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Topic:Equine Science
Equine Science encompasses the study of horses and their management, health, and performance. This field integrates various scientific disciplines such as biology, genetics, nutrition, physiology, and veterinary medicine to understand and improve the well-being and capabilities of horses. Areas of focus include equine anatomy, reproduction, behavior, and disease prevention. Research in equine science aims to enhance horse care, optimize training and performance, and address health challenges. This page compiles peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine science, providing insights into the latest advancements and methodologies in the field.
The gait of pacers. 1: kinematics of the racing stride. Standardbred pacers have been studied under race conditions to describe the gait of the pacer, and to determine relationships between stage of the race, finish order and selected gait kinematics. Overlap increased with the stage of the race while pacing speed decreased marginally for low order pacers and increased for high order finishers. High order finishing pacers appear to have greater stance and stride lengths than do low order finishers. Pacers could be separated into low order and high order groups on the basis of their movement patterns. High order pacers exhibited greater ranges of li...
The pattern of venous drainage of the equine ileocaecal junction. The veins draining the ileocaecal junctions of horses (n = 19), donkeys (n = 3) and a plains zebra, (Equus burchelli antiquorum) were injected with latex via the ileocolic vein, and dissected. In all specimens the ileocaecal papilla was drained by 2 major papillary veins: one cranial and one caudal to the papilla. A smaller dorsal vein drained either into the cranial or into the caudal vein. The submucosal veins seemed to increase in number in the ileocaeacal junction to form a venous plexus. This plexus, together with veins from the caecum and the distal ileum immediately bordering the ileoca...
Kinematic analysis of the instant centers of rotation of the equine metacarpophalangeal joint. A kinematic analysis of the instant centers of rotation analysis was performed on 21 metacarpophalangeal joints from 11 horses. Manual and computerized methods were used to locate the instant center of rotation on photocopies of transparent composite tracings of a series of radiographs of each joint. The instant centers of rotation of the proximal phalanx about the distal portion of the third metacarpal bone were located consistently on or near the eminence for attachment of the collateral ligaments. The instant centers of rotation of the sesamoids about the distal portion of the third metacar...
Speed, stride frequency and energy cost per stride: how do they change with body size and gait? In this study we investigate how speed and stride frequency change with body size. We use this information to define 'equivalent speeds' for animals of different size and to explore the factors underlying the six-fold difference in mass-specific energy cost of locomotion between mouse- and horse-sized animals at these speeds. Speeds and stride frequencies within a trot and a gallop were measured on a treadmill in 16 species of wild and domestic quadrupeds, ranging in body size from 30 g mice to 200 kg horses. We found that the minimum, preferred and maximum sustained speeds within a trot and a...
The gait of pacers. 2: factors influencing pacing speed. Standardbred pacers were studied at four different nominated speeds and selected gait kinematics were analysed to determine factors which contribute to pacing speed. A deterministic model is proposed in which pacing speed is a function of stride length and stride timing variables. Stance length and suspension time remained relatively constant over the different pacing speeds. Variables which discriminated best between pacing speeds were suspension length and overlap time. At near maximal speed, the pacers increased speeds with increased stride length. This was attributed to an increased suspen...
cis- and trans-acting regulation of gene expression of equine infectious anemia virus. Deletion analysis of the equine infectious anemia virus long terminal repeat revealed that sequences responsive to virus-specific transactivation are located within the region spanning the transcriptional start site (-31 to +22). In addition, an active exon of a trans-acting factor (tat) was identified downstream of pol and overlapping env (nucleotides 5264 to 5461). Activation by tat is accompanied by an increase in the steady-state levels of mRNA directed by the equine infectious anemia virus long terminal repeat.
The effect of dietary protein level on exercising horses. Six mature Quarter Horse mares were used in a crossover design to assess the effect of dietary protein level on metabolic response to exercise. After a 2-wk adaptation period to either a 12.9% (control) or an 18.5% CP (high-protein) diet, each mare performed a standard exercise test. The test consisted of a 15-min exercise period at 4.5 m/sec on a 9% grade motorized treadmill. Exercise resulted in an increase in heart rate (P less than .001), but there was no difference (P less than .05) between dietary treatments. In the jugular vein, lactate increased (P less than .01) from 6.3 to 52.0 mg/10...
Reproductive physiology of the nonpregnant mare. An overview and update. This article reviews the reproductive events in the nonpregnant mare with emphasis on recent advances. The discussion is restricted to the salient features of puberty (prenatal and prepubertal events), seasonality (gonadotropins, photoperiod, and other modifying factors), and the estrous cycle (hormones, estrus, diestrus, and the control of cyclicity) in the nonpregnant mare.
Ultrasonic imaging of equine ovarian follicles and corpora lutea. One of the most profound theriogenology applications of transrectal diagnostic ultrasonography in mares involves the imaging of ovarian follicles and corpora lutea. The resolving capabilities (frequency) and quality of the scanner directly affect the minimal size of a structure that can be imaged and the quality of the image. High-frequency scanners (5 or 7.5 MHz) of good quality can image a 2-mm follicle and the corpus luteum throughout its functional life. A low-frequency scanner (3 or 3.5 MHz) can image a 6-mm follicle and the corpus luteum for several days after ovulation. Equine follicles...
Control of the estrous cycle in the mare. All current approaches to manipulating the reproductive biology of the nonpregnant mare are discussed.
Kinetics and kinematics of the equine hind limb: in vivo tendon strain and joint kinematics. Strains of the suspensory ligament and deep digital flexor, superficial digital flexor, and long digital extensor tendons in the equine (pony) hind limb were recorded in vivo, using implanted strain gauges consisting of silicone rubber tubes filled with mercury. The relationship between strain gauge signals and tendon strains was obtained from tension-strain tests performed on isolated tendons after death of the ponies. During normal walking, maximal tendon strain (elongation over initial length, relative to the length of the structures at first ground contact) was 3.1% in the suspensory ligam...
Metabolism of naturally occurring [13C]glucose given orally to horses. In 5 horses, 13CO2/12CO2 ratios in expired air were determined using isotope mass spectroscopy to investigate metabolism of naturally occurring [13C]glucose. Oral glucose tolerance tests (OGTT) were performed using maize or beet glucose. Maize has a higher 13C concentration than that of most plants. The 13CO2/12CO2 ratios after OGTT was performed using maize glucose were compared with 13CO2/12CO2 ratios in expired air after OGTT was performed using beet glucose. The ratio also was determined during the period horses were not fed. Using OGTT, all horses were glucose tolerant. The OGTT performed...
The effect of artificial photoperiod at the end of the breeding season on plasma testosterone concentrations in stallions. Testosterone concentrations in stallions showed a seasonal trend with peak concentrations in the spring (April and May in Britain) and lowest concentrations in the period from December to February. The effect on this pattern of changing the length of the photoperiod at the end of the normal breeding season (mid-summer's day) was studied in 2 experiments. In the first experiment artificial illumination was organised from 21 June to mimic the effect of transfer to a southern hemisphere spring and summer, that is short days becoming longer. The stallions had low concentrations of testosterone in ...
Diagnosis and correction of twin pregnancy in the mare. Reproductive Physiology 1. Twin pregnancies result in high rates of abortion, stillbirth, and neonatal mortality. 2. Twins develop subsequent to multiple ovulations. Multiple ovulations are related to breed, parity, and mare history. Multiple ovulations are most frequently seen in Thoroughbred and Draft mares. Multiple ovulations are more common in barren and perhaps maiden mares than in lactating mares, and they are more common in certain individual mares. 3. Equine embryos are motile in the uterus from the time of first detection (Days 9 to 10) until fixation (Day 16). They are frequently lo...
Mechanism of binding of horse liver alcohol dehydrogenase and nicotinamide adenine dinucleotide. The binding of NAD+ to liver alcohol dehydrogenase was studied by stopped-flow techniques in the pH range from 6.1 to 10.9 at 25 degrees C. Varying the concentrations of NAD+ and a substrate analogue used to trap the enzyme-NAD+ complex gave saturation kinetics. The same maximum rate constants were obtained with or without the trapping agent and by following the reaction with protein fluorescence or absorbance of a ternary complex. The data fit a mechanism with diffusion-controlled association of enzyme and NAD+, followed by an isomerization with a forward rate constant of 500 s-1 at pH 8: E E...
Embryo reduction before day 11 in mares with twin conceptuses. Incidence of embryo reduction (natural elimination of one member of a twin set) before d 11 was studied by comparing the number of ultrasonically detected conceptuses per ovulation between single and double ovulators. Effect of unilateral (n = 24) vs bilateral (n = 26) double ovulations on the incidence of embryo reduction also was considered. Each of 50 double-ovulating mares was matched with two single ovulators yielding 100 ovulations, or potential embryos, per group. Frequency with which an ovulation resulted in a conceptus was greater for single ovulators (85%, P less than .01) and for bi...
Respiratory airflow patterns in ponies at rest and during exercise. The exercise-induced changes in the equine breathing pattern were studied by analyzing tidal breathing flow-volume loops recorded in ten ponies both at rest and during a standardized exercise. Airflow, tidal volume, esophageal pressure and mask pressure were simultaneously recorded before, during and after a treadmill exercise. From the collected data, respiratory frequency and total pulmonary resistance were calculated, tidal breathing flow-volume loops were retraced using a computerized method and loop indices were measured for each period of the experimental protocol. For each pony, results...
