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.

The aim of the study was to assess the changes of blood parameters in 12 three-week-old Polish Merino sheep subjected to experimental jaagsiekte sheep retrovirus (JSRV) infection.Material and Methods: Haematological (WBC with leukocyte subpopulations: GRA, LYM, MID, and RBC, MCV, MCH, MCHC, HGB, HCT, PLT, and MPV) and biochemical blood parameters (acid/base balance, cation/anion content, and gasometry) were determined in blood samples collected one month after JSRV infection, then at four-week intervals for five consecutive months.Results: A decrease in RBC, HCT, MCV, PLT, MPV, and LYM values in comparison with controls was found in the last month of observation. On the other hand, at the same time, an increase in HGB, MCH, MCHC, WBC, MID, and GRA indices was observed. Moreover, at the end of experiment blood gasometric indices such as pCO₂, HCO₃, and tCO₂, and Na and K ion concentrations were higher in the affected lambs than in the healthy animals. The pH values of the challenged animals exhibited less alkaline character than in the case of controls, which was associated with a decrease in O₂% saturation. However, the majority of differences between JSRV inoculated and control groups was not statistically significant.Conclusion: The observed changes in the examined blood parameters can be considered as prodromal symptoms in the preclinical phase of adenocarcinoma development associated with JSRV infection.

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 determine effects of leukotriene (LT) C4 on ion transport across equine tracheal epithelium. Sample: Tracheal epithelium from cadavers of 24 horses considered free of respiratory tract disease. Procedures: Mucosae were mounted into Ussing chambers, and short-circuit current (Isc) was monitored over time. Effects of LTC4 were examined for various conditions, including addition of amiloride (10μM) to the mucosal bath solution, addition of bumetanide (10μM) to the serosal bath solution, addition of barium (1mM) to the serosal bath solution, and substitution of gluconate for chloride and HEPES for bicarbonate in bath solutions. Electrolyte transport was assessed via 22Na and 36Cl isotope fluxes. Results: Addition of LTC4 (50nM) to the serosal bath solution caused an increase in Isc for basal conditions and a larger increase after pretreatment with amiloride. The increase was negated in part by the addition of bumetanide to the serosal bath solution and further reduced by substitution of HEPES for bicarbonate in bath solutions. Remaining current was reduced to values less than those before treatment with LTC4 by the addition of barium to the serosal solution. There was a small increase in Isc after the addition of amiloride and substitution of gluconate for chloride. Radioisotope flux indicated that addition of LTC4 to the serosal bath solution increased chloride secretion and reduced sodium absorption. Conclusions and Clinical Relevance: LTC4 stimulated chloride secretion through a predominately bumetanide-sensitive pathway, with a smaller contribution from a bicarbonate-dependent pathway. Thus, LTC4 appears to be a potential mediator of airway hypersecretion in horses.

Objective—To induce ischemia and reperfusion injury in the large colon mucosa of horses in vivo and evaluate the recovery and effects of components of an organ transplant solution on mucosal recovery in vitro. Animals—6 healthy horses. Procedures—Horses were anesthetized, and ischemia was induced for 60 minutes in the pelvic flexure, which was followed by reperfusion for 240 minutes. Ischemic (n = 4 horses), reperfused (6), and adjacent control (6) colonic mucosae were isolated for in vitro testing and histologic examinations. Tissues were mounted in Ussing chambers with plain Krebs Ringer bicarbonate (KRB), KRB with N-acetylcysteine (NAC), or KRB with a modified organ transplant solution (MOTS). Transepithelial electrical resistance (TER) and mannitol flux were used to assess mucosal integrity. Data were analyzed by use of ANOVA and Kruskal-Wallis tests. Results—The TER in reperfused tissues was similar to the TER in control tissues and greater than the TER in ischemic tissues, which was consistent with morphological evidence of recovery in reperfused tissues. Mannitol flux was greater in ischemic tissues than in reperfused tissues. The TER and mannitol flux were not significantly affected by incubation of mucosa with NAC or MOTS. Conclusions and Clinical Relevance—Ischemia induced during the brief period allowed rapid mucosal repair and complete recovery of tissue barrier properties during reperfusion. Therefore, reperfusion injury was not observed for this method of ischemic damage in equine colonic mucosa.

Objective-To compare effects of electroacupuncture and butorphanol on hemodynamic and respiratory variables and rectal analgesia in mares after controlled rectal distention. Animals-8 healthy mares. Procedure-Each horse received saline (0.9% NaCl) solution (0.01 mL/kg, IV; control treatment), butorphanol tartrate (0.1 mg/kg, IV), or 2 hours of electroacupuncture (EA) at acupoints Bladder 21, 25, and 27 on both sides of the vertebral column, Bai hui, and Stomach 36 (right side only). Order of treatments in each mare was randomized. At least 7 days elapsed between treatments. A balloon was inserted in the rectum of each mare, and controlled distention of the balloon (pressures of ≤ 220 mm Hg) was used to measure nociceptive rectal pain threshold. Rectal temperature and cardiovascular and respiratory variables were measured before (baseline) and 5, 15, 30, 60, 90, and 120 minutes after onset of each treatment. Results-Butorphanol produced greater increases in rectal pain threshold, compared with EA (mean +/- SD, 214 +/- 24 vs 174 +/- 35 mm Hg of balloon pressure). Electroacupuncture produced minimal cardiovascular and respiratory changes. Although clinically not important, butorphanol produced moderate significant increases in heart and respiratory rates, arterial blood pressure, and rectal temperature and decreases in arterial oxygen tension. Arterial pH, carbon dioxide tension, bicarbonate concentrations, base excess, Hct, and concentration of total solids were not significantly different from baseline values after EA, butorphanol, and control treatments. Conclusions and Clinical Relevance-Electroacupuncture and butorphanol (0.1 mg/kg, IV) may provide useful rectal analgesia in horses.

Objective-To determine cutaneous analgesia, hemodynamic and respiratory effects, and β-endorphin concentration in spinal fluid and plasma of horses after acupuncture and electroacupuncture (EA). Animals-8 healthy 10- to 20-year-old mares that weighed between 470 and 600 kg. Procedure-Each horse received 2 hours of acupuncture and 2 hours of PAES at acupoints Bladder 18, 23, 25, and 28 on both sides of the vertebral column as well as sham needle placement (control treatment). Each treatment was administered in a random order. At least 7 days elapsed between treatments. Nociceptive cutaneous pain threshold was measured by use of skin twitch reflex latency (STRL) and avoidance to radiant heat (≤ 50°C) in the lumbar area. Skin temperature, cardiovascular and respiratory variables, and β-endorphin concentration in spinal fluid (CSF-EN) and plasma (plasma-EN) were measured. Results-Acupuncture and EA significantly increased STRL and skin temperature. The CSF-EN was significantly increased from baseline values 30 to 120 minutes after onset of EA, but it did not change after acupuncture and control treatments. Heart and respiratory rates, rectal temperature, arterial blood pressure, Hct, total solids and bicarbonate concentrations, base excess, plasma-EN, and results of blood gas analyses were not significantly different from baseline values after acupuncture, EA, and control treatments. Conclusion and Clinical Relevance-Administration of EA was more effective than acupuncture for activating the spinal cord to release beta-endorphins into the CSF of horses. Acupuncture and PAES provided cutaneous analgesia in horses without adverse cardiovascular and respiratory effects.

Cardiovascular effects of epidurally administered morphine, a morphine-xylazine combination, and saline solution (control) during isoflurane-maintained anesthesia were assessed in 6 healthy dogs. Anesthesia was induced with isoflurane in O2 and was maintained at 2.0% end-tidal isoflurane concentration. Ventilation was controlled to maintain PaCO2 at 35 to 45 mm of Hg. The dorsal pedal artery was cannulated for measurement of systolic, mean, and diastolic pressures, and for blood sample collection. Arterial blood pH and gas tensions were determined every 30 minutes. Cardiac output was determined by thermodilution. The ECG, heart rate, body temperature, central venous pressure, mean pulmonary artery pressure, pulmonary capillary wedge pressure, end-tidal isoflurane concentration, and CO2 tension were monitored. Systemic and pulmonary vascular resistance, arterial HCO3(-) concentration, base excess, and cardiac index were calculated. After baseline measurements were taken, morphine (0.1 mg/kg of body weight) in 5 ml of isotonic saline solution, morphine and xylazine (0.1 mg of morphine and 0.09 mg of xylazine/kg) in 5 ml of isotonic saline solution, or 5 ml of isotonic saline solution was injected into the lumbosacral epidural space. Data were recorded at 5, 15, 30, 45, 60, 75, 90, 105, and 120 minutes after epidural injection. Statistical analysis included ANOVA for repeated measures. Significance was set at P < 0.05. None of the measured variables was significantly different among the 3 treatments at any time. Results of the study indicated that epidural administration of morphine or morphine and xylazine is not associated with significant cardiovascular side effects during isoflurane-maintained anesthesia in dogs.

The effects of single IV injections of sodium bicarbonate (0.5 mEq/kg of body weight, 1 mEq/kg, 2 mEq/kg, and 4 mEq/kg) on serum osmolality, serum sodium, chloride, and potassium concentrations, and venous blood gas tensions in 6 healthy cats were monitored for 180 minutes. Serum osmolality increased and remained significantly (P less than 0.05) increased for 120 minutes in cats given 4 mEq of sodium bicarbonate/kg. Serum sodium was increased significantly (P less than 0.05) for 30 minutes in cats given 4 mEq of sodium bicarbonate/kg. Serum sodium decreased and remained significantly (P less than 0.05) decreased for 120 minutes in cats given 1 g of 20% mannitol/kg, and serum osmolality was significantly (P less than 0.05) decreased at 30 and 60 minutes. Serum chloride decreased significantly (P less than 0.05) for 10 minutes in cats given 1 mEq of sodium bicarbonate/kg, and was significantly decreased for 30 minutes in cats given 2 mEq and 4 mEq of sodium bicarbonate/kg. Serum chloride decreased and remained significantly (P less than 0.05) decreased for 30 minutes in cats given 1 g of 20% mannitol/kg. Serum sodium and serum osmolality did not change significantly (P less than 0.05) in cats given 4 ml of 0.9% sodium chloride/kg. Serum potassium decreased significantly (P less than 0.05) for 10 minutes in cats given 1 mEq of sodium bicarbonate/kg, and for 120 minutes in cats given 2 mEq/kg or 4 mEq/kg. There was a significantly (P less than 0.05) greater decrease in serum potassium that lasted for 30 minutes after giving sodium bicarbonate at the dosage of 4 mEq/kg, compared with other dosages given. Serum potassium did not change significantly in cats given 1 g of 20% mannitol/kg, but was significantly (P less than 0.05) decreased 10 minutes following 4 ml of 0.9% sodium chloride/kg. Sodium bicarbonate infusion significantly (P less than 0.05) increased venous blood pH and plasma bicarbonate concentration in all cats. The magnitude and duration of these changes were significantly greater following administration of sodium bicarbonate at dosages of 2 mEq/kg and 4 mEq/kg. Significant (P less than 0.05) increases in PCO2 were associated only with the highest dosage of sodium bicarbonate (4 mEq/kg). Base excess increased significantly (P less than 0.05) in all cats following sodium bicarbonate infusion. There were significantly (P less than 0.05) greater increases in base excess lasting 30 minutes following administration of sodium bicarbonate at dosages of 2 mEq/kg and 4 mEq/kg. Significant (P less than 0.05) changes in venous blood pH, PCO2, or bicarbonate were not observed in cats given 4 ml of 0.9% sodium chloride/kg, or in cats given 1 g of 20% mannitol/kg. Base excess was significantly (P less than 0.05) increased for 10 minutes in cats given 1 g of 20% mannitol/kg. As expected, 4 mEq of sodium bicarbonate/kg induced the most time- and dosage-related effects. Caution should be used when administering sodium bicarbonate IV to cats at dosages greater than 2 mEq/kg, because of the potential for important acid-base and electrolyte changes.