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Topic:Morphometry
Morphometry in horses refers to the quantitative analysis of the form, structure, and size of horses. This scientific discipline involves measuring various physical dimensions and proportions of horses to assess their conformation, growth patterns, and breed characteristics. Common morphometric parameters include body length, height at the withers, girth circumference, and limb proportions. These measurements can provide insights into the suitability of horses for specific disciplines, their health status, and genetic traits. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, applications, and implications of morphometric analysis in equine science.
Determination of hoof mass and centre of mass from morphological measurements. Determination of net joint moments and powers requires accurate measurements of mass and centre of mass (COM) for the limb segments. The objective of this research was to develop regression equations for calculating mass and COM of the hoof segment that are applicable over a wide range of hoof morphologies. Ninety-one hooves (mean +/- s.d. 0.99 +/- 0.50 kg) were weighed and the 3-dimensional COM determined using a mass balance technique. Ten morphological variables were measured and used as independent variables in linear regressions with dependent variables of mass and centre of mass. The reg...
Relationships between third metacarpal bone parameters and surface strains. The relationships were explored between measurements of bone quality, size (quantity) and shape, and strain data collected during treadmill exercise at 4 and 12 m/s from the third metacarpal bones of 6 yearling and 6 mature Thoroughbred racehorses. Peak strains in yearling and mature Thoroughbred horses during exercise were related to the size and shape of the third metacarpal bone. The peak strains were significantly lower in horses with a greater cross-sectional area of bone and with a greater proportion of the bone in the dorsal cortex. There was no consistent relationship between peak stra...
Quantitative analysis of the optic nerve of the horse (Thoroughbred). Three optic nerves (L1, R2, R3) 12-18 mm behind the eyeball of the horse (Thoroughbred) were investigated quantitatively under light and electron microscopes. Thin sections at the thickness of 0.35 microm were cut, stained by toluidine blue and observed under the light microscope. The areas of the optic nerve and the axon bundles were 20.03 +/- 1.04 and 16.59 +/- 0.79 mm2 (mean +/- SD, n=3), respectively. The axon numbers for optic nerve L1, R2 and R3, estimated from light micrographs, were about 481 x 10(3), 543 x 10(3), and 494 x 10(3), respectively. Axons of optic nerve L1 were also counted...
Morphology of the laminar junction in relation to the shape of the hoof capsule and distal phalanx in adult horses (Equus caballus). The purpose was to investigate whether differences in equine hoof shape, which are inferred to alter foot function, are accompanied by differences in morphology of the laminar junction. Ten fore feet from adult horses were segregated into normal and low-angle groups, depending on the dorsal angle of the hoof wall. Twenty measurements of external hoof shape and four of the enclosed distal phalanx were tested for differences between groups, and for intragroup correlations. Three measurements of laminar morphology (spacing, orientation and degree of bend) were recorded for samples of up to 50 pri...
The hindlimb in walking horses: 2. Net joint moments and joint powers. The objective of the study was to describe net joint moments and joint powers in the equine hindlimb during walking. The subjects were 5 sound horses. Kinematic and force data were collected synchronously and combined with morphometric information to determine net joint moments at each hindlimb joint throughout stance and swing. The results showed that the net joint moment was on the caudal/plantar side of all hindlimb joints at the start of stance when the limb was being actively retracted. It moved to the cranial/dorsal side around 24% stride at the hip and stifle and in terminal stance at t...
Topography of ganglion cells in the retina of the horse. Topography of ganglion cells in the retina of the horse (Thoroughbred) was analyzed in the wholemount retina stained with cresyl violet, and a total number of ganglion cells were estimated. Sizes of ganglion cells were also measured and size spectra were analysed. The main results showed that: (1) a common point in 4 wholemount retinae, based on cell densities and retinal locations, was that a retina could be divided into 5 regions, namely visual streak, nasal, temporal, dorsal and ventral region to the visual streak. A maximum cell density of 4,000 cells/mm2 was found in the visual streak. An...
Stereological estimation of volume-weighted mean glomerular volume from arbitrary sections of the equine kidney. Mean glomerular volume has previously been estimated, using stereological techniques, specifically the point-sampled intercept (PSI), either from isotropic or from vertical sections. As glomeruli are approximately spherical structures, the same stereological technique was carried out on vertical and arbitrary sections to determine whether section orientation had any effect on mean glomerular volume estimation. Equine kidneys from 10 individuals were analysed using the PSI method of estimating volume-weighted mean glomerular volume (MGV); for each kidney, arbitrary and vertical sections were an...
Morphometric study of the equine navicular bone: age-related changes and influence of exercise. Navicular bones from the four limbs of 95 horses, classified in 9 categories, were studied. The effects of age on navicular bone morphometry and histomorphometry were estimated, after adjustment of the data to even out the effects of front and rear limbs, morphometrical type, sex, weight, and size. All the external measurements of the navicular bone decreased significantly with increasing age. From the histomorphometrical data, cortical bone volume decreased with age in most horses, whereas cancellous bone volume and, in particular, the marrow spaces increased. The increase in the cancellous b...
Effect of age on immunocytochemical staining characteristics of adenohypophyseal cells in Mongolian pony mares and stallions. To determine the effect of age on immunocytochemical staining characteristics of adenohypophyseal cells of Mongolian pony mares and stallions. Methods: 35 Mongolian ponies. Methods: Pituitary glands from 1- to 22-year-old horses of both sexes were collected at a commercial slaughterhouse in China and allocated into 7 groups according to age and sex: prepubertal stallions (n = 5; 1 to 2 years old), young stallions (6; 3 to 7 years old), middle-aged stallions (4; 10 to 12 years old), old stallions (5; 15 to 22 years old), young mares (3; 3 to 7 years old), middle-aged mares (5; 10 to 12 years ol...
Cross-species and intraspecies morphometric analysis of the corpus callosum. A cross-species morphometric study of the corpus callosum was performed in the rat, rabbit, cat, dog, horse, cow and human. Across species, the results indicate a strong, although less than linear, dependency of callosal size on brain weight. This relation tends to lose significance within species. This is consistent with other morphometric studies indicating a tendency to decrease the correlations between morphometric variables in within-species analyses as compared to between-species analyses. There are species differences in the relative size of some callosal segments particularly in the po...
Shape, orientation and spacing of the primary epidermal laminae in the hooves of neonatal and adult horses (Equus caballus). Circumferential and proximodistal variations in the morphology of the primary epidermal laminae of six neonatal and five adult equine feet were documented. Three parameters were quantified: interlaminar spacing, the orientation of the laminae with respect to the overlying wall, and any angulation within the laminae themselves ('internal angle'). In adult feet, the laminae were most closely spaced at the dorsum, the spacing increasing gradually towards the heels. In foals there was a non-significant trend for the dorsal laminae to be more widely spaced than those in more caudal parts of the foo...
Standardisation of muscular biopsy of gluteus medius in French trotters. Morphometric measurements were taken from 41 French trotters of various ages and both sexes. Biopsy location was determined for the dorsal compartment as being one-third of the distance from the tuber sacrale to the tuber coxae and for the ventral compartment as being one-third of the distance from the tuber coxae to the caudal Cd1-Cd2 intervertebral joint. Ten horses were biopsied at these 2 sites at a sampling depth equal to half the total depth of the compartment as measured by ultrasonography. The percentage of slow and fast myosin heavy chain fibres was measured by using an immunoenzymati...
Radiographic measures of bone shape in young thoroughbreds during training for racing. The aim of this study was to determine if changes in the shape of the third metacarpal bone (MC3) during the first preparation for racing in young Thoroughbred racehorses could be measured radiographically. Lateral radiographs of each MC3 were taken when the horses commenced training, every 2 weeks for 10 weeks, and again at 6 months after the start of training. The width of the dorsal cortex (DC), palmar cortex (PC), and medulla (M) were measured at a position 2.5 cm distal to the nutrient foramen before the subject of each radiograph was identified. The following ratios were calculated: z = ...
Age-related morphometry of equine incisors. In the present study the age-related morphological characteristics of 948 equine incisors were investigated. After extraction, total incisival length and root length were measured at the vestibular side of the teeth. Equine incisors reach their maximal length 2-3 years after eruption. Notwithstanding severe occlusal wear, this maximal length is maintained during most of the horses' life due to prolonged root formation. Root formation, at the rate of 2.5 mm per year, starts at the age of 5-6 years and continues until the age of 17. As the root of the incisor develops, its apical foramen narrows...
Relationship between the degree of endometrial periglandular fibrosis and the presence of angiotensin-converting enzyme in the equine endometrium. Endometrial periglandular fibrosis (EPF) has been proposed as a possible aetiology for equine embryonic and fetal loss. However, the pathophysiology of EPF is not well understood. Angiotensin-converting enzyme (ACE) is found in macrophages, endothelium (during angiogenesis) and myofibroblasts at sites of fibrosis in the heart, kidneys, liver and skin in several species. An increase in local tissue ACE-binding activity appears to be a critical event in the initiation and progression of fibrosis in these tissues. The aim of this study was to investigate the correlation between ACE activity in th...
Morphometric study of the equine navicular bone: variations with breeds and types of horse and influence of exercise. Navicular bones from the 4 limbs of 95 horses, classified in 9 categories, were studied. The anatomical bases were established for the morphometry of the navicular bone and its variations according to the category of horse, after corrections were made for front or rear limb, sex, weight, size and age. In ponies, navicular bone measurements were smallest for light ponies and regularly increased with body size, but in horses, navicular bone dimensions were smallest for the athletic halfbred, intermediate for draft horse, thoroughbreds and sedentary halfbreds and largest for heavy halfbreds. The ...
Calcified cartilage morphometry and its relation to subchondral bone remodeling in equine arthrosis. The calcified layer of articular cartilage is known to be affected by age and mechanical factors that may play a role in the development of arthrosis. Because these factors are also related to subchondral remodeling and sclerosis, a morphometric study was carried out in fluorochrome-labeled animals to determine whether the level of subchondral remodeling affected the thickness of the calcified cartilage layer and its irregularity and vascularity at the interface with subchondral bone. These parameters were also studied at a site of increased mechanical stress. The area and thickness of the cal...
Tubule density of the stratum medium of horse hoof. The number of tubules/mm2 (tubule density) of horse hoof horn was quantified in samples taken from the left forefeet of 8 randomly selected slaughterhouse horses in order to establish the normal tubule density characteristics at the midline dead centre (MDC) for the stratum medium of horse hoof. In the past the measurement of tubule distribution within the hoof has lacked objectivity. The horse hoof tubule density results are compared to a recent objective study carried out on pony hoof. A similar 4 zone pattern of tubule density was observed, although the precise zonal boundaries and tubule d...
The influence of speed and height at the withers on the kinematics of sound horses at the hand-led trot. The influence of speed and height at the withers on some biokinematic stride parameters (linear, temporal and angular) was measured in 15 Spanish Thoroughbreds (Andalusian Purebred) trotted hand-led along a track; analysis was made of the correlation between speed and height at the withers and of some biokinematic parameters of equine locomotion. Both height at the withers and speed were positively and significantly correlated to the linear parameters examined. Temporal parameters did not reveal a significant correlation with the height at the withers. The correlations with the angular paramet...
Morphologic changes and xanthine oxidase activity in the equine jejunum during low flow ischemia and reperfusion. To determine whether xanthine oxidase and dehydrogenase activities are altered during low flow ischemia and reperfusion of the small intestine of horses. Methods: 5 clinically normal horses without histories of abdominal problems. Methods: With the horse under general anesthesia, a laparotomy was performed and blood flow to a segment of the distal jejunum was reduced to 20% of baseline for 120 minutes and was then reperfused for 120 minutes. Biopsy specimens were obtained before, during, and after ischemia for determination of xanthine oxidase and dehydrogenase activities, and for histologic a...
Immunocytochemical differences in adenohypophyseal cells among adult Mongolian pony mares, stallions, and geldings. To analyze the sex difference in 6 kinds of adenohypophyseal cells of Mongolian ponies and the effect of prepubertal orchidectomy on adenohypophyseal cells. Methods: Pituitary glands collected from 15 adult Mongolian ponies, 5 to 10 years old: 5 stallions, 5 mares, and 5 geldings, orchidectomized between the ages of 1 and 2 years. Methods: Morphologic comparison of 6 kinds of adenohypophyseal cells among mares, stallions, and geldings was done, using immunocytochemistry and morphometry. Results: A sex difference was evident in the percentage of somatotrophs, gonadotrophs (follicle-stimulating ...
Morphometric study of the equine navicular bone: comparisons between fore and rear limbs. Navicular bones collected from the four limbs of 95 sound horses were studied. The anatomic bases have been laid down about morphometry of the navicular bones and their variations according to limbs, after corrections have been made for morphologic type, gender, weight, size and age. All the dimensions of the navicular bone (except for the thickness) were larger in the fore limb. This phenomenon probably reflects an attempt to compensate for the greater forces exerted upon the fore limbs during exercise and at rest. Navicular bones collected from the four limbs of 61 sound horses were studied ...
Immunocytochemical localization of adrenocorticotropic hormone-immunoreactive cells of the pars intermedia in thoroughbreds. To analyze and characterize adenoma and hyperplasia of the pars intermedia (PI) of Thoroughbred mares. Methods: 165 Thoroughbred mares, without clinical signs of hyperadrenocorticism that had been euthanatized or had died, of causes such as sudden death, colic, pneumonia, or trauma, and were necropsied. Five of those horses, 17 to 25 years old, had a large pituitary gland at necropsy. Eight mares, 5 to 15 years old with normal-size pituitary gland, were selected at random for comparison. Methods: A morphologic comparison of the pituitary gland between horses with and without tumors of the PI w...
Sperm head morphometry analysis of ejaculate and dismount stallion semen samples. The evaluation of seminal characteristics is important in the clinical detection of stallion subfertility. Conventional semen evaluation includes subjective determination of sperm concentration, motility, and gross morphology. Due to the subjectivity and variability of the manual morphology assessment, computer automated sperm morphology analyses has been developed. Computer automated sperm morphology analysis was applied in the current study to determine if the morphometric measurements of sperm heads from collected and dismount samples of the same ejaculate were similar. If the post-ejaculat...
A light microscopic and ultrastructural examination of calcified dental tissues of horses: 1. The occlusal surface and enamel thickness. Gross and microscopic examinations were undertaken on 46 cheek (molar and premolar) and 4 incisor equine teeth that were fractured, or sectioned either with a lathe or diamond saw. Specimens were examined without treatment, after decalcification or acid etching, utilising light, and scanning and transmission electron microscopy. In some horses, the occlusal surface of the teeth were covered with an organic pellicle. The occlusal surface of the underlying equine enamel contained different wear patterns, including polished areas, local fractures, wedge-shaped pits, striations and depressions. Oc...
Exercise-induced changes in the lung of Shetland ponies: ultrastructure and morphometry. The ultrastructural changes in pulmonary alveoli produced by running two ponies on a high speed treadmill at 7.6 m/sec, 3-degree incline, for 2 min support the hypothesis of pulmonary capillary stress failure as an explanation for exercise-induced pulmonary hemorrhage (EIPH). Light microscopy combined with scanning and transmission electron microscopy confirmed the presence of red blood cells and proteinaceous material in the alveolar lumina and interstitial swelling in approximately one third of the pulmonary alveoli examined. Morphometric analysis revealed that the blood-gas barrier was 30-7...
Relationship between ossification of the cartilages of the foot and conformation and radiographic measurements of the front feet in Finnhorses. One hundred Finnhorse cadaver front feet were measured and examined both radiographically and visually to report the incidence of various foot problems and their relationship to ossification of the cartilages of the foot. Ossification extending above the proximal border of the navicular bone and/or separate centres of ossification were found in 36 feet, and the lateral cartilages showed more ossification than the medial cartilages. The feet were generally broad with well developed frogs, but the long toe-low heel syndrome was a relatively common finding. Ossification of the cartilages correlat...
An age-related study of morphology and cross-link composition of collagen fibrils in the digital flexor tendons of young thoroughbred horses. The superficial digital flexor tendon is the most commonly injured tendon in the racing Thoroughbred. Despite the clinical significance of this structure, only limited data exist regarding normal age-related morphology of the tensile units, the collagen fibrils. The age at which these collagen fibrils become mature in composition and structure may be of importance. Consequently, the association of age and collagen fibril crosslink composition, diameter distribution and crimp morphology in the superficial and deep digital flexor tendons of Thoroughbreds up to and including three years of age ha...
Linear assessment of the thoroughbred horse: an approach to conformation evaluation. A linear assessment trait evaluation system is proposed to allow quantitative description of the static conformation of the horse. Measurements were made on 27 selected traits. The system was tested initially for repeatability of measurements on 4 horses. Twenty-one of the selected traits were satisfactory and 6 proved unsatisfactory in terms of reproducibility. A population of 101, superior 2- and 3-year-old Thoroughbreds and 19 premium Thoroughbred stallions were similarly assessed. More than 65% of the traits exhibited large (CV > 10%) phenotypic variation within the sampled population. ...
