Renal health in horses encompasses the study of kidney function, disorders, and their management in equine species. The kidneys are vital organs responsible for filtering waste products from the blood, regulating fluid balance, and maintaining electrolyte levels. Renal disorders in horses can arise from various causes, including dehydration, toxins, infections, and congenital abnormalities. Common conditions affecting equine renal health include acute kidney injury and chronic kidney disease. Diagnostic methods often involve blood tests, urinalysis, and imaging techniques to assess kidney function and structure. This page gathers peer-reviewed research studies and scholarly articles that explore the physiology, pathology, and therapeutic approaches related to renal health in horses.
Byars TD, Simpson JS, Divers TJ, Shiner KA, Rantanen NW.Percutaneous nephrostomy was used to provide urine output in a 3-year-old Thoroughbred filly with azotemia and obstructive ureterolithiasis. Previous left ureteral surgery had failed to provide clinical improvement, and the filly became more azotemic. Nephrostomy was performed in the standing patient, with ultrasonographic guidance and local anesthesia. Continuing IV fluid therapy and diuresis through the nephrostomy tube resulted in a decrease in clinical signs of azotemia. However, the filly developed a cecal impaction, which ruptured during surgery because of colic, and was euthanatized.
Crews HM, Dean JR, Ebdon L, Massey RC.The speciation of cadmium in retail pig kidney has been examined by size-exclusion chromatography (SEC) coupled directly to inductively coupled plasma mass spectrometry (ICP-MS). Approximately 35% of the cadmium from uncooked kidney was soluble after aqueous extraction at pH 8 and SEC - ICP-MS revealed three discrete peaks whose retention times corresponded to estimated relative molecular masses of 1.2 x 10(6), 7.0 x 10(4) and 6 x 10(3)-9 x 10(3). In the cooked kidney, 35% of the Cd was soluble and was all associated with a peak of a relative molecular mass (Mr) of 6 x 10(3)-9 x 10(3). After s...
Cantor GH, Palmer GH, Fenwick BW.The concentrations of several post mortem aqueous humour chemical constituents were compared with ante mortem serum chemical values in the horse. Urea nitrogen and creatinine values in post mortem aqueous humour were good predictors of ante mortem serum values. Aqueous humour urea nitrogen increased only slightly and creatinine did not change significantly for up to 24 h after death. Formulae were derived for calculating estimated ante mortem serum urea nitrogen and creatinine from aqueous humour values obtained after death. These results from normal horses identify analytes that are accurate ...
Koizumi N, Inoue Y, Ninomiya R, Fujita D, Tsukamoto T.The concentrations of Cd, Zn, Cu, and metallothionein (MT) in the liver, renal cortex, and renal medulla were determined in 24 male and 15 female younger thoroughbreds (age 27 to 97 months) and two old male horses (age 154 months and 190 months). High correlations were found between Zn and MT in the liver (partial correlation coefficient 0.836), between Cd and MT in the renal cortex (partial correlation coefficient 0.786), and between Cd and Zn in the renal cortex (partial correlation coefficient 0.675), while the correlation between Cd and MT in the liver was low (partial correlation coeffici...
Trim CM, Moore JN, Clark ES.An ultrasonic flow probe was implanted around a branch of the left renal artery in five horses. The effects of dopamine were studied in the unsedated horses 10 days after surgery. Three experiments, separated by at least two days, were performed in random order on each horse. In two experiments, dopamine was infused intravenously for 60 mins at either 2.5 and 5.0 micrograms/kg bodyweight (bwt)/min. Saline was infused for 60 mins before and after each infusion, and for 180 mins in the third experiment as a control. Renal blood flow increased during administration of dopamine at both dose rates ...
Edwards DJ, Love DN, Raus J, Baggott JD.Neomycin was administered intramuscularly to four normal adult horses at a dose rate of 10 mg/kg bodyweight every 12 h for 10 days (21 doses). The pharmacokinetic behaviour of neomycin with multiple dosing was characterised and a range of blood chemical and urinary parameters examined for evidence of nephrotoxicity. There was evidence of physical renal tubular injury (enzymuria and cylindriuria) within four days of neomycin administration but this subsided following cessation of treatment. No significant functional nephrotoxicity was detected. More severe nephrotoxicity might be expected in il...
Voss KA, Norred WP, Plattner RD, Bacon CW.Currently there is no convenient bioassay to determine the potential toxicity of corn naturally contaminated with Fusarium moniliforme. A short-term bioassay would be useful for future investigations aimed at isolating as yet unidentified toxins produced by this fungus. Two groups of five male Sprague-Dawley rats were each fed one of two F. moniliforme contaminated corn samples, designated CS-1 and CS-2, that were associated with separate field cases of equine leukoencephalomalacia (ELEM). A control group, also consisting of five male rats, was fed uncontaminated seed corn. All animals survive...
Edwards DJ, Brownlow MA, Hutchins DR.Urine and blood samples were taken at the same time from normal adult horses presented for routine investigations to establish reference values for a variety of parameters reported to be useful in the clinical evaluation of renal function. Blood biochemical values were consistent with previous studies and had well-defined normal ranges. Parameters representing urine concentration and electrolyte excretion however, varied widely reflecting the ability of the healthy kidney to change the composition of urine in response to differences in environment and management. Percent creatinine clearance r...
Whitwell KE, Harris P, Farrington PG.Four out of 12 horses grazing a field in Berkshire, England, suffered a prostrating illness and died within 12 to 72 h. Serum biochemical abnormalities, including markedly elevated muscle enzymes, were demonstrated and at post mortem widespread myodegeneration was found in both skeletal muscle and myocardium. Urine analysis revealed myoglobinuria, and renal changes were seen histologically. Although similar pathologically, the clinical syndrome and circumstances of the outbreak were not typical of equine exertional rhabdomyolysis (EER). The outbreak bore a striking resemblance to other reporte...
Sloet van Oldruitenborgh-Oosterbaan MM, Kalsbeek HC.A 14-year-old Friesian breeding mare had strangury, depression, inappetence, neutrophilia and uraemia. Its urine had a low specific gravity and contained protein, blood cells and bacteria. Rectal examination showed that both kidneys and ureters were enlarged. Post mortem examination confirmed the diagnosis of pyelonephritis and revealed that small tumours in the vulva were probably the cause of the uropathy.
Anderson WI, Picut CA, Georgi ME.Heavy renal infection in a pony with Klosiella equi resulted in moderate diffuse tubular nephrosis and tubular rupture. Multifocal non-suppurative interstitial nephritis was associated with ruptured tubules. Ultrastructural examination of sporoblasts demonstrated both the presence of a bilaminated membrane encasing organisms and nuclear budding. Endogenous corticosteroid production probably led to the development of an immune-compromized state and subsequent extensive parasitic replication.
Clarke LL, Ganjam VK, Fichtenbaum B, Hatfield D, Garner HE.The effect of feeding frequency and associated meal size on the renin-angiotensin-aldosterone system (RAAS) in seven horses was examined. A daily maintenance ration of hay-grain pellets was provided either as a multiple feeding regimen (MF), in which the ration was divided into six equal portions fed at 4-h intervals, or as a single large feeding (SF) given from 9 A.M. until 11 A.M. Plasma renin activity (PRA), aldosterone (PAC), cortisol (PCC), protein concentration (TP), packed cell volume (PCV), and serum sodium and potassium were measured serially. To prevent significant RAAS stimulation d...
Stover SM, Steffey EP, Dybdal NO, Franti CE.Five horses were anesthetized similarly by use of xylazine, guaifenesin, thiamylal sodium, and halothane in oxygen on 3 consecutive days, and minor surgical procedures were performed. For 1 to 10 days after the last anesthetic exposure, clinical, hematologic, and serum biochemical features were monitored, and after necropsy, histologic examination of major organ tissues was performed. Predominant hematologic changes from base-line values included leukocytosis (maximal at 27 hours, 10,500 +/- 1,750 cells/microliter), neutrophilia (maximal at 51 hours, 7,485 +/- 1,719 cells/microliter), and lymp...
Rapp HJ.During the combination of oral and intravenous application of saline solution for treatment of the COPD of horses the level of hydraemia basing on the total protein concentration in the serum, the urine production and the specific weight of urine was determined. Additionally the development of serum concentration and of renal excretion rates of potassium, calcium and magnesium were ascertained. The level of hydraemia resulting from the combined method is almost identical with the solely intravenous performed hyperinfusion therapy. Due to the excessive application of fluid an extremely high lev...
Smith CM, Steffey EP, Baggot JD, Dunlop CI, Farver TB.Inhalation anesthetics decrease the clearance of some drugs that are eliminated by renal excretion. The purpose of the study reported here was to investigate the effects of halothane anesthesia on the pharmacokinetics and urinary excretion of gentamicin sulfate, using the horse as a model. Using a crossover design, pharmacokinetic values after a single IV dose of gentamicin (4 mg/kg) were compared in halothane-anesthetized and unanesthetized horses. Compared with unanesthetized horses, the anesthetized horses had significant decreases in total body clearance (P less than 0.01) and apparent vol...
Morris CF, Robertson JL, Mann PC, Clark S, Divers TJ.A syndrome characterized clinically by oliguria, progressive severe azotemia, and edema of the abdomen and groin was seen in 2 horses. Treatment with fluids, diuretics, and corticosteroids administered intravenously was ineffective, and the horses were euthanatized. Microscopically, there was severe necrotizing angiopathy with profuse fibrin deposition in renal glomeruli and sinusoids of peripheral lymph nodes. The signs observed in the horses resembled hemolytic-uremic syndrome in human beings.
Kohn CW, Chew DJ.Laboratory evaluation of renal function in horses has advanced dramatically in the last 10 years largely as a result of the interest generated by the creative approach to diagnostic indices taken by Brobst, Traver, Coffman, and others. Some methods of assessing renal function discussed here are clearly outside the scope of a practice environment but are available in referral hospitals for use in difficult or unusual cases. Other methods described, such as calculation of fractional excretions and urine to serum creatinine ratios, are accessible and readily interpreted by the veterinary practiti...
Johnston JK, Neely DP, Latterman SA.A 4.5-month-old Standard-bred filly was referred for evaluation of pigmenturia. Initially, the pigmenturia had resolved with the administration of antibiotics, only to recur after their withdrawal. A dark red urine sample contained numerous RBC, WBC, and gram-negative rods (Escherichia coli). Ultrasonography revealed the right kidney to be large, with multiple cystic structures and a dilated renal pelvis and calices. Cystoscopy revealed a large blood clot within the bladder and urine coming from the left ureteral opening. Urine was not observed coming from the right ureter. It was suspected th...
Bertone JJ, Traub-Dargatz JL, Fettman MJ, Wilke L, Wrigley RH, Jaenke R, Paulsen ME.Sequential reciprocals of serum creatinine concentration and sodium sulfanilate clearance half-times were used to monitor a horse with chronic renal failure. The horse was diagnosed as having polycystic kidney disease; at least one cyst was of distal tubular origin. Using the plots of the sequential data, a reasonably accurate prediction was made for complete renal decompensation to develop.
De Lange JF, Gummow B, Turner GV, Redman AR.This is the first known isolation in the Republic of South Africa (RSA) of the serovar pomona from the organs of porcine foetuses as well as from the renal lymph nodes of slaughter pigs showing chronic nephritis. In addition, the serovar pomona was isolated from the kidneys of 87.5% of the slaughter pigs examined. The success of these isolations was attributed in part to the refining of 2 existing isolation techniques which complement each other. Using the microscopic agglutination test, serum samples taken from the same farming unit showed evidence of antibodies to the serovar pomona in 89 ou...
Hinchcliff KW, McKeever KH, Schmall LM, Kohn CW, Muir WW.We investigated the effects of 1 h of sustained submaximal exertion on the renal and systemic hemodynamics of six horses. The horses ran on a treadmill at a speed that produced heart rates of 55-60% of each horse's maximum heart rate. Exertion produced heart rates of 121 +/- 6.6 and 126 +/- 6.1 (SE) beats/min after 15 and 60 min, respectively. Cardiac output increased significantly (P less than 0.05) from 70.1 +/- 3.1 to 246.2 +/- 4.7 ml.min-1.kg body wt-1 after 15 min of exertion and thereafter did not change. There was no significant change from rest in p-aminohippuric acid and creatinine cl...
Hollis AR, Ousey JC, Palmer L, Stoneham SJ, Corley KT.Norepinephrine is a potent vasopressor that increases arterial blood pressure but may have adverse effects on renal blood flow. The combination of norepinephrine and dobutamine may lead to improved renal perfusion compared to an infusion of norepinephrine alone. The effects of these drugs in the normotensive neonatal foal have not been reported. Objective: Norepinephrine increases arterial blood pressure. Adding dobutamine to a norepinephrine infusion will change the renal profile during the infusions without changing the arterial blood pressure. Methods: Eight conscious Thoroughbred foals wer...
Hardefeldt LY.Four neonatal foals were presented, over a 2-year period, (2011-2012) with aimlessly walking, head pressing, 'chewing gum' seizures and ataxia. The neurological lesion was consistent with increased intracranial pressure in all cases. All foals had severe hyponatraemia and azotaemia identified on biochemistry. Hyponatraemia was transient in 3/4 cases, with the foal in the final case requiring long-term sodium supplementation. Three foals survived to hospital discharge; one was euthanased because of anuric renal failure and one of the surviving foals was euthanased with septic osteomyelitis 2 we...
MacLeay JM, Wilson JH.A 14-year-old Arabian mare was admitted for lethargy, anorexia, and low fecal output. On the basis of laboratory, physical examination, and electrocardiographic findings, diagnoses of type-II renal tubular acidosis (RTA), impaction of the large colon, and ventricular tachycardia were made. Diagnosis of type-II RTA was based on measurement of a low fractional excretion value for potassium and fractional excretion value for sodium within the reference range. In contrast, horses with type-I RTA have high fractional excretion values for sodium and fractional excretion values for potassium within r...
Bozorgmanesh R, Thornton J, Snyder J, Fletcher C, Mack R, Coyne M, Murphy R, Hegarty E, Slovis N.Symmetric dimethylarginine (SDMA) is a renal biomarker correlated with glomerular filtration rate (GFR). Objective: Describe changes in SDMA in clinically healthy foals and their mares during the first month postfoaling. Methods: Convenience sampling of healthy periparturient Thoroughbred mares and their full-term foals from a population of client-owned horses. Methods: Serum and EDTA whole blood samples were collected from mares in their last month of pregnancy and then from mares and foals at approximately <12 hours, 48 hours, 7 days, and 30 days postbirth. Samples were processed ...
Beldoménico HR, Baroni E, Campagnoli DU, Sigrist ME, Rubio M, Boggio JC.In this paper we report the results of surveys conducted in Argentina between 1997 and 1998 to know the Cd concentrations in kidney from horses of different age, sex, and origin. Cd in renal cortex and medulla was positively correlated, and higher concentrations in the cortex were found. No significant differences between values from left and right kidneys of the same animal were found. An increase in Cd levels with age of animals were observed, and no sex incidence was verified in renal Cd composition. No detectable residues were found in the fetuses tested. Levels observed in Argentine equin...
Satué K, Montesinos P, Muñoz A.In women and females of different species of laboratory animals, oestrogens stimulate the renin-angiotensin-aldosterone system (RAAS) by increasing tissue and circulating levels of angiotensinogen and renin during the preovulatory period. Progesterone and cortisol compete with aldosterone for mineralocorticoid receptors, which results in increased Na+ reabsorption during the postovulatory period. The purpose of the current research was to analyse the relationship of oestradiol-17β, progesterone and cortisol with RAAS in 23 mares during an oestrous cycle. During the preovulatory period, signif...
Erkert RS, Macallister CG.Isoxsuprine hydrochloride has been suggested for use in horses for treatment of navicular syndrome and laminitis. The drug has been shown to be a beta-adrenoreceptor antagonist with beta-adrenoreceptor agonistic properties, with both characteristics contributing to vasodilation and uterine relaxation. In addition, the drug is capable of decreasing blood viscosity and platelet aggregation. Studies have shown i.v. isoxsuprine to have a plasma half-life of <3 h with a large apparent volume of distribution. Cardiovascular effects resolve rapidly following i.v. administration, but are absent wit...
Zatzman ML, Clarke L, Ray WJ, Garner HE, Traver D.Simultaneous renal clearances of inulin (CIN), p-aminohippurate (CPAH), and creatinine (CCR) were measured in hydrated mares (6 ponies and 2 horses). The CIN and CPAH were determined during steady-state infusion at 3 different infusion rates. A 6-fold change in plasma IN concentration did not produce alteration in CIN, nor was there a difference between the ponies and horses (P greater than 0.2). The overall average (mean +/- SEM) was 190.6 +/- 5.89 ml . min-1 . 100 kg of body weight-1. There was no difference noted between simultaneous CIN and CPAH. Clearance of PAH remained essentially const...
Olsén L, Ingvast-Larsson C, Bondesson U, Broström H, Tjälve H, Larsson P.The pharmacokinetics of the histamine H(1)-antagonist cetirizine and the effects of pretreatment with the antiparasitic macrocyclic lactone ivermectin on the pharmacokinetics of cetirizine were studied in horses. After oral administration of cetirizine at 0.2 mg/kg bw, the mean terminal half-life was 3.4 h (range 2.9-3.7 h) and the maximal plasma concentration 132 ng/mL (101-196 ng/mL). The time to reach maximal plasma concentration was 0.7 h (0.5-0.8 h). Ivermectin (0.2 mg/kg bw) given orally 1.5 h before cetirizine did not affect its pharmacokinetics. However, ivermectin pretreatment 12 h be...
Kohn CW, Strasser SL.Urine samples were obtained from 6 healthy mares. During a 2-day acclimation period, mares were kept in stalls, fed sweet feed and mixed grass hay, and allowed free access to water and trace mineral salt. The mares were crosstied in their stalls within reach of hay, salt, and water for 24 hours during which urine was obtained by constant flow via indwelling Foley catheters. Twenty-four-hour urine production was 7,649 to 11,904 ml/day (mean = 9,212 +/- 1,9285) or 14.7 to 25.1 mlĝ/day. (mean = 19.3 +/- 4.1). Urinary excretion and clearance of electrolytes and protein were determined from aliquo...
Byars TD, Simpson JS, Divers TJ, Shiner KA, Rantanen NW.Percutaneous nephrostomy was used to provide urine output in a 3-year-old Thoroughbred filly with azotemia and obstructive ureterolithiasis. Previous left ureteral surgery had failed to provide clinical improvement, and the filly became more azotemic. Nephrostomy was performed in the standing patient, with ultrasonographic guidance and local anesthesia. Continuing IV fluid therapy and diuresis through the nephrostomy tube resulted in a decrease in clinical signs of azotemia. However, the filly developed a cecal impaction, which ruptured during surgery because of colic, and was euthanatized.
Sams RA, Detra RL, Muir WW.The pharmacokinetics and metabolism of doxapram in horses administered intravenous (iv) doses of 0.275, 0.55 and 1.1 mg doxapram/kg bodyweight (bwt) were investigated. Plasma doxapram concentrations decreased rapidly after drug administration and the disappearance of doxapram from plasma was best described by a polyexponential equation. Median values of total body clearance were 10.9, 10.6 and 10.9 ml/min/kg bwt for the three doses and were independent of dose. The steady-state volume of distribution was approximately 1,200 ml/kg bwt and the median biological half-life ranged from 121 to 178 m...
This work proposes an application of a minimal complexity physiologically based pharmacokinetic model to predict tramadol concentration vs time profiles in horses. Tramadol is an opioid analgesic also used for veterinary treatments. Researchers and medical doctors can profit from the application of mathematical models as supporting tools to optimize the pharmacological treatment of animal species. The proposed model is based on physiology but adopts the minimal compartmental architecture necessary to describe the experimental data. The model features a system of ordinary differential equations...
Flick M, Vinther AML, Jacobsen S, Berg LC, Gimeno M, Verwilghen D, Howden W, Averay K, van Galen G.Serum neutrophil gelatinase-associated lipocalin (sNGAL) is a marker of renal injury, and its concentrations are affected by inflammation. Therefore, it could serve as a useful biomarker of disease or fitness in high-level competition. However, it has not yet been determined if sNGAL concentrations are affected by exercise. The aim of this study was to determine whether concentrations of equine sNGAL were affected by 1000 m galloping as the form of exercise used in the study. Pre- and post-gallop sNGAL, serum amyloid A, and creatinine concentrations were evaluated in 14 healthy Thoroughbred r...
Edwards DJ, Love DN, Raus J, Baggott JD.Neomycin was administered intramuscularly to four normal adult horses at a dose rate of 10 mg/kg bodyweight every 12 h for 10 days (21 doses). The pharmacokinetic behaviour of neomycin with multiple dosing was characterised and a range of blood chemical and urinary parameters examined for evidence of nephrotoxicity. There was evidence of physical renal tubular injury (enzymuria and cylindriuria) within four days of neomycin administration but this subsided following cessation of treatment. No significant functional nephrotoxicity was detected. More severe nephrotoxicity might be expected in il...
Sarasola P, McKellar QA.Bacampicillin hydrochloride is an ester prodrug that is hydrolyzed to ampicillin after its absorption from the gastrointestinal tract. It was administered intragastrically at a dose rate of 13.5 mg/kg of body weight to ponies and horses, and was highly bioavailable (F = 41.0%), compared with other penicillins in adult horses. The high peak ampicillin plasma concentration of 6.1 +/- 0.5 micrograms/ml achieved and persistence of the antibiotic at concentration of 0.3 +/- 0.1 microgram/ml 6 hours after its intragastric administration, suggest that bacampicillin hydrochloride may reach suitable ba...
Foreman JH, Potter KA, Bayly WM, Liggitt HD.A 7-month-old male Quarter Horse was examined because of severe cachexia, which had begun 2 months earlier. The foal was emaciated and weak despite an excellent appetite. Percutaneous biopsy revealed multiple areas of subcutaneous steatitis with mineralization. Radiography demonstrated calcification of the nuchal ligament. The foal died 9 days after admission. Necropsy revealed mineralized lesions throughout the fascial planes and adipose tissues of the thorax, abdomen, and skeletal muscles, with little to no involvement of muscular tissue. Serum magnesium, copper, and thyroxine concentrations...
