Omneity® Pellets
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Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Surgical repair of urethral transection in a horse. A recently castrated horse was examined because of preputial and ventral abdominal swelling, prolapse of the preputial fold, and serosanguinous fluid dripping from the external urethral orifice. After a poor response to initial medical management, a urethral laceration was found during exploratory surgery. Half of the ventral portion of the corpus cavernosum penis had been transected. Primary closure was followed by healing without complications.
Equine neutrophil locomotion in response to Streptococcus zooepidemicus. The neutrophil is involved in the defence of the mare's uterus against micro-organisms. The ability of Streptococcus zooepidemicus and its growth products to induce shape changes or directional locomotion (chemotaxis) of equine neutrophils was investigated; no effect was found.
Hydrocortisone secretion: production rate and pulse characterization by numerical deconvolution. Based on serial blood sampling over 24 h, hydrocortisone was shown to be secreted episodically in the horse. The purpose of the present experiment was to characterize peaks and troughs by analyzing the instantaneous secretion rate profile obtained by a deconvolution technique rather than from the plasma concentration time profile. Kinetic parameters of hydrocortisone were determined following intravenous bolus and intravenous perfusion of hydrocortisone. Stationary and nonlinearity of hydrocortisone disposition were demonstrated. With the use of clearance values calculated from constant perfus...
Biotransformation of 1-dehydrotestosterone in the equine male castrate: identification of the neutral unconjugated and glucuronic acid conjugated metabolites in horse urine. The in vivo biotransformation of (1,2(n)-3H)1-dehydrotestosterone was studied in three equine male castrates and a number of neutral metabolites were identified in the urinary unconjugated and glucuronic acid conjugate fractions by gas chromatography/mass spectrometry. The metabolites were extracted from aliquots of the 0-24 h urine samples by Amberlite XAD-2 and separated into combined unconjugated plus glucuronic acid conjugated and sulphoconjugated fractions by Sephadex LH-20 column chromatography. After enzymatic hydrolysis of the glucuronides, the crude neutral unconjugated steroids plus ...
Influence of furosemide treatment on fluid and electrolyte balance in horses. Alterations in electrolyte and acid-base balance were studied in 6 horses for 8 hours after furosemide administration (1 mg/kg of body weight, IM), and the results were compared with those for 5 healthy untreated horses (controls) kept under identical environmental conditions. In the treated group, decreases in plasma potassium, chloride, and calcium concentrations and increases in total plasma protein content persisted for the 8-hour observation period, whereas there was no change in plasma sodium concentration, osmolality, or packed cell volume. Plasma bicarbonate concentration and PCO2 rema...
Prevalence of Eimeria leuckarti (Flesch, 1883) and intensity of faecal oocyst output in a herd of horses during a summer grazing season. The prevalence of Eimeria leuckarti infection and the intensity of faecal oocyst output were determined in a herd of 14 mares and their foals in northwest Germany using a sedimentation technique at weekly intervals during a summer grazing season from May to September. None of the mares, but all foals shed oocysts on at least one occasion. The patent periods lasted up to 16 weeks. The mean intensity of oocyst output (0.1-33 o.p.g.) was very low. No clinical signs of gastrointestinal disorder were noticed in any of the foals during this study.
Opsonins in uterine washings influencing in vitro activity of equine neutrophils. Uterine washings were found to promote neutrophil mediated killing of Streptococcus zooepidemicus. Depletion of complement and/or specific antibody from the washings significantly reduced bactericidal activity. Phagocytosis of yeast by uterine washings was complement dependent. Inhibition of the classical pathway significantly reduced opsonic activity indicating that, in addition to direct activation via the alternate pathway, antibody may also be involved in yeast phagocytosis.
The nutritional status of pregnant and non-pregnant mares grazing South East Queensland pastures. It has been reported that the increasing nutritional demands from mid to late pregnancy of grazing mares may not be met when these stages of gestation coincide with pastures being affected by frost. It was established in this study that grass/legume pastures could support the nutritional requirements of brood mares by providing digestible energy intakes of 68.0 and 91.7 MJ/day and digestible nitrogen intake of 91.2 and 138 g/day during mid and late pregnancy, respectively.
World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines for evaluating the efficacy of equine anthelmintics. These guidelines have been designed to assist in the planning, operation and interpretation of studies which would serve to assess the efficacy of drugs against internal parasites of horses. Although the term anthelmintic is used in the title and text, these guidelines include studies on drug efficacy against larvae of horse bot flies, Gasterophilus spp, which are non-helminth parasites commonly occurring in the stomach of horses. The advantages, disadvantages and application of critical and controlled tests are presented. Information is also provided on selection of animals, housing, feed, do...
An immunochemical demonstration of a pregnancy-specific protein in the horse and its use in the serological detection of early pregnancy. Two-dimensional crossed immunoelectrophoresis of sera from pregnant and non-pregnant horses, using antisera developed against early pregnant mare serum, revealed the presence of two immunologically related proteins one of which appeared to be specific to the pregnant state. This pregnancy-specific protein had beta 2-electrophoretic mobility and was first detectable at Day 6 after successful mating with a stallion. The second protein had gamma 2-electrophoretic mobility and was present in sera from pregnant and non-pregnant horses. The proteins were termed beta 2-horse pregnancy protein and gam...
Characteristics of milk ejection, associated intramammary pressure changes and oxytocin release in the mare. The neuroendocrine reflex theory of milk ejection was investigated in the horse under natural suckling conditions. To this end 12 lactating mares were provided with acute jugular catheters and with intramammary pressure (IMP) recording catheters. The foal had free access to the contralateral mammary complex. Intramammary pressure could thus be recorded while blood was drawn simultaneously for oxytocin analysis from the undisturbed animal. Suckling periods associated with a characteristic increase in IMP lasted significantly longer than unsuccessful nursing attempts. Elements of successful suck...
Attempts to prevent equine post neurectomy neuroma formation through retrograde transport of two neurotoxins, doxorubicin and ricin. Digital neurectomies, performed to relieve pain and lameness, are often complicated postoperatively by formation of painful neuromas. In this study attempts were made to deliver lethal doses of neurotoxin to the cell bodies of the transected digital nerve fibres via long-distance retrograde axon transport and, thereby, prevent the regenerative changes that lead to neuroma formation. After applying doxorubicin in various ways to the digital nerve stumps of ponies, degenerating or necrotic neurones appeared only sporadically in the spinal ganglia. Although doxorubicin was largely ineffective in ...
Cortical somatosensory-evoked potentials in the horse. Cortical somatosensory-evoked potentials (SEP) were recorded from thoracic and pelvic limbs in 15 horses (13 Thoroughbreds and 2 Quarter Horses). Ulnar nerve SEP were evoked by electrical stimulation of the lateral palmar branch of the ulnar nerve at the level of the metacarpophalangeal joint. Recordings were taken between electrodes at 2 cm lateral to the vertex (contralateral to the stimulated limb) and the midpoint of the interorbital line. Four peaks were found in all recordings: N1, P1, N2, and P2. Latencies to the peaks were 39.0 +/- 2.7, 45.5 +/- 5.3, 50.4 +/- 5.2, and 62.3 +/- 3.7 ms (...
Kairi virus identified from a febrile horse in Argentina. A virus isolated from the blood of a febrile horse in Argentina was identified as a strain of Kairi virus. This is the fifth Bunyamwera serogroup virus isolated from livestock and wild animals in the Americas. Bunyamwera serogroup viruses have been isolated from febrile humans in the Americas and Africa.
Clinical, histopathological, and immunological responses of ponies to Ehrlichia sennetsu and subsequent Ehrlichia risticii challenge. Ehrlichia risticii has a close antigenic relationship to E. sennetsu. Sera of ponies experimentally infected with E. risticii, the etiologic agent of Potomac horse fever, consistently reacted with E. sennetsu, a human pathogen, in indirect fluorescent-antibody (IFA) testing, while human E. sennetsu convalescent serum reacted with E. risticii by IFA testing and immunoferritin labeling of cells infected in vitro. Two ponies injected intravenously with live E. sennetsu did no develop clinical illness. Subsequent injection with live E. sennetsu did not develop clinical illness. Subsequent injectio...
Delayed repair of an extensive lip laceration in a colt using an Estlander flap. A vascularized full-thickness Estlander flap was used to repair a defect involving approximately 40% of the left lower lip of a colt. Postoperative problems were (1) providing nutritional support, (2) minimizing movement at the surgical site, and (3) partial wound dehiscence resulting in a salivary fistula. The surgical site healed well and the colt was left with a fully functional and cosmetic lower lip.
Prognostic index for acute abdominal crisis (colic) in horses. Selected physical and laboratory findings in 29 horses with acute abdominal crisis were evaluated retrospectively with a logistic regression equation to predict survival or death. Of 17 variables examined, 2 were found to have good predictive correlation. Serum lactate and packed cell volume had a combined predictive value of 94%. Packed cell volume mean values of 43 and 50%, respectively, differentiated survival from death. Serum lactate values of 28.18 mg/dl and 51.28 mg/dl differentiated survival and death. Analysis of data from a previous study of 36 horses with the logistic regression equ...
The use of intraneural doxorubicin in association with palmar digital neurectomy in 28 horses. Painful neuroma formation after palmar digital neurectomy in the horse is common. Experimentally, injection of doxorubicin (Adriamycin) into the proximal transected nerve stump has been shown to prevent axon sprouting and neuroma formation for up to 5 months. This procedure was used in 28 horses with navicular disease, preexisting painful neuroma, or wing fractures of the distal phalanx. At 1 month, 16 horses had incisional complications. At 1 year, 15 horses were sound. Eight horses were lame, although three were improved. Three horses required a second surgical procedure, two of which became...
BCG emulsion immunotherapy of equine sarcoid. Of 61 horses with sarcoids treated with intralesional injection of a double emulsion incorporating inactivated bacillus Calmette Guérin organisms, 36 (59 per cent) showed complete regression and 11 (18 per cent) showed partial regression. The majority of cases required only one treatment. Not all sarcoids were responsive to this therapy; those not responding were usually large or on horses with multiple sarcoids.
A method for reproducing fatal idiopathic colitis (colitis X) in ponies and isolation of a clostridium as a possible agent. Severe colitis was induced in two ponies after oral pretreatment with clindamycin and lincomycin, followed by intestinal content from two horses which had died from naturally-occurring idiopathic colitis. Two ponies treated with antibiotic alone, and two ponies treated with intestinal content alone, were unaffected. In a further study, three ponies treated on separate occasions with lincomycin, administered orally, died or were destroyed 67 to 72 h after initial treatment. No established salmonella, yersinia or campylobacter pathogens were isolated from these ponies, but a clostridium closely ...
Effects of cimetidine and ranitidine on basal gastric pH, free and total acid contents in horses. The basal gastric pH, free and total acid contents from five adult horses were determined at two-hour intervals for six- to eight-hour periods. The basal gastric pH, free and total acid contents varied from 2.14 +/- 0.08 to 2.41 +/- 0.14, 28.63 +/- 8.27 to 17.89 +/- 2.86 mmol litre-1 and 41.38 +/- 9.72 to 37.38 +/- 3.70 mmol litre-1, respectively. Cimetidine (8.8 mg kg-1 orally) and ranitidine (2.2 mg kg-1 orally) increased the basal gastric pH to above 3.6 (P less than 0.05) with a concomitant reduction of 75 per cent and 75 to 100 per cent in the basal gastric free acid content, respectively...
Production of monovalent anti-Bothrops asper antivenom: development of immune response in horses and neutralizing ability. A monovalent antivenom was produced by immunizing two horses with venom of the pit viper Bothrops asper (Ophidia: Viperidae). Although development of the immune response against four toxic and enzymatic activities of the venom was similar in both horses during the first two thirds of the immunization schedule, antibody response in one of the horses reached much higher levels in the last part of the immunization. Immunoelectrophoretic analysis indicates that there were precipitating antibodies in the sera of these horses during all the stages of immunization. However, immunoprecipitation did no...
Biochemical indicators of bone formation in foals after transfer from pasture to stables for the winter months. Serum alkaline phosphatase activity and serum concentrations of osteocalcin, free thyroxine, protein, and cholesterol were measured in 14 foals monthly from birth to 1 year of age. A transient decrease (P less than 0.05) in alkaline phosphatase activity and osteocalcin, free thyroxine, and cholesterol concentrations was found in November after transferring the horses from pasture to stables for the winter months. During the 2 subsequent months, serum alkaline phosphatase activity and osteocalcin concentration increased slightly. Protein concentration was highest in late fall and decreased (P l...
Preferred landing sites of Culicoides species (Diptera: Ceratopogonidae) on a horse in Israel and its relevance to summer seasonal recurrent dermatitis (sweet itch). Six hundred and twenty culicoides of five species were collected from a bait horse at Kannot, Israel, between April and September 1986. Seventy-two per cent of the midges were collected from the belly and 27 per cent from the dorsal aspect of the body, ie, the sweet itch summer seasonal recurrent dermatitis (SSRD) zone. Midges were active mainly from half an hour prior to half an hour after sunset. Only Culicoides puncticollis, C imicola and C schultzei group were collected in considerable numbers. While C imicola was present continuously throughout the season, the appearance of the two other ...
Effect of administration of an alpha 2-adrenergic agonist, xylazine, on pulsatile gonadotrophin secretion in anoestrous horse mares. Two experiments were performed to test the hypothesis that the seasonal suppression of gonadotrophin pulse frequency in anoestrous horse mares reflects inhibitory neural mechanisms. In a preliminary experiment (Exp. 1) conducted in February, 4 anoestrous mares were sedated by repeated intravenous injections of xylazine, an alpha 2-adrenergic receptor agonist. On the day of treatment, 1-2 LH pulses were observed in xylazine-treated mares. In contrast, during a 12-h period only 1/8 untreated control mares exhibited a LH pulse. In Exp. 2, the effect of xylazine-induced sedation on pulsatile gonad...
