Maintaining mineral homeostasis as well as the secretion and metabolism of mineralotropic hormones is important for healthy of periparturient dairy cows. To increase the activity of mineralotropic hormones, blood pH can be adjusted. The purpose of this study was to investigate changes in blood pH and the mechanism of action of this change in induced hypercalcaemic cows. Six non-lactating Holstein cows were used in a 2 × 2 crossover design. To induce hypercalcaemia, calcium borogluconate was administered subcutaneously to experimental cows and normal saline was administered subcutaneously to control cows. Blood and urine samples were collected serially after administration. Whole blood without any anticoagulant was processed with a portable blood gas analyser. Plasma concentration and urinary excretion of calcium were measured. In hypercalcaemic cows, both blood and urine calcium levels were significantly increased at 8 h compared to those at 0 h (P < 0.05), and a spontaneous increase in blood pH was also observed. The calcium concentration in plasma was highest at 2 h after administration (3.02 ± 0.27 mmol/L). The change in pH correlated with that in bicarbonate (r = 0.781, P < 0.001) rather than that in partial pressure of CO₂ (r = 0.085, P = 0.424). Hypercalcaemia induced a spontaneous change in blood pH through the bicarbonate buffer system and this system may be a maintainer of calcium homeostasis.

Introduction: Clinical doses of anaesthetic agents were administered to rabbits and effects on the brain, heart, and liver were investigated biochemically and histopathologically. Material and Methods: The rabbits were randomly divided into three main groups (16 rabbits each) and each group into study (n = 8) and control (n = 8) groups. All study group rabbits received 3 mg/kg of midazolam (M) intramuscularly. Group 1.1 (M) received nothing further, group 2.1 (MK) also received 25 mg/kg of ketamine, and group 3.1 (MKI) besides ketamine was also given 2% isoflurane to induce anaesthesia for 30 min. NaCl solution in the same volume as midazolam and ketamine was injected into the controls. Results: In clinical evaluation significant differences were detected in respiratory and heart rates. In blood gas analysis the PO2 and PCO2 values showed statistical differences in anaesthesia intervals. Significant biochemical value changes were recorded in creatine kinase-Mb, glucose, and total protein. Histopathological liver examinations revealed higher total apoptotic and normal cell numbers in the MK than in the M and MKI groups. Apoptotic cell numbers were statistically significant in M and MK groups. Conclusion: Anaesthetic agents may increase programmed apoptosis. The MKI anaesthetics combination was found to cause less cell destruction in general than the other study groups. It was indicated that MKI was the safer anaesthetic combination in rabbits.

Intestinal obstruction such as atresia coli causes pathophysiological changes in gastrointestinal tissue due to the rise of intra-abdominal pressure. The aim of this study is to determine the intestinal damage with intestinal biomarkers in calves with atresia coli. The study was conducted on 40 Holstein calves diagnosed with atresia coli with mild to moderate abdominal distention and 10 healthy Holstein calves which served as the control. Blood samples were collected from all calves, and then serum concentrations of intestinal biomarkers were estimated, namely intestinal fatty acid binding protein (IFABP), liver fatty acid binding protein (LFABP), trefoil factor 3 (TFF3), and intestinal alkaline phosphatase (IAP), using commercially available specific bovine ELISA kits. An automatic blood gas analyser was employed for determining the lactate concentration. The concentrations of serum LFABP (P < 0.01), IFABP, TFF3, IAP, and blood lactate (P < 0.001) were significantly higher in calves with atresia coli than in healthy calves. The calves affected with atresia coli exhibited severe intestinal damage, and IFABP, LFABP, and TFF3 have significant diagnostic importance and play a useful role in determining the intestinal damage due to intestinal obstruction. High levels of IAP and lactate may serve as a signal for the development of intestinal injury.

OBJECTIVE To evaluate the effects of providing 100% O2, compared with provision of room air, in sedated spontaneously breathing inland bearded dragons (Pogona vitticeps). ANIMALS 8 adult bearded dragons. PROCEDURES Animals were sedated with alfaxalone (20 mg/kg, SC) and received 21% O2 (equivalent to room air) or 100% O2 via face mask (flow rate, 1 L/min) in a randomized, blinded, complete crossover study (2-week interval between treatments). Sedation variables, cardiopulmonary variables, venous blood gas values, and postsedation food intake were evaluated. RESULTS Respiratory rate, heart rate, oxygen saturation, and sedation quality were comparable between treatments. Venous blood gas analysis revealed a higher total Pco2 and HCO3− concentration for the 21% O2 treatment. Postsedation food intake was not affected by the inspired oxygen fraction provided during sedation. CONCLUSIONS AND CLINICAL RELEVANCE The fraction of inspired oxygen did not appear to have clinically relevant effects on physiologic variables of bearded dragons during and after sedation. Therefore, provision of 100% O2 can be considered for use in sedated bearded dragons without the risk of inducing hypoventilation. Similarly, failure to provide 100% O2 would be unlikely to result in clinically relevant consequences in healthy sedated bearded dragons.

OBJECTIVE To compare the effects of MK-467 and hyoscine butylbromide on detomidine hydrochloride–induced cardiorespiratory and gastrointestinal changes in horses. ANIMALS 6 healthy adult horses. PROCEDURES Horses received detomidine hydrochloride (20 μg/kg, IV), followed 10 minutes later by MK-467 hydrochloride (150 μg/kg; DET-MK), hyoscine butylbromide (0.2 mg/kg; DET-HYO), or saline (0.9% NaCl) solution (DET-S), IV, in a Latin square design. Heart rate, respiratory rate, rectal temperature, arterial and venous blood pressures, and cardiac output were measured; blood gases and arterial plasma drug concentrations were analyzed; selected cardiopulmonary variables were calculated; and sedation and gastrointestinal borborygmi were scored at predetermined time points. Differences among treatments or within treatments over time were analyzed statistically. RESULTS With DET-MK, detomidine-induced hypertension and bradycardia were reversed shortly after MK-467 injection. Marked tachycardia and hypertension were observed with DET-HYO. Mean heart rate and mean arterial blood pressure differed significantly among all treatments from 15 to 35 and 15 to 40 minutes after detomidine injection, respectively. Cardiac output was greater with DET-MK and DET-HYO than with DET-S 15 minutes after detomidine injection, but left ventricular workload was significantly higher with DET-HYO. Borborygmus score, reduced with all treatments, was most rapidly restored with DET-MK. Sedation scores and pharmacokinetic parameters of detomidine did not differ between DET-S and DET-MK. CONCLUSIONS AND CLINICAL RELEVANCE MK-467 reversed or attenuated cardiovascular and gastrointestinal effects of detomidine without notable adverse effects or alterations in detomidine-induced sedation in horses. Further research is needed to determine whether these advantages are found in clinical patients and to assess whether the drug influences analgesic effects of detomidine.

OBJECTIVE To evaluate hemodynamic, respiratory, and sedative effects of buccally administered detomidine gel and reversal with atipamezole in dogs. ANIMALS 8 adult purpose-bred dogs. PROCEDURES Arterial and venous catheters were placed. Baseline heart rate, respiratory rate, cardiac output (determined via lithium dilution with pulse contour analysis), oxygen delivery, systemic vascular resistance, arterial blood gas values, and sedation score were obtained. Detomidine gel (2.0 mg/m2) was administered on the buccal mucosa. Cardiopulmonary data and sedation scores were obtained at predetermined times over 180 minutes. Atipamezole (0.1 mg/kg) was administered IM at 150 minutes. Reversal of sedation was timed and scored. Data were analyzed with an ANOVA. RESULTS Compared with baseline values, heart rate was lower at 45 to 150 minutes, cardiac output and oxygen delivery were lower at 30 to 150 minutes, and systemic vascular resistance was increased at 30 to 150 minutes. There were no significant changes in Paco2, Pao2, or lactate concentration at any time point, compared with baseline values, except for lactate concentration at 180 minutes. All dogs became sedated; maximum sedation was detected 75 minutes after administration of detomidine. Mean ± SD time to recovery after atipamezole administration was 7.55 ± 1.89 minutes; sedation was completely reversed in all dogs. No adverse events were detected. CONCLUSIONS AND CLINICAL RELEVANCE Buccally administered detomidine gel was associated with reliable and reversible sedation in dogs, with hemodynamic effects similar to those induced by other α2-adrenoceptor agonists. Buccally administered detomidine gel could be an alternative to injectable sedatives in healthy dogs.

OBJECTIVE To assess pulmonary hemodynamics and alveolar oxygenation in dogs anesthetized with propofol or isoflurane during one-lung ventilation (OLV) in a closed-thoracic experimental model. ANIMALS 6 healthy Beagles. PROCEDURES Dogs were anesthetized with each of 3 protocols (constant rate IV infusion of propofol [0.4 to 1.0 mg/kg/min], isoflurane at the minimum alveolar concentration [MAC], and isoflurane 1.5 MAC), with a 7-day washout period between anesthetic sessions. During each session, dogs were intubated with a double-lumen endotracheal tube, positioned in right lateral recumbency, and administered atracurium (0.1 to 0.2 mg/kg, IV, q 30 min) to allow mechanical ventilation throughout a 2-hour observation period. Dogs underwent two-lung ventilation for 30 minutes, OLV of the right lung for 1 hour, and two-lung ventilation for another 30 minutes. Pulmonary hemodynamic and blood gas variables were evaluated at predetermined times and compared among protocols and over time within each protocol. RESULTS Alveolar oxygenation was not impaired, and mean heart rate and pulmonary artery pressure and occlusion pressure were similar among the 3 protocols. One-lung ventilation caused a significant increase in the arteriovenous shunt fraction only when dogs were anesthetized with isoflurane at 1.5 MAC. Dogs developed respiratory acidosis, which was exacerbated by OLV, during all anesthetic sessions. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated pulmonary hemodynamics and alveolar oxygenation during OLV in a closed-thoracic model were similar regardless of whether dogs were anesthetized with propofol or isoflurane. One-lung ventilation can be successfully performed in dogs by use of a double-lumen endotracheal tube and either propofol or isoflurane.

OBJECTIVE To evaluate the influence of respiratory tract disease (ie, recurrent airway obstruction [RAO]) and mode of inhalation on detectability of inhaled budesonide in equine plasma and urine samples. ANIMALS 16 horses (8 healthy control horses and 8 horses affected by RAO, as determined by results of clinical examination, blood gas analysis, bronchoscopy, and cytologic examination of bronchoalveolar lavage fluid). PROCEDURES 4 horses of each group inhaled budesonide (3 μg/kg) twice daily for 10 days while at rest, and the remaining 4 horses of each group inhaled budesonide during lunging exercise. Plasma and urine samples were obtained 4 to 96 hours after inhalation and evaluated for budesonide and, in urine samples, the metabolites 6β-hydroxybudesonide and 16α-hydroxyprednisolone. RESULTS Detected concentrations of budesonide were significantly higher at all time points for RAO-affected horses, compared with concentrations for the control horses. All samples of RAO-affected horses contained budesonide concentrations above the limit of detection at 96 hours after inhalation, whereas this was found for only 2 control horses. Detected concentrations of budesonide were higher, but not significantly so, at all time points in horses that inhaled budesonide during exercise, compared with concentrations for inhalation at rest. CONCLUSIONS AND CLINICAL RELEVANCE Results of this study indicated that the time interval between inhalation of a glucocorticoid and participation in sporting events should be increased when inhalation treatment is administered during exercise to horses affected by respiratory tract disease.

To investigate the effects of a xylazine infusion during isoflurane anesthesia on global perfusion parameters and gastrointestinal oxygenation and microperfusion, 8 adult warmblood horses were sedated with xylazine and anesthesia induced with midazolam and ketamine. Horses were mechanically ventilated during anesthesia. After 3 h of stable isoflurane anesthesia (FEIso 1.3 Vol %), a xylazine infusion with 1 mg/kg body weight (BW) per hour was started for 1 h and then stopped. Before, during, and after xylazine infusion, heart rate (HR), arterial blood pressure (MAP), cardiac output (CO), central venous pressure (CVP), and pulmonary artery pressure (PAP) were measured and systemic vascular resistance (SVR) was calculated. Arterial blood gases were taken and oxygen delivery (DO2) and alveolar dead space (VDalv) were calculated. Further intestinal oxygen and microperfusion were measured using white light spectroscopy and laser Doppler flowmetry. Surface probes were placed via median laparotomy on the stomach, the jejunum, and the colon. Wilcoxon rank-sum test was used to compare values over time (P < 0.05). During xylazine infusion, MAP, CVP, PAP, SVR, and VDalv increased significantly, whereas CO, DO2, and intestinal microperfusion decreased. Intestinal oxygenation remained unchanged. All parameters returned to pre-xylazine values within 1 h after stopping xylazine infusion. A xylazine infusion during constant isoflurane anesthesia in horses impairs global and intestinal perfusion without changing tissue oxygenation in normoxic healthy horses. Further studies are necessary, however, to evaluate whether a possible reduction of isoflurane concentration by xylazine infusion will ameliorate these negative effects.