Search Results

You are looking at 1 - 8 of 8 items for

  • Author or Editor: Joseph J. Bertone x
  • Refine by Access: All Content x
Clear All Modify Search

SUMMARY

Blood constituents and vascular volume indices were determined in 5 standing horses by use of 2-period crossover experimental design. Horses were either administered hypertonic (2,400 mosm/kg of body weight, iv) or isotonic (300 mosm/kg, iv) saline solution. Each solution was administered at a dosage of 5 ml/kg (infusion rate, 80 ml/min). Samples for determination of pcv, plasma volume, blood volume, plasma osmolality, total amount of plasma protein and plasma concentrations of protein, Na, K, and Cl were collected at 0 hour (baseline, before fluid infusion) and 0.5 hour (at the end of fluid infusion), and subsequently, at 0.25- or 0.5-hour intervals for 4.5 hours. All horses were given the predetermined dose of fluids by 0.5 hour after beginning the saline infusion. Values of P ≤ 0.05 were considered significant.

Administration of hypertonic saline solution was associated with decreased mean body weight by 4.5 hours, but weight change after isotonic saline administration was not significant. Other than body weight and plasma protein concentration, between-trial difference (treatment effect) was not observed for any measured variable or index. The F values indicated that increasing the number of horses would have not changed these results. A time effect was evident across both trials, so that mean (±sd) plasma volume increased (12.3 ± 1.07%) and mean plasma protein concentration (−12.1 ± 1.03%) and pcv (−11.9 + 0.67%) decreased proportionately and transiently in association with administration of either fluid at that volume. Other time effects included increased plasma osmolality and Na and Cl concentrations. Blood volume estimates and total amount of plasma protein remained unchanged. These data indicate that in conscious clinically normal horses, changes in plasma protein concentration reflect changes in plasma volume and that blood volume may be regulated by alterations in plasma volume and red cell mass. These data also indicate that changes in plasma volume and constituent concentrations may be similar in response to administration of either 0.9% (300 mosm/kg) or 7.2% (2,400 mosm/kg) NaCl solutions (5 ml/kg) and that clinically normal horses can rapidly regulate variable Na loads.

Free access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To use noninvasive approaches to assess stress in New York City (NYC) carriage horses during the course of their daily routine to determine whether use of these horses affected their well-being.

DESIGN Prospective case control study.

ANIMALS 13 (5 mares and 8 geldings) stabled working NYC carriage horses and 5 pastured (nonworking) NYC carriage horses (1 mare and 4 geldings).

PROCEDURES Samples for determination of fecal glucocorticoid and salivary cortisol concentrations were collected on 3 successive days from 10, 8, and 9 working carriage horses during rest (time 1), preparation for work (time 2), and return to the stable (time 3) and at 1 hour after work (time 4). Infrared thermography (IRT) measurements were made to determine maximum temperature of the medial canthus at each time point. Fecal samples were also collected from 5 pastured carriage horses for determination of glucocorticoid concentrations.

RESULTS No difference was found in mean ± SE fecal glucocorticoid concentrations between pastured (22.1 ± 9.8 ng/g) and working (19.5 ± 4.2 ng/g) carriage horses. A significant difference was found in salivary cortisol concentrations of working carriage horses between time 3 (0.96 ± 0.06 ng/mL) and time 4 (0.77 ± 0.07 ng/mL). The IRT measurement at time 2 (35.5 ± 0.64°C [95.9 ± 1.2°F]) was significantly lower than that at time 3 (36.2 ± 0.64°C [97.1 ± 1.2°F]). No other differences in IRT measurements were found.

CONCLUSIONS AND CLINICAL RELEVANCE These working NYC carriage horses did not have physiologic responses indicative of a negative welfare status.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Cardiovascular responses to sublethal endotoxin infusion (Escherichia coli, 50 μg/ml in lactated Ringer solution at 100 ml/h until pulmonary arterial pressure increased by 10 mm of Hg) were measured 2 times in 5 standing horses. In a 2-period crossover experimental design, horses were either administered hypertonic (2,400 mosm/kg of body weight, iv) or isotonic (300 mosm/kg, iv) NaCl solution after endotoxin challenges. Each solution was administered at a dose of 5 ml/kg (infusion rate, 80 ml/min). Complete data sets (mean arterial, central venous, and pulmonary arterial pressures, pulmonary arterial blood temperature, cardiac output, total peripheral vascular resistance, heart rate, plasma osmolality, plasma concentration of Na, K, Cl, and total protein, blood lactate concentration, and pcv) were collected at 0 (baseline, before endotoxin infusion), 0.25, 1, 1.5, 2, 2.5, 3, 3.5, 4, and 4.5 hours after initiation of the endotoxin infusion. Blood constituents alone were measured at 0.5 hour and cardiovascular variables alone were evaluated at 0.75 hour. By 0.25 hour, endotoxin infusion was completed, a data set was collected, and saline infusion was initiated. By 0.75 hour, saline solutions had been completely administered.

Mean (± sem) cardiac output decreased (99.76 ± 3.66 to 72.7 ± 2.35 ml/min/kg) and total peripheral resistance (1.0 ± 0.047 to 1.37 ± 0.049 mm of Hg/ml/min/kg) and pulmonary arterial pressure (33.4 ± 0.86 to 58.3 ± 1.18 mm of Hg) increased for both trials by 0.25 hour after initiation of the endotoxin infusion and prior to fluid administration. For the remainder of the protocol, cardiac output was increased and total peripheral resistance was decreased during the hypertonic, compared with the isotonic, saline trial. Cardiac output was decreased and total peripheral resistance was increased during the isotonic saline trial, compared with baseline values. Both trials were associated with increased blood lactate concentration, but lactate values during the isotonic saline trial were greater and remained increased above baseline values for a longer period (4 hours) than during the hypertonic saline trial (2.5 hours). It was concluded for this model of endotoxemia, that iv administered hypertonic saline solution was associated with more-desirable cardiovascular and metabolic responses than was an equal volume of isotonic saline solution.

Free access
in American Journal of Veterinary Research

SUMMARY

The relevance of site and the influence of exercise on third carpal articular cartilage proteoglycan (pg) were assessed in 16 horses. Six horses were exercised (exercised group) for 30 minutes, 3 times/wk, for 6 weeks. The other 10 horses (nonexercised group) were housed in box stalls for the same 6-week period. At week 6, articular cartilage from the proximal surface of the right third carpal bone was harvested and cultured with radioactive sulfate to label newly synthesized pg. Endogenous pg was measured by use of a uronic acid assay. Newly synthesized and endogenous pg were characterized by use of Sepharose CL-2B chromatography, composite gel electrophoresis, and/or immunoblot analysis with monoclonal antibody 1C6 directed against the hyaluronic acid-binding region on pg.

There was a significant (P = 0.0002) effect of exercise, but not site, on newly synthesized pg, which was increased in the exercised horses, compared with the nonexercised horses at the end of the 6-week study period. The increase in newly synthesized pg was not reflected in the existing cartilage matrix as there was no significant difference between groups in endogenous pg. However, there was a significant (P = 0.01) effect of site on endogenous pg, with the nest of sites located in the palmar aspect of the radial facet containing a greater concentration of endogenous pg than the nests of sites located on the dorsal aspect of the radial facet or all sites on the intermediate facet. Most newly synthesized pg in both groups consisted of hydrodynamically small pg monomers. However, there was a change in the profile of newly synthesized pg at some sites in the exercised horses to include an early elution peak on Sepharose CL-2B, which may contain aggregating pg. All sites in both groups contained a diverse population of endogenous large and small pg on toluidine blue-stained composite gels that reacted with monoclonal antibody 1C6, indicating the potential to bind to hyaluronic acid.

Free access
in American Journal of Veterinary Research