Urinary health in horses encompasses the study of the equine urinary system, which includes the kidneys, ureters, bladder, and urethra. This system is responsible for filtering blood, removing waste products, and regulating fluid and electrolyte balance. Conditions affecting urinary health can range from infections and obstructions to renal dysfunction and urolithiasis. Monitoring urinary health involves assessing clinical signs, conducting urinalysis, and utilizing imaging techniques. This page compiles peer-reviewed research studies and scholarly articles that explore the anatomy, physiology, pathophysiology, and clinical management of urinary health issues in horses.
Firth EC.A case of vesical calculus in which haematuria was not a presenting sign is described. Methods of removal of vesical calculi are discussed. In this case, urethral sphincterotomy facilitated delivery.
Palmer E, Jousset B.Eight mares were observed clinically for 14 months to detect oestrus and ovarian activity, and assays of urinary oestrogens and plasma progesterone were performed. Cyclical ovarian activity occurred during 60% of the experimental period. Persistent luteal activity was found over 20% of the period and for the rest of the time activity was absent. Cyclical activity was characterized by the alternation of periods of low and high progesterone levels corresponding to the follicular and luteal phases of the ovarian cycle. During the follicular phase, urinary oestrogen levels increased to a maximum o...
Rawlings CA, Bisgard GE.Renal clearance and excretion of endogenous substances were studied in 13 small adult ponies (152 plus or minus 93 (standard deviation (SD)) kg). Normal data of serum and urinary concentrations, clearance, and excretion of creatinine, osmolality, free water, sodium, potassium, and chloride during a 12-hour period are presented. Significant linear regressions on body weight (BW) were obtained for creatinine clearance (Ccr (ml/hr) = 127.2 times BW (kg) - 1553), osmolar clearance (Cosm(ml/hr) = 1.81 times BW (kg) m0.3), and free water (CH2O(ml/hr) = - 1.43 BW (kg) - 25.0). Compared with renal exc...
Prado ES, Webster ME, Prado JL.Horse urinary kallikrein when incubated with horse plasma formed kallidin (lysylbradykinin) from the kininogens in the plasma. Horse plasma, like human plasma, was found to contain an aminopeptidase capable of converting kallidin to bradykinin. No evidence, however, could be found that the plasma contained an aminopeptidase capable of converting Met-Lys-bradykinin to kallidin, thus eliminating the possibility that the kallikrein had released Met-Lys-bradykinin which was converted to kallidin during the 1–5 min incubations. The method used for identification of the kinins is rapid, gives a go...
Babel I, Stella RC, Prado ES.Previous experiments indicated that horse urinary kallikrein (UK) hydrolyzes salminei- e and polyarginine, a but not polylysine. This paper reports the action of UK on bradykinyl-serine, methionyllysyl-bradykinin and lysyllysyl-bradykinin.
Squire KR, Adams SB.A 450-kg yearling Clydesdale filly was determined to have bilateral ectopic ureters. The resulting incontinence caused severe malodorous perineal dermatitis. Bladder capacity was measured at 800 ml. The urethral sphincter lacked tone, and the horse was seen to urinate in a normal manner only 2 or 3 times a week. A midline celiotomy was performed, and the ureters were identified by cannulation from the ectopic openings. The ureters were ligated, and the cut ends were anastomosed to the dorsal bladder surface by an extravesicular end-to-side technique. A partial thickness seromuscular layer of t...
Neumann RD, Ruby AL, Ling GV, Schiffman P, Johnson DL.Urinary calculi from 17 horses with urolithiasis were examined to study their mineral content and ultrastructure. Among the analytic methods used were X-ray diffractometry, scanning electron microscopy, and electron microprobe analysis. The calculi initially were observed by use of a stereoscopic dissecting microscope and generally were found to have nodular surfaces surrounding a banded or granular-to-chalky interior. Observation by scanning electron microscopy revealed an intricate pattern of irregularly concentric, fine bands and spherules. These had a round, finely banded, globular texture...
Dyke TM, Hinchcliff KW, Sams RA.The objectives of this study were to determine the effect of phenylbutazone premedication on the pharmacokinetics and urinary excretion of frusemide in horses; and on frusemide-induced changes in urinary electrolyte excretion. Six Standardbred mares were used in a 3-way crossover design. The pharmacokinetics and renal effects of frusemide (1 mg/kg bwt i.v.) were studied with and without phenylbutazone premedication (8.8 mg/kg bwt per os 24 h before, followed by 4.4 mg/kg bwt i.v. 30 min before frusemide administration). A control (saline) treatment was also studied. Administration of frusemide...
Baerveldt MC, Klein WR.It is well documented that the incidence of rupture of the urinary bladder or urachus is highest in newborn male foals and occurs during the (usually uncomplicated) parturition. Important clinical symptoms include frequent passing of small quantities of urine, abdominal distention and positive abdominal undulation. Hyperkalaemia, hyponatraemia, hypochloraemia and an elevated serum creatinine level are often present. The serum blood urea nitrogen concentration may be normal or only slightly elevated. The creatinine concentration in the peritoneal fluid is invariably higher than that in serum, a...
Auge BK, Preminger GM.The surgical management of urinary calculus disease has changed dramatically in the past two decades. Minimally invasive options have made open stone surgery nearly obsolete. The development of shock wave lithotripsy, percutaneous nephrostolithotomy techniques and intracorporeal lithotripsy devices has conferred unprecedented management tools for upper tract stones. Moreover, transfusion rates, hospital costs, and convalescence periods have been markedly reduced when compared to open surgery. Likewise, the advent of fiberoptic technology has resulted in miniaturization of ureteroscopes making ...
Holt PE, Mair TS.Bladder paralysis and sabulous urolithiasis were diagnosed in 10 horses with urinary incontinence. Additional neurological deficits in the hindquarters were detected in five of them. Treatment by catheter drainage and bladder lavage was unsuccessful, and all the horses were destroyed within 14 months of presentation. Neuritis of the cauda equina was diagnosed post mortem in one horse, but the cause of the paralysis was not identified in the others, although radiography revealed abnormal lumbosacral vertebral angulation in one case.
Duesterdieck-Zellmer KF.The prevalence of equine urolithiasis has been estimated to be low. In horses with clinical signs of urolithiasis, uroliths are most commonly encountered in the urinary bladder, but it is not uncommon to detect uroliths in more than one location. The most common clinical signs for cystic calculi are urine scalding of the hind limbs, hematuria, tenesmus and dysuria. Numerous surgical techniques and approaches have been described for the treatment of urolithiasis in horses; however, independent of which approach is chosen, the goal should be to remove all calculi completely from the urinary trac...
Saulez MN, Cebra CK, Heidel JR, Walker RD, Singh R, Bird KE.A 17-year-old gelding was evaluated because of dysuria, inappetence, and weight loss. Cystoscopy revealed severe mucosal ecchymoses with luminal hemorrhage and accumulations of crystalloid sludge. Analysis of a urine sample revealed isosthenuria, an alkaline pH, pyuria, hematuria, bacteriuria, and numerous calcium carbonate crystals. Histologic examination of bladder mucosa biopsy specimens revealed severe neutrophilic infiltration with mineralization. A diagnosis of encrusted cystitis exacerbated by sabulous urolithiasis was made. A Corynebacterium sp susceptible to penicillin, sulfonamide, a...
Desantis S, Santamaria N, Zizza S, Accogli G, Mastrodonato M, Scillitani G, Mentino D.Urothelium is a multilayer epithelium covering the inner surface of the urinary bladder that acts as a blood-urine barrier and is involved in maintaining the wellbeing of the whole organism. Glycans serve in the maturation and differentiation of cells and thus play a key role in the morphology and function of the multilayered epithelium. The aim of the present study was to examine the glycoprotein pattern of the horse urinary bladder urothelium by lectin histochemistry. Methods: The study involved urinary bladders from four horse stallions. Tissue sections were stained with a panel of eleven l...
Judy CE, Galuppo LD.To describe a technique for endoscope-assisted disruption and removal of urinary calculi using a holmium:YAG laser in sedated, standing horses. Methods: Retrospective study. Methods: Six horses with urinary calculi. Methods: A holmium:YAG laser was used to disrupt naturally occurring urinary calculi in horses (4 geldings, 1 stallion, 1 mare). Ischial urethrotomy was performed in male horses to provide a portal for the endoscope and laser fiber. Calculus fragments were removed by a combination of lavage, transendoscopic basket snare removal, forceps, and digital manipulation. Ischial urethrotom...
Beard W.To describe parainguinal laparocystotomy for urolith removal and to report outcome. Methods: Prospective clinical study. Methods: Ten geldings with uroliths. Methods: Signalment, number, size, type of uroliths, surgical technique, and complications were recorded. Long-term follow-up was obtained by telephone interviews with the client and/or examination by the referring veterinarian. Results: Cystic calculi, 3-9 cm in diameter, were removed by parainguinal laparocystotomy. Mean surgical time was 59 minutes (range, 40-100 minutes). With this approach, ligation of the pudendal or superficial epi...
Straticò P, Suriano R, Sciarrini C, Varasano V, Petrizzi L.To report laparoscopic-assisted cystotomy and inguinal cystostomy for treating bladder urolithiasis in a gelding. Methods: Clinical report. Methods: Twelve-year-old Appaloosa gelding. Methods: A laparoscopic approach was used to locate and grasp the bladder, which was exteriorized through an enlarged instrument portal for cystotomy to remove the calculus. During withdrawal, the calculus fragmented into multiple pieces. To avoid urethral occlusion and facilitate elimination of these fragments, an inguinal cystostomy was created. The seromuscular layer of the bladder was circumferentially secure...
Lund CM, Ragle CA, Lutter JD.An 11-year-old Arabian gelding was evaluated for hematuria, stranguria, and pollakiuria that had been observed for 1 week. Results: Transrectal palpation revealed a 5-cm firm round mass in the urinary bladder. Cystoscopy and transrectal ultrasonography confirmed the diagnosis of urinary bladder urolithiasis. Results: A multiportal transparalumbar fossa laparoscopic approach was selected for cystotomy and urolith removal. Cystotomy and urolith removal was performed with sedation and local anesthesia with the horse standing. No perioperative complications were observed. Urination returned to nor...
McCue PM, Troedsson MH, Liu IK, Stabenfeldt GH, Hughes JP, Lasley BL.Thirty-seven seasonally anoestrous mares were divided into treatment and control groups and given 10 micrograms of native GnRH (GnRH) per hour using a peristaltic pump, or 10 micrograms GnRH agonist (GnRHa) twice daily, beginning on either 13 January, 13 February or 14 March. Treatment with GnRH was equally effective in inducing ovulation in January (4/5), February (4/5) and March (3/4). GnRHa treatment was more effective in inducing ovulation in February (4/5) and March (4/4) than in January (2/8). Peak luteinizing hormone (LH) concentrations in mares induced to ovulate with GnRH (7.4 +/- 1.5...
Schumacher J, Varner DD, Schmitz DG, Blanchard TL.A urethral defect, presumed to communicate with the corpus spongiosum penis, caused hematuria in seven geldings and hemospermia in three stallions. Hematuria in geldings occurred at the end of urination. Hematuria was not observed in stallions with hemospermia. A linear urethral defect was identified, by endoscopic examination, on the convex surface the urethra at the level of the ischial arch of each horse. Cause of the defect was not determined. Two stallions were successfully treated for hemospermia, one by temporary subischial urethrostomy combined with sexual rest for 10 weeks, and the ot...
Nelson EA, Sanchez LC, Mallicote MF, Warren LK, Robelen AM, Reuss SM. To compare urine urinary pH, blood pH and concentration of electrolytes in blood of healthy horses fed an anionic salt supplement to achieve diets with a dietary cation-anion difference (DCAD) of -40 or 0 mEq/kg DM, with horses a fed a diet with a DCAD of 85 mEq/kg DM. Eight healthy horses received each of three diets in a randomised crossover design. Diets consisted of grass hay and concentrate feed, with a varying amount of an anionic supplement to achieve a DCAD of 85 (control), 0 or -40 mEq/kg DM. They were fed for 14 days each with a washout period of 7 days between. Urine pH was m...
Schinköthe J, Gerlach K, Ulrich RG, Brehm W.A 12-y-old Shetland Pony was presented with a mucus-secreting fistula in the right paralumbar fossa. Surgery was performed to unravel the origin of the fistula. The horse died under anesthesia and was forwarded to autopsy. The right kidney was markedly atrophic and fibrotic, consistent with unilateral end-stage kidney. The right ureter was markedly thickened, but with luminal continuity leading into the urinary bladder where a partial obstruction caused by nodular para-ureteral fat necrosis was evident. The lumen of the cutaneous fistula was continuous with the right ureter; therefore, we diag...
Easther R, Manthorpe E, Woolford L, Kawarizadeh A, Hemmatzadeh F, Ferlini Agne G.Equine idiopathic haemorrhagic cystitis (EIHC) is a recently described form of aseptic cystitis in horses in which there is no discernible underlying cause. This case report describes a 9-year-old Thoroughbred gelding that presented with stranguria, pollakiuria, and haematuria. Cystoscopy revealed ulceration and haemorrhage of the bladder mucosa, diffuse mural hyperaemia and marked urine sedimentation. Histopathological evaluation of the bladder revealed chronic active ulcerative neutrophilic, lymphoplasmacytic, and eosinophilic cystitis. There was no bacterial or fungal growth upon culture bu...
Geburek F, Stadler P.Conventional treatments of equine tendon injuries lead to an unsatisfactory healing process that usually results in a relatively high recurrence rate. Therefore, in recent years so-called regenerative therapeutics were studied scientifically in vitro and in laboratory animals. These include substances that ideally lead to the formation of replacement tissue, which in contrast to the low quality scar, has similar functional properties as the original intact tendon. Currently, a plethora of different substrates is either commercially available or can be produced in practice with the help of kits...
Divers TJ, Byars TD, Spirito M.Bilateral ureteral defects were diagnosed as the cause of depression and azotemia in an 8-day-old Thoroughbred filly. The azotemia resulted from accumulation of urine in the retroperitoneal area. A ventral midline laparotomy was performed, and defects found in both the left and right ureter were repaired. Uroperitoneum and abdominal distention, presumably from urine leakage at the left ureteral surgery site, were detected on the fourth postoperative day and necessitated abdominal drainage. Thirty-six hours later, the leakage stopped spontaneously, and the foal recovered normally. This report s...
Schumacher SA, Kamr AM, Lakritz J, Burns TA, Bertone AL, Toribio RE.Intravenous magnesium sulfate (MgSO4) is used in equine practice to treat hypomagnesemia, dysrhythmias, neurological disorders, and calcium dysregulation. MgSO4 is also used as a calming agent in equestrian events. Hypercalcemia affects calcium-regulating hormones, as well as plasma and urinary electrolytes; however, the effect of hypermagnesemia on these variables is unknown. The goal of this study was to investigate the effect of hypermagnesemia on blood parathyroid hormone (PTH), calcitonin (CT), ionized calcium (Ca2+), ionized magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl-) ...
Wood T, Weckman TJ, Henry PA, Chang SL, Blake JW, Tobin T.Our investigation of the urine of grazing horses at the University of Kentucky shows that the mean pH level is about 7.9, and if their diet is supplemented with grain, it is about 7.4. There appears to be no significant effect of time of day or year on urine pH levels in horses. However, horses taken from pasture and supplemented with grain in a stalled environment show a slight decrease in urine pH. Additionally, we investigated the effects of storage on pH levels. Equine urine samples appear to be quite stable with regard to pH for 48h, but then show a marked increase. Urine pH can have a gr...
Floeck M.Ultrasonography is a helpful diagnostic tool in cattle with urinary tract disorders. It can be used to diagnose pyelonephritis, urolithiasis, hydronephrosis, renal cysts, renal tumors, amyloidosis, cystitis, bladder paralysis, bladder rupture, bladder neoplasms, and, occasionally, nephrosis, glomerulonephritis, and embolic nephritis. This article describes the anatomy, scanning technique, indications, limitations, normal and pathologic sonographic appearance of the bovine urinary tract. References from horses and humans are included, especially when the sonographic findings in these species ma...
Adams LG, Senior DF.The literal meaning of lithotripsy is the "act of breaking stones." There are two forms of lithotripsy available for use in veterinary medicine: electrohydraulic shock-wave lithotripsy (EHL) and extracorporeal shock-wave lithotripsy (ESWL). With EHL, a shock-wave is generated immediately adjacent to a urolith within the urinary bladder. In dogs, nephroliths or ureteroliths can be successfully treated with ESWL. With ESWL, the shock-waves are generated outside the body and directed toward the urolith.
Alexander K, Dunn M, Carmel EN, Lavoie JP, Del Castillo JR.Glomerular filtration rate (GFR), an important parameter of renal function, is difficult to assess clinically. Serum creatinine and blood urea nitrogen measurements lack sensitivity, whereas radionuclide determination of GFR is not always available and requires postinjection patient isolation. GFR can be determined using computed tomography (CT), most commonly via Patlak plot analysis. Four adult cats, two adult dogs, and a foal underwent abdominal CT under general anesthesia for various diseases of the upper urinary tract. CT-GFR was measured with a single-slice dynamic acquisition and Patlak...
Gronwall R.Endogenous creatinine clearance and renal excretion of phenylbutazone, osmotically active material, and compounds contributing to the urinary refractive index were studied in 12 Thoroughbred mares after no treatment, after water administration, or after furosemide administration. Urine was quantitatively collected, using urinary bladder catheters. On average, urine flow of the mares was 9 microliters/min/kg without treatment and increased to about 50 microliters/min/kg after water administration and to about 70 microliters/min/kg after furosemide administration. Water administration increased ...
Genetzky RM, Hagemoser WA.Two mature horses were examined for changes in laboratory and physical findings after experimentally induced bladder rupture. The postrupture laboratory diagnostic changes, which provide valuable information for a correct diagnosis are described. Hematology, serum and peritoneal fluid sodium, potassium, calcium, phosphorous, creatinine, urea nitrogen, albumin and peritoneal fluid components were measured and evaluated versus time. Hyponatremia and hyperkalemia occurred, as well as increased concentrations of peritoneal fluid potassium and inorganic phosphorus. In addition, peritoneal fluid cre...
Ramsay L, Eberhardt C, Schoster A.Reports of leptospirosis in horses are limited. Objective: To describe the clinical and diagnostic findings of acute systemic leptospirosis in horses. Methods: Eleven client-owned horses presented to an equine hospital because of acute onset of disease between 2015 and 2023. Methods: Retrospective case series. Horses diagnosed with leptospirosis by 1 or more of urine PCR, serologic microscopic agglutination test (MAT), and histopathology. Results: Common clinical signs included lethargy (10), anorexia (10), fever (9), tachypnea (9), abnormal lung sounds (9), and epistaxis (6). Acute kidney inj...
de Melo UP, Ferreira C.This report describes five cases of urinary incontinence in Quarter Horse mares associated with the development of sabulous cystitis. The animals in this study had a history of persistent urinary incontinence for eight months, with clinical signs of continuous dribbling urine during rest and movement. The initial treatment with antibiotics and anti-inflammatory drugs was ineffective. Clinical examination revealed severe scalding in the perineal region and on the medial aspect of the hind limbs, along with neurological signs such as ataxia, hind limb paresis, and diminished perineal reflexes. T...
