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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.
Evidence that changes in LH pulse frequency may regulate the seasonal modulation of LH secretion in ovariectomized mares. To determine whether tonic LH secretion in ovariectomized mares is characterized by pulsatile release, frequent blood samples (every 15 min) were collected from 5 ovariectomized horse mares in nine 8-h periods between February and May. Mean serum LH concentrations increased 9-fold and were associated with a 4-fold increase in mean LH pulse frequency. These results provide the first evidence of pulsatile LH release in ovariectomized mares and suggest that the increasing daylengths of the spring months may increase serum LH by increasing LH pulse frequency.
Phloroglucinol microassay for plasma xylose in dogs and horses. The phloroglucinol microassay technique for measuring plasma concentrations of xylose was compared with the more tedious orcinolferric chloride technique. Sequential blood samples were collected from 5 dogs and 6 horses every 30 minutes after oral administration of 0.5 g of D-xylose/kg of body weight. Comparison of the results by regression analysis shows a highly significant (P less than 0.01) positive linear correlation for both dogs (r = 0.95) and horses (r = 0.77). These results indicate that xylose in canine and equine plasma can be accurately measured by the phloroglucinol technique.
Effects of testosterone, dihydrotestosterone and estradiol on gonadotropin release after gonadotropin releasing hormone administration in cyclic mares. Sixteen intact cyclic mares were treated on the fourth day of estrus and then every other day for a total of six injections with 1) testosterone propionate, 2) dihydrotestosterone (DHT) benzoate, 3) estradiol (E2) benzoate or 4) safflower oil. Mares were given gonadotropin releasing hormone (GnRH) on Day 3 of estrus (pretreatment) and again 24 h after the last steroid or oil injection. Treatment with testosterone propionate resulted in a greater (P less than 0.05) follicle-stimulating hormone (FSH) response to the second injection of GnRH compared with all other treatments. Treatment with DHT ...
Esophagotomy in the pony: comparison of surgical techniques and form of feed. Esophageal healing was studied in 12 ponies after cervical esophagotomy. The esophagus was sutured, feed and water were withheld for 48 hours, and then all ponies were permitted to eat. In group I (n = 6), a longitudinal esophagotomy was made. In group II (n = 6), a rotational esophagotomy was made with the mucosal incision 180 degrees away from the incision in the esophageal muscle. Three ponies in each group were fed a soft diet ad libitum for 9 days, and then were allowed access to hay and grain. The remaining ponies were fed hay and grain. The esophagotomies of all hay-fed ponies dehisced ...
Phenylbutazone kinetics and metabolite concentrations in the horse after five days of administration. Phenylbutazone (PBZ) was administered (8.8 mg/kg of body weight) every 24 hours for 5 consecutive days, orally for the first 4 days and IV on day 5. The half-life (t 1/2) after this daily administration was 6.2 hours and the volume of distribution was 0.152 +/- 0.014 L/kg; the bioavailability after oral administration was 91.8 +/- 2.5%. The plasma concentration of PBZ at experimental hour (EH) 24 (24 hours after the 1st oral dose) was 1.7 +/- 0.39 micrograms/ml and increased to 4.2 +/- 0.29 micrograms/ml at EH 48 (24 hours after the 2nd oral dose). Values at EH 72, 96, and 120 (24 hours after ...
Mechanical properties of equine hoof wall tissue. The mechanical properties of pigmented equine hoof wall tissue were determined for samples taken from the inner and outer portions of the stratum medium of the toe. Two properties, the modulus of elasticity and proportional limit, which are measures of the rigidity and yield point, respectively, of the tissue, were studied for samples compressed in 3 orthogonal directions. All samples tested were anisotropic. Inner wall samples were less rigid and had a lower yield point than outer wall samples.
Survey of 79 referral colic cases. The clinical, surgical and/or necropsy diagnosis of 79 horses admitted to a referral clinic for evaluation of colic are reported. Twenty-one horses were presented with conditions amenable to medical treatment and all were subsequently discharged. Exploratory laparotomies were performed on 44 horses during the present study, in some cases as a diagnostic procedure preceding euthanasia. In general, in surgical cases the mortality rate was highest for problems involving the small intestine, followed by those affecting the large colon and then the small colon. Postoperative sequelae included perit...
Glutathione peroxidase activity in the blood of healthy horses given different selenium supplementation. Glutathione peroxidase (GSH-px) activity in the blood is correlated to the amount of selenium which was given to the horse. Currently recommended doses of selenium seem to be sufficient in order to prevent selenium deficiency. The blood GSH-px in foals reflects the amount of selenium given to the mare during pregnancy.
Use of an autogenous cancellous bone graft in the treatment of subchondral bone cysts in the medial femoral condyle of the horse. The clinical features, diagnosis and radiological findings of eight cases of a subchondral bone cyst involving the medial condyle of the femur are described. Surgical treatment, which comprised performing an arthrotomy of the femorotibial joint, curetting and packing the cystic cavity with an autogenous cancellous bone graft, is described.
Prognosis in equine colic: a study of individual variables used in case assessment. The individual merit of the use of 43 variables to assess the prognosis of equine colic cases was examined. The following variables revealed highly significant (P less than 0.001) differences between cases which survived and those which died: blood pressure; heart rate; oral mucosal capillary refill time; degree of mental depression; venous haemoglobin concentration, haematocrit, erythrocyte count, urea concentration and lactate concentration; peritoneal fluid lactate concentration; and haematocrit/plasma protein and serum protein concentration ratios. Thus, in general, variables which assesse...
A retrospective clinical study of osteochondrosis dissecans in 21 horses. Osteochondrosis dissecans was diagnosed clinically and radiographically in 31 joints of 21 horses. The horses ranged in age from 8 months to 5 years at the time of presentation. The usual age of onset of clinical signs was 18 to 24 months. Presenting complaints included joint effusion and lameness of either gradual or sudden onset. In Thoroughbred horses, the stifle joint was the most common site of lesions and in Standardbred horses lesions occurred more commonly in the hock. In 16 of the 21 horses, the contralateral joint was radiographed and 9 of these horses had bilateral lesions. Thorough...
Changes of the fibrocartilage in navicular disease in horses. A histological and histochemical investigation of navicular bones. Histological and histochemical investigations of the fibrocartilage of facies flexoria from navicular bones of horses with navicular disease have shown alterations similar to those described in the hyaline articular cartilage in osteoarthritic joints.
Follicle stimulating hormone, luteinising hormone and progesterone concentrations in the blood of thoroughbred mares exhibiting single and twin ovulations. The concentrations of follicle stimulating hormone, luteinising hormone and progesterone were measured in serial blood samples taken throughout one or more oestrous cycles from 12 Thoroughbred mares, some of which exhibited single and others twin ovulations. The resulting profiles clearly demonstrated that no simple relationship exists between circulating gonadotrophin levels and subsequent ovulation rate in the mare. However, plasma progesterone concentrations during dioestrus are, as expected, higher following twin than single ovulations. The findings suggest that the underlying cause of twi...
Transfer of adult Strongylus vulgaris via stomach tube. Patent infections with Strongylus vulgaris were established in 6 of 8 helminth-free ponies given 41 to 101 adult worms via nasogastric tube. The parasites were removed from the cecum and ventral colon and transferred within 1 to 2 hours of the death of the donor horses. Eggs were found in the feces of the recipients in 2 or 3 days; egg counts reached maximum, 28 eggs per gram of feces, at 4 weeks after ponies were inoculated. In 6 ponies euthanatized 3 to 7 weeks after parasitic transfers were done, 28% of the inoculated worms were found alive at necropsy. A 7th pony was maintained as a donor ...
Experimental production of neonatal isoerythrolysis in the foal. Serological evidence with or without clinical signs of neonatal isoerythrolysis was experimentally produced in 6 of 8 foals born to mares allo-immunized with washed erythrocytes from the stallion. Blood group antigens were determined in all mares, stallions and foals, and the incompatible antigenic factor(s) responsible for the disease were defined. In 5 of 8 foals born to alloimmunized mares, a single antigenic factor difference accounted for the erythrocyte incompatibility between mare and foal. The erythrocyte antigen suspected as the most responsible for isoerythrolysis observed was A1. Ag...
Evaluation of a series of testing procedures to predict neonatal isoerythrolysis in the foal. A series of modified (field) tests were compared to a crossmatch between mare and foal for their reliability in predicting neonatal isoerythrolysis (NI) in eight foals born to experimentally alloimmunized mares. In the field tests, mare's serum, plasma and colostrum were combined with foal erythrocytes washed by a modified procedure to determine which combination was the best predictor of impending NI. A consistent grading system for agglutination and hemolysis was employed. The field tests using mare's plasma demonstrated less agglutination and hemolysis than tests where serum was employed. I...
Induction of male sex behavior in pony mares with testosterone propionate. Two pony mares were administered 150 mg of testosterone propionate every other day for 20 days (ten injections) and every ten days there-after. An additional two mares and one stallion were not treated and served as controls. Testosterone propionate was dissolved in absolute ethanol and administered subcutaneously. Sex behavior tests were conducted 26 and 40 days after the first injection. Control mares exhibited very little male sex behavior. Both testosterone propionatetreated mares, however, exhibited mounting, sniffing, flehmen, biting and vocalization behavior in the presence of an estrou...
Phenoxymethyl penicillin in the horse: an alternative to parenteral administration of penicillin. This preliminary study evaluated phenoxymethyl penicillin (Penicillin V) as an alternative to parenteral administration of penicillin in horses. Penicillin V was administered orally to five horses at two different doses and plasma levels of the drug were determined at timed intervals. The results were evaluated by regression analysis. Following the administration of penicillin V at a dose of 66,000 IU/kg or 110,000 IU/kg, the mean peak plasma levels obtained were 1.55 micrograms/mL and 2.34 micrograms/mL respectively. A plasma level two to four times above the minimal inhibitory concentration ...
Assessment of the efficacy of an abductor muscle prosthesis for treatment of laryngeal hemiplegia in horses. Four variations of abductor muscle prosthesis for treating laryngeal hemiplegia were evaluated in 153 horses by questionnaire, and in the 100 Thoroughbred racehorses in this group survival analysis was used to compare their racing performances and earnings with those of 400 control horses. The questionnaire indicated that the technique which included a ventriculectomy and 2 prostheses was regarded as being the most successful (P less than 0.01) and resulted in the least residual stertor (P less than 0.001). Survival analysis showed that there was no significant difference between the treated g...
Treatment of equine cutaneous neoplasia by radiotherapy using iridium 192 linear sources. The treatment of equine cutaneous tumours by conventional or cryosurgical techniques can be limited where the position of the tumour makes radical excision or freezing impractical or dangerous. Radiotherapy provides an effective and practical alternative. The use of iridium pins with guide needles allows accurate positioning of sources and uniform radiation fields to be achieved. The subsequent removal of the pins reduces the period of incapacity and reduces the radiation risk when compared to permanently implanted sources. Twenty-seven tumours on 26 horses were treated by this method with a 1...
Segmental epidural and subarachnoid analgesia in conscious horses: a comparative study. Six adult horses were used to compare the effects of segmental epidural analgesia (SEA) and segmental subarachnoid analgesia (SSA). A 17-gauge Huber point directional needle was used to place a catheter with stylet into the epidural space or the subarachnoid space at the lumbosacral intervertebral junction and to catheterize the thoracolumbar epidural or subarachnoid space. The position of the catheter was confirmed radiographically. A 2% solution of mepivacaine hydrochloride was used at average doses of 80 mg (4 ml) to produce SEA and 30 mg (1.5 ml) to produce SSA. Onset of analgesia in respo...
[Primary closure of the scrotal wound in the castration of stallions]. A method of castration in stallions is reported on, in which primary closure of the wound caused by castration was attempted. Primary wound-healing occurred in 90 per cent of 110 stallions showing normally descended testicles, whereas this proportion was 97.4 per cent in thirty-eight unilaterally cryptorchid stallions in which the normally descended testicle was removed using the method described. It is concluded that the present method of castration will only be successful when surgery is carried out under strictly aseptic conditions.
