Body fluids in horses encompass a variety of liquid substances that play integral roles in maintaining physiological balance and supporting vital functions. These fluids include blood, lymph, synovial fluid, cerebrospinal fluid, and gastrointestinal secretions, each serving distinct purposes in the equine body. Blood circulates nutrients and oxygen to tissues while removing waste products. Lymph is involved in immune responses and the transport of lipids. Synovial fluid lubricates joints, facilitating smooth movement. Cerebrospinal fluid protects the brain and spinal cord, providing a cushioning effect. Gastrointestinal secretions aid in digestion and nutrient absorption. This page compiles peer-reviewed research studies and scholarly articles that investigate the composition, function, and clinical relevance of body fluids in equine health and disease.
Kuroda T, Minamijima Y, Niwa H, Mita H, Tamura N, Fukuda K, Kuwano A, Sato F.Cephalothin (CET) concentrations in body fluids (plasma, synovial fluid, pleural fluid, peritoneal fluid, and aqueous humor) and tissue samples (bone, lung, jejunum, hoof, and subcutaneous tissue) were investigated to consider the treatment of infectious diseases in horses. CET 22 mg/kg body weight was intravenously administered to 12 horses. Samples were collected from four different horses at 1, 3, and 5 hr after administration. The CET concentration in body fluids other than aqueous humor was maintained above the MIC90 values of Streptococcus zooepidemicus and Staphylococcus aureus until 5 ...
Waller AP, Lindinger MI.Exercise results in rapid and large extracellular to intracellular fluid shifts, as well as significant sweating losses of water and ions. It is unknown whether ions within oral electrolyte supplements are taken up by muscle (and other soft tissues) and whether oral supplementation can effectively offset sweating losses. Pre-loading with 8 L of a balanced hypotonic electrolyte supplement attenuated extracellular fluid losses, increased exercise duration and increased sweating fluid and ion losses during submaximal exercise. Supplemented electrolytes appear in skeletal muscle within 1 h after...
McCrae P, Guigand C, Jones KB, Thueson ES, Troudt TA, Warlick LM, Sides RH, Jones JH, Bayly WM, Léguillette R.High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) ( = 0.007, = 0.007), e...
Latman NS, Keith N, Nicholson A, Davis M.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 ...
Passler NH, Chan HM, Stewart AJ, Duran SH, Welles EG, Lin HC, Ravis WR.The purpose of this study was to assess safety and alterations in body fluid concentrations of voriconazole in normal horses on days 7 and 14 following once daily dose of 4 mg/kg of voriconazole orally for 14 days. Body fluid drug concentrations were determined by the use of high performance liquid chromatography (HPLC). On day 7, mean voriconazole concentrations of plasma, peritoneal, synovial and cerebrospinal fluids, aqueous humor, epithelial lining fluid (ELF), and urine were 1.47 +/- 0.63, 0.61 +/- 0.22, 0.70 +/- 0.20, 0.62 +/- 0.26, 0.55 +/- 0.32, 79.45 +/- 69.4, and 1.83 +/- 0.44 microg...
Maes A, Garré B, Desmet N, van der Meulen K, Nauwynck H, De Backer P, Croubels S.Two methods are presented for the determination of 'respectively' the plasma protein unbound and total concentration of acyclovir in horse plasma and body fluids: first, a liquid-liquid extraction was performed on plasma, combined with HPLC-fluorescence detection for the total plasma concentration; second a more sensitive method using high-performance liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) was described for plasma and for body fluids analysis. To obtain the unbound concentration of acyclovir in plasma, a simple deproteinizati...
Colitz CM, Latimer FG, Cheng H, Chan KK, Reed SM, Pennick GJ.To determine the pharmacokinetics of voriconazole following IV and PO administration and assess the distribution of voriconazole into body fluids following repeated PO administration in horses. Methods: 6 clinically normal adult horses. Methods: All horses received voriconazole (10 mg/kg) IV and PO (2-week interval between treatments). Plasma voriconazole concentrations were determined prior to and at intervals following administration. Subsequently, voriconazole was administered PO (3 mg/kg) twice daily for 10 days to all horses; plasma, synovial fluid, CSF, urine, and preocular tear film con...
Adams AR, Haines GR, Brown MP, Gronwall R, Merritt K.Pharmacokinetics of difloxacin and its distribution within the body fluids and endometrium of 6 mares were studied after intragastric (IG) administration of 5 individual doses. Difloxacin concentrations were serially measured in serum, urine, peritoneal fluid, synovial fluid, cerebrospinal fluid, and endometrium over 120 h. Bacterial susceptibility to difloxacin was determined for 174 equine pathogens over a 7-month period. Maximum serum concentration (Cmax) was 2.25 +/- 0.70 microg/mL at 3.12 +/- 2.63 h and Cmax after the 5th dose was 2.41 +/- 0.86 microg/mL at 97.86 +/- 1.45 h. The mean elim...
Jacks S, Giguère S, Gronwall PR, Brown MP, Merritt KA.To determine the pharmacokinetics of azithromycin and its concentration in body fluids and bronchoalveolar lavage cells in foals. Methods: 6 healthy 6- to 10-week-old foals. Methods: Azithromycin (10 mg/kg of body weight) was administered to each foal via i.v. and intragastric (i.g.) routes in a crossover design. After the first i.g. dose, 4 additional i.g. doses were administered at 24-hour intervals. A microbiologic assay was used to measure azithromycin concentrations in serum, peritoneal fluid, synovial fluid, pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. Resul...
Johnson PJ.This article presents a brief overview of the physiology of homeostasis in the horse and discusses the units of measurement by which dissolved electrolytes are assessed. Differences in electrolyte composition between compartments of the body and the manner in which water is exchanged between them are reviewed. The mechanisms by which alterations in osmolality and effective circulating volume are detected and the physiological responses to those alterations are presented.
McCutcheon LJ, Geor RJ.The objectives of this study were to: 1) determine incremental and total sweat fluid and ion losses during and following (a) exercise training and (b) a treadmill Speed and Endurance exercise test (SEET) which simulated running speeds and distances required for each phase of an Olympic level (CCI****) 3-day-event in cool and hot ambient conditions and 2) determine the requirement for ion supplementation based on the calculated ion losses associated with these activities. Six exercise-trained Thoroughbred horses completed 2 weeks of exercise training in each of 2 ambient conditions: cool, dry (...
Giguère S, Sweeney RW, Bélanger M.To investigate the pharmacokinetics of enrofloxacin in adult horses. Methods: 2-dose oral and i.v. cross-over trial followed by multiple oral doses. Methods: 8 clinically normal adult horses. Methods: Enrofloxacin was administered at dosages of 2.5 mg/kg of body weight to 4 horses and 5.0 mg/kg to 4 other horses. Each dose was given by the intragastric and i.v. routes, using a cross-over design. After the first intragastric dose, 5 additional doses were administered at 12-hour intervals. Enrofloxacin concentrations were measured in serum, synovial fluid, peritoneal fluid, urine, CSF, and endom...
McCutcheon LJ, Geor RJ, Hare MJ, Ecker GL, Lindinger MI.The objective of this study was to determine the composition and extent of sweat losses during submaximal exercise under hot and humid conditions and to compare these findings with the same exercise protocol conducted under cool, dry and hot, dry conditions. Five Thoroughbred horses (age 3 to 6) completed exercise tests under each of 3 environmental conditions in random order: cool, dry (CD), room temperature (T) = 20 degrees C, relative humidity (RH) = 45-55%; hot, dry (HD), T = 32-34 degrees C, RH = 45-55%; and hot, humid (HH), T = 32-34 degrees C, RH = 80-85%. Horses exercised at 50% of the...
Dowling PM, Wilson RC, Tyler JW, Duran SH.The pharmacokinetics of ciprofloxacin was investigated in healthy, mature ponies. Ciprofloxacin was administered intravenously to six ponies at a dose of 5 mg per kg body weight. Seven days later, ciprofloxacin was administered orally to each pony at the same dose. Intravenous ciprofloxacin concentration vs. time data best fit a two-compartment open model with first-order elimination from the central compartment. Mean plasma half-life, based on the terminal phase, was 157.89 min (harmonic mean). Total body clearance of ciprofloxacin was 18.12 +/- 3.99 mL/min/kg. Volume of distribution at stead...
Bourdon R.Toxicomania and doping give rise to an increasing number of drug measurements in the body fluids. Consequently the analysts have to face, at one and the same time, ethical and analytical problems. Should the analyst participate to investigations organised in order to disclose a toxicomania in a working place? The author suggests a positive answer as long as the adduct person benefits to a social and medical care. What is the analytical meaning of a positive test? Taking into account the increasing sensitivity of the methods used, thresholds have to be established, at least for the blood concen...
Dunkle NJ, Bottoms GD, Fessler JF, Knox K, Roesel OF.A study was conducted to determine whether body fluids undergo a net shift from one compartment to another during endotoxin-induced shock in the pony, and whether flunixin meglumine alters these endotoxin-induced changes in the volumes of body fluid compartments. Total blood, RBC, and plasma volumes were determined, using 51Cr-labeled RBC and PCV that were corrected for trapped plasma. Total body water was measured by distribution of 3HOH. Arterial blood pressure was measured directly, using a blood pressure transducer. Treatment (flunixin meglumine, 1.1 mg/kg of body weight) was given to 6 of...
Spurlock GH, Landry SL, Sams R, McGuirk S, Muir WW.Plasma volume, extracellular fluid volume (ECFV), and total body water (TBW) were measured before and after endotoxin (Escherichia coli) administration in 6 conscious adult horses. Evan's blue dye, sodium thiocyanate, and antipyrine were the test substances used to estimate plasma volume, ECFV, and TBW, respectively. Pharmacokinetic analysis of plasma concentration vs time was used to determine changes in body fluid compartments. The pathophysiologic effects of endotoxin were monitored by clinical evaluation, blood chemical changes, and blood gas determinations. All horses became dyspneic with...
Giguère S, Sweeney RW, Bélanger M.To investigate the pharmacokinetics of enrofloxacin in adult horses. Methods: 2-dose oral and i.v. cross-over trial followed by multiple oral doses. Methods: 8 clinically normal adult horses. Methods: Enrofloxacin was administered at dosages of 2.5 mg/kg of body weight to 4 horses and 5.0 mg/kg to 4 other horses. Each dose was given by the intragastric and i.v. routes, using a cross-over design. After the first intragastric dose, 5 additional doses were administered at 12-hour intervals. Enrofloxacin concentrations were measured in serum, synovial fluid, peritoneal fluid, urine, CSF, and endom...
McCutcheon LJ, Geor RJ, Hare MJ, Ecker GL, Lindinger MI.The objective of this study was to determine the composition and extent of sweat losses during submaximal exercise under hot and humid conditions and to compare these findings with the same exercise protocol conducted under cool, dry and hot, dry conditions. Five Thoroughbred horses (age 3 to 6) completed exercise tests under each of 3 environmental conditions in random order: cool, dry (CD), room temperature (T) = 20 degrees C, relative humidity (RH) = 45-55%; hot, dry (HD), T = 32-34 degrees C, RH = 45-55%; and hot, humid (HH), T = 32-34 degrees C, RH = 80-85%. Horses exercised at 50% of the...
Dowling PM, Wilson RC, Tyler JW, Duran SH.The pharmacokinetics of ciprofloxacin was investigated in healthy, mature ponies. Ciprofloxacin was administered intravenously to six ponies at a dose of 5 mg per kg body weight. Seven days later, ciprofloxacin was administered orally to each pony at the same dose. Intravenous ciprofloxacin concentration vs. time data best fit a two-compartment open model with first-order elimination from the central compartment. Mean plasma half-life, based on the terminal phase, was 157.89 min (harmonic mean). Total body clearance of ciprofloxacin was 18.12 +/- 3.99 mL/min/kg. Volume of distribution at stead...
Jacks S, Giguère S, Gronwall PR, Brown MP, Merritt KA.To determine the pharmacokinetics of azithromycin and its concentration in body fluids and bronchoalveolar lavage cells in foals. Methods: 6 healthy 6- to 10-week-old foals. Methods: Azithromycin (10 mg/kg of body weight) was administered to each foal via i.v. and intragastric (i.g.) routes in a crossover design. After the first i.g. dose, 4 additional i.g. doses were administered at 24-hour intervals. A microbiologic assay was used to measure azithromycin concentrations in serum, peritoneal fluid, synovial fluid, pulmonary epithelial lining fluid (PELF), and bronchoalveolar (BAL) cells. Resul...
Dunkle NJ, Bottoms GD, Fessler JF, Knox K, Roesel OF.A study was conducted to determine whether body fluids undergo a net shift from one compartment to another during endotoxin-induced shock in the pony, and whether flunixin meglumine alters these endotoxin-induced changes in the volumes of body fluid compartments. Total blood, RBC, and plasma volumes were determined, using 51Cr-labeled RBC and PCV that were corrected for trapped plasma. Total body water was measured by distribution of 3HOH. Arterial blood pressure was measured directly, using a blood pressure transducer. Treatment (flunixin meglumine, 1.1 mg/kg of body weight) was given to 6 of...
McCutcheon LJ, Geor RJ.The objectives of this study were to: 1) determine incremental and total sweat fluid and ion losses during and following (a) exercise training and (b) a treadmill Speed and Endurance exercise test (SEET) which simulated running speeds and distances required for each phase of an Olympic level (CCI****) 3-day-event in cool and hot ambient conditions and 2) determine the requirement for ion supplementation based on the calculated ion losses associated with these activities. Six exercise-trained Thoroughbred horses completed 2 weeks of exercise training in each of 2 ambient conditions: cool, dry (...
Colitz CM, Latimer FG, Cheng H, Chan KK, Reed SM, Pennick GJ.To determine the pharmacokinetics of voriconazole following IV and PO administration and assess the distribution of voriconazole into body fluids following repeated PO administration in horses. Methods: 6 clinically normal adult horses. Methods: All horses received voriconazole (10 mg/kg) IV and PO (2-week interval between treatments). Plasma voriconazole concentrations were determined prior to and at intervals following administration. Subsequently, voriconazole was administered PO (3 mg/kg) twice daily for 10 days to all horses; plasma, synovial fluid, CSF, urine, and preocular tear film con...
Passler NH, Chan HM, Stewart AJ, Duran SH, Welles EG, Lin HC, Ravis WR.The purpose of this study was to assess safety and alterations in body fluid concentrations of voriconazole in normal horses on days 7 and 14 following once daily dose of 4 mg/kg of voriconazole orally for 14 days. Body fluid drug concentrations were determined by the use of high performance liquid chromatography (HPLC). On day 7, mean voriconazole concentrations of plasma, peritoneal, synovial and cerebrospinal fluids, aqueous humor, epithelial lining fluid (ELF), and urine were 1.47 +/- 0.63, 0.61 +/- 0.22, 0.70 +/- 0.20, 0.62 +/- 0.26, 0.55 +/- 0.32, 79.45 +/- 69.4, and 1.83 +/- 0.44 microg...
Maes A, Garré B, Desmet N, van der Meulen K, Nauwynck H, De Backer P, Croubels S.Two methods are presented for the determination of 'respectively' the plasma protein unbound and total concentration of acyclovir in horse plasma and body fluids: first, a liquid-liquid extraction was performed on plasma, combined with HPLC-fluorescence detection for the total plasma concentration; second a more sensitive method using high-performance liquid chromatography combined with heated electrospray ionization tandem mass spectrometry (LC-HESI-MS/MS) was described for plasma and for body fluids analysis. To obtain the unbound concentration of acyclovir in plasma, a simple deproteinizati...
Waller AP, Lindinger MI.Exercise results in rapid and large extracellular to intracellular fluid shifts, as well as significant sweating losses of water and ions. It is unknown whether ions within oral electrolyte supplements are taken up by muscle (and other soft tissues) and whether oral supplementation can effectively offset sweating losses. Pre-loading with 8 L of a balanced hypotonic electrolyte supplement attenuated extracellular fluid losses, increased exercise duration and increased sweating fluid and ion losses during submaximal exercise. Supplemented electrolytes appear in skeletal muscle within 1 h after...
Latman NS, Keith N, Nicholson A, Davis M.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 ...
Bourdon R.Toxicomania and doping give rise to an increasing number of drug measurements in the body fluids. Consequently the analysts have to face, at one and the same time, ethical and analytical problems. Should the analyst participate to investigations organised in order to disclose a toxicomania in a working place? The author suggests a positive answer as long as the adduct person benefits to a social and medical care. What is the analytical meaning of a positive test? Taking into account the increasing sensitivity of the methods used, thresholds have to be established, at least for the blood concen...
Spurlock GH, Landry SL, Sams R, McGuirk S, Muir WW.Plasma volume, extracellular fluid volume (ECFV), and total body water (TBW) were measured before and after endotoxin (Escherichia coli) administration in 6 conscious adult horses. Evan's blue dye, sodium thiocyanate, and antipyrine were the test substances used to estimate plasma volume, ECFV, and TBW, respectively. Pharmacokinetic analysis of plasma concentration vs time was used to determine changes in body fluid compartments. The pathophysiologic effects of endotoxin were monitored by clinical evaluation, blood chemical changes, and blood gas determinations. All horses became dyspneic with...
Adams AR, Haines GR, Brown MP, Gronwall R, Merritt K.Pharmacokinetics of difloxacin and its distribution within the body fluids and endometrium of 6 mares were studied after intragastric (IG) administration of 5 individual doses. Difloxacin concentrations were serially measured in serum, urine, peritoneal fluid, synovial fluid, cerebrospinal fluid, and endometrium over 120 h. Bacterial susceptibility to difloxacin was determined for 174 equine pathogens over a 7-month period. Maximum serum concentration (Cmax) was 2.25 +/- 0.70 microg/mL at 3.12 +/- 2.63 h and Cmax after the 5th dose was 2.41 +/- 0.86 microg/mL at 97.86 +/- 1.45 h. The mean elim...
Kuroda T, Minamijima Y, Niwa H, Mita H, Tamura N, Fukuda K, Kuwano A, Sato F.Cephalothin (CET) concentrations in body fluids (plasma, synovial fluid, pleural fluid, peritoneal fluid, and aqueous humor) and tissue samples (bone, lung, jejunum, hoof, and subcutaneous tissue) were investigated to consider the treatment of infectious diseases in horses. CET 22 mg/kg body weight was intravenously administered to 12 horses. Samples were collected from four different horses at 1, 3, and 5 hr after administration. The CET concentration in body fluids other than aqueous humor was maintained above the MIC90 values of Streptococcus zooepidemicus and Staphylococcus aureus until 5 ...
Johnson PJ.This article presents a brief overview of the physiology of homeostasis in the horse and discusses the units of measurement by which dissolved electrolytes are assessed. Differences in electrolyte composition between compartments of the body and the manner in which water is exchanged between them are reviewed. The mechanisms by which alterations in osmolality and effective circulating volume are detected and the physiological responses to those alterations are presented.
McCrae P, Guigand C, Jones KB, Thueson ES, Troudt TA, Warlick LM, Sides RH, Jones JH, Bayly WM, Léguillette R.High pulmonary blood pressure contributes to exercise-induced pulmonary hemorrhage. The objective of this study was to use bioimpedance spectroscopy to assess body fluid compartment volumes under 3 conditions in 6 racehorses: i) Pre- and post-supramaximal treadmill exercise (control); ii) Exercise 4 hours after furosemide (0.5 mg/kg body weight, IV); iii) Exercise, removal of ~14 L of blood and subsequent reinfusion of the blood. Statistical analysis used linear mixed effects models. Body compartment volumes did not change during the control runs. Total body water (TBW) ( = 0.007, = 0.007), e...
