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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.
Metabolism of methandrostenolone in the horse: a gas chromatographic-mass spectrometric investigation of phase I and phase II metabolism. The phase I and phase II metabolism of the anabolic steroid methandrostenolone was investigated following oral administration to a standardbred gelding. In the phase I study, metabolites were isolated from the urine by solid-phase extraction, deconjugated by acid catalysed methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. GC-MS analysis indicated the major metabolic processes to be sequential reduction of the A-ring and hydroxylation at C6 and C16. In the phase II study, unconjugated, beta-glucuronidated and sulfated metabolites were fractionated and deconjugated us...
Successful production of offspring after superovulation and in vitro culture of embryos from domestic ferrets (Mustela putorius furos). In an effort to expand the use of ferrets as models for genetic disease, several experimental parameters that are required for successful genetic manipulation in this species were investigated. Optimum superovulation (19.3 +/- 0.6 oocytes and embryos per female) was achieved after injections of 100 iu equine chorionic gonadotrophin (eCG) and 150 iu human chorionic gonadotrophin (hCG). The ovulation rate achieved by the treatment was more than double that induced by mating. Mating with a male immediately after hCG treatment did not significantly alter the number of oocytes ovulated or the numbe...
Horse resistance to natural infestations of Anocentor nitens and Amblyomma cajennense (Acari: Ixodidae). The objective of this study was to investigate some aspects of horse resistance to natural infestations of Anocentor nitens and Amblyomma cajennense over a 2-year period. Free-living stages of A. nitens were used to evaluate the influence of season of the year on horse resistance. Every 2 weeks, 10 selected engorged females, weighing 150-329 mg, were removed from naturally infested horses and were individually placed into glass tubes closed with a cotton stopper, and maintained in an incubator. The biological parameters evaluated varied according to the season of the year, i.e., reproductive e...
Daily treatment of horses with equine somatotropin from 4 to 16 months of age. Fourteen foals between 4 and 4.5 mo of age were used to determine the effects of 12 mo of daily treatment with equine somatotropin (eST) on growth, metabolic, and hormonal characteristics. The foals were paired by sex, type, and lineage, and one of each pair was administered eST daily at 20 microg/kg of BW. Body weights, body measurements, and assessments of glucose tolerance and feedback effects on endogenous somatotropin (ST) secretion were made routinely. Treatment with eST did not alter (P > 0.10) BW, height at withers, length of body, widths of chest and rump, heart girth, length of he...
Rapid intrachain binding of histidine-26 and histidine-33 to heme in unfolded ferrocytochrome C. Time-resolved spectroscopic studies of unfolded horse iron(II) cytochrome c have suggested that the imidazole side chains of His26 and His33 bind transiently to the heme iron on microsecond time scales, after photodissociation of a carbon monoxide ligand from the heme. Our studies of four variants of cytochrome c (horse wild type, horse H33N, horse H33N/H26Q, and tuna wild type), unfolded in guanidine hydrochloride at pH 6.5, demonstrate that these side chains are responsible for the observed microsecond spectral changes. As His33 and then His26 are eliminated from the horse wild-type sequence...
Loading the problem loader: the effects of target training and shaping on trailer-loading behavior of horses. The purpose of this study was to develop an effective method for trailer loading horses based on principles of positive reinforcement. Target training and shaping were used to teach trailer-loading behavior to 5 quarter horse mares in a natural setting. All 5 had been trailer loaded before through the use of aversive stimulation. Successive approximations to loading and inappropriate behaviors were the dependent variables. After training a horse to approach a target, the target was moved to various locations inside the trailer. Horses started training on the left side of a two-horse trailer. A...
Detection of rabies virus RNA isolated from several species of animals in Brazil by RT-PCR. Brain samples from different animal species including humans: five vampire bats, 14 cattle, 12 dogs, 11 cats, two horses, one pig, one sheep and three humans collected from various geographical regions of Brazil were found to be positive for rabies by means of the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). The brain samples were retested for rabies by means of the reverse transcription and polymerase chain reaction (RT-PCR) with 2 primer sets (P1/P2 and RHNI/RHNS3), which amplified full or partial regions on the nucleoprotein (N) gene of the rabies virus, respectivel...
In vitro microelectrode study of the electrical properties of smooth muscle in equine ileum. Intracellular microelectrode recordings were made from smooth muscle cells in cross-sectional preparations of equine ileum, superfused in vitro. Membrane potential oscillations and spike potentials were recorded in all preparations, but recordings were made more readily from cells in the longitudinal muscle layer than from cells in the circular layer. The mean (se) resting membrane potential (RMP) of smooth muscle cells in the longitudinal muscle layer was -51.9 (1.2) mV, and the membrane potential oscillations in this layer had a mean amplitude of 4.8 (0.4) mV, a frequency of 9.0 (0.1) cycles...
[Eight polymorphic blood protein systems in Arab horses from Turkey]. Analysis of the blood protein system was used to study the genetic composition of Arabian horses. Biochemical markers of eight polymorphic loci (Tf, Al, Es, AlB, Gc, Hb, PGD, and PGM) were electrophoretically identified in blood samples. A total of 43 phenotypes were identified for these polymorphic systems. The Tf, Hb, and Es loci appeared to be more polymorphic than the other loci studied. Statistically significant differences between the observed and expected genotypic frequencies were found for the PGD and PGM loci (P < 0.05 and P < 0.01, respectively). Individual allele frequencies,...
Damper for bad vibrations. This research presents the hypothesis and findings that short muscle fibers in horses and other large mammals may protect bones and tendons from damaging vibrations during running, negating the previous […]
Horses damp the spring in their step. The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle-tendon units.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes...
Detection of DNA damage in response to cooling injury in equine spermatozoa using single-cell gel electrophoresis. Single-cell gel electrophoresis (SCGE), or comet assay, has the ability to detect damage at the single cell level and has not been reported for equine sperm. The ability to detect nuclear damage at the single cell level could aid in the advancement of protocols for optimal semen preservation. The goals of these experiments were to adapt this assay for use with equine sperm and to utilize the assay for determining the integrity of equine sperm DNA following treatments with storage at various decreased temperatures (-20 degrees C and 5 degrees C). Results from experiments in which sperm were fro...
Advancements in cryopreservation of domestic animal embryos. The development of embryo freezing technologies revolutionized cattle breeding. Since then, advancements in cryobiology, cell biology, and domestic animal embryology have enabled the development of embryo preservation methodologies for our other domestic animal species, including sheep and goats. Recently, technologies have been developed to cryopreserve pig embryos, notorious for their extreme sensitivity to cooling; horse embryo cryopreservation is in its infancy. While cryopreservation can enhance the utilization of in vitro embryo production technologies, cryosurvival of in vitro-produced ...
Cultures of equine respiratory epithelial cells and organ explants as tools for the study of equine influenza virus infection. Equine nasal turbinate epithelial cells and tracheal rafts were maintained with sustained viability in culture. Both types of culture supported productive replication of equine influenza virus (equine-2, subtype H3N8) and cell death occurred through apoptosis following viral infection. Thus, primary respiratory epithelial cell and organ cultures of equine origin may be valuable as alternatives to the intact animal for studying the virus-host interaction of equine respiratory viruses including influenza.
Population study and validation of paternity testing for Thoroughbred horses by 15 microsatellite loci. Microsatellite 15 TKY System was characterized for parentage verification of horse registry. The Microsatellite 15 TKY System was constructed by using 15 microsatellites, TKY279, TKY287, TKY294, TKY297, TKY301, TKY312, TKY321, TKY325, TKY333, TKY337, TKY341, TKY343, TKY344, TKY374, and TKY394, to provide stringent PCR-based microsatellite typing specifically optimized for multicolor fluorescence detection. The Microsatellite 15 TKY System showed good resolutions for 250 unrelated Thoroughbred horses, and the probability of exclusion (PE) at each microsatellite ranged from 0.437 to 0.621, resul...
An approach to assessment of the efficiency of dietary energy utilization by horses and ponies kept at riding schools. The ratio of calculated net energy intake (NEi) to calculate net energy requirement (NEr) might serve as an indicator of the efficiency of dietary energy utilization. The ratio was determined for 93 horses and ponies from 10 riding schools. For each animal with an assumed constant body weight, energy intake and energy requirements were assessed. On average, the estimated NEi was 14% greater than NEr. There was a significant, negative association between crude fibre intake and the NEi: NEr ratio. Earlier work indicated that extra fat intake may lead to over estimation of the calculated energy v...
Effects of exercise on biomechanical properties of the superficial digital flexor tendon in foals. To determine the effects of exercise on biomechanical properties of the superficial digital flexor tendon (SDFT) in foals. Methods: 43 Dutch Warmblood foals. Methods: From 1 week until 5 months of age, 14 foals were housed in stalls and not exercised, 14 foals were housed in stalls and exercised daily, and 15 foals were maintained at pasture. Eight foals in each group were euthanatized at 5 months, and remaining foals were housed together in a stall and paddock until euthanatized at 11 months. After euthanasia, SDFT were isolated and fit in a material testing system. Mean cross-sectional area ...
Effects of oral administration of phenylbutazone to horses on in vitro articular cartilage metabolism. To evaluate the effects of orally administered phenylbutazone on proteoglycan synthesis and chondrocyte inhibition by IL-1beta in articular cartilage explants of horses. Methods: 11 healthy 1- to 2-year-old horses. Methods: Horses were randomly assigned to the control (n = 5) or treated group (4.4 mg of phenylbutazone/kg of body weight, p.o., q 12 h; n = 6). Articular cartilage specimens were collected before treatment was initiated (day 0), after 14 days of treatment, and 2 weeks after cessation of treatment (day 30). Proteoglycan synthesis and stromelysin concentration in cartilage extracts ...
[Analysis of the genetic structure of the breeding nucleus of the Russian population of purebred Thoroughbred horses at the Extension locus using molecular DNA typing]. Results of the first in Russia survey of the gene pool of the breeding nucleus of the Russian population of thoroughbred horses by means of PCR analysis of the E (Extension) locus MC1R gene mutations are presented. The data on the structure of breeding populations from the leading stud farms Voskhod and Oros with regard to color phenotypes as well as genotype and allele frequencies are presented. The population structure parameters are discussed with respect to possible specific features of microevolution processes.
The equine larynx. Abstract Extract A series of landmark studies on the function of the equine larynx was conducted by a group of researchers at Massey University between 1970 and 1987. These studies commenced with investigations on the normal laryngeal anatomy and physiology (Goulden et al 1976a; Anderson et al 1980; Quinlan et al 1982), and progressed to a clinical appraisal of laryngeal hemiplegia, the most important clinical disease affecting the horse's larynx (Goulden and Anderson 198 lab, 1982). The studies concluded with a series of in-depth cytological and pathological studies of the intrinsic laryngeal...
Blood plasma concentrations of insulin-like growth factor-I (IGF-I) in resting standardbred horses. A survey of standardbred horses was conducted to build up a normal population profile for insulin like growth factor-I (IGF-I) concentrations in racing standardbreds and to ascertain how age, sex and geographic location affect IGF-I. Blood samples were drawn by jugular venepuncture from 202 racing standardbred horses aged one to eight years located in five different geographic regions of New Zealand. IGF-I concentrations were determined by insulin like growth factor-I binding protein (IGFBP)-blocked radioimmunoassay validated for the horse. As described in other species, age played a significa...
Morphology, histochemistry, and function of epaxial cervical musculature in the horse (Equus caballus). The semispinalis capitis and splenius muscles of the horse were analyzed for gross morphology, microarchitecture, fiber length, and fiber type. Although these two muscles are similar in size and anatomical position, they are very different from one another in structural design and histochemistry, implying diverse functional roles in the animal's behavior. The histochemical staining profile was limited to two fiber types: slow oxidative and fast glycolytic. The splenius muscle has simple architecture, long fibers, and a 60/40 ratio of SO to FG cross-sectional area. The semispinalis capitis has ...
Advances in cooled semen technology. In the horse industry, milk or milk-based extenders are used routinely for dilution and storage of semen cooled to 4-8 degrees C. Although artificial insemination (AI) with chilled and transported semen has been in use for several years, pregnancy rates are still low and variable related to variable semen quality of stallions. Over the years, a variety of extenders have been proposed for cooling, storage and transport of stallion semen. Fractionation of milk by microfiltration, ultrafiltration, diafiltration and freeze-drying techniques has allowed preparation of purified milk fractions in ord...
The cream dilution gene, responsible for the palomino and buckskin coat colours, maps to horse chromosome 21. The colour locus historically referred to as C in the horse is linked to microsatellites markers on horse chromosome 21. Preliminary results demonstrated linkage of Ccr, thought to be the cream dilution variant of the C locus, to HTG10. An analysis of horse chromosome 21 using additional families confirmed and established a group of markers linked to Ccr. This work also improved the resolution of previously reported linkage maps for this chromosome. Linkage analysis unambiguously produced the map order: SGCV16-(19.1 cM)-HTG10-(3.8 cM)-LEX60/COR73-(1.3 cM)-COR68-(4.5 cM)- Ccr-(11.9 cM)-LEX31. C...
Point mutation of neu oncogene in animal peripheral nerve sheath tumors. Thirty-four peripheral nerve sheath tumors of four domesticated animal species were characterized and assayed for point mutation of the neu oncogene. Based on their morphoimmunophenotype, 32 tumors were classified as schwannomas. Schwannoma morphology was characterized by the presence of Antoni type A and B pattern and immunoreactivity for S-100 protein and vimentin. Two anaplastic and metastatic tumors originating from spinal cord root, immunonegative for S-100 protein and positive for vimentin, were classified as malignant peripheral nerve sheath tumors (MPNSTs). Four malignant schwannomas a...
A method to determine mechanical energy conservation and efficiency in equine gait: a preliminary study. Metabolic and mechanical energy costs of locomotion can be combined to calculate locomotor efficiency, which is the quotient of the mechanical energy and metabolic costs. The purpose of this pilot study was to evaluate the mechanical and metabolic energy costs of locomotion at a range of 7 trotting speeds (2.5 to 6.2 m/s) on a level treadmill. A single, sound Thoroughbred horse was modelled as a system of 15 linked segments incorporating all 4 limbs, head, neck and trunk. The horse performed a continuous incremental exercise test at increasing trotting speeds while VO2 was recorded using a bre...
