VD projection measurements performed better than the LAT measurements. These results suggest that although there was some variation between different observers, relatively consistent vascular measurements could be obtained. The described fluoroscopic angiography protocol is a repeatable and reliable technique that could be useful for the diagnosis and monitoring of cardiovascular diseases in birds.

Absorption of grapiprant in red-tailed hawks (Buteo jamaicensis) is decreased when administered with food.

OBJECTIVE: Describe the pharmacokinetics of grapiprant administered orally with food to red-tailed hawks (RTHAs; Buteo jamaicensis) and compare the results with previously described grapiprant pharmacokinetics administered without food in this species. ANIMALS: 6 healthy adult RTHA (3 males, 3 females) under human care. PROCEDURES: A single dose of grapiprant (30 mg/kg) was given orally to RTHAs, followed by force-feeding. Blood samples were obtained at 14 time points for 120 hours postgrapiprant administration. Plasma concentrations of grapiprant were measured via tandem liquid chromatography-mass spectrometry. Nonparametric superimposition using pharmacokinetic modeling software used plasma concentrations to calculate simulations of grapiprant plasma concentrations for 30 mg/kg administered orally with food every 12 hours. RESULTS: The arithmetic mean maximum plasma concentration was 405.8 ng/mL, time to maximum plasma concentration was 16 hours, and harmonic mean terminal half-life was 15.6 hours. Simulations determined 30 mg/kg every 12 hours could attain minimum effective concentrations (> 164 ng/mL) reported in dogs for a sustained period of approximately 20 hours. CLINICAL RELEVANCE: Grapiprant plasma concentrations were achieved above the canine therapeutic concentrations within 16 hours postmedication. Mean concentrations were maintained for approximately 20 hours. Simulations support a dosing frequency of 12-hour intervals with food reaching minimum effective concentrations established for canines, although it is unknown whether these plasma concentrations are therapeutic for birds. Bioaccumulation was not noted on simulations secondary to increased grapiprant administration. Further research including multidose assessments at this current dose with food, in vitro pharmacological characterization, and pharmacodynamic studies in this species are warranted.

Pharmacokinetics of grapiprant administered to red-tailed hawks (Buteo jamaicensis) after food was withheld for 24 hours.

OBJECTIVE: To identify an oral dose of grapiprant for red-tailed hawks (RTHAs; Buteo jamaicensis) that would achieve a plasma concentration > 164 ng/mL, which is considered therapeutic for dogs with osteoarthritis. ANIMALS: 6 healthy adult RTHAs. PROCEDURES: A preliminary study, in which grapiprant (4 mg/kg [n = 2], 11 mg/kg [2], or 45 mg/kg [2]) was delivered into the crop of RTHAs from which food had been withheld for 24 hours, was performed to obtained pharmacokinetic data for use with modeling software to simulate results for grapiprant doses of 20, 25, 30, 35, and 40 mg/kg. Simulation results directed our selection of the grapiprant dose administered to the RTHAs in a single-dose study. Plasma grapiprant concentration, body weight, and gastrointestinal signs of RTHAs were monitored. RESULTS: On the basis of results from the preliminary study and simulations, a grapiprant dose of 30 mg/kg was used in the single-dose study. The geometric mean maximum observed plasma concentration of grapiprant was 3,184 ng/mL, time to maximum plasma grapiprant concentration was 2.0 hours, and the harmonic mean terminal half-life was 17.1 hours. No substantial adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Although the single dose of grapiprant (30 mg/kg) delivered into the crop achieved plasma concentrations > 164 ng/mL in the RTHAs, it was unknown whether this concentration would be therapeutic for birds. Further research that incorporates multidose assessments, safety monitoring, and pharmacodynamic data collection is warranted on the use of grapiprant in RTHAs from which food was withheld versus not withheld.

Pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica).

OBJECTIVE: To determine the pharmacokinetics of amantadine after oral administration of single and multiple doses to orange-winged Amazon parrots (Amazona amazonica). ANIMALS: 12 adult orange-winged Amazon parrots (6 males and 6 females). PROCEDURES: A single dose of amantadine was orally administered to 6 birds at 5 mg/kg (n = 2), 10 mg/kg (2), and 20 mg/kg (2) in a preliminary trial. On the basis of the results, a single dose of amantadine (10 mg/kg, PO) was administered to 6 other birds. Two months later, multiple doses of amantadine (5 mg/kg, PO, q 24 h for 7 days) were administered to 8 birds. Heart rate, respiratory rate, behavior, and urofeces were monitored. Plasma concentrations of amantadine were measured via tandem liquid chromatography-mass spectrometry. Pharmacokinetic parameter estimates were determined via noncompartmental analysis. RESULTS: Mean ± SD maximum plasma concentration, time to maximum plasma concentration, half-life, and area under the concentration-versus-time curve from the last dose to infinity were 1,174 ± 186 ng/mL, 3.8 ± 1.8 hours, 23.2 ± 2.9 hours, and 38.6 ± 7.4 µg·h/mL, respectively, after a single dose and 1,185 ± 270 ng/mL, 3.0 ± 2.4 hours, 21.5 ± 5.3 hours, and 26.3 ± 5.7 µg·h/mL, respectively, at steady state after multiple doses. No adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE: Once-daily oral administration of amantadine at 5 mg/kg to orange-winged Amazon parrots maintained plasma concentrations above those considered to be therapeutic in dogs. Further studies evaluating safety and efficacy of amantadine in orange-winged Amazon parrots are warranted.

Pharmacokinetics of maropitant citrate in New Zealand White rabbits (Oryctolagus cuniculus).

OBJECTIVE: To determine the pharmacokinetics and adverse effects of maropitant citrate after IV and SC administration to New Zealand White rabbits (Oryctolagus cuniculus). ANIMALS: 11 sexually intact (3 males and 8 females) adult rabbits. PROCEDURES: Each rabbit received maropitant citrate (1 mg/kg) IV or SC. Blood samples were collected at 9 (SC) or 10 (IV) time points over 48 hours. After a 2-week washout period, rabbits received maropitant by the alternate administration route. Pharmacokinetic parameters were calculated. Body weight, food and water consumption, injection site, mentation, and urine and fecal output were monitored. RESULTS: Mean ± SD maximum concentration after SC administration was 14.4 ± 10.9 ng/mL and was detected at 1.25 ± 0.89 hours. Terminal half-life after IV and SC administration was 10.4 ± 1.6 hours and 13.1 ± 2.44 hours, respectively. Bioavailability after SC administration was 58.9 ± 13.3%. Plasma concentration at 24 hours was 2.87 ± 1.69 ng/mL after IV administration and 3.4 ± 1.2 ng/mL after SC administration. Four rabbits developed local dermal reactions at the injection site after SC injection. Increased fecal production was detected on the day of treatment and 1 day after treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Plasma concentrations of rabbits 24 hours after SC and IV administration of maropitant citrate (1 mg/kg) were similar to those of dogs at 24 hours. Reactions at the SC injection site were the most common adverse effect detected. Increased fecal output may suggest an effect on gastrointestinal motility. Additional pharmacodynamic and multidose studies are needed.

Prophylactic and therapeutic effects of twice-daily famciclovir administration on infectious upper respiratory disease in shelter-housed cats.

OBJECTIVES: In humans with herpetic disease, early or pre-emptive famciclovir therapy reduces disease duration and severity. This prospective, masked, placebo-controlled study tested therapeutic and prophylactic effects of two famciclovir doses given to cats for 7 days following shelter entry. METHODS: Cats were assigned to prophylactic or therapeutic study arms based on clinical evidence of herpetic disease at study entry. Cats in the therapeutic arm received no treatment (n = 19), placebo (lactose; n = 18) or famciclovir at ~30 (n = 21) or ~90 mg/kg (n = 20) PO q12h for 7 days. Cats in the prophylactic arm received no treatment (n = 25) or famciclovir at ~30 (n = 28) or ~90 mg/kg (n = 27) PO q12h for 7 days. Disease scores, body weight, conjunctival feline herpesvirus 1 (FHV-1) shedding, and adoption rates were recorded on days 1 (admission), 8 (end of therapy) and 15 (1 week after cessation of therapy). RESULTS: No significant differences in clinical scores were observed among groups in the prophylactic or therapeutic arms at any of the three time points. However, within the therapeutic arm, viral shedding on day 8 was significantly higher in cats receiving no treatment than in those receiving ~30 or ~90 mg/kg famciclovir, and this effect persisted 1 week after famciclovir was stopped (day 15) only in cats receiving ~30 mg/kg, although this approached significance in cats receiving ~90 mg/kg. No significant differences in adoption rates were detected among groups in either arm throughout the study. CONCLUSIONS AND RELEVANCE: Although we did not demonstrate a statistically or clinically significant effect of famciclovir administration upon clinical signs of infectious upper respiratory disease or adoption, when it was administered at ~30 or ~90 mg/kg q12h for 1 week famciclovir reduced conjunctival FHV-1 shedding. This suggests a potential role in interrupting the infectious cycle within a shelter population; however, cost in time and resources, and stress and pathogen transmission induced by oral administration should be considered.

Effects of three fentanyl plasma concentrations on the minimum alveolar concentration of isoflurane in Hispaniolan Amazon parrots (Amazona ventralis).

OBJECTIVE To determine effects of 3 plasma concentrations of fentanyl on the minimum alveolar concentration of isoflurane (MACiso) and cardiovascular variables in Hispaniolan Amazon parrots (Amazona ventralis). ANIMALS 6 adult parrots. PROCEDURES In phase 1, anesthesia was induced and maintained with isoflurane; intermittent positive-pressure ventilation was provided. The MACiso was determined for each bird by use of a bracketing method and supramaximal electrical stimulus. Fentanyl (20 µg/kg) was administered IV, and blood samples were collected over time to measure plasma fentanyl concentrations for pharmacokinetic calculations. In phase 2, pharmacokinetic values for individual birds were used for administration of fentanyl to achieve target plasma concentrations of 8, 16, and 32 ng/mL. At each concentration, MACiso and cardiovascular variables were determined. Data were analyzed with mixed-effects multilevel linear regression analysis. RESULTS Mean ± SD fentanyl plasma concentrations were 0 ng/mL, 5.01 ± 1.53 ng/mL, 12.12 ± 3.58 ng/mL, and 24.93 ± 4.13 ng/mL, and MACiso values were 2.09 ± 0.17%, 1.45 ± 0.32%, 1.34 ± 0.31%, and 0.95 ± 0.14% for fentanyl target concentrations of 0, 8, 16, and 32 ng/mL, respectively. Fentanyl significantly decreased MACiso in a dose-dependent manner. Heart rate and blood pressure significantly decreased at all fentanyl doses, compared with values for MACiso at 0 ng of fentanyl/mL. CONCLUSIONS AND CLINICAL RELEVANCE Fentanyl significantly decreased the MACiso in healthy Hispaniolan Amazon parrots, but this was accompanied by a depressive effect on heart rate and blood pressure that would need to be considered for application of this technique in clinical settings.

Founder events, isolation, and inbreeding: Intercontinental genetic structure of the domestic ferret.

Domestication and breeding for human-desired morphological traits can reduce population genetic diversity via founder events and artificial selection, resulting in inbreeding depression and genetic disorders. The ferret (Mustela putorius furo) was domesticated from European polecats (M. putorius), transported to multiple continents, and has been artificially selected for several traits. The ferret is now a common pet, a laboratory model organism, and feral ferrets can impact native biodiversity. We hypothesized global ferret trade resulted in distinct international genetic clusters and that ferrets transported to other continents would have lower genetic diversity than ferrets from Europe because of extreme founder events and no hybridization with wild polecats or genetically diverse ferrets. To assess these hypotheses, we genotyped 765 ferrets at 31 microsatellites from 11 countries among the continents of North America, Europe, and Australia and estimated population structure and genetic diversity. Fifteen M. putorius were genotyped for comparison. Our study indicated ferrets exhibit geographically distinct clusters and highlights the low genetic variation in certain countries. Australian and North American clusters have the lowest genetic diversities and highest inbreeding metrics whereas the United Kingdom (UK) cluster exhibited intermediate genetic diversity. Non-UK European ferrets had high genetic diversity, possibly a result of introgression with wild polecats. Notably, Hungarian ferrets had the highest genetic diversity and Hungary is the only country sampled with two wild polecat species. Our research has broad social, economic, and biomedical importance. Ferret owners and veterinarians should be made aware of potential inbreeding depression. Breeders in North America and Australia would benefit by incorporating genetically diverse ferrets from mainland Europe. Laboratories using ferrets as biomedical organisms should consider diversifying their genetic stock and incorporating genetic information into bioassays. These results also have forensic applications for conserving the genetics of wild polecat species and for identifying and managing sources of feral ferrets causing ecosystem damage.

Pharmacokinetics of buprenorphine after intravenous and oral transmucosal administration in guinea pigs (Cavia porcellus).

OBJECTIVE To determine pharmacokinetics and sedative effects of buprenorphine after IV and oral transmucosal (OTM) administration in guinea pigs. ANIMALS 14 male guinea pigs (6 adults for preliminary experiment; eight 8 to 11-week-old animals for primary study). PROCEDURES A preliminary experiment was conducted to determine an appropriate buprenorphine dose. In the primary study, buprenorphine (0.2 mg/kg) was administered IV or OTM, and blood samples were obtained. The pH of the oral cavity was measured before OTM administration. Sedation was scored for 6 hours on a scale of 0 to 3 (0 = no sedation and 3 = heavy sedation). After a 7-day washout period, procedures were repeated in a crossover manner. Plasma buprenorphine concentration was quantified, and data were analyzed with a noncompartmental pharmacokinetic approach. RESULTS Mean peak plasma buprenorphine concentrations were 46.7 and 2.4 ng/mL after IV and OTM administration, respectively. Mean time to maximum plasma buprenorphine concentration was 1.5 and 71.2 minutes, and mean terminal half-life was 184.9 and 173.0 minutes for IV and OTM administration, respectively. There was a range of sedation effects (0 to 2) for both routes of administration, which resolved within the 6-hour time frame. CONCLUSIONS AND CLINICAL RELEVANCE On the basis of pharmacokinetic parameters for this study, buprenorphine at 0.2 mg/kg may be administered IV every 7 hours or OTM every 4 hours to maintain a target plasma concentration of 1 ng/mL. Further studies are needed to evaluate administration of multiple doses and sedative effects in guinea pigs with signs of pain.

Pharmacokinetics of a concentrated buprenorphine formulation in red-tailed hawks (Buteo jamaicensis).

OBJECTIVE To determine the pharmacokinetics and sedative effects of 2 doses of a concentrated buprenorphine formulation after SC administration to red-tailed hawks (Buteo jamaicensis). ANIMALS 6 adult red-tailed hawks. PROCEDURES Concentrated buprenorphine (0.3 mg/kg, SC) was administered to all birds. Blood samples were collected at 10 time points over 24 hours after drug administration to determine plasma buprenorphine concentrations. After a 4-week washout period, the same birds received the same formulation at a higher dose (1.8 mg/kg, SC), and blood samples were collected at 13 time points over 96 hours. Hawks were monitored for adverse effects and assigned agitation-sedation scores at each sample collection time. Plasma buprenorphine concentrations were quantified by liquid chromatography-tandem mass spectrometry. RESULTS Mean time to maximum plasma buprenorphine concentration was 7.2 minutes and 26.1 minutes after administration of the 0.3-mg/kg and 1.8-mg/kg doses, respectively. Plasma buprenorphine concentrations were > 1 ng/mL for mean durations of 24 and 48 hours after low- and high-dose administration, respectively. Mean elimination half-life was 6.23 hours for the low dose and 7.84 hours for the high dose. Mean agitation-sedation scores were higher (indicating some degree of sedation) than the baseline values for 24 hours at both doses. No clinically important adverse effects were observed. CONCLUSIONS AND CLINICAL RELEVANCE Concentrated buprenorphine was rapidly absorbed, and plasma drug concentrations considered to have analgesic effects in other raptor species were maintained for extended periods. Most birds had mild to moderate sedation. Additional studies are needed to evaluate the pharmacodynamics of these doses of concentrated buprenorphine in red-tailed hawks.

Comparison of intraosseous pentobarbital administration and thoracic compression for euthanasia of anesthetized sparrows (Passer domesticus) and starlings (Sturnus vulgaris).

OBJECTIVE To compare intraosseous pentobarbital treatment (IPT) and thoracic compression (TC) on time to circulatory arrest and an isoelectric electroencephalogram (EEG) in anesthetized passerine birds. ANIMALS 30 wild-caught adult birds (17 house sparrows [Passer domesticus] and 13 European starlings [Sturnus vulgaris]). PROCEDURES Birds were assigned to receive IPT or TC (n = 6/species/group). Birds were anesthetized, and carotid arterial pulses were monitored by Doppler methodology. Five subdermal braided-wire electrodes were used for EEG. Anesthetic depth was adjusted until a continuous EEG pattern was maintained, then euthanasia was performed. Times from initiation of euthanasia to cessation of carotid pulse and irreversible isoelectric EEG (indicators of death) were measured. Data (medians and first to third quartiles) were summarized and compared between groups within species. Necropsies were performed for all birds included in experiments and for another 6 birds euthanized under anesthesia by TC (4 sparrows and 1 starling) or IPT (1 sparrow). RESULTS Median time to isoelectric EEG did not differ significantly between treatment groups for sparrows (19.0 and 6.0 seconds for TC and IPT, respectively) or starlings (88.5 and 77.5 seconds for TC and IPT, respectively). Median times to cessation of pulse were significantly shorter for TC than for IPT in sparrows (0.0 vs 18.5 seconds) and starlings (9.5 vs 151.0 seconds). On necropsy, most (14/17) birds that underwent TC had grossly visible coelomic, pericardial, or perihepatic hemorrhage. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that TC might be an efficient euthanasia method for small birds. Digital pressure directly over the heart during TC obstructed venous return, causing rapid circulatory arrest, with rupture of the atria or vena cava in several birds. The authors propose that cardiac compression is a more accurate description than TC for this procedure.

Pharmacokinetics and safety of ceftiofur crystalline free acid in New Zealand White rabbits (Oryctolagus cuniculus).

OBJECTIVE To determine the pharmacokinetics and adverse effects following SC administration of ceftiofur crystalline free acid (CCFA) in New Zealand White rabbits. ANIMALS 6 adult sexually intact female New Zealand White rabbits. PROCEDURES Each rabbit was administered 40 mg of CCFA/kg SC. A blood sample was obtained immediately before (0 minutes), at 5 and 30 minutes after, and at 1, 1.5, 2, 3, 4, 8, 12, 24, 48, 72, 95, 120, 144, and 168 hours after administration, and plasma concentrations of ceftiofur free acid equivalents (CFAE) were measured. Pharmacokinetic parameters were calculated. For each rabbit, body weight, food consumption, fecal output, and injection site were monitored. Minimum inhibitory concentrations of ceftiofur for 293 bacterial isolates from rabbit clinical samples were determined. RESULTS Mean ± SD peak plasma concentration of CFAE and time to maximum plasma concentration were 33.13 ± 10.15 µg/mL and 1.75 ± 0.42 hours, respectively. The mean terminal half-life of CFAE was 42.6 ± 5.2 hours. Plasma CFAE concentration was > 4 µg/mL for approximately 24 hours and > 1 µg/mL for at least 72 hours after CCFA administration. An apparently nonpainful subcutaneous nodule developed at the injection site in 3 of 6 rabbits. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that CCFA (40 mg/kg) could be administered SC every 24 to 72 hours to New Zealand White rabbits to treat infections with ceftiofur-susceptible bacteria. Single-dose administration of CCFA resulted in minimal adverse effects. Additional studies are needed to evaluate the effects of repeated CCFA administration in New Zealand White rabbits.

Pharmacokinetics of a single intramuscular injection of ceftiofur crystalline-free acid in red-tailed hawks (Buteo jamaicensis).

OBJECTIVE: To determine the pharmacokinetics and adverse effects at the injection site of ceftiofur crystalline-free acid (CCFA) following IM administration of 1 dose to red-tailed hawks (Buteo jamaicensis). ANIMALS: 7 adult nonreleasable healthy red-tailed hawks. PROCEDURES: In a randomized crossover study, CCFA (10 or 20 mg/kg) was administered IM to each hawk and blood samples were obtained. After a 2-month washout period, administration was repeated with the opposite dose. Muscle biopsy specimens were collected from the injection site 10 days after each sample collection period. Pharmacokinetic data were calculated. Minimum inhibitory concentrations of ceftiofur for various bacterial isolates were assessed. RESULTS: Mean peak plasma concentrations of ceftiofur-free acid equivalent were 6.8 and 15.1 µg/mL for the 10 and 20 mg/kg doses, respectively. Mean times to maximum plasma concentration were 6.4 and 6.7 hours, and mean terminal half-lives were 29 and 50 hours, respectively. Little to no muscle inflammation was identified. On the basis of a target MIC of 1 µg/mL and target plasma ceftiofur concentration of 4 µg/mL, dose administration frequencies for infections with gram-negative and gram-positive organisms were estimated as every 36 and 45 hours for the 10 mg/kg dose and every 96 and 120 hours for the 20 mg/kg dose, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Study results suggested that CCFA could be administered IM to red-tailed hawks at 10 or 20 mg/kg to treat infections with ceftiofur-susceptible bacteria. Administration resulted in little to no inflammation at the injection site. Additional studies are needed to evaluate effects of repeated CCFA administration.

Pharmacokinetics of hydromorphone hydrochloride after intravenous and intramuscular administration of a single dose to American kestrels (Falco sparverius).

OBJECTIVE: To determine the pharmacokinetics of hydromorphone hydrochloride after IV and IM administration in American kestrels (Falco sparverius). ANIMALS: 12 healthy adult American kestrels. PROCEDURES: A single dose of hydromorphone (0.6 mg/kg) was administered IM (pectoral muscles) and IV (right jugular vein); the time between IM and IV administration experiments was 1 month. Blood samples were collected at 5 minutes, 1 hour, and 3 hours (n = 4 birds); 0.25, 1.5, and 9 hours (4); and 0.5, 2, and 6 hours (4) after drug administration. Plasma hydromorphone concentrations were determined by means of liquid chromatography with mass spectrometry, and pharmacokinetic parameters were calculated with a noncompartmental model. Mean plasma hydromorphone concentration for each time was determined with naïve averaged pharmacokinetic analysis. RESULTS: Plasma hydromorphone concentrations were detectable in 2 and 3 birds at 6 hours after IM and IV administration, respectively, but not at 9 hours after administration. The fraction of the hydromorphone dose absorbed after IM administration was 0.75. The maximum observed plasma concentration was 112.1 ng/mL (5 minutes after administration). The terminal half-life was 1.25 and 1.26 hours after IV and IM administration, respectively. CONCLUSION AND CLINICAL RELEVANCE: Results indicated hydromorphone hydrochloride had high bioavailability and rapid elimination after IM administration, with a short terminal half-life, rapid plasma clearance, and large volume of distribution in American kestrels. Further studies regarding the effects of other doses, other administration routes, constantrate infusions, and slow release formulations on the pharmacokinetics of hydromorphone hydrochloride and its metabolites in American kestrels may be indicated.

Evaluation of thermal antinociceptive effects after oral administration of tramadol hydrochloride to American kestrels (Falco sparverius).

OBJECTIVE: To evaluate the thermal antinociceptive and sedative effects and duration of action of tramadol hydrochloride after oral administration to American kestrels (Falco sparverius). ANIMALS: 12 healthy 3-year-old American kestrels. PROCEDURES: Tramadol (5, 15, and 30 mg/kg) and a control suspension were administered orally in a masked randomized crossover experimental design. Foot withdrawal response to a thermal stimulus was determined 1 hour before (baseline) and 0.5, 1.5, 3, 6, and 9 hours after treatment. Agitation-sedation scores were determined 3 to 5 minutes before each thermal stimulus test. RESULTS: The lowest dose of tramadol evaluated (5 mg/kg) significantly increased the thermal foot withdrawal thresholds for up to 1.5 hours after administration, compared with control treatment values, and for up to 9 hours after administration, compared with baseline values. Tramadol at doses of 15 and 30 mg/kg significantly increased thermal thresholds at 0.5 hours after administration, compared with control treatment values, and up to 3 hours after administration, compared with baseline values. No significant differences in agitation-sedation scores were detected between tramadol and control treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated oral administration of 5 mg of tramadol/kg significantly increased thermal nociception thresholds for kestrels for 1.5 hours, compared with a control treatment, and 9 hours, compared with baseline values; higher doses resulted in less pronounced antinociceptive effects. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times would be needed to fully evaluate the analgesic and adverse effects of tramadol in kestrels and other avian species.

Evaluation of thermal antinociceptive effects and pharmacokinetics after intramuscular administration of butorphanol tartrate to American kestrels (Falco sparverius).

OBJECTIVE: To evaluate antinociceptive effects and pharmacokinetics of butorphanol tartrate after IM administration to American kestrels (Falco sparverius). ANIMALS: Fifteen 2- to 3-year-old American kestrels (6 males and 9 females). PROCEDURES: Butorphanol (1, 3, and 6 mg/kg) and saline (0.9% NaCl) solution were administered IM to birds in a crossover experimental design. Agitation-sedation scores and foot withdrawal response to a thermal stimulus were determined 30 to 60 minutes before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment. For the pharmacokinetic analysis, butorphanol (6 mg/kg, IM) was administered in the pectoral muscles of each of 12 birds. RESULTS: In male kestrels, butorphanol did not significantly increase thermal thresholds for foot withdrawal, compared with results for saline solution administration. However, at 1.5 hours after administration of 6 mg of butorphanol/kg, the thermal threshold was significantly decreased, compared with the baseline value. Foot withdrawal threshold for female kestrels after butorphanol administration did not differ significantly from that after saline solution administration. However, compared with the baseline value, withdrawal threshold was significantly increased for 1 mg/kg at 0.5 and 6 hours, 3 mg/kg at 6 hours, and 6 mg/kg at 3 hours. There were no significant differences in mean sedation-agitation scores, except for males at 1.5 hours after administration of 6 mg/kg. CONCLUSION AND CLINICAL RELEVANCE: Butorphanol did not cause thermal antinociception suggestive of analgesia in American kestrels. Sex-dependent responses were identified. Further studies are needed to evaluate the analgesic effects of butorphanol in raptors.

Evaluation of thermal antinociceptive effects after intramuscular administration of hydromorphone hydrochloride to American kestrels (Falco sparverius).

OBJECTIVE: To evaluate the antinociceptive and sedative effects and duration of action of hydromorphone hydrochloride after IM administration to American kestrels (Falco sparverius). ANIMALS: 11 healthy 2-year-old American kestrels. PROCEDURES: Hydromorphone (0.1, 0.3, and 0.6 mg/kg) and an equivalent volume of saline (0.9% NaCl) solution (control treatment) were administered IM to kestrels in a masked randomized complete crossover study design. Foot withdrawal response to a thermal stimulus was determined 30 to 60 minutes before (baseline) and 0.5, 1.5, 3, and 6 hours after treatment administration. Agitation-sedation scores were determined 3 to 5 minutes before each thermal test. RESULTS: Hydromorphone at 0.6 mg/kg, IM, significantly increased the thermal foot withdrawal threshold, compared with the response after administration of saline solution, for up to 3 hours, and hydromorphone at 0.1, 0.3, and 0.6 mg/kg, IM, significantly increased withdrawal responses for up to 6 hours, compared with baseline values. No significant differences in mean sedation-agitation scores were detected between hydromorphone and saline solution treatments; however, appreciable sedation was detected in 4 birds when administered 0.6 mg of hydromorphone/kg. CONCLUSIONS AND CLINICAL RELEVANCE: Hydromorphone at the doses evaluated significantly increased the thermal nociception threshold for American kestrels for 3 to 6 hours. Additional studies with other types of stimulation, formulations, dosages, routes of administration, and testing times are needed to fully evaluate the analgesic and adverse effects of hydromorphone in kestrels and other avian species and the use of hydromorphone in clinical settings.

Isolation and characterization of microsatellite markers in the domestic ferret (Mustela putorius furo).

The domestic ferret (Mustela putorius furo) is an important model organism for the study of avian influenza and other diseases of humans and animals, as well as a popular pet animal. In order to evaluate genetic diversity and study disease relationships in ferrets, 22 nuclear microsatellite loci (17 dinucleotide and 5 tetranucleotide) were developed from ferret genomic libraries and organized into seven multiplex sets. Polymorphism was preliminarily assessed in one population in Australia and one in the USA, sampled with 25 individuals each. The loci displayed allelic diversity ranging from 1 to 5 alleles, and expected and observed heterozygosities ranging from 0.04 to 0.65 and 0.04 to 0.76, respectively. Additionally, the loci amplified products in 15 samples from the wild ancestor, European polecat (Mustela putorius) and domestic ferret-polecat hybrids. In polecat/hybrid samples, allelic diversity ranged from 3 to 8 alleles, and expected and observed heterozygosities ranged from 0.13 to 0.81 and 0.13 to 0.80 respectively. These markers will be useful for molecular assessments of genetic diversity and applications to evolution, ecology, and health in domestic ferrets and wild polecats.

Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter.

OBJECTIVE: To determine within a cat shelter effects of dietary lysine supplementation on nasal and ocular disease and detection of nucleic acids of Chlamydophila felis, feline calicivirus (FCV), and feline herpesvirus (FHV-1). ANIMALS: 261 adult cats. PROCEDURES: Cats were fed a diet containing 1.7% (basal diet; control cats) or 5.7% (supplemented diet; treated cats) lysine for 4 weeks. Plasma concentrations of lysine and arginine were assessed at the beginning (baseline) and end of the study. Three times a week, cats were assigned a clinical score based on evidence of nasal and ocular disease. Conjunctival and oropharyngeal swab specimens were tested for FHV-1, FCV, and C felis nucleic acids once a week. RESULTS: Data were collected from 123, 74, 59, and 47 cats during study weeks 1, 2, 3, and 4, respectively. By study end, plasma lysine concentration in treated cats was greater than that in control cats and had increased from baseline. There was no difference between dietary groups in the proportion of cats developing mild disease. However, more treated cats than control cats developed moderate to severe disease during week 4. During week 2, FHV-1 DNA was detected more commonly in swab specimens from treated versus control cats. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary lysine supplementation in the amount used in our study was not a successful means of controlling infectious upper respiratory disease within a cat shelter. Rather, it led to increases in disease severity and the incidence of detection of FHV-1 DNA in oropharyngeal or conjunctival mucosal swab specimens at certain time points.

Composition and characteristics of urinary calculi from guinea pigs.

OBJECTIVE: To determine the mineral composition of calculi, anatomic locations of the calculi, and findings of urinalysis and bacteriologic culture of urine and calculi in guinea pigs with urolithiasis. DESIGN: Cross-sectional study. ANIMALS: 127 guinea pigs. PROCEDURES: Records of urinary calculi that had been submitted to the University of California Stone Laboratory from 1985 through 2003 were reviewed. In addition, submissions of urinary calculi for evaluation by the laboratory were prospectively solicited from 2004 through 2007. Prospectively obtained calculi were accompanied by a urine sample for urinalysis and bacteriologic culture and a completed questionnaire. All calculi were analyzed by use of polarized light microscopy and infrared spectroscopy. A subset of calculi was examined by means of x-ray diffractometry (XRD). RESULTS: 83% (43/52) of calculi from the laboratory database and 93% (70/75) of calculi that were prospectively solicited were composed of 100% calcium carbonate. Analysis via XRD confirmed that 5 of 6 calculi from a subset that had the greatest gross morphologic variation were composed of 100% calcite. Although many guinea pigs had received anti-microbials before bacteriologic cultures of urine were performed, Corynebacterium renale was isolated from 5 urine samples. CONCLUSIONS AND CLINICAL RELEVANCE: Contrary to findings of other studies, urinary calculi analyzed for the present study were most commonly composed of 100% calcium carbonate, and infrared spectroscopy or XRD was necessary to differentiate this mineral from others. Treatments, including diet and husbandry practices, should be developed to help prevent development of calcium carbonate calculi in guinea pigs.