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Topic:Animal Studies
Animal studies involving horses encompass a range of research focused on understanding equine biology, behavior, and health. These studies often investigate various aspects of horse physiology, genetics, nutrition, and disease pathology. Researchers utilize animal studies to explore the effects of different treatments, management practices, and environmental factors on horse welfare and performance. The findings from such studies contribute to the development of improved care strategies and health interventions. This page gathers peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of animal studies conducted on horses, providing insights into their application in advancing equine science.
Comparison of herniorrhaphy versus clamping of umbilical hernias in horses: a retrospective study of 93 cases (1982-1994). Many uncomplicated umbilical hernias have been managed successfully in foals by the application of a hernia clamp. Isolated reports of complications following clamp application have led some authors to suggest that it is an unsuitable method of treatment. Little information has been published comparing the complication rates associated with the use of hernia clamps and herniorrhaphy in the treatment of umbilical hernias. The purpose of this retrospective study was to report the characteristics of clinical cases of umbilical hernia and to compare the complication rates following these 2 treatme...
Pharmacokinetics and tolerance of florfenicol in Equidae. Florfenicol was administered to horses and ponies at a dose rate of 22 mg/kg bwt by i.v., i.m. and oral routes. Following i.v. administration it had an elimination half-life of 1.8 ± 0.9 h, a body clearance of 0.4 ± 0.11/h.kg and a volume of distribution at steady-state of 0.7 ± 0.2 1/kg. It was highly bioavailable following i.m. (81%) and oral (83%) administration. Less than 15% of the administered dose was excreted unchanged in the urine during the 30 h following administration. Animals treated with florfenicol had elevated bilirubin concentrations. Florfenicol was well tolerated by anima...
Oxygen affinity and Bohr effect responses to 2,3-diphosphoglycerate in equine and human blood. The dependence of blood oxygen affinity and the Bohr effect on the concentration of 2,3-diphosphoglycerate (DPG) in erythrocytes was investigated in 24 trotter horses and 24 healthy men. The oxygen tension at half saturation and standard conditions (P50st at pH 7.4, PCO2(40) mmHg and 37 degrees C) and the carbon dioxide or fixed-acid-induced Bohr effect (dlogP50/dpH) were determined. Samples of fresh blood and blood depleted of or enriched with DPG were studied. In the absence of measurable DPG, the equine and human blood had similar mean (SD) values of P50st (16.6 [0.6] and 16.2 [0.7] mmHg, r...
Strain-rate-dependent mechanical properties of the equine hoof wall. The mechanical properties of fully hydrated equine hoof wall were examined at various loading rates in compact tension (CT) fracture, tensile and three-point bending dynamic tests to determine possible effects of hoof wall viscoelasticity on fracture toughness and tensile parameters. Four cross-head rates were used in CT tests: 1.7 x 10(-5), 1.7 x 10 (-3), 1.7 x 10(-2) and 2.5ms-1; four strain rates were used in tensile tests: 1.6 x 10(-3), 3.2 x 10(-2), 0.33 and 70s(-1). Speeds for the highest test rates were achieved using a large, custom-built impact pendulum. Bending test frequencies range...
Cardiopulmonary effects of medetomidine in sheep and in ponies. Medetomidine was administered intravenously to six sheep at 5, 10 and 20 micrograms kg-1 and to one horse and four ponies at 5 and 10 micrograms kg-1. In both species medetomidine resulted in significant decreases in heart rate and cardiac output and, initially, in an increase in arterial blood pressure. In the ponies this increase in blood pressure was followed by a significant and prolonged decrease, but in the sheep the secondary decrease in blood pressure was not statistically significant. In the sheep, the three doses of medetomidine resulted in profound and significant decreases in arter...
The effects of locomotor-respiratory coupling on the pattern of breathing in horses. 1. To investigate the effect of locomotor activity on the pattern of breathing in quadrupeds, ventilatory response was studied in four healthy horses during horizontal and inclined (7%) treadmill exercise at different velocities (1.4-6.9 m s(-1)) and during chemical stimulation with a rebreathing method. Stride frequency (f(s)) and locomotor-respiratory coupling (LRC) were also simultaneously determined by means of video recordings synchronized with respiratory events. 2. Tidal volume (V(T)) was positively correlated with pulmonary ventilation (V(E)) but significantly different linear regressi...
Voltage-dependent calcium currents and cytosolic calcium in equine airway myocytes. 1. The relationship between voltage-dependent calcium channel current (I(Ca)) and cytosolic free calcium concentration ([Ca2+]i) was studied in fura-2 AM-loaded equine tracheal myocytes at 35 degrees C and 1.8 mM Ca2+ using the nystatin patch clamp method. The average cytosolic calcium buffering constant was 77 +/- 3 (n = 14), and the endogenous calcium buffering constant component is likely to be between 15 and 50. 2. I(Ca) did not evoke significant calcium-induced calcium release (CICR) since (i)[Ca2+]i scaled with the integrated I(Ca) over the full voltage range of evoked calcium currents, ...
Transvaginal aspiration. This article describes in detail the procedures for collection of equine oocytes using a transvaginal ultrasound probe. Success in obtaining oocytes from humans, bovines, and horses are presented. The effect of repeated follicular aspiration of both cattle and horses is reviewed.
Early embryonic development and evaluation of equine embryo viability. Tremendous progress has been made in the development of assisted reproductive techniques that may enhance the reproductive efficiency of the horse. However, techniques that involve the manipulation of oocytes and/or embryos may themselves be detrimental to embryo viability and subsequent development. Therefore, an objective method of assessing viability of embryos before and/or after oocyte/embryo manipulation is desirable. At this time, morphologic evaluation is the most widely used method of determining the viability of equine embryos. Although morphologic assessment of embryo quality will n...
[Acute pain in the horse and one possibility for its objective evaluation]. To judge acute processes of pain objectively the results are told of a determination of adrenaline and noradrenaline in the plasma of 30 horses suffering from pain. Besides a scheme basing on an awarding of points is developed to ascertain changes of physiological and ethological parameters caused by pain. These results in changes of behaviour are compared to results determined by laboratory experiments. Concerning pain of medium and high level a relation to the concentration of catecholamines is noticed. Therefore the total of certain clinical observations is suitable for graduating acute pai...
Methods for the Detection of Trichinellosis in Horses. Twelve horses were infected with various doses of Trichinella spiralis and then tested for infection using direct (artificial digestion) and indirect (enzyme immunoassay) methods. Horses became infected in a dose-dependent manner. Larvae accumulated preferentially in the tongue, followed by the masseter, neck, supraspinatus, trapezius, and diaphragm. At lower infection levels, the tongue harbored several times more parasites than were found in other tissues. The sensitivity of artificial digestion methods for detecting infections was directly related to sample size. One-gram samples were not r...
Seasonality and freezability vs routine parameters in stallion semen. The fertilizing ability of stallion semen was analyzed using fresh and frozen samples, obtained before (June-July) or during (October-November) the breeding season. Thirty ejaculates obtained from 4 stallions were used. The analysis comprises routine seminogram; ATP concentration (Comhaire et al., 1983); subjective and objective motility and sperm velocity (Makler, 1980). Freezing was done following the technique of Martin et al. (1979). Sperm velocity, ATP content and objective motility in ejaculates of subjective motility >50% show values of 14.0 + or - 0.84 mu m s(-1); 4.8 + or - 2.7x10(...
Viability of split-thickness skin grafts attached with fibrin glue. Full-thickness, circular, cutaneous wounds (4 cm diameter) were created on metacarpi and metatarsi of 5 horses. On day 6, all 4 wounds on each horse received a stored autogenous split-thickness sheet graft. Grafts were obtained from the horse's ventrolateral thorax with a pneumatic dermatome at the time the cutaneous wounds were created. Grafts were coapted to the granulation bed of 2 wounds of each horse with fibrin glue. Grafts were coapted to the cutaneous margin of all 4 wounds of each horse with cyanoacrylate glue. Bandages were changed daily until the study ended at 14 d. When the bandag...
Zoo-FISH delineates conserved chromosomal segments in horse and man. Human chromosome specific libraries (CSLs) were individually applied to equine metaphase chromosomes using the fluorescence in situ hybridization (FISH) technique. All CSLs, except Y, showed painting signals on one or several horse chromosomes. In total 43 conserved chromosomal segments were painted. Homoeology could not, however, be detected for some segments of the equine genome. This is most likely related to the very weak signals displayed by some libraries, rather than to the absence of similarity with the human genome. In spite of divergence from the human genome, dated 70-80 million yea...
Cloning and sequencing of an equine insulin-like growth factor I cDNA and its expression in fetal and adult tissues. A cDNA for equine insulin-like growth factor I (IGF I) has been isolated by reverse transcriptase-polymerase chain reaction and subsequently sequenced. The sequenced fragment contained 465 bp including the coding regions for the signal peptide, the entire mature protein, and 4 amino acids into the E-peptide. Like its human counterpart, the mature equine IGF I peptide contains 70 amino acids and was 100% homologous between horse and man. The 49-amino-acid signal peptide had the threonine in position 26 of the human signal peptide substituted by isoleucine. The nucleotide homology across the ent...
Ageing horses by an examination of their incisor teeth: an (im)possible task? It is generally considered that the age of a horse can be determined by examining its incisor teeth. However, the criteria used to determine age from dental configurations differ widely. The existence of this variety of rules and guidelines was the challenge for the present examination. Detailed descriptions of the incisor teeth of 212 horses of registered age were recorded and the results were compared with the age criteria of various authors. The time at which teeth were shed and the appearance of dental stars seemed to be more reliable features than the disappearance of the cups. The disapp...
The integrative control of adrenocorticotrophin secretion: a critical role for corticotrophin-releasing hormone. Perifused equine anterior pituitary cells were used to investigate the relationships between the secretion of ACTH and substances known to either stimulate (corticotrophin-releasing hormone (CRH), and arginine vasopressin (AVP)) or inhibit (cortisol) ACTH secretion. The experiments were designed to mimic the hormone milieu present in vivo in the horse, with cortisol (0 or 100 nmol/l) and CRH (0 or 0.02 nmol/l) perifused continuously, and pulses of AVP (10 nmol/l) applied for 5 min at 30-min intervals. In columns perifused with 0.02 nmol CRH/l there was no significant overall effect of 100 nmol...
Tendon strain in the forelimbs as a function of gait and ground characteristics and in vitro limb loading in ponies. Strains in the tendons of the m. flexor digitalis superficialis (superficial digital flexor, SDFT) and m. flexor digitalis profundus (deep digital flexor, DDFT) tendons, the accessory ligament of the deep digital flexor muscle (inferior check ligament, ICL) and the m. interosseus medius (suspensory ligament, SL) of 5 ponies were recorded at the walk and trot using mercury-in-silastic strain gauges (MISS), on a hard surface (brick pavement) and on sand. The horses were shod with normal, flat shoes. On pavement, strain in the SDFT, DDFT and SL increased significantly from the walk (2.19%, 1.15% ...
Influence of shoeing on ground reaction forces and tendon strains in the forelimbs of ponies. Strains in the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), accessory ligament of the deep digital flexor muscle (inferior check ligament [ICL]) and the interosseus medius muscle (suspensory ligament [SL]) in the right forelimb of 5 ponies were measured using mercury-in-silastic strain gauges a few hours after implantation. Tendon strains were recorded at the walk with normal flat shoes, egg-bar shoes, a 7 degrees increased hoof angle accomplished by application of a heel-wedge and a 7 degrees decreased hoof angle using a toe-wedge, consecutively. Ground reactio...
Prevalence of sarcocysts in livestock of northwest Ethiopia. A survey of Sarcocystis was conducted in cattle, sheep, goats, donkeys and chickens. A total of 671 haematoxylin-eosin (H-E) stained muscle tissue samples, including diaphragm, masseter, cardiac and oesophageal musculatures were examined. Additionally, cardiac muscle samples from 40 fetuses were included. An infestation rate of 93% in sheep, 82% in cattle, 81% in goats, 16.6% in donkeys and 6.6% in chickens was noted. The infestation rate of diaphragm, masseter, cardiac and oesophageal musculatures seems to be similar. None of the 40 fetal heart muscle samples from bovine, ovine, caprine and d...
Similarities and differences in supporting and chromaffin cells in the mammalian adrenal medullae: an immunohistochemical study. The adrenal medulla is a typical paraganglion, having the same origin as the sympathetic ganglia, and contains at least two types of parenchymal cells: chromaffin cells and supporting cells. We previously reported that the extent of cellular association of chromaffin cells with supporting cells was remarkably higher in noradrenaline (NA)-than in adrenaline (A)-cell regions in the adrenal medullae of the rat and pig. Methods: Cryostat sections of adrenal medullae of nine mammalian species fixed with Zamboni fluid for 24 h were immunostained by ABC methods using antisera to S-100 protein and PNM...
Pharmacokinetics of lignocaine in Icelandic horses after infiltration anaesthesia. The pharmacokinetics of lignocaine was studied in four Icelandic horses after infiltration anaesthesia. A total of 240 mg of the drug was injected on either side of the left foreleg, over the medial and lateral branches of the palmar nerve. Blood samples were collected up to seven hours after injection and the concentrations of the drug in plasma were determined by gas chromatography/mass spectrometry. The results showed that lignocaine was rapidly absorbed. A mean maximum concentration of 232 ng/ml was observed after 20 minutes. In three of the horses the decline in the plasma concentration o...
Differential suppression of endometrial prostaglandin F2alpha by the equine conceptus. Prostaglandin F2alpha secretion by the uterine endometrium between Days 13 and 14 postovulation causes luteal regression in mares. A mechanism involving interruption or suppression of this secretion causes pregnancy to be maintained. The present study was designed to determine the age of the conceptus when maximal suppression of PGF2alpha secretion occurs. Mares were examined daily during estrus with ultrasonography (day 0 = day of ovulation). Conceptus tissues were recovered nonsurgically on Days 9 (n = 7), 12 (n = 5), 13 (n = 5), and 16 (n = 7) and uterine biopsies on Day 14. Both uterine an...
Lipid peroxide levels and superoxide-scavenging abilities of Sera obtained from hotbred (Thoroughbred) horses. Hotbred (Thoroughbred) horses were grouped into three classes according to the levels of constant physical exercise (foals, 6 months old; racing horses, 5 years old; horses for breeding, 6-10 years old), and lipid peroxide levels in their sera were measured as thiobarbituric acid-reactive substances. No significant differences were observed among them. The superoxide-scavenging abilities of sera were measured next; to examine the antioxidative properties of hotbreds, and were found to be highest in the racing horses. The higher scavenging ability of the racing horses might contribute to keep t...
