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Topic:Veterinary Research
Veterinary research in horses encompasses the study of diseases, health management, and medical treatments specific to equine species. This field investigates various aspects of horse health, including infectious diseases, metabolic disorders, and musculoskeletal conditions. Researchers focus on understanding the pathophysiology of equine ailments, developing diagnostic tools, and evaluating therapeutic interventions. The study of horse health also involves examining preventive measures such as vaccination protocols and nutritional management to promote overall well-being. This page collects peer-reviewed research studies and scholarly articles that explore the diverse areas of veterinary science related to horses, providing insights into disease mechanisms, treatment strategies, and advancements in equine healthcare.
Auditory brain stem response testing in anesthetized horses. Auditory brain stem response testing, using insert earphones, was performed in 10 healthy horses given general anesthesia. The procedure involved clicks of alternating polarity delivered at a rate of 25 clicks/s. Wave forms, including five peaks, were commonly identified. Latencies were measured in milliseconds for waves I through V for all intensities. Latencies of all waves decreased as stimulus intensity increased. For waves I through V, a least-squares regression line was determined for each horse, using all responses between 87-dB sound pressure level (SPL) and 136-dB SPL, inclusive. Slop...
Thoroughbred blood serum inorganic phosphate concentrations in relation to feeding regime and racing performance. Horses receiving a pelleted or cubed dietary supplementation with roughage, have serum inorganic phosphate (SIP) concentrations consistently below an accepted mean of 1,032 mmol l-1 or 3, 1 mg dl-1. Further, it has been reported that the best eight, two-year-old Irish Thoroughbred track performers of 51 horses tested over a 10 month period, had significantly lower SIP concentrations than the worst eight track performers. In an endeavour to assess any nutritive effect on SIP concentrations and also to assess any effect of SIP concentrations on track performance, metabolic blood profiles from 30...
The pathology of a case of biliary atresia in a foal. The pathological features of biliary atresia in a foal are described. A 4-week-old American Saddler foal was presented for autopsy following an illness characterised by clinical features indicative of hepatic failure. The significant macroscopical lesions occurred in the liver which was extremely enlarged, mottled in appearance and indurated. Bile stasis was evident. Lobular distinction was absent and on sectioning, large bile ducts were absent. A moderate ascites, hydrothorax and hydropericardium and a mild anasarca and intermuscular oedema accompanied the hepatic lesion. The diagnosis of bil...
Functional genes for cellobiose utilization in natural isolates of Escherichia coli. The genes for utilization of cellobiose are normally cryptic in both laboratory strains and natural isolates of Escherichia coli. A survey of natural isolates of E. coli reveals that functional genes for cellobiose utilization, while rare, are present. The fraction of E. coli that utilized cellobiose ranged from less than 0.01% in human fecal samples to 7% in fecal samples obtained from horses. Samples obtained from sheep, cows, dogs, and pigs contained 0.1 to 0.5% cellobiose-positive E. coli. Neither the previously identified cel genes nor the bgl genes from E. coli K-12 were expressed during...
Gonadotropin-releasing hormone treatment induces follicular growth and ovulation in seasonally anestrous mares. A study was conducted to evaluate the effectiveness of gonadotropin-releasing hormone (GnRH) pulse infusion to stimulate follicular development and induce ovulation in seasonally anestrous standardbred mares. Seventeen mares were selected for use in this experiment, on the basis of a previous normal reproductive history, and were housed under a photoperiod of 8L:16D beginning one week prior to the start of the experiment (second week in January). Mares were infused with 20 micrograms (n = 7) or 2 micrograms (n = 6) GnRH/h, or were subjected to photoperiod treatment only (controls, n = 4). Seru...
Applications of equine models of acute inflammation. The Ciba-Geigy Prize for Research in Animal Health. The development of reproducible models of acute inflammation in which inflammatory heat is easily quantified and from which inflammatory exudate is readily harvested has facilitated studies in the horse of the actions of steroids and non-steroidal anti-inflammatory drugs (NSAIDS). Blockade of the synthesis of eicosanoids and suppression of inflammatory heat by clinical dose rates of NSAIDS suggests a causal link between the two events and provides further evidence for a role of these compounds in acute equine inflammation. The tendency for enolic and carboxylic acids NSAIDS to accumulate in in...
Development of equine models of inflammation. The Ciba-Geigy Prize for Research in Animal Health. Two experimental models of acute non-immune inflammation have been developed to enable studies of the biochemical composition and cellular content of exudates to be undertaken. Both are based on the creation of a mild, reproducible and reversible inflammatory reaction, which is free from uncontrolled incidental factors and which causes minimal distress to the experimental animals. The polyester sponge model involves the insertion of small polyester sponge strips soaked in sterile carrageenan solution into subcutaneous neck pouches and their serial removal. The tissue-cage model is based on the...
Cellular aspects of inflammation. The Ciba-Geigy Prize for Research in Animal Health. The migration of leucocytes to sites of acute and chronic inflammation is an event of central importance to the maintenance of inflammatory processes; extravascular leucocytes are responsible for generating chemical mediators of inflammation and the phagocytosis of particulate matter. They may also be involved in the conversion of acute to chronic inflammatory lesions. Leucocytes are attracted to sites of tissue injury by a range of chemoattractants. This paper describes the development of a method for separating on Percoll gradients purified populations of equine polymorphonuclear and mononuc...
Comparison of radioimmunoassay and enzyme-linked immunoassay for the measurement of progestogen in equine plasma and milk. Milk and plasma samples were obtained every 48 hours from eight pony mares for 40 days after foaling. Progestogen concentrations in milk and plasma were measured using an enzyme-linked immunoassay (ELISA) and compared with radioimmunoassay of the plasma. In general the three assays showed similar trends in progestogen concentration changes but absolute values varied considerably. Difficulty could occur in interpreting the results from single samples taken at times when progestogen concentrations were either rising (ie, after ovulation) or falling. ELISA could be used on plasma obtained by allo...
Hereditary multiple exostosis. A comparative human-equine-epidemiologic study. Hereditary multiple exostosis (HME), a bone tumor first described by Virchow, has been studied over a period of 15 years on a comparative basis. The horse, an excellent biomedical model for this physically deforming multiple bone tumor in man, has been utilized in this study. The etiology, hereditary pattern, potential for malignancy and other aspects of this strange affliction need additional clarification. This in-depth study of 261 individuals from 144 families was compared with that of 55 horses bearing the HME trait, selectively bred and studied over the same period. Important information...
Synthesis and absorption of cysteine from the hindgut of the horse. The extent to which cysteine synthesised by microbes within the hindgut of the horse is incorporated into plasma cysteine was estimated by an isotopic technique in two horses fed four different diets. The results showed that between 1 per cent and 6 per cent of the plasma cysteine was of microbial origin. It is argued that the maximum contribution of microbial cysteine, and presumably other amino acids of microbial origin, to the plasma pool is 12 per cent of the net supply. These data support the hypothesis that microbial amino acid synthesis within the hindgut of the horse does not significa...
Contrast radiography in the investigation of sinus tracts and abscess cavities in the horse. Contrast radiography is a valuable technique in the investigation of infected foci in the horse. Its simplest form, a metal probe, will demonstrate the direction and, in the case of a short tract, the extent of the lesion. However, liquid contrast agents often give more information by following the course of long, tortuous sinus tracts, accurately delineating the boundaries of lesions and identifying the presence of foreign bodies.
Successful transfer of the embryos of Przewalski’s horses (Equus przewalskii) and Grant’s zebra (E. burchelli) to domestic mares (E. caballus). Blastocysts were collected non-surgically from 2 Przewalski's horse and 2 Grant's zebra mares and transferred extra-specifically to domestic horse and donkey recipients. Nine Przewalski's horse embryos were transferred surgically, and 2 non-surgically, to domestic Welsh-type pony mares. After surgical transfer, 7 (77.8%) pregnancies were established and 4 foals were born. Twelve Grant's zebra embryos were transferred surgically to 5 pony and 7 domestic donkey recipients respectively and 1 non-surgically to a donkey; 3 (60%) zebra-in-horse pregnancies were established and 2 went to term. Only 2...
Congenital vascular tumours in the skin of horses. Congenital vascular tumours in the skin of the legs of two horses showed histological features at biopsy which were consistent with capillary haemangioma but, at necropsy, one tumour had invaded the superficial digital flexor tendon and was therefore classified as a haemangiosarcoma.
Effect of povidone-iodine on in vitro locomotion of equine neutrophils. Incubation of equine neutrophils with povidone-iodine solutions of greater than or equal to 0.2 per cent resulted in total inhibition of migration under agarose. This was caused by the cytotoxic effects of the solutions as shown by pyknosis and cell lysis. Lower concentrations of povidone-iodine, however, did not adversely affect neutrophil viability or locomotion.
Pharmacokinetics and serum concentrations of cephapirin in neonatal foals. Six healthy foals, from 4 to 6 days of age, were given a single IM injection of sodium cephapirin (250 mg/ml) at a rate of 20 mg/kg of body weight. Serum concentrations of cephapirin were measured serially over an 8-hour period. The mean peak serum concentration was 21.2 micrograms/ml at 10 minutes. The overall elimination rate constant was 1.06/hr and the elimination half-life was 0.70 hour. The apparent volume of distribution at steady state was 1.06 L/kg and plasma clearance was 1,105 ml/hr/kg.
Pharmacokinetics of phenobarbital in the horse. Pharmacokinetics of phenobarbital was examined in 6 mature horses after 12 mg of phenobarbital/kg of body weight was infused over 20 minutes. Biexponential decrease in serum phenobarbital concentrations was observed with a distribution-phase half-life of 0.101 +/- 0.086 hour (mean +/- SD) and a terminal-phase elimination half-life of 18.3 +/- 3.65 hours. The volume of distribution at steady state was 0.803 +/- 0.070 L/kg. Total body clearance of phenobarbital was 30.8 +/- 6.2 ml/h/kg. The high clearance in the horse seems to explain the markedly shorter half-life of phenobarbital in this speci...
Identification of hindleg lameness. The use of markers placed over the tuber coxae on each side of a horse to aid identification of the relative movement of these structures at the trot, for teaching and research purposes, is described. In each case of hindleg lameness studied, the tuber coxae on the lame side showed a consistent increase in vertical displacement relative to that of the contralateral limb, and a characteristic pattern of movement throughout the stride irrespective of the site or cause of pain.
Multivariate statistical analysis of stride-timing measurements of nonfatigued racing Thoroughbreds. Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0....
Allergic dermatitis (sweet itch) of Icelandic horses in Sweden: an epidemiological study. A survey of allergic dermatitis (sweet itch) in Sweden contained information on 441 Icelandic horses. Results of a questionnaire indicated that approximately 15 per cent of the country's Icelandic horses suffered from the disease. The prevalence of allergic dermatitis was significantly higher among horses imported from Iceland (26.2 per cent) compared to that of Swedish-born animals (6.7 per cent). In addition, horses born in Iceland were significantly more severely affected than horses born in Sweden. The risk of allergic dermatitis in Sweden appeared to be more than six times higher for hors...
Bactericidal activity of peripheral blood neutrophils during the oestrous cycle and early pregnancy in the mare. The oestrous cycles of 20 mixed-breed mares were synchronized with daily injections of 10 mg oestradiol-17 beta and 150 mg progesterone given i.m. for 10 days. On the 10th day, 10-15 mg prostaglandin F-2 alpha was administered i.m. to induce oestrus. Neutrophils were isolated from jugular blood on the 2nd or 3rd day of oestrus, Days 5 and 7 after ovulation or during early pregnancy (Days 18-34 of pregnancy). Neutrophils were challenged with Staphylococcus aureus and their bactericidal activity examined after 30 and 120 min of incubation for a reduction of colony forming units. Bactericidal act...
Evaluation of ivermectin paste in the treatment of ponies for Parascaris equorum infections. Twenty ponies less than 18 months of age and infected with Parascaris equorum were treated with either 0.2 mg of ivermectin/kg of body weight (n = 10) or a placebo (n = 10; controls). Five control and 5 ivermectin-treated ponies were euthanatized 14 and 35 days after treatment, respectively. At necropsy, the small intestinal contents, lungs, and liver were examined for larvae and/or adult P equorum. Significantly (P less than 0.02) higher mean total numbers of P equorum were found in the small intestinal contents of the controls on day 14 (51) and on day 35 (21) than in the ivermectin-treated ...
Antimicrobial susceptibility of microorganisms isolated from equine orthopedic patients. Positive cultures were obtained from 60 equine orthopedic cases during a 12 year period (1974-1985). These cases consisted of 34 long or cuboidal bone fractures, 13 arthrotomy/arthroscopy procedures for removal or internal fixation of a fracture, 7 proximal splint bone fractures, and 6 facial or mandibular fractures. Excluding the 13 arthrotomies, only 10 (21%) of the 47 were open fractures. Multiple organisms were isolated from 36 cases (20 long or cuboidal bone fractures, 7 splint bone fractures, 5 mandibular fractures, and 4 intra-articular fractures). Of the 142 isolates, 35 (24%) were mem...
Absorption of neomycin from the equine uterus: effect of stage of oestrous cycle and volume of vehicle. Plasma concentrations of neomycin were measured following intrauterine infusion of 3.3 mg/kg bodyweight neomycin sulphate. Mares in oestrus absorbed approximately 6 per cent of neomycin infused whereas mares in a luteal phase absorbed 56 per cent. The volume of infusate also affected absorption as increased volume resulted in decreased absorption. The decreased absorption both during oestrus and when large volumes were used was probably due to reflux of antibiotic through the cervix.
Complement-induced equine neutrophil adhesiveness and aggregation. Equine neutrophils (PMN) were isolated from citrated normal blood by density gradient separation on Ficoll-Hypaque to greater than 96% purity and 98% viability and an average of 3.78 x 10(7) PMN/ml. The agonist C5a des Arg was used in serial dilutions of whole zymosan-activated equine plasma (ZAP) or was partially purified from ZAP by column chromatography. Purified equine PMN exhibited rapid aggregation following incubation with C5a des Arg which was further dependent on the availability of divalent cations, especially Mg++. The microfilament disruptive agent cytochalasin B (5 micrograms/50 m...
