"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.
Chen SS, Engel PC.1. The inactivation of horse liver alcohol dehydrogenase by pyridoxal 5'-phosphate in phosphate buffer, pH8, at 10 degrees C was investigated. Activity declines to a minimum value determined by the pyridoxal 5'-phosphate concentration. The maximum inactivation in a single treatment is 75%. This limit appears to be set by the ratio of the first-order rate constants for interconversion of inactive covalently modified enzyme and a readily dissociable non-covalent enzyme-modifier complex. 2. Reactivation was virtually complete on 150-fold dilution: first-order analysis yielded an estimate of the r...
Plotka ED, Foley CW, Witherspoon DM, Schmoller GC, Goetsch DD.Concentrations of progesterone and estrogen were measured in peripheral blood plasma samples from mares around the time of ovulation. Samples were collected every 2 hours from 36 hours before, to 26 hours after, ovulation and assayed by radioimmunoassay. Progesterone concentrations were between 60 and 100 pg/ml for the period 24 hours before ovulation through 8 hours after ovulation. By 10 hours after ovulation, concentrations increased to 140 pg/ml and, by 26 hours after ovulation, reached 346 pg/ml. Plasma estrogen concentrations did not change significantly throughout the same period.
Hara A, Taketomi T.Equine renal glycopshingolipids were composed of galactocerebroside, glucocerbroside, ceramide dihexoside, ceramide trihexoside, sulfatide, globoside I, Forssman globoside, and hematoside. Free ceramide and sphingomyelin were also found in equine kidney. Their long chain bases consisted of sphingosine, dihydrosphingosine, C18-phytosphingosine, and C20-phytosphingosine, whereas the fatty acids were separated into two groups: nonhydroxy and hydroxy fatty acids. Ceramide monohexoside was separated into five spots by TLC on borax-impregnated plates. The major component of ceramide monohexoside was...
Thomas RJ.An antigen for the gel diffusion test for equine infectious anaemia (EIA) was prepared from the spleen of a horse experimentally infected with the CQ strain of the virus. The antigen produced a single, distinct line of precipitation when tested against a range of known positive serums, and did not react with pre-inoculation and known negative serums. Extracts prepared from uninfected spleens displayed no reaction when similarly tested. Serum from 34 of 451 Queensland horses contained detectable levels of antibody to EIA virus. The positive serums were from horses in widely separated areas of t...
Sack WO.The nerve distribution to the digit of the horse was studied with the compound microscope in serial transverse sections of fetal limbs and plotted on life-size outlines of the horse's foot. It was learned that there is much variation in the topography of the branches of the principal nerves. There is no mirror-image nerve distribution on the 2 sides of the foot. The dorsal branch of the ulnar nerve does not extend below the fetlock. The communication between the palmar metacarpal nerves and branches of the dorsal branch of the digital nerves is only a crossing of nerves without exchange of fib...
Warme PK, Scheraga HA.The reported X-ray structure of horse-heart ferricytochrome c has been refined by conformational energy calculations, using a three-stage computational procedure. In stage I, the atomic positions are adjusted to conform to idealized bond lengths and bond angles characteristic of small amino acid derivatives, while yet remaining as close as possible to the X-ray coordinates. In stage II, atomic overlaps are eliminated by adjusting the backbone and side-chain dihedral angles to minimize the nonbonded energy, hydrogen-bonded energy, and rotational energy contributions. In the final stage of refin...
Drew B, Barber WP, Williams DG.On a thoroughbred stud four foals were born with greatly enlarged thyroids and leg weakness. Two foals died within 18 hours of birth, the others subsequently recovered. An enlarged thyroid was also evident in one of the resident mares. The thyroids from the dead foals were hyperplastic. Feed analyses showed that the mares had an iodine intake of about 83 mg daily, 8-8 ppm of the dietary dry matter, due almost entirely to the high iodine content of a proprietary compound horse nut which had been fed at the daily rate of 12 lb per head. It was concluded from the histology of the thyroids, the hi...
Hall LW, Trim CM.Horses breathing spontaneously under halothane anaesthesia were subjected to expiratory resistance by the introduction of a water-trap into the expiratory limb of a circle absorber. Resistances of 10 and 20 cm H2O produced no significant increase in PaO2 (P greater than 0.05) during halothane/air and halothane/oxygen anaesthesia. The imposition of resistance was associated with an increase in PaCO2 and a significant increase in mixed venous PCO2. In three animals subjected to 20 cm H2O resistance under halothane/air anaesthesia, the cardiac output was reduced (P less than 0.01). It was conclud...
Pauli B, Althaus S, Von Tscharner C.Migrating fourth-stage larvae of Strongylus vulgaris, a parasite of equines, damage the intima of the anterior mesenteric artery and its larger branches and induce thrombus formation on the injured sites. As the time of larval passage through each of these branches has been exactly determined in earlier experiments, the aim of the present studies is to contribute to a more complete understanding of repair mechanisms in the process of time after thrombotic vascular injuries. Methods: five foals were separated individually to specially cleaned stables and given anthelmintic treatment till the ag...
Meurice A, Pujol R, De Fourmestraux C, Coquillon M, Tessier C.Surgical approaches to the equine rectum and perirectal area are described in the literature. However, surgeries in this region can be challenging. Objective: To describe the surgical anatomy of the presacral space and to evaluate its access using a retroperitoneoscopic approach. Methods: Ex vivo experiment. Methods: Preliminary dissections were performed in two cadavers to define the boundaries of the presacral space and to determine portal locations for the surgical approach. After that, nine cadavers were used for experimental presacral retroperitoneoscopic procedure in a standing position....
Freeman DE.Wounds of the esophagus and trachea are uncommon, but closed wounds can be difficult to diagnose and treat. Esophageal wounds are the more serious and can be life-threatening; however, appropriate surgical and medical treatment applied without delay can be successful in some cases, especially in full-thickness longitudinal wounds. Tracheal wounds are usually less severe, but the high risk of iatrogenic injuries to the trachea should be recognized. Also, tracheal injuries can limit the athletic potential of a horse.
Ahern BJ, Bayliss IPM, Zedler ST, Getman LM, Richardson DW.To report on a series of 4 horses with supraglenoid tubercle fractures repaired with locking compression plates. Methods: Case series. Methods: Four horses ranging in age from 6 weeks to 20 months and weighing from 121 to 425 kg with supraglenoid tubercle fractures of 1 day to 6 weeks in duration. Methods: Supraglenoid tubercle fractures were reduced and stabilized with transversely positioned locking compression plate(s) with and without additional tension band wiring. Results: All fractures reached bony union. Two postoperative surgical site infections were managed with drainage and antibiot...
Schumacher J, Taintor J, Schumacher J, Degraves F, Schramme M, Wilhite R.The role of the communicating branch between the medial and lateral palmar nerves of horses (i.e. the ramus communicans) in conveying sensory impulses proximally should be determined to avoid errors in interpreting diagnostic anaesthesia of the palmar nerves. Objective: Sensory nerve fibres in the ramus communicans of horses pass proximally from the lateral palmar nerve to merge with the medial palmar nerve, but not vice versa. Objective: To determine the direction of sensory impulses through the ramus communicans between lateral and medial palmar nerves. Methods: Pain in a thoracic foot was c...
Colles CM.This paper describes the application of foil strain gauges to the hoof wall, and the use of measuring equipment to monitor weightbearing and changes in hoof shape in shod and unshod horses. It concludes that the systems can detect hoof movement and that results are reproducible. It is also concluded that the use of a conventional nailed on iron shoe restricts flexion and spreading of the hoof wall at the ground surface, but has little effect on the degree of expansion of the heels of the foot.
Schmid DO, Ek N, Braend M.A silent allele in the transferrin locus (Tf) was observed in a Thoroughbred mare and in five of her offspring from three different matings. Evidence for the silent allele was obtained by quantitative immunodiffusion studies.
Anderson BH, Ethell MT.A number of methods for the local delivery of drugs to musculoskeletal tissues in the horse are now available. Further research is required to document the disposition of drugs delivered by such methods and to correlate this information with efficacy. Perhaps the greatest potential area for the methods discussed is the treatment of synovial and bone infections. To be able to provide high and sustained therapeutic concentrations of antimicrobials to the site of infection should increase the chances of success in such cases. These methods of drug delivery need to be used in conjunction with othe...
Lamarque D, Haessler C, Champion R, Granga D, Bendina , Steinmetz P, Guelina A, Maurice Y.An epidemic of human and animal anthrax raged in Chad mainly in the Department of Chari Baguirmi from September to December 1988, infesting more than 50% of donkeys and horses. 716 human cases have been reported, with 88 deaths. Thanks to a geographical distribution of animal and human prevalence, one sees immediately the interdependency between sanitary state of live-stock and public health. An unusual means of transmission from donkey to donkey by insects as the vector is suggested to explain the intensity of animal epidemics. Two strains of B. anthracis were isolated and described. Systemat...
Schneider RK, Ratzlaff MC, White KK, Hopper SA.To determine effect of 3 half-limb casts on bone strains recorded from the proximal phalanx (P-1) and third metacarpal bone (MCIII) of equine cadaver limbs, using a mechanical testing machine. Methods: 12 equine cadaver limbs and 4 live horses. Methods: Bone strains were recorded at middorsal P-1 and the dorsal cortical aspect of the distal third of MCIII while limbs were variably loaded with 100 to 1,000 lb of force. To determine ability of the cast to protect the distal portion of the limb from weight-bearing loads, strains were recorded with the limb in 1 of the 3 casts and with it unsuppor...
Burrows GE, MacAllister CG, Tripp P, Black J.The potential for interactions between chloramphenicol, phenylbutazone, acepromazine and thiamylal and chloramphenicol, rifampin, and phenylbutazone were evaluated in two groups of experiments. In the first, five horses were given thiamylal intravenously (iv) (6.6 mg/kg) after pretreatment with acepromazine, and the time of recumbency was determined. Administration of chloramphenicol iv (25 mg/kg) 1 h prior to anaesthesia significantly lengthened the recumbency time from 21.8 +/- 4.8 mins to 36.0 +/- 8.3 mins. There was an apparent but not statistically significant decrease in recumbency time ...
Peeters MWJ, Thursby JJ, Watson HE, Berner D.Palmaroproximal-palmarodistal oblique (PaPr-PaDiO) radiographs are regularly obtained for a full evaluation of the navicular bone (NB). Despite their routine use, different acquisition techniques are described. Objective: To determine optimal foot placement and beam angle for obtaining PaPr-PaDiO views. Methods: In vitro experiment. Methods: A convenience sample of 26 disarticulated forelimbs were placed in six different positions using a leg press to mimic the weight-bearing position. In each position, navicular PaPr-PaDiO images were obtained with eight different beam angles. The resulting 1...
Wille KH, Zahner M.The vascular system of the large intestine of 12 horses was examined by means of vascular corrosion casts, histology and transmission electron microscopy providing the following results. The Aa. et Vv. breves et longae leave the mesenteric vessels, respectively the subserously on the teniae lying cecal vessels to reach the tela subserosa at the mesenteric margin. The short vessels enter the deeper layers of the wall instantly, whereas the Aa. et Vv. longae move towards the submucosa by penetrating the muscular layers after a variable subserous course. The tela submucosa contains an arterial an...
Körber HD.Radiographic examination is a valuable means for the identification of ossified lateral cartilage. The extent and stages of development of the ossification can be determined. The active stage of development of ossified lateral cartilage, which by itself can provoke lameness, can be defined. By means of the X-ray it is tried to differentiate the three kinds of ossification: the enchondral, the peri- and parachondral ossification of the lateral cartilage. Centres of ossification and fractures of the ossified lateral cartilage are described.
Shrauner B, Blikslager A, Davis J, Campbell N, Law M, Lustgarten M, Prange T.The large size of the adult horse prevents the use of advanced imaging modalities in most areas of the axial skeleton, including the lumbosacral vertebral column. Traditional imaging techniques are frequently unable to pinpoint the underlying pathology in horses with caudal back pain. In man, lumbosacral epiduroscopy is used to diagnose and treat subjects with chronic back and leg pain. This technique may close the diagnostic gap in horses with similar clinical signs. Objective: To evaluate the safety and feasibility of lumbosacral epiduroscopy in the standing adult horse. Methods: Descriptive...
