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Topic:Body Weight
Body weight in horses is a fundamental parameter that influences various aspects of equine management and health. It is a measure of the horse's mass, often assessed using scales or estimated through body condition scoring and weight tapes. Body weight is integral for determining appropriate feed rations, medication dosages, and workload capacities. Variations in body weight can indicate changes in health status, nutritional adequacy, or fitness levels. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies for assessing body weight, its implications on equine health and performance, and its role in management practices.
The pituitary and testicular responses to GnRH challenge between 4 and 14 months of age in thoroughbred colts born in spring and autumn. Gonadotropin releasing-hormone analogue (buserelin) challenges were carried out every 8 weeks from 4 to 14 months of age on thoroughbred colts born in the spring (n = 6) or autumn (n = 5) to define the onset of puberty. In all colts, luteinizing hormone (LH) secretion followed a seasonal pattern, with high baseline and maximal concentrations in the spring and summer and low concentrations in the winter. Testosterone concentrations were undetectable before spring and, thus, autumn-born colts were younger than spring-born colts when a testosterone response to buserelin was first observed. Mean w...
Changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and association with racing performance. To evaluate changes over time in echocardiographic measurements in young Standardbred racehorses undergoing training and racing and determine whether there was any relationship between cardiac dimensions and racing performance. Methods: Longitudinal observational study. Methods: 103 horses. Methods: 2-dimensional and M-mode echocardiography was performed 4 times at 6-month intervals. Results: Significant cardiac enlargement took place during the study period as indicated by increases in left ventricular internal diameter in diastole (LVIDd), estimated left ventricular muscle mass (LV mass), an...
Left ventricular size and systolic function in Thoroughbred racehorses and their relationships to race performance. Cardiac morphology in human athletes is known to differ, depending on the sports-specific endurance component of their events, whereas anecdotes abound about superlative athletes with large hearts. As the heart determines stroke volume and maximum O(2) uptake in mammals, we undertook a study to test the hypothesis that the morphology of the equine heart would differ between trained horses, depending on race type, and that left ventricular size would be greatest in elite performers. Echocardiography was performed in 482 race-fit Thoroughbreds engaged in either flat (1,000-2,500 m) or jump racin...
Effects of feeding a blend of grains naturally contaminated with Fusarium mycotoxins on feed intake, metabolism, and indices of athletic performance of exercised horses. An experiment was conducted to determine the effect of feeding blends of grains naturally contaminated with Fusarium mycotoxins to mature, exercised horses, and to test the efficacy of a polymeric glucomannan mycotoxin adsorbent (GM polymer) in preventing Fusarium mycotoxicoses. Six mature, mixed-breed mares with an average BW of 530 kg were assigned to one of three dietary treatments for 21 d in a replicated 3 x 3 Latin square design. Feed consumed each day was a combination of up to 3.5 kg of concentrates and 5.0 kg of mixed timothy/alfalfa hay (as-fed basis). The concentrates fed included 1...
Influence of starch intake on growth and skeletal development of weanling horses. Forty-four weanling horses were used in two experiments to evaluate the effect of starch intake on growth and skeletal development. In Exp. 1, the weanlings were fed either a grain-based, high-starch (31.1%, DM basis) concentrate or a by-product-based, low-starch (0.0%) concentrate with coastal bermudagrass (Cynodon dactylon) hay. Corn oil was used to equalize the energy concentration of the concentrates. The concentrate:hay ratio was 64:36 (as-fed basis), and intake was the same for both diets. Body weight gains were greater by the weanlings consuming the high-starch concentrate (0.81 vs. 0.6...
Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 1. Study design, and clinical, nutritional, radiological and histological observations. This is the first in a series of papers reporting studies in 2-year-old Thoroughbred racehorses that aimed to determine the response of musculoskeletal tissues to early training on grass and sand racetracks. In this paper, the experimental set-up of the whole study is described, and nutritional, workload, and clinical, radiographic and pathological outcomes are reported, including semi-quantitative assessment of macroscopic changes in articular cartilage. Methods: The study group comprised 14 two-year-old Thoroughbred fillies reared entirely at pasture. Of these, seven were selected by a licen...
Seasonal reproduction in the mare: possible role of plasma leptin, body weight and immune status. The primary objective of this study was to evaluate the possible role of leptin, body weight and immune status on reproductive activity throughout the transition period from cyclicity to seasonal anestrus, during anestrus and resumption of ovarian activity in Lusitano mares. Mares in good body condition were monthly monitored throughout 2 years (10 mares in each year) for evaluation of their reproductive status by sequential ultrasonography and plasma progesterone determinations. On the second year, all mares were weighed. Progesterone and leptin were assayed by radioimmunoassay (RIA). Paramet...
Aerobic training, but not creatine supplementation, alters the gluteus medius muscle. The aim of the present study was to investigate the effect of oral supplementation of creatine on the muscular responses to aerobic training. Twelve purebred Arabian horses were submitted to aerobic training for 90 d, with and without creatine supplementation, and evaluated with respect to BW and BCS and to the area and frequency of the different types of muscle fibers in the gluteus medius. Supplementation consisted of the daily administration of 75 g of creatine monohydrate mixed into the ration for the 90 d of training. Physical conditioning was conducted on a high-performance treadmill, an...
Energetic and kinematic consequences of weighting the distal limb. It is well known that adding a load to a horse's back increases its energetic costs of locomotion, but the magnitude of increase obtained by loading the most distal portion of limb has not been measured. Objective: To measure oxygen consumption in horses with mass added to the back and hooves. Because such mass distribution alters inertial parameters of the limbs, kinematic measurements were made to quantify the magnitude of change in limb movement. Methods: Steady-state oxygen consumption was measured in 6 horses with a load of 2.4 kg. The load was either carried on the back or distributed eq...
Effect of dental floating on weight gain, body condition score, feed digestibility, and fecal particle size in pregnant mares. To investigate the effect of routine dental floating on weight gain, body condition score, feed digestibility, and fecal particle size in pregnant mares fed various diets. Methods: Randomized controlled clinical trial. Methods: 56 pregnant mares. Methods: Mares were randomly allocated to 1 of 4 feed groups (n = 14 mares/group). All horses were sedated and an oral examination was performed, after which dental floating was performed on 7 horses in each group. Body weight was measured, and a body condition score was assigned before and at various times for 24 weeks after dental floating. Feed dig...
Evaluation of pituitary gland anatomy and histopathologic findings in clinically normal horses and horses and ponies with pituitary pars intermedia adenoma. To determine size and weight of the pituitary gland and associations between pituitary gland size and weight and sex and age in horses without clinical signs associated with pituitary pars intermedia adenoma (PPIA) and horses and ponies with PPIA. Methods: Pituitary glands from 100 horses without clinical signs of PPIA and 19 horses and 17 ponies with PPIA. Methods: Pituitary glands were weighed, measured, and examined histologically by use of H&E stain. Masson trichrome and periodic acid-Schiff staining were used, when appropriate. Histologic lesions in the pars intermedia, pars distalis,...
The influence of calcium intake on phosphorus digestibility in mature ponies. Literature data show conflicting results on the effect of feeding high calcium (Ca) levels on phosphorus (P) digestibility in ponies. None of the studies reported involved a dose response as to the effect of Ca intake on apparent P digestibility while keeping P intake constant. Thus, the influence of high dietary Ca level on apparent P digestibility was studied in balance trials by feeding six mature ponies three different Ca levels against a constant P intake. The ponies received 148, 316 and 535 mg Ca/kg BW/day with the low, intermediate and high Ca diet. Phosphorus intake was approximately ...
Correlation between plasma alpha-melanocyte-stimulating hormone concentration and body mass index in healthy horses. To evaluate the correlation between plasma alpha-melanocyte-stimulating hormone (alpha-MSH) concentration and body mass index (BMI) in healthy horses. Methods: 82 healthy horses. Methods: Plasma alpha-MSH concentration was determined by radioimmunoassay. At the time blood samples were collected, body condition scores (BCS) were determined and measurements of girth circumference, body length, and height were obtained. Weight was estimated by use of the following formula: estimated weight (kg) = [girth (cm)2 x length (cm)]/11,877. Body mass index was calculated as estimated weight (kg)/height (m...
Management of hemodynamic changes associated with removal of a large abdominal myofibroblastic tumor in a pony. A 22-year-old female Welsh-cross pony was evaluated because of intermittent colic, signs of depression, pyrexia, anorexia, muscle wasting with abdominal distention, and weight gain over the preceding 12 months. A large abdominal mass was detected and surgically removed; the hemodynamic alterations and complications caused by the dramatic fluid losses and shifts that can occur in association with removal of a large abdominal mass required extensive postoperative management. Monitoring of clinical and hematologic variables such as attitude, heart rate, mucous membrane color, mean arterial blood ...
Influence of weight bearing and hoof position on Doppler evaluation of lateral palmar digital arteries in healthy horses. To describe the pulsed-wave Doppler tracing of the equine lateral palmar digital artery and its modification in relation to standardized changes in posture. Methods: 17 healthy Saddlebred horses. Methods: Pulsed-wave Doppler examinations of left and right lateral palmar digital arteries of the horses were performed. The baseline examination was performed on each forelimb while horses were standing squarely with the body weight equally distributed among the 4 limbs (BED position). For each forelimb, the examination was repeated during 3 standardized modifications of the horse's posture (non-wei...
Onset of puberty in pasture-raised Thoroughbreds born in southern hemisphere spring and autumn. There is little information on age, weight and time of year of puberty in Thoroughbred horses, and the interpretation of such data is difficult due to the wide variety of descriptions of the onset of puberty. Objective: To examine the age, bodyweight and date of onset of puberty in Thoroughbreds born in spring and autumn. Methods: Bodyweight data and blood samples were collected in 59 pasture-raised Thoroughbred horses. Five autumn-born and 18 spring-born colts and 3 autumn-born and 33 spring-born fillies were examined from birth to age 13 and 17 months. A testosterone concentration >2 s.d....
Effect of hypothyroidism on the blood lipid response to higher dietary fat intake in mares. Blood lipid and lipoprotein concentrations were measured and compared between euthyroid and thyroidectomized mares on low-fat or high-fat diets to test the hypothesis that hypothyroidism alters the blood lipid response to higher dietary fat intake. Four healthy adult mares and four adult mares that had been thyroidectomized 3 to 6 mo earlier were placed on low-fat or high-fat diets according to a replicated 2 x 2 Latin square design consisting of two 5-wk feeding periods separated by a 2-wk washout interval. Plasma lipid concentrations were measured at 0, 3, 4, and 5 wk, and plasma lipase acti...
Influence of fasting and exercise on the daily rhythm of serum leptin in the horse. The hormone leptin is secreted by white adipocytes and regulates food intake and energy expenditure in rodents and humans. The goal of the present study was to investigate the existence of a daily rhythm of serum leptin in horses and its dependence on fasting and physical exercise. A robust daily rhythm of leptin was found in both athletic and sedentary horses, with a daytime trough and a peak in the dark phase. While physical exercise never induced changes in circulating leptin, fasting reliably affected serum leptin levels. Food deprivation did not abolish the daily rhythm of serum leptin, b...
Effects of continuous rate intravenous infusion of butorphanol on physiologic and outcome variables in horses after celiotomy. A randomized, controlled, blinded clinical trial was performed to determine whether butorphanol administered by continuous rate infusion (CRI) for 24 hours after abdominal surgery would decrease pain and surgical stress responses and improve recovery in horses. Thirty-one horses undergoing exploratory celiotomy for abdominal pain were randomly assigned to receive butorphanol CRI (13 microg/kg/h for 24 hours after surgery; treatment) or isotonic saline (control). All horses received flunixin meglumine (1.1 mg/kg IV q12h). There were no significant differences between treatment and control horse...
Effects of cereal grain supplementation on apparent digestibility of nutrients and concentrations of fermentation end-products in the feces and serum of horses consuming alfalfa cubes. Twenty geldings (five groups; similar age and BW) were used in a completely randomized design experiment to determine effects of grain supplementation of an alfalfa-cube diet on apparent nutrient digestibility and hindgut fermentation. The geldings were housed individually, fed their diets in two equal meals (0600 and 1800), and adapted to five dietary treatments over 6 wk. The treatments were alfalfa cubes (1% of BW; DM basis) without (control) or with one of four rolled cereal grains (i.e., barley, corn, naked oats, or oats) to provide a target level of 0.4% of BW as total nonstructural carb...
Association between race history and risk of superficial digital flexor tendon injury in Thoroughbred racehorses. To determine whether race history, including the number of races and total race distance, was associated with risk of superficial digital flexor tendon (SDFT) injury in Thoroughbred racehorses in Japan. Methods: Matched case-control study. Methods: 515 Thoroughbred racehorses (case horses) that sustained an SDFT injury during training or racing in Japan during 2002 and 951 horses (control horses) without SDFT injury that were matched with case horses on the basis of age and month of the latest race. Methods: Variables related to race history were compared between case and control horses by mea...
Soybean hulls as an alternative feed for horses. Soybean hulls have been successfully fed to ruminant animals as an economical substitute for hay. This feedstuff is a source of highly digestible fiber that does not contain starch. The purpose of this trial was to evaluate soybean hulls as a replacement fiber in horse diets. Four cecally cannulated Quarter Horse geldings, aged 6 to 10 yr and averaging 502 kg, were used in a 4 x 4 Latin square design with 21-d periods. Diets consisted of alfalfa/bromegrass hay (14.4% CP, 58.1% NDF, 39.1% ADF; DM basis) with the replacement of either 0, 25, 50, or 75% (as-fed basis) unpelleted soybean hulls (13...
Phenytoin sodium as a treatment for ventricular dysrhythmia in horses. Five adult horses with ventricular extra systoles (VES) and 2 with ventricular tachycardia (VT) refractory to treatment with rest, anti-inflammatory drugs, lidocaine, or procainamide were treated with phenytoin sodium p.o. q12h. The starting dosage of phenytoin was 20 or 22 mg/kg body weight (BW) q12h, and the maintenance dosage varied from 8 to 17 mg/kg BW q12h. The mean +/- standard deviation therapeutic blood concentration of total phenytoin was 8.8 +/- 2.1 mg/L, and the mean concentration of free phenytoin of 2.5 +/- 0.5 mg/L was relatively constant at a range of 24 to 29% of the total phe...
Treatment and follow-up of clinical cyathostominosis in horses. The results of the treatment with moxidectin or ivermectin of 20 horses with clinical cyathostominosis were studied during a 3-week observation period. Both treatments were effective in completely eliminating larvae from the faeces within 1 or 2 weeks, but no significant improvement in body weight or clinical parameters could be demonstrated over the observation period. The poor short time results of the treatment support the need for an adequate prevention of cyathostominosis in horses.
Growth rate consists of baseline and systematic deviation components in Thoroughbreds. The objective of this study was to establish a procedure for differentiating a baseline curve from a systematic deviation in weight-age data, and hence to develop a physiological growth model for the Thoroughbred. A total of 2,698 records for 175 foals was obtained during a period of 8 yr (1994 to 2001). Weight-age data were fit with a sigmoid growth equation, W = A(1 + be(-kt))M, where W is BW at age t, A is the asymptotic value of W, b is a scaling parameter that defines the degree of maturity at t = 0, k is a rate constant, and M defines the point of inflection in the sigmoid curve in relat...
Quantitative evaluation of equine deep digital flexor tendon morphology using magnetic resonance imaging. Injury of the distal aspect of the deep digital flexor tendon (DDFT) is a recognized cause of lameness, but diagnosis is difficult. This study aimed to improve understanding of DDFT morphology and pathology using retrospective evaluation of magnetic resonance (MR) images. We hypothesized that: (1) The distal aspect of the DDFT in normal horses would have a repeatable proximal/distal pattern and symmetry between limbs and between lobes; (2) DDFT dimensions would be related to bodyweight, navicular bone dimensions and hoof size; (3) this symmetry and pattern would be lost in DDFT injury; and (4)...
Nutrition and the critically ill horse. A nutritional plan should be incorporated into every treatment plan of the critically ill patient. Weight loss and cachexia are the result of prevalence of catabolic processes over anabolic processes in addition to absolute or relative increased demands and decreased food intake.
The influence of maternal size on pre- and postnatal growth in the horse: III Postnatal growth. The growth parameters exhibited by seven Thoroughbred (Tb) foals that had experienced a 'restricted' in utero existence following transfer as embryos to the uteri of smaller Pony (P) mares (Tb-in-P) and, conversely, six P foals that experienced a 'luxurious' in utero existence after transfer to larger Tb mares (P-in-Tb), were compared from birth to 3 years of age with those exhibited by six normal Tb-in-Tb and six P-in-P foals conceived by within-breed artificial insemination. Bodyweight, height at the withers, girth, poll-to-nose length, crown-rump length and three foreleg longbone measuremen...
Weight prediction from linear measures of growing Thoroughbreds. Monitoring weight of foals is a useful management practice to aid in maximising athletic potential while minimising risks associated with deviations from normal growth. Objective: To develop predictive equations for weight, based on linear measurements of growing Thoroughbreds (TBs). Methods: Morphometric equations predicting weight from measurements of the trunk and legs were developed from data of 153 foals. The accuracy, precision and bias of the best fitting equation were compared to published equations using a naive data set of 22 foals. Results: Accuracy and precision were maximised with...
Use of multifrequency bioelectrical impedance analysis for estimation of total body water and extracellular and intracellular fluid volumes in horses. To evaluate the use of multifrequency bioelectrical impedance analysis (MF-BIA) for estimating total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV) in horses. Methods: 9 healthy mares. Methods: TBW and ECFV were measured by use of deuterium oxide and sodium bromide dilution techniques, respectively. Intracellular fluid volume was calculated as the difference between TBW and ECFV. Concurrently, MF-BIA recordings were obtained by use of 4 anatomic electrode positions and 3 measurements of length. Models for MF-BIA data were created for all combinations...
