Subclinical ketosis risk prediction in dairy cows based on prepartum metabolic indices / [Previsão do risco de cetose subclínica em vacas de leite, baseado nos índices metabólicos pré-parto]

Ketosis can seriously impair cow performance. This study detected changes in prepartum blood metabolic parameters for predicting postpartum ketosis occurrence in dairy cows. Body condition score (BCS) was assessed before and after delivery. Blood samples of 63 cows were collected from 10 days before calving to 10 days after calving to measure metabolic parameters including ß-hydroxybutyric acid (BHBA), non-esterified fatty acid (NEFA), glucose (GLU), total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin (IBIL), total protein (TP), albumin (ALB), globulin (GLO), alanine aminotransferase (ALT), and aspartate aminotransferase (AST). There was a postpartum subclinical ketosis incidence of 42.25%. Compared with prepartum, plasma, levels of BHBA, AST, and NEFA significantly increased postpartum, and prepartum AST (R=0.57) and NEFA (R=0.45) showed a significant positive correlation with ketosis postpartum. Plasma GLU level significantly decreased postpartum and was significantly negatively correlated with ketosis (R=-0.21). Receiver operating characteristic curve analysis revealed prepartum BSC < 2.88, and prepartum plasma AST > 68.0 U/L, GLU < 3.97mmol/L, NEFA > 0.27mmol/L, and BHBA > 0.43mmol/L, indicating a high risk of subclinical ketosis postpartum. These levels can be used as risk indicators to predict the occurrence of subclinical ketosis in postpartum cows.(AU)

A cetose pode trazer sérios prejuízos ao desempenho da vaca. Este estudo detectou alterações nos parâmetros metabólicos do sangue pré-parto para prever a cetose pós-parto que ocorre em vacas leiteiras. O escore de condição corporal (ECC) foi avaliado antes e após o parto. Foram coletadas amostras de sangue de 63 vacas entre 10 dias antes e 10 dias após o parto para medir os parâmetros metabólicos, incluindo ácido ß-hidroxibutírico (BHBA), ácido graxo não esterificado (NEFA), glicose (GLU), bilirrubina total (TBIL), bilirrubina direta (DBIL), bilirrubina indireta (IBIL), proteína total (TP), albumina (ALB), globulina (GLO), alanina aminotransferase (ALT) e aspartato aminotransferase (AST). Houve uma incidência de cetose subclínica pós-parto de 42,25%. Em comparação com o pré-parto, o plasma, os níveis de BHBA, AST e NEFA aumentaram significativamente no pós-parto, e AST no pré-parto (R = 0,57) e NEFA (R = 0,45) mostraram uma correlação significativa positiva com cetose pós-parto. O nível plasmático de GLU diminuiu significativamente no pós-parto e foi negativamente correlacionado com a cetose de forma significativa (R = -0,21). A análise da curva característica de operação do receptor revelou BSC pré-parto <2,88 e AST plasmático pré-parto> 68,0 U / L, GLU <3,97mmol / L, NEFA> 0,27mmol / L e BHBA> 0,43mmol / L, indicando um alto risco de cetose subclínica pós-parto. Esses níveis podem ser usados ​​como indicadores de risco para prever a ocorrência de cetose subclínica em vacas no pós-parto.(AU)

Cardiac Troponin I and Amino-Terminal Pro B-Type Natriuretic Peptide in Dogs With Stable Chronic Kidney Disease.

BACKGROUND: Increased concentrations of N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) in dogs with azotemia have been documented. Knowledge of mechanisms behind increased concentrations of cardiac biomarkers in dogs with azotemia is warranted for correct interpretation of test results. OBJECTIVES: The aim of the article was to investigate possible associations between plasma concentrations of cTnI and NT-proBNP, respectively, and patient characteristics, glomerular filtration rate (GFR), a plasma volume factor (PVF) derived from scintigraphic examination (PVf), systolic blood pressure (SBP), selected hematologic and biochemical variables, and echocardiographic measurements in dogs with stable chronic kidney disease (CKD) and in healthy dogs. ANIMALS: Fifty student-, staff-, and client-owned dogs were included. Twenty-three of the dogs were healthy and 27 were diagnosed with CKD. METHODS: In this cross-sectional observational study, dogs with a previous diagnosis of CKD and healthy control dogs were included. At inclusion, all dogs were characterized by physical examination, repeated blood pressure measurements, complete urinalysis, hematology and biochemistry panel, echocardiography, abdominal ultrasound examination of the entire urinary tract, and scintigraphic examination for measurement of GFR. RESULTS: Plasma volume factor and PCV were independently associated with NT-proBNP (Radj2 = 0.42; P < .0001). Age, body weight (BW), and SBP were independently associated with cTnI (Radj2 = 0.50; P < .0001). CONCLUSIONS AND CLINICAL IMPORTANCE: Neither NT-proBNP nor cTnI concentrations were independently associated with measured GFR. Thus, findings were not suggestive of passive accumulation of either marker, suggesting that increased circulating concentrations of cTnI and NT-proBNP can be interpreted similarly in dogs with stable CKD as in dogs without CKD.

Effects of hydration on scintigraphic glomerular filtration rate measured using integral and plasma volume methods in dogs with suspected renal disease.

The current standard scintigraphic method for estimating glomerular filtration rate (GFR) in dogs is the integral method, which normalizes renal GFR to body weight. The plasma volume method, that is normalizing GFR to plasma volume, has been reported to be more physiologically correct. The aim of this prospective study was to test the effect of hydration status on GFR measured by these two methods in a group of dogs with suspected renal disease. Eleven dogs were recruited. All dogs underwent standardized scintigraphic examinations before and after 15 ml/kg of fluid was administered intravenously at 5-7 ml/kg/min. Individual kidney GFR estimates (n = 22) were calculated using both methods and a consensus of two observers who were unaware of clinical findings. Individual kidney GFR increased significantly (P = 0.0008) after fluid administration using the integral method and individual kidney GFR using the plasma volume method remained constant. Percentage differences for individual kidney GFR before and after fluid administration were 31.4 ± 58.1% (change ± 95% CI) for the integral method and 0.1 ± 70% (change ± 95% CI) for the plasma volume method. Intravenously administered fluid increased individual kidney GFR from low to normal in 10 of 22 kidneys using the integral method and in 1 of 22 kidneys using the plasma volume method. Findings supported the use of the plasma volume method for scintigraphic calculation of GFR in dogs with suspected renal disease and indicated that errors of kidney status classification may more likely occur when the integral method is used.

Intravenous hypertonic saline solution (7.5%) and oral electrolytes to treat of calves with noninfectious diarrhea and metabolic acidosis.

OBJECTIVE: The aim of this study was to compare the efficacy of treating osmotic diarrhea and dehydration in calves with hypertonic saline solution (HSS) IV, isotonic electrolyte solution (IES) PO, and a combination of these 2 solutions (HSS + IES). EXPERIMENTAL DESIGN: Eighteen male calves 8-30 days of age were used to evaluate the efficacy of 3 methods of fluid therapy after induction of osmotic diarrhea and dehydration. The diarrhea and dehydration were induced by administration of saccharose, spironolactone, and hydrochlorothiazide for 48 hours. The animals were randomly divided into 3 experimental groups: Group 1: 7.2% hypertonic saline solution-HSS (5 mL/kg IV); Group 2: oral isotonic electrolyte solution IES (60 mL/kg PO); or Group 3: HSS+IES. Clinical signs and laboratory finding observed 48 hours post-induction (Time 0) included diarrhea, dehydration, lethargy, and metabolic acidosis. RESULTS: Calves treated with HSS + IES experienced decreases in hematocrit, total protein concentration, albumin concentration, urea nitrogen concentration, and plasma volume as well as increases in blood pH, blood bicarbonate concentration, and central venous pressure between 1 and 3 hours post-treatment. These findings also were observed in animals treated with IES, however, at a slower rate than in the HSS + IES-treated animals. Animals treated with HSS continued to display signs of dehydration, lethargy, and metabolic acidosis 24 hours post-treatment. CONCLUSION: Treatment with a combination of HSS and IES produced rapid and sustainable correction of hypovolemia and metabolic acidosis in calves with noninfections diarrhea and dehydration.

Plasma potassium-lowering effect of oral glucose, sodium bicarbonate, and the combination thereof in healthy neonatal dairy calves.

Hyperkalemia is a common complication in neonatal diarrheic dairy calves and is corrected by administration of glucose or sodium bicarbonate. Although the hypokalemic effect of glucose is well established in other species, controversial results are reported for sodium bicarbonate. Our objective was to study the effect and mechanism of action of glucose and sodium bicarbonate on the potassium homeostasis of healthy neonatal dairy calves. Nine healthy neonatal Holstein-Friesian calves underwent 3 oral treatments with 2L of NaHCO(3) (150 mmol/L), glucose (300 mmol/L), and glucose+NaHCO(3) solution (300 mmol/L+150 mmol/L) in randomized order. Blood was obtained before treatment (T(0)) and at 30-min intervals thereafter. Changes between each time point and T(0) were determined for all parameters. Urine was collected volumetrically to determine total renal potassium excretion over an 8-h posttreatment period. Plasma volume changes were extrapolated from changes in plasma protein concentration. Treatment and time effects were tested with repeated-measures ANOVA. Multivariate stepwise regression analysis using dummy variable coding was conducted to identify associations between changes in plasma potassium concentration ([K]) and changes in plasma glucose concentration ([glucose]), blood base excess, and plasma volume. Oral glucose and sodium bicarbonate treatments decreased [K] by 25 and 19%, respectively, whereas the combination of both compounds caused an intermediate [K] decline (22%). For the glucose treatment, the decline in [K] was only associated with changes in plasma [glucose] (partial R(2)=0.19). In NaHCO(3)-treated calves, [K] decline was associated with change of extracellular volume (partial R(2)=0.31) and blood base excess (partial R(2)=0.19). When glucose and NaHCO(3) were combined, [K] decline was associated with changes in plasma volume (partial R(2)=0.30), BE (R(2)=0.22), and [glucose] (partial R(2)=0.03). Our results indicate that glucose lowers plasma [K] mainly through an insulin-dependent intracellular translocation of K, whereas NaHCO(3) causes hypokalemia through hemodilution followed by intracellular translocation of K caused by the strong ion effect. The combination of glucose and NaHCO(3) at the dosage used in this study does not have an additive hypokalemic effect. When combined, hemodilution and strong ion effect have the strongest effect on plasma [K], whereas the insulin-dependent effect of glucose appears to be blunted.

Determination of body water compartments in neonatal foals by use of indicator dilution techniques and multifrequency bioelectrical impedance analysis.

OBJECTIVE: To determine values for total body water (TBW), extracellular fluid volume (ECFV), intracellular fluid volume (ICFV), and plasma volume (PV) in healthy neonatal (< 24 hours old) foals and to create a multifrequency bioelectrical impedance analysis (MF-BIA) model for use in neonatal foals. ANIMALS: 7 healthy neonatal foals. PROCEDURES: Deuterium oxide (0.4 g/kg, IV), sodium bromide (30 mg/kg, IV), and Evans blue dye (1 mg/kg, IV) were administered to each foal. Plasma samples were obtained following an equilibration period, and the TBW, ECFV, ICFV, and PV were calculated for each foal. An MF-BIA model was created by use of morphometric measurements from each foal. RESULTS: Mean ± SD values were obtained for TBW (0.744 ± 0.024 L/kg), ICFV (0.381 ± 0.018 L/kg), ECFV (0.363 ± 0.014 L/kg), and PV (0.096 ± 0.015 L/kg). The 95% limits of agreement between the MF-BIA and indicator dilution techniques were within ± 2 L for TBW and ECFV. CONCLUSIONS AND CLINICAL RELEVANCE: Fluid volumes in neonatal foals were found to be substantially larger than fluid volumes in adult horses. Multifrequency bioelectrical impedance analysis may be a useful technique for predicting TBW, ICFV, and ECFV in neonatal foals.

Bioelectrical impedance analysis determination of water content and distribution in the horse.

A horse's hydration status is critical to its health. The accurate and quantitative determination of it has been problematic because of size, length and density of hair, and uneven topography. The objective of this study was to validate a bioelectrical impedance analysis (BIA) method for objectively quantifying hydration status. Monofrequency BIA values and simple biometric measurements were used to construct predictive equations for total body water, plasma, extracellular, and intra-cellular fluid volumes. These predictive equations were correlated with standard body fluid dilution reference methods. The result was an accuracy of ±0.64% for total body water, ±0.17% for plasma volume, ±1.91% for extra-cellular fluid, and ±0.57% for intra-cellular fluid compartments. Less than 5 min was required for all of the measurements and determinations. Therefore, it appears that an accurate measurement of body fluid distribution can be performed on horses using a fast, easy, non-invasive, inexpensive BIA method.

Plasma volume and electrolyte changes following intravenous infusion of hypertonic hydroxyethyl starch versus mannitol in healthy dogs.

In a prospective cross-over study, the duration and magnitude of effect on the electrolyte and plasma volume changes of intravenous (IV) hypertonic hydroxyethyl starch (hyperHES) (7.5%/6%) and mannitol (20%) were compared. Eight Beagle dogs received an IV infusion of 4mL/kg hyperHES (group H) and 4mL/kg mannitol 20% (group M) on separate occasions. Urine and blood samples were taken in the first (T(60)) and second (T(120)) hour after infusion. Significant increases in plasma volume at each time point in group H and M were noted when compared to baseline (start of infusion=T(0)) level. There was no significant difference between groups. Both fluids resulted in diuresis, although no significant difference between groups was noted. A significant increase in plasma sodium (Na) was demonstrated in group H between T(0) and T(60) with a significant increase in the Na and chloride (Cl) fractional excretion (FE) between T(0), T(60) and T(120). In group M no changes in plasma electrolyte concentrations were detected, although FE of Na, Cl and K was increased significantly between T(0) and T(60). In conclusion, hyperHES and mannitol appear to have a volume expanding effect lasting at least 120 min. The hypernatraemia induced by hyperHES was minimal compared to previous reports of hypertonic saline use, and no clinical side effects were noted. HyperHES showed comparable effects to mannitol in increasing plasma volume and diuresis and could be considered for these applications.

Influence of different oral rehydration solutions on abomasal conditions and the acid-base status of suckling calves.

The aim of the study was to investigate the influence of oral rehydration solutions (ORS) on milk clotting, abomasal pH, electrolyte concentrations, and osmolality, as well as on the acid-base status in blood of suckling calves, as treatment with ORS is the most common therapy of diarrhea in calves to correct dehydration and metabolic acidosis. Oral rehydration solutions are suspected to inhibit abomasal clotting of milk; however, it is recommended to continue feeding cow's milk or milk replacer (MR) to diarrheic calves to prevent body weight losses. Three calves with abomasal cannulas were fed MR, MR-ORS mixtures, or water-ORS mixtures, respectively. Samples of abomasal fluid were taken before and after feeding at various time points, and pH, electrolyte concentrations, and osmolality were measured. The interference of ORS with milk clotting was examined in vivo and in vitro. To evaluate the effects of ORS on systemic acid-base status, the Stewart variables strong ion difference ([SID]), acid total ([A(tot)]), and partial pressure of CO2 (pCO2) were quantified in venous blood samples drawn before and after feeding. Calves reached higher abomasal pH values when fed with MR-ORS mixtures than when fed MR. Preprandial pH values were re-established after 4 to 6 h. Oral rehydration solutions prepared in water increased the abomasal fluid pH only for 1 to 2 h. Oral rehydration solutions with high [SID(3)] ([Na(+)] + [K(+)] - [Cl(-)]) values produced significantly higher abomasal pH values and area under the curve data of the pH time course. Caseinomacropeptide, an indicator of successful enzymatic milk clotting, could be identified in every sample of abomasal fluid after feeding MR-ORS mixtures. The MR-ORS mixtures with [SID(3)] values > or =92 mmol/L increased serum [SID(3)] but did not change venous blood pH. Oral rehydration solutions do not interfere with milk clotting in the abomasum and can, therefore, be administered with milk. In this study, MR-ORS mixtures with high [SID(3)] values caused an increase of serum [SID(3)] in healthy suckling calves and may be an effective treatment for metabolic acidosis in calves suffering from diarrhea.

Niveles plasmáticos de mieloperoxidasa y proteína C reactiva en conejos machos en Nueva Zelanda expuestos a una dieta hiperlipidémica / Plasma concentration of myeloperoxidase and C reactive protein in male New Zealand rabbits, exposed to a hyperlipidemic diet

La Mieloperoxidasa (MPO) y la Proteína C Reactiva (PCR) han sido implicados en la fisiopatología de la aterosclerosis. El objetivo del presente estudio fue determinar las concentraciones plasmáticas de MPO y PCR y su relación con la formación de ateromas en conejos. Se estudiaron 23 conejos machos Nueva Zelanda: Grupo 1: conejarina y verdura; Grupo 2: Huevo y conejarina. El periodo experimental duró 13 semanas. Se determinó perfil lipídico por métodos enzimáticos, MPO por ELISA y PCR por turbidimetría en 0 13va semana. Se realizó estudio histológico de aorta. Los resultados revelaron que la PCR se elevó en el grupo 2 al final del estudio (p<0,05). No se observó diferencias en MPO en el grupo 2 en el estudio. En cuanto a los ateromas se evidenciaron lesiones tipo I y II en los conejos del grupo 2. En conclusión, se encontró que la PCR y no la MPO son marcadores de aterosclerosis según nuestras condiciones experimentales.

Myeloperoxidase (MPO) and C-reactive protein (CRP) have been implicated in atherosclerosis. The objective of the present study was to determine plasma concentration MPO and CRP and its relationship of formation of aortic lesions in rabbits. 23 male New Zealand rabbits were study: Group 1: “conejarina” (commercial rabbit food) and vegetables; Group 2: egg and conejarina. The experiment lasted 13 weeks. Lipid profile was done by enzymatic methods, MPO by ELISA, and PCR by turbidimetry in weeks 0 and 13. Histological study of rabbits’ aorta was done. Results revealed that in group 2 CRP increased at final study (p <0.05). No differences were observed in MPO values in the experiment. Regarding atheroma, group 2 presented type I and II lesions. In conclusion only CRP is marker of atherosclerosis according to our experimental conditions.

Hyperhydration prior to a simulated second day of the 3-day moderate intensity equestrian competition does not cause arterial hypoxemia in Thoroughbred horses.

Dehydration and the associated impairment of cardiovascular and thermoregulatory function comprise major veterinary problems in horses performing prolonged exercise, particularly under hot and humid conditions. For these reasons, there is considerable interest in using pre-exercise hyperhydration to help maintain blood volume in the face of the excessive fluid loss associated with sweat production during prolonged exertion. However, recently it was reported that pre-exercise hyperhydration causes arterial hypoxemia in horses performing moderate intensity exercise simulating the second day of an equestrian 3-day event competition (E3DEC) which may adversely affect performance (Sosa Leon et al. in Equine Vet J Suppl 34:425-429, 2002). These findings are contrary to data from horses performing short-term maximal exertion, wherein hyperhydration did not affect arterial O2 tension/saturation. Thus, our objective in the present study was to examine the impact of pre-exercise hyperhydration on arterial oxygenation of Thoroughbred horses performing an exercise test simulating the second day of an E3DEC. Control and hyperhydration studies were carried out on seven healthy Thoroughbred horses in random order, 7 days apart. In the control study, horses received no medications. In the hyperhydration experiments, nasogastric administration of NaCl (0.425 g/kg) 5 h pre-exercise induced a plasma volume expansion of 10.9% at the initiation of exercise. This methodology for inducing hypervolemia was different from that of Sosa Leon et al. (2002). Blood-gas tensions/pH as well as plasma protein, hemoglobin and blood lactate concentrations were measured pre-exercise and during the exercise test. Our data revealed that pre-exercise hyperhydration neither adversely affected arterial O2 tension nor hemoglobin-O2 saturation at any time during the exercise test simulating the second day of an E3DEC. Further, it was observed that arterial blood CO2 tension, pH, and blood lactate concentrations also were not affected by pre-exercise hyperhydration. However, hemodilution in hyperhydrated horses caused an attenuation of the expansion in the arterial to mixed-venous blood O2 content gradient during phases B and D of the exercise protocol, which was likely offset by an increase in cardiac output. It is concluded that pre-exercise hyperhydration of horses induced in the manner described above is not detrimental to arterial oxygenation of horses performing an exercise test simulating the second day of an E3DEC.

Gender differences in the blood volume of conscious Sprague-Dawley rats.

Reference values of blood volume (BV) and plasma volume (PV) of animal species are given as functions of body weight and gender specification generally is not given. Considering the common observation of a decreased hematocrit (Hct) in the females of many species, the BV, the PV, or both must differ between genders. The present study was performed to determine the magnitude of those differences. We measured Hct and PV in 24 female and 23 male Sprague-Dawley rats in their 12th week of life. The rats were surgically prepared with indwelling femoral arterial catheters 4 d prior to the determination of BV. Evan's Blue dye dilution was used to determine PV in conscious, quietly resting animals. BV was calculated as PV/(1-Hct). Mean Hct was 2% lower in female rats than males, and PV (mean +/- 1 standard deviation) was 4.86 +/- 0.54 ml/100 g in females compared with 4.12 +/- 0.32 ml/100 g in males. Calculated BV in female rats was 7.84 +/- 0.70 ml/100 g compared with 6.86 +/- 0.53 ml/100 g in males. When precise estimates of BV or PV are needed for research or dosing purposes, gender differences of 18% for PV and 14% for BV must be considered. In addition, species other than the rat may have similar discrepancies between sexes, and the prudent investigator must determine individual volume assessments of both sexes before assumptions of BV and PV for a species can be made.

The effect of 7.2% hypertonic saline solution on the duration of sodium gradient between the cerebrospinal fluid and the venous circulation in the dog.

To determine the duration of water movement from cerebrospinal fluid (CSF) into venous blood by the infusion of 7.2% hypertonic saline solution (HSS), the sodium gradient between venous blood and CSF were examined. Venous sodium concentrations remained higher than that in CSF for duration of 60 min following HSS infusion. By 90 min, the CSF sodium concentration reached the equilibrium with venous sodium concentration. Those data suggests that the duration of time during which water moved from CSF into capillaries in brain by the gradient of sodium concentration was less than 90 min.

Collection of blood and plasma from the mouse.

There are many elements in plasma that can act as surrogate markers of the physiological well-being of a mouse, thus making the collection of blood and plasma a general technique with many applications in mouse phenotyping. For example, the presence of certain enzymes in plasma can serve as markers of tissue toxicity (AST, ALT) and general function, and the more sophisticated lipid and lipoprotein profile tests (cholesterol, LDL) can point to dyslipidemias. As many of the tests available to measure these parameters have been adapted to automated systems in a high-throughput fashion, they have become part of the first line of screening protocols in mouse phenotyping. In this section, general techniques associated with collection and processing of blood are described.

Frusemide results in an extracellular to intracellular fluid shift in horses.

REASONS FOR PERFORMING STUDY: Frusemide (Lasix) is commonly used diuretic in horse racing and equine clinical practice. While pharmacology, pharmacodynamics, renal and haematological effects of frusemide have been studied in horses, its effects on the distribution of fluid within the horse remain unknown. OBJECTIVE: To quantify the effects of frusemide on extracellular and intracellular fluid shifts. METHODS: Horses were infused with 1 mg/kg body mass (n = 7) or 2 mg/kg (n = 9) i.v. frusemide. Total body water (TBW), extracellular fluid volume (ECFV) and plasma volume (PV) were measured using D2O, NaSCN and Evans blue dilution. Change in ECFV was assessed from the change in plasma [protein] and from repeated infusion/dilution of NaSCN. RESULTS: Frusemide resulted in a 0.020 +/- 0.002 l/kg decrease in TBW within 120 min. At 120 min after frusemide infusion the ECFV losses were nearly double the TBW losses, therefore ECFV loss in excess of TBW loss is seen as an increase in ICFV. CONCLUSIONS: Frusemide resulted in a net shift of fluid (electrolytes and water) from the extracellular to intracellular fluid compartment. POTENTIAL RELEVANCE: The fluid shifts that occur within horses administered frusemide has not previously been characterised. The intracellular shift of fluid is of performance and clinical significance.

Hydration of exercised standardbred racehorses assessed noninvasively using multi-frequency bioelectrical impedance analysis.

REASONS FOR PERFORMING STUDY: In human and animal clinical practice, multi-frequency bioelectrical impedance analysis (MF-BIA) is increasingly used as a diagnostic tool to assess hydration of intra-and extracellular fluid compartments. Accurate determination of changes in hydration status within individuals over time has remained problematic due to the requirement for complete impedance-frequency relationships at the time points of interest. OBJECTIVES: To use MF-BIA in 13 Standardbred racehorses and 7 'endurance' research horses to determine if MF-BIA could be used to track changes in total body water (TBW), intracellular fluid volume (ICFV) and extracellular fluid volume (ECFV) resulting from exercise. METHODS: Jugular venous blood was sampled at rest and for 2-13 h following exercise. TBW, ECFV and plasma volume (PV) were measured at rest using indicator dilution techniques (D2O, thiocyanate and Evans Blue, respectively). TBW, ECFV, ICFV and PV were correlated to impedance measures and predictive equations used to determine hydration status from MF-BIA measures. RESULTS: TBW loss continued throughout the recovery period, and was primarily borne by the ECF compartment at 90 min of recovery. CONCLUSIONS: MF-BIA predictions of compartmental hydration status were significantly correlated to measured/calculated decreases in these compartments. POTENTIAL RELEVANCE: Practical applications for MF-BIA in horses include monitoring of hydration status during transport and competition, assessment of body compostion, clinical health assessment and critical care management.

Comparison of a small volume of hypertonic saline solution and dextran 40 on hemodynamic alternations in conscious calves.

The hemodynamic effects of rapid intravenous (IV) administration of 10% dextran 40 in saline solution (D40) and 7.2% hypertonic saline solution (HSS) in calves were compared. Calves received isotonic saline solution (ISS), HSS or D40 (3 calves/group) and were monitored of blood pressure, and cardiac output (CO) for 180 min. HSS and D40 infusions induced a significant increase in relative plasma volume reaching 134.9+/-2.8 and 125.0+/-1.9%, respectively at the end of fluid infusion. In the HSS group, CO, cardiac index (CI) and stroke volume (SV) remained constant at low levels after 90 minutes despite the maximal values of CO, CI and SV at the end of infusion, reaching 21.0+/-6.3 l/min (p<0.05), 177.8+/-14.2 ml/min/kg (p<0.001) and 0.20+/-0.03 l/beat (at t=10 min, p<0.001), respectively. In contrast, CI and SV in the D40 group showed significant increases to 14.7+/-2.9 l/min and 153.5+/-17.2 ml/min/kg, respectively, at the end of fluid infusion. And those values remained constant at higher levels than those of the before infusions values throughout the experimental periods. Positive effects for hemodynamic alternations of D40 in calf practice were milder and longer than those of HSS. Therefore, the D40 infusion should be explored as a possible treatment for dehydrated calves, since rapid infusion of D40 may be safe and more beneficial for rehydrating more than HSS treatment.

Comparison of a small volume of hypertonic saline solution and dextran 40 on hemodynamic alternations in conscious calves

The hemodynamic effects of rapid intravenous (IV) administration of 10% dextran 40 in saline solution (D40) and 7.2% hypertonic saline solution (HSS) in calves were compared. Calves received isotonic saline solution (ISS), HSS or D40 (3 calves/group) and were monitored of blood pressure, and cardiac output (CO) for 180 min. HSS and D40 infusions induced a significant increase in relative plasma volume reaching 134.9 +/- 2.8 and 125.0 +/- 1.9%, respectively at the end of fluid infusion. In the HSS group, CO, cardiac index (CI) and stroke volume (SV) remained constant at low levels after 90 minutes despite the maximal values of CO, CI and SV at the end of infusion, reaching 21.0 +/- 6.3 l/min (p<0.05), 177.8 +/- 14.2 ml/min/kg (p < 0.001) and 0.20 +/- 0.03 l/beat (at t = 10 min, p < 0.001), respectively. In contrast, CI and SV in the D40 group showed significant increases to 14.7 +/- 2.9 l/min and 153.5 +/- 17.2 ml/min/kg, respectively, at the end of fluid infusion. And those values remained constant at higher levels than those of the before infusions values throughout the experimental periods. Positive effects for hemodynamic alternations of D40 in calf practice were milder and longer than those of HSS. Therefore, the D40 infusion should be explored as a possible treatment for dehydrated calves, since rapid infusion of D40 may be safe and more beneficial for rehydrating more than HSS treatment.

Ureteral ligation prevents the haemodynamic effect of frusemide in pentobarbitol anaesthetised horses.

Frusemide reduces pulmonary vascular pressures in resting horses and attenuates exercise-induced increases in these pressures in exercising horses. The mechanism underlying these effects of frusemide is unclear. We tested the hypothesis that the haemodynamic effects of frusemide are dependent on diuresis by examining the effect of frusemide in anaesthetised horses in which diuresis was prevented by ligation of ureters. Twenty four horses were assigned randomly to one of 4 treatments: 1) frusemide (1 mg/kg bwt i.v.) and intact ureters; 2) frusemide and ligated ureters; 3) saline placebo and ligated ureters; and 4) frusemide and phenylbutazone (4.4 mg/kg bwt i.v. 12 h and 15 min before frusemide) and ligated ureters. Frusemide administration to anaesthetised horses with intact ureters increased plasma total protein concentration and reduced mean right atrial, pulmonary artery and aortic pressures. There was no significant effect of frusemide administration on haemodynamic variables or plasma total protein concentration in horses with ligated ureters. The combination of frusemide and phenylbutazone increased mean right atrial, pulmonary artery and aortic pressures in horses with ligated ureters. This study demonstrates that, in anaesthetised horses, the haemodynamic effect of frusemide is dependent upon diuresis. We interpret these results as providing further evidence that the haemodynamic effect of frusemide in horses is attributable to a reduction in plasma and blood volume.

Evaluation of isotonic sodium bicarbonate solution for alkalizing effects in conscious calves.

After intravenous (i.v.) infusion of various volumes of 1.35%-isotonic sodium bicarbonate solution (ISB), acid-base equilibrium, blood pressure, plasma volume and biochemical parameters in healthy Holstein calves were studied. Four calves each were randomly assigned to the low-dose (LD; i.v. infusion of 5 ml/kg ISB), middle-dose (MD; i.v. infusion of 10 ml/kg ISB) and the high-dose groups (HD; i.v. infusion of 15 ml/kg ISB). Administration volumes of ISB in the LD, MD and HD groups were decided based on the first half volumes of 5, 10 and 15 mEq of base requirement by the acceptable equation. Systemic, pulmonary artery and central venous pressures, cardiac output and plasma osmotic pressure were not changed by ISB infusion and remained constant throughout the experiment for all groups. There was good correlation (r(2) = 0.950) between relative changes in base excess and infused volume of bicarbonate (y=2.491x). The coefficient of distribution for bicarbonate ions was calculated to be 0.401 (=1/2.491). Therefore, it is suggested that a value of 0.4 would be most appropriate when calculating the base requirements in calves. Therefore, the first half volumes of ISB correcting base deficits of 5, 10 and 15 mEq in calves were estimated to be 6, 12 and 18 ml/kg, respectively. On the basis of the findings in this study, ISB may be used to correct metabolic acidosis without altering the plasma osmotic pressure, hemodynamic status and respiratory function in the calves.