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Topic:Clinical Study
Clinical studies in equine research involve the systematic investigation of health and disease in horses through structured scientific methods. These studies aim to evaluate the safety and efficacy of treatments, understand disease mechanisms, and improve veterinary care practices. Clinical studies can include randomized controlled trials, observational studies, and case-control studies. They may focus on various aspects such as pharmacokinetics, therapeutic interventions, and diagnostic techniques. This page compiles peer-reviewed research studies and scholarly articles that explore the design, implementation, and findings of clinical studies in equine medicine, providing insights into their impact on horse health and veterinary practices.
[Antithrombin III determination in horses. Reference values and acquired antithrombin III deficiency]. Antithrombin III (AT III) determinations were done in healthy and sick horses using the chromogenic substrate Chromozym TH. Reference values for adult horses at 25 degrees C were 18-25 IU AT III per ml plasma and 84-118% AT III activity of normal horse plasma, respectively. Precision and accuracy were good (intra assay coefficient of variation less than 2%, accuracy 10%). Surgical operations on healthy horses led to a biphasic decrease in AT III activity touching the lower border of the reference values on the second postoperative day. Other reasons for acquired AT III deficiencies included di...
Apneic oxygenation in anesthetized ponies and horses. Apneic oxygenation was studied in six ponies for 30 minutes, and six horses for 10 minutes. Arterial blood was sampled at regular intervals for measurement of oxygen and carbon dioxide tensions (PaO2 and PaCO2) and calculation of alveolar-arterial oxygen tension difference (PAO2-PaO2). In both groups of animals, PaO2 decreased rapidly during the first 3 minutes of apnea, then more slowly. Although the mean value was above 100 mmHg at 10 minutes, there was considerable inter-animal variability. Before apnea, PAO2-PaO2 was slightly, but not significantly, larger in horses than in ponies and incr...
Diagnostic and surgical arthroscopy of the equine shoulder joint. An arthroscopic technique for examination and surgical treatment of conditions of the shoulder joint was evaluated in eight normal horses and two horses with osteochondrosis lesions. A single arthroscope entry point caudal to the infraspinatus tendon allowed inspection of the cranial, lateral, and caudal surfaces of the shoulder joint. With the humeral head and glenoid cavity distracted by a curved forceps, the entire cartilage surface of the shoulder could be examined. The caudomedial portion of the humeral head was seen better with a 70 degree angled arthroscope. Instruments for intra-articu...
PGF-2 alpha release, progesterone secretion and conceptus growth associated with successful and unsuccessful transcervical embryo transfer and reinsertion in the mare. The outcome of 23 collections and reinsertions of conceptuses on Days 10.5-13.5, 4 transfers of Day-10.5, and 13 transfers of Day-6.5 embryos (ovulation = Day 0) was monitored in 30 mares. Blood samples were taken before and after each procedure to measure plasma 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), and then daily for progesterone determinations. Mares were also subjected to daily teasing for detection of oestrus, and to uterine ultrasonography for tracing the development of the conceptus. After the reinsertions, 12/23 conceptuses were detectable immediately after the procedure...
Comparison of progesterone and progesterone + oestrogen on total and specific uterine proteins in pony mares. Eight ovariectomized pony mares were used to test the effect of various doses of progesterone (0, 50, 150, 450 mg/day, in oil, i.m., for 10 days) on progesterone and LH in the peripheral circulation, and on total protein and uteroferrin in uterine secretions. Progesterone increased uteroferrin, but there were no differences amongst doses of progesterone. Progesterone treatment decreased LH, and tended to increase total protein. Eighteen ovariectomized mares were given vehicle, oestradiol (10 mg/day, in oil, i.m.), progesterone or progesterone + oestradiol for 28 days. Both the last two steroid...
Bronchoalveolar lavage in the newborn foal. Two bronchoalveolar lavages, 24 h apart, were performed on 15 foals, ranging in age from 1 to 21 days. In the first lavage, a numerical deficiency in alveolar macrophages was demonstrated in foals up to 2 weeks of age when compared with older (2-3 years of age) horses. Alveolar macrophages obtained from the lungs of 2-3-day-old foals also demonstrated significant impaired chemotactic function. In the second lavage, although an increase of alveolar macrophages was noted, a dramatic increase of polymorphonuclear neutrophil (PMN) mobilization occurred in the foals, thus providing a phagocytic bac...
Radionuclide, radiographic, and histomorphometric evaluation of healing of surgically created subchondral defects in equine bone. In the present study, radionuclide scintigraphy and radiography were used to evaluate the rate and degree of healing that occurred in surgically created subchondral bone defects in horses. Following radionuclide scintigraphy and radiography the horses were killed, and histomorphometric analysis was performed on the defect sites. The histomorphometric results were compared to the radionuclide scintigraphic and radiographic results to determine which noninvasive technique provided the most accurate information concerning healing of the bone defects. It was concluded that radionuclide scintigraph...
Early pregnancy loss in brood mares. During 1985, linear-array ultrasonography was used to study early pregnancy loss in commercial brood mares: 600/1115 (54%) of the cycles resulted in detected pregnancy at Week 2 after ovulation and 80 (13%) of these pregnancies resulted in early pregnancy loss. The pregnancy loss rate was significantly higher (P less than 0.05) for twin pregnancies (10/41) than for singleton pregnancies (70/559). The pregnancy loss rate was significantly higher (P less than 0.05) at 2-4 weeks (29/60) than at 6-8 weeks (12/60). The pregnancy rate was significantly less (P less than 0.05) for post-partum mares i...
[Establishment of a re-entrant ileo-cecal fistula in Equidae]. A re-entrant cannulation of the digestive tract was performed in Equidae (ponies and donkeys) between the distal extremity of the ileum and the base of the caecum. The operative technique was conceived to avoid risks of infection of the peritoneal cavity: the openings of the ileum and of the caecum were achieved only after the closure of the abdominal wall incision. Two donkeys were still alive ten months after the operation. This method can provide a convenient model for digestibility studies in Equidae, particularly for assessment of the pre-caecal digestibility.
Infusion of gonadotrophin-releasing hormone (GnRH) induces ovulation and fertile oestrus in mares during seasonal anoestrus. In Exp. 1, 30 Standardbred mares in deep seasonal anoestrus were divided into 3 equal groups and treated with 0, 50 (G50) or 100 (G100) ng GnRH kg-1h-1 for 28 days via osmotic minipumps. Ovulation occurred in 0/10, 3/10 and 7/10 mares respectively (P less than 0.05). Plasma GnRH profiles (Days -6, 0, 2, 6, 12, 20, 28 and 34 relative to pump insertion) were dose-dependent (P less than 0.01) and peaked on Day 12 of infusion. Mean daily plasma LH concentrations were biphasic in treated mares that ovulated, with LH peaks occurring around Day 6 and Days 16-20. By contrast, in treated mares that did...
Induction of ovulation in anoestrous mares with a slow-release implant of a GnRH analogue (ICI 118 630). A total of 18 experimental pony and 136 commercial maiden, barren and foaling Thoroughbred mares in seasonal or lactation-related anoestrus were injected subcutaneously with 1 or 2 slow-release D,L-lactide-glycolide co-polymer implants impregnated with 0.9 or 1.8 mg of the potent GnRH analogue, ICI 118 630, to give a daily release of, respectively, 30 or 60 micrograms analogue for 28 days; 32 of the Thoroughbred mares were also given a daily oral dose of 27.5 mg allyl trenbolone for 5 days after injection of the implant. Thirteen pony (76%) and 120 Thoroughbred (88%) mares ovulated 3-18 days a...
Antipyrine and lidocaine are cleared faster in horses than in humans: acetaminophen may be handled similarly. The following studies were designed to evaluate plasma elimination kinetics of intravenously administered antipyrine, acetaminophen and lidocaine among 9 healthy adult horses and 9 healthy drug-free humans (3 each per drug group), in order to compare potential species differences in drug-metabolizing ability. Acetaminophen is largely biotransformed in humans by hepatic glucuronide and sulfate conjugation, whereas both antipyrine and lidocaine are oxidized by hepatic microsomal mixed-function oxidases. Thus, plasma clearances of these drugs are thought to reflect differences in hepatic oxidativ...
Oxytocin stimulation of plasma 15-keto-13,14-dihydro prostaglandin F-2 alpha during the oestrous cycle and early pregnancy in the mare. In Exp. 1, 4 mares were given oxytocin intravenously (10 i.u./500 kg body wt) daily between Days 9 and 14 (Day 0 = day of ovulation) when pregnant and on Days 9-14, 16, 18, 20 when non-pregnant (not inseminated). In the non-pregnant mares the increase in plasma PGFM response to oxytocin was greater at Day 13 (235 +/- 54 pg/ml) than at Day 11 (113 +/- 38 pg/ml; P less than 0.05) and was maximum at Day 16. However, these animals did not return to oestrus and plasma progesterone did not fall below 4 ng/ml. There was no significant increase in response to oxytocin between Days 9 and 14 in the preg...
Electrophysiological studies on atrial fibrillation. We tested the multiple-wavelet hypothesis by studying the initiation and maintenance of atrial fibrillation in normal mules, horses, cows, calves, and goats. Persistence of atrial fibrillation in animals with a large atrial mass was compared with results in adult goats and calves having a smaller atrial mass. Atrial stimulation in clinically normal cows, mules, calves, and goats was accomplished using an intra-atrial stimulating catheter with rapid atrial pacing (30/s). Once initiated, atrial fibrillation persisted for 95,120,125 min, 3 days, and 8 weeks in five adult cows, respectively. In co...
Secretion of luteinizing hormone and follicle stimulating hormone in intact and ovariectomized mares in summer and winter. Sequential samples of blood were drawn via jugular catheters every 15 min for 24 h from four mares in each of five reproductive states: intact anestrous mares in winter, intact diestrous mares in summer, intact estrous mares in summer, ovariectomized mares in winter and ovariectomized mares in summer. Estrous mares were sampled on d 4 or 5 of estrus and diestrous mares on d 10 or 11 of diestrus. Each sample of plasma was assessed for concentrations of luteinizing hormone (LH) and follicle stimulating hormone (FSH) in two independent radioimmunoassays. A computer program was developed that dete...
Induction of ovulation in cyclic mares by administration of a synthetic prostaglandin, fenprostalene, during oestrus. Fenprostalene (250 micrograms) or saline was given at 60 h after the onset of oestrus in alternate oestrous periods to 8 mares for 4 cycles. Onset of oestrus and stage of cycle were determined by daily teasing, palpation and ultrasonography until time of treatment when follicular development was monitored at 12-h intervals to confirm ovulation. Serum progesterone concentrations were monitored daily. The interval from treatment to ovulation was significantly decreased (41.25 vs 73.50 h; P = 0.001) as was the duration of oestrus (5.63 vs 6.88 days; P = 0.005). There was no significant difference...
Plasma endotoxin levels in horses subjected to carbohydrate induced laminitis. Thirteen (65 per cent) of 20 horses subjected to carbohydrate overload developed Obel Grade 3 lameness within 56 h. Increases in plasma endotoxin from control levels of less than 0.1 ng/litre to values ranging from 2.4 to 81.53 ng/litre were measured in 11 (85 per cent) of 13 horses during the onset of Obel Grade 3 lameness. Obel Grade 3 lameness was associated with rises in plasma Gram-negative endotoxin levels in 11 (92 per cent) of 12 horses. Two peak increases separated by 16 h were verified in five (45 per cent) of 11 horses that exhibited both endotoxaemia and Obel Grade 3 lameness. The ...
Proteins in stallion seminal plasma. Motility and fertility of frozen-thawed semen differs greatly amongst stallions. Differences in seminal plasma might be one cause of this variation. For 8 ejaculates from each of 17 stallions, seminal plasma was saved at -20 degrees C and spermatozoa were cryopreserved. Based on post-thaw sperm motility, seminal plasma samples from 7 stallions (2 good, 3 variable, 2 poor sperm motility) were selected for measurement of electrolytes, protein content and analysis by sodium dodecylsulphate gel electrophoresis (10% gel, Coomassie blue stain). Variation in seminal plasma was significant (P less tha...
The interaction of cadmium and selenium in horse kidney cortex in relation to histopathological changes. The kidney cortex of 32 Finnish horses was analysed chemically for cadmium (Cd) and selenium (Se) content and by light microscopy for histopathological changes of the tissues. Cd concentrations in kidney cortex ranged from 6.9 to 91.6 mg/kg wet weight with an average of 31.9 mg/kg. Se concentrations ranged from 0.5 to 1.5 mg/kg with an average of 1.0 mg/kg. The age of the horses varied from 1.5 to 32 years; mean age was 16 years. Cd levels in kidney cortex seemed to increase linearly up to an age of about 16 years. In old (over 16 years) horses no such correlation could be found. Se concentrat...
Detection of serum antibodies against Ehrlichia risticii in Potomac horse fever by enzyme-linked immunosorbent assay. An indirect enzyme-linked immunosorbent assay (ELISA) was developed which was specific and sensitive in detecting antibodies to Ehrlichia risticii in Potomac horse fever (PHF). The ELISA antibody titers were correlated with the indirect fluorescent antibody (IFA) titers. E. risticii propagated in human histiocyte culture was purified on renografin gradient and the band of the organisms at a density of 1.182 g/ml was used as antigen. ELISA antibody titers were determined through computer assisted analysis, the observed antibody titers were derived by serial serum dilutions and using a resultant...
Relationship of age and season and consumption of Senecio vulgaris to LH/hCG receptors in the stallion testis. Testes were obtained from 70 colts and stallions and were pooled according to age (4 months to 23 years) to determine the relationship of age to LH/hCG receptor kinetics. The receptor concentration (Rt) increased from 0.069 x 10(-11) M/mg crude membrane fraction (CMF) for the 4-14-month pools to 0.464 x 10(-11) M for the 2-3-year-old pools. A 10-fold increase in testicular size also occurred, and so the total number of receptors per testis was significantly increased. A further increase to 1.237 x 10(-11) M/mg CMF was observed for stallions older than 5 years. No differences in binding affinit...
Influence of season and frequency of ejaculation on production of stallion semen for freezing. In an attempt to define optimal season and ejaculation frequency for frozen semen, semen was collected from 6 stallions (3 horses and 3 ponies) 3 times per week or every day, alternating every week, for 1 year. The semen was evaluated and frozen. All the samples were thawed at the end of the experiment. At collection, fresh semen evaluations showed that winter (as opposed to spring and summer) was associated with low sexual behaviour, small volumes of spermatozoa and gel, high sperm concentration and lower motility. The high ejaculation frequency yielded a decreased volume, concentration of sp...
Use of a novel non-steroidal anti-inflammatory drug in the horse. In a two-part cross-over experiment in six ponies, an acute inflammatory reaction was generated by injecting carrageenin solution into subcutaneously-implanted tissue-cages lined with fibrovascular granulation tissue. In each part of the cross-over, half of the ponies received a novel phenylpyrazoline anti-inflammatory agent (BW540C) orally and half received a placebo treatment. BW540C inhibited platelet cyclo-oxygenase for 24 h but the reductions in exudate eicosanoid concentrations were less pronounced. A significant suppression in the rise of surface skin temperature in BW540C-treated ponie...
Dietary molybdenum as a putative copper antagonist in the horse. Four horses were stabled and fed a diet of hay ad libitum, and 2 kg oats per animal per day, for a month. The basic diet was then supplemented with molybdenum, at a rate of 20 mg/kg dry matter for 4.5 months. For one month of this period the diet was supplemented also with sulphur at a rate of 1.2 g/kg dry matter. Analyses of jugular blood samples, obtained at intervals varying between two and 20 days, showed no evidence of a decline in total plasma copper or of an increased proportion of trichloroacetic acid (TCA) insoluble copper in plasma over this period. In separate studies, two other hor...
The effects of ammonium sulfate and acid on horse and human serum butyrylcholinesterase (EC 3.1.1.8). 1. Results of laboratory experiments which compared horse and human serum butyrylcholinesterase (EC 3.1.1.8) with respect to their acid inactivation and ammonium sulfate protection show: 2. Horse serum butyrylcholinesterase is more resistant to inactivation at pH 3.0 than human serum butyrylcholinesterase. 3. The loss of activity at pH 3.0 for both horse and human butyrylcholinesterase does not follow first order kinetics. 4. Both human and horse serum butyrylcholinesterase are protected from pH 3.0 inactivation by ammonium sulfate concentrations up to 33% saturation (1.37 M).
[Endometrial cysts in the mare. 2. Clinical studies: occurrence and significance]. Endometrial cysts were found in 11 (13.4%) of 82 mares of various breeds by clinical examinations. Endometrial cysts were diagnosed by hysteroscopy and ultrasonic echography. Typical images are described. The importance of endometrial cysts is discussed with regard to differential diagnosis of early pregnancy and uterine pathology. There was no evidence of cysts in mares under 10 years of age. Mares with endometrial cysts had a 10% higher history of disturbed fertility than mares without endometrial cysts. Seven of nine mares with cystic structures in the uterus became pregnant. Endometrial cy...
Cardiovascular and respiratory measurements in awake and isoflurane-anesthetized horses. Circulatory and respiratory function was monitored in nonmedicated, spontaneously breathing horses (n = 7) immediately before, during, and 1 hour after 85 +/- 4.1 (X +/- SEM) minutes of constant 1.57% isoflurane in O2 anesthesia. Comparison of values during anesthesia with those obtained while horses were awake revealed a significant (P less than 0.05) decrease in arterial blood pressure that was related to a slight, but insignificant, decrease in cardiac output and peripheral vascular resistance. Although isoflurane anesthesia and recumbency resulted in a significant (P less than 0.05) decrea...
Influence of chlorhexidine on seminal patterns in stallions. Ejaculates were collected at 3-day intervals before, during and after a washing procedure with chlorhexidine (2%). Semen motility and pathology were determined before and after deep-freezing. Blood samples were taken before and within 1 h after washing procedures and then extracted in ether. This was followed by HPL chromatography. Chlorhexidine concentrations in blood and seminal plasma were distinctly higher in the treated stallions than in control groups. Concentrations in the control groups were below the detection limit of the column. Significant correlations between decreasing semen qual...
Release of LH, FSH and GnRH into pituitary venous blood in mares treated with a PGF analogue, luprostiol, during the transition period. Nine mares received cannulae to collect blood from the pituitary venous outflow in the intercavernous sinus (ICS) and the jugular vein; in 4 mares, only jugular cannulae were used. Those 4 mares and 3 of the mares with cannulae in both positions received 7.5 mg luprostiol i.m. and 1 mare with both cannulae was treated with 3.75 mg uprostiol i.v. Blood samples were kept before and after treatment at 2-, 5- or 10-min intervals and concentrations of LH, FSH and GnRH were determined by RIA. Treatments resulted in an immediate sharp rise of LH and FSH in ICS and jugular blood samples within 2-10 mi...
Serum immunoreactive gastrin activity in horses: basal and postprandial values. Using commercially available diagnostic reagents, serum immunoreactive gastrin activity was measured in five normal horses that were starved of food and water for 24 hours. Blood samples were taken every 15 minutes for two hours. The horses were then fed a pelleted diet for 15 minutes and samples were taken every 15 minutes for a further two hours. Three further samples were taken at hourly intervals. The total sampling period was seven hours. Basal immunoreactive gastrin activity was lower than that reported in other mammals, ranging from a mean of 7.0 pg/ml to 13.8 pg/ml. At 30, 60 and 75 mi...
