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Topic:Horses
"Horses" is a broad topic that encompasses various aspects of equine biology, behavior, and management. This category includes studies on the anatomy, physiology, and genetics of horses, as well as their behavior, nutrition, and care. Research in this area may also cover the historical and cultural significance of horses, their roles in agriculture, sport, and therapy, and the challenges associated with their conservation and welfare. The page aggregates peer-reviewed research articles and scholarly studies that explore the multifaceted relationships between humans and horses, examining both scientific and socio-economic perspectives.
Identification of anatomic features of the equine clitoris as potential growth sites for Taylorella equigenitalis. A median clitoral sinus, as a space canalized from epithelial cells, was distinguishable developmentally in equine fetuses from 33-mm crown-rump length (CRL) to 500-mm CRL (including a mule of 21-mm CRL). In saggital sections of the clitoris of a 480-mm CRL fetus, indentations under the transverse frenular fold were identified as lateral sinuses of the clitoris. Unlike the median sinus, they were shallow; it therefore could not be anatomically substantiated that the lateral sinuses were of sufficient depth to support the growth of the partial anaerobe Taylorella equigenitalis, the organism of ...
Squamous cell carcinoma originating from an epithelial scar in a horse. A Quarter Horse stallion developed an abscess over the left gluteal region after an IM injection of antihistamine. The wound healed with considerable fibrous scarring and some persistent granulation tissue. The lesion was static for 2 years before the granulation tissue went through a 6-month period of progressive enlargement. At that time, histopathologic diagnosis of squamous cell carcinoma was made from excisional biopsy. Six months after diagnosis, the horse had lost body weight and the lesional diameter had further increased, so the horse was euthanatized.
Serodiagnosis of equine monocytic ehrlichiosis in selected groups of horses in Minnesota. Antibody titer to Ehrlichia risticii was determined, in 2,549 equine serum samples, using an indirect fluorescent antibody assay. During 1986, samples were obtained from the Minnesota State-Federal Equine Infectious Anemia Diagnostic Laboratory, the Minnesota Racing Laboratory, from horses admitted to the University of Minnesota Veterinary Teaching Hospital, and as a result of field investigations of horses with acute diarrhea. Results of the study revealed antibody prevalence of 33, 24, 47, and 25% for the respective groups. There was no statistical association between seropositive status and...
Lymphocytic-plasmacytic enteritis in two horses. The primary hematologic abnormalities in 2 adult horses with chronic weight loss were hypoalbuminemia and hyperglobulinemia. One horse was anemic, had subclinical disseminated intravascular coagulation, and prolonged plasma sulfobromophthalein half-life. Small-intestinal dysfunction with malabsorption was indicated by abnormal D-xylose absorption test results. Clinicopathologic and pathologic findings were consistent with a diagnosis of malabsorption and protein-losing enteropathy, attributable to lymphocytic and plasmacytic infiltration of the intestine.
Surgical treatment of tarsal sheath effusion associated with an exostosis on the calcaneus of a horse. A 2-year-old Thoroughbred colt was referred for evaluation of effusion within the tarsal sheath and associated lameness of the right hind limb. Conservative treatment consisting of needle aspiration and pressure bandaging had been unsuccessful. Radiography of the right tarsus revealed proliferative periosteal reaction along the distal caudal border of the sustentaculum tali and medial aspect of the calcaneus. The owners elected conservative treatment, using a local injection of corticosteroid and pressure bandaging the tarsus. Five months later, the severity of the effusion and lameness had in...
Nonulcerative keratouveitis in five horses. Five horses with severe nonulcerative keratouveitis had corneal lesions characterized by a pink stromal infiltrate that initially appeared in the stroma near the limbus. Unremitting iridocyclitis also was evident. In 3 horses, microscopic lesions consisted of marked corneal stromal fibrosis, with mild to severe inflammatory cellular infiltration. Corticosteroids and mydriatic/cycloplegics applied topically and corticosteroids and nonsteroidal anti-inflammatory medications administered parenterally were used with varying degrees of success to control pain and retain vision.
Seroepidemiologic survey of antibodies to Ehrlichia equi in horses of northern California. The prevalence of antibodies to Ehrlichia equi in horses from the foothill regions of northern California and from the Sacramento valley (non-foothill area) was determined, using an indirect fluorescent antibody test. Horses from foothill regions had a higher prevalence of seropositivity (10.4%) and higher titer (1:10 to 1:80) than did those from non-foothill regions (3.1%; titer less than or equal to 1:10). Fifty percent of healthy horses on a foothill farm enzootic for E equi had titer to E equi, suggesting that infection with E equi can be subclinical. Six veterinarians surveyed from northe...
Bilateral renal dysplasia with nephron hypoplasia in a foal. Bilateral renal dysplasia and nephron hypoplasia was diagnosed in a Quarter Horse foal with clinical signs of lethargy, convulsions, and diarrhea. Laboratory evaluation revealed anemia, hypoproteinemia, leukopenia, hyponatremia, hypochloremia, and hyposmolality. The foal also had high concentrations of serum creatinine, BUN, and phosphorus. Evaluation of urinary indices revealed a high ratio of urinary gamma-glutamyl-transferase activity to concentration of creatinine, as well as a high fractional clearance ratio of sodium and potassium. Intravenous treatment with saline solution (0.9% NaCl) a...
Rapid diagnosis of equine influenza. During an epizootic of equine influenza in Norway caused by influenza A/equine (H3N8) virus the efficacy of rapid virus diagnosis by the indirect immunofluorescence technique was evaluated. The antiserum used in the test was a polyclonal influenza A virus antiserum with reactivity directed mainly against the common nucleoprotein and matrix protein. This antiserum possessed sufficient reactivity for the detection of virus-infected exfoliated nasopharyngeal cells. Nasopharyngeal smear samples from 92 horses were examined and a positive diagnosis was obtained for 57 (62 per cent). Paired serum sa...
[Successful use in horses of deep-frozen semen specimens stored for 18 years]. In 1970 semen from a Haflinger-stallion was frozen by the pellet method. 18 years later semen samples were used to inseminate 4 mares. Inseminations were performed shortly after ovulation with a total number of motile spermatozoa between 150 and 636 x 10(6), the percentage of motile spermatozoa being 20% to 40%. Three mares conceived after a single insemination, one mare got pregnant after 4 inseminations during 3 oestrous periods. Meanwhile, 3 foals were born and one of the mares is still pregnant. The results demonstrate that long-term storage of frozen semen in liquid nitrogen does not impa...
The relationship between peak expiratory sound intensity and peak expiratory flow rate in the thoroughbred horse during exercise. Peak expiratory sound intensity (dB SPL), obtained by means of a radiostethoscope, and peak expiratory flow rate, obtained using a mask incorporating a thermistor flow sensor, were measured in six Thoroughbreds over a range of stride rates from 100 to 140 strides per min. The results show linear relationships between peak dB SPL and stride rate, peak expiratory flow rate and stride rate and also between peak expiratory flow rate and peak dB SPL. Peak expiratory dB SPL can therefore indicate peak expiratory flow rate.
Effects of treadmill elevation on heart rate, blood lactate concentration and packed cell volume during graded submaximal exercise in ponies. Six ponies performed a standardised exercise test on a motorised treadmill at each of three randomly assigned treadmill elevations (1, 4, or 7 degrees). The exercise test consisted of four, 4 min increments of increasing treadmill speed from 1.0 to 3.4 m/sec. Heart rate, blood lactate concentration, and packed cell volume (PCV) were determined, during the last min of each exercise level, and at 4 and 12 mins post exercise. Regardless of treadmill elevation, no differences were observed in pre-exercise heart rate (49 +/- 2) beats/min), lactate (1.2 +/- 0.1 mM), and PCV (0.32 +/- 0.01 litres. Du...
Alterations in plasma volume, plasma constituents, renin activity and aldosterone induced by maximal exercise in the horse. Plasma volume (PV) decreased by 13 per cent following the completion of 1,000 m of maximal exercise in the horse. This study demonstrated that the critical reduction in PV following maximal exercise occurred within 10 mins of completion of exercise, as previously reported in man. Total plasma protein (TPP) increased by 23 per cent at 2 and 5 mins, and by 21 per cent at 10 mins post exercise. Therefore, it does not appear to be an accurate measurement to assess the degree of PV contraction in the horse. Protein was apparently added to the intravascular space either during or following exercise....
Methodology and repeatability of a standardised treadmill exercise test for clinical evaluation of fitness in horses. This paper describes the methodology necessary to perform a clinical exercise test and the expected variability in an individual horse's exercise test measurements based on comparing the results of two repetitions of the test with six horses. The exercise test measurements were obtained with an open flow respiratory gas analysis system, fast time response lactate analyser and an on-board heart rate monitor during an incremental inclined treadmill exercise test. With the exception of peak venous lactate concentration (LACpeak), the results indicate that the mean variability in peak oxygen consu...
[Meadow saffron (Colchicum autumnale) in hay and colic in horses]. Following feeding of a new delivery of hay (bought in Southern Germany) 3 horses out of a unit of 17 developed colic within a few days one horse died. Post-mortem there was an intensive accumulation of serous or serous-haemorrhagic fluid in the thorax and abdomen. The hay was heavily contaminated by autumn crocus (colchicum autumnale)--about 1.48% of total mass. Other feedstuffs were of good quality and following removal of the affected hay no further cases of colic occurred. The pathological findings also indicated a colchicine intoxication.
Effect of show jumping on heart rate, blood lactate and other plasma biochemical values. This study investigated some physiological responses to exercise performed by a horse during show jumping. The effects of jumping on heart rate (HR), blood lactate (LA) and some other blood values were studied in nine normal horses participating at the Belgian Junior Championship. Venous blood was sampled before and immediately after the show jumping and was analysed for packed cell volume, LA, blood glucose (GLU), total plasma protein, bicarbonate, sodium, potassium (K+), chloride, calcium and activities of plasma lactate dehydrogenase, creatine phosphokinase (CK) aspartate amino transferase ...
In vitro antimicrobial activity of defensins against ocular pathogens. New approaches to antimicrobial therapy for ocular pathogens must overcome organisms that are resistant to current therapeutic modalities. This investigation examined the antimicrobial activity of novel antimicrobial neutrophil peptides (defensins NP-1 and NP-5) against isolates from clinical ocular microbial infections in humans and horses. The test panel of human clinical isolates included Candida albicans, an alpha-hemolytic Streptococcus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Morganella morganii. The test panel of equine pathogens included three clinical isolates of P aerug...
Quantification of skin displacement in the proximal parts of the limbs of the walking horse. Displacement of skin over the underlying skeletal structures in the proximal parts of the limbs was investigated in four walking Dutch Warmblood horses. Movement of the skin was visualised with self adhesive spot labels whereas that of the skeletal parts was visualised indirectly by means of a plastic strip connected to a transcutaneous Steinmann pin, driven into the bone of interest. Consistent results for all four horses were found. Individual and mean total displacements ranged from 1 to 4 cm (distal scapula) to 13 to 17 cm (caudal part of the greater trochanter of the femur). Displacements...
The effect of an acute angulation of the hind hooves on diagonal synchrony of trotting horses. High speed cinematography was used to measure the timing and distance characteristics of the trot in five sound horses. Two farriery treatments were compared: (1) normal, in which the dorsal hoof wall was aligned with the pastern axis in all four feet and (2) acute hind hoof angulation, in which the hind toes were allowed to grow relatively longer than the heels, so that the angulation was approximately 10 degrees lower than the normal hind hoof angle for the individual animal. Comparison between the two treatments showed that the acute hind hoof angulation was associated with significant incr...
A quantitative analysis of skin displacement in the trotting horse. Skin displacement was investigated at 16 sites in the front and hind limbs of four Dutch Warmblood horses at the trot. For visualisation of the bone under the skin, a measuring device mounted on a Steinmann pin driven into the bone under investigation, was employed. Mean displacements ranged from 8 mm (X-displacements proximal and distal metacarpus) to 142 mm (Y-displacement caudal part of greater trochanter). When compared with previously determined skin displacement patterns at walk, mean displacements at trot were of the same magnitude whereas the shape of the time-displacement curve was di...
Cardiorespiratory drift during exercise in the horse. The purpose of the present study was to measure the time-course and degree of cardiovascular and respiratory 'drift' during constant submaximal exercise in the horse. One Thoroughbred and four Morgan mares were instrumented for simultaneous measurement of respiratory and blood gases which also enabled cardiac output (Q) to be calculated. Data were collected at rest, and at 10, 20 and 30 mins during a constant workload which elicited an initial exercising heart rate (HR) of 150 beats/min, and an approximate 15-fold increase in oxygen consumption (VO2). Significant cardiac and respiratory drift ...
Bicarbonate loading in the thoroughbred: dose, method of administration and acid-base changes. Two studies were undertaken in an attempt to investigate the optimal dose, route and time course required to 'bicarbonate load' the Thoroughbred. During the first study a test solution of sodium bicarbonate (NaHCO3) and a control solution of water were administered via a nasogastric tube to six horses. Blood acid-base status was determined immediately prior to and for 24 h following intubation. During the second study a standardised feed was given to four horses, with and without NaHCO3 supplementation. This was followed by a further trial involving the addition of glucose and NaHCO3 to a stan...
Intra-abdominal hemorrhage associated with a granulosa-thecal cell neoplasm in a mare. A 9-year-old American Saddlebred mare was referred because of abdominal distention and signs of abdominal pain. Copious peritoneal fluid obtained by abdominocentesis appeared to be frank blood. Rectal and ultrasonographic evaluation of the abdomen revealed a large mass at the distal tip of the right uterine horn. The mare was euthanatized and necropsied and the mass was determined to be a granulosa-thecal cell neoplasm. The most common clinical sign of granulosa-thecal cell neoplasm is infertility or abnormal sexual behavior. Hemoperitoneum is infrequently associated with neoplasms in horses.
A computer-derived protocol using recursive partitioning to aid in estimating prognosis of horses with abdominal pain in referral hospitals. In order to determine which variables are useful and accurate in estimating prognosis in horses with abdominal pain, data were analyzed from 231 horses presented at a veterinary teaching hospital. Using multiple stepwise discriminant analysis in a recursive partition model, we obtained a decision protocol that identified survivors and nonsurvivors. The prevalence of survivors was 61% in this population. The sensitivity, specificity, and positive and negative predictive values of this model were 71, 83, 87 and 65%, respectively. This decision protocol was validated by Jackknife classification a...
The role of the reciprocal apparatus in the hind limb of the horse investigated by a modified CODA-3 opto-electronic kinematic analysis system. The function of the reciprocal apparatus in the hind limb of the horse was studied by kinematic gait analysis. For recording purposes a modified opto-electronic CODA-3 kinematic analysis system was used. The raw kinematic data were corrected for skin displacement artifacts by use of recently developed correction models. It was concluded that contradictory findings about the coupling of tarsal and stifle joints by the reciprocal apparatus, when comparing in vitro and in vivo studies, can be fully attributed to artifacts due to the movement of the skin markers over the underlying bony structures...
