"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.
Strzemienski PJ, Benson CE, Acland HM, Kenney RM.Two groups of 3 mares were inoculated with Haemophilus equigenitalis or Pseudomonas aeruginosa on the 1st day of estrus. Uterine flushing samples were recovered on day 3 of estrus and day 8 after ovulation for each cycle. Mares were killed 22, 25, and 30 days after inoculation with P aeruginosa and 45, 46, and 49 days after inoculation with H equigenitalis. Pseudomonas aeruginosa was recovered from the uterus of 2 mares 48 hours after inoculation. Although the initial flushing sample of 1 of these 2 mares had an increased total protein concentration, there appeared to be little difference betw...
Steiss JE, Forsyth G.The effect of needle electromyography (EMG) on serum creatine kinase (CK) activity was determined, using clinically normal dogs (males and females; n = 8) and horses (females; n = 8). All animals appeared normal on EMG evaluation. Serum CK was measured before and 4, 24, and 48 hours after EMG. Except for a single 24-hour sample in a dog, the animals did not have abnormally increased serum CK activity after EMG. For dogs and horses, mean values were increased, but within normal range at 4 and 24 hours and returned to base-line values by 48 hours after EMG. For dogs, but not for horses, these CK...
Gross TL, LeBlanc MM.The effect of seasonal morphologic variation of equine endometrium on histologic interpretation of periglandular fibrosis was investigated in 5 mares. Endometrial tissue was procured monthly and examined microscopically for the degree of periglandular fibrosis. A prognostic category for each mare was based on the mean number of fibrotic foci per linear field of 5.5 mm. It was found that seasonal changes reflected in endometrial glands and stroma influenced quantitative assessment of fibrosis. This occasionally resulted in a change in the assigned prognostic category. Marked nonseasonal variati...
Presson BL, Hamm D, Yazwinski TA, Pote LM.Critical tests were performed on 6 horses to evaluate the antiparasitic effectiveness of oxfendazole given in combination with trichlorfon in a paste formulation. Treatments were given orally as a single dose. The rates of active ingredient administration were 2.5 and 40 mg/kg of body weight for oxfendazole and trichlorfon, respectively. The combined activities of the 2 antiparasitic compounds proved 100% efficacious in the removal of adult Strongylus vulgaris, S edentatus, Oxyuris equi, and Parascaris equorum. Fourth stage O equi, and 2nd and 3rd instars of Gasterophilus nasalis also were com...
Chang CK, Ward B, Ebina S.Carbon monoxide- and oxygen-binding rates and affinities were measured for horse heart myoglobins reconstituted with synthetic hemes lacking peripheral methyl and vinyl groups. There is an apparent correlation between heme size and ligand specificity, i.e. larger m values (ratios of CO vs O2 association rates, l'/k') with smaller hemes. However, this correlation broke down with the most dealkylated heme. This is interpreted as resulting from protein conformational changes altering the steric crowdedness at the O2-binding site. Spectral properties and autoxidation rates also corroborate this vi...
Blue HB, Blue MG, Kenney RM, Merritt TL.Forty uterine fluid samples were obtained from 4 mares classified as resistant to uterine bacterial infection. The uterus of each mare was flushed with 50 ml of saline solution during estrus and diestrus of successive estrous cycles. Bacteria or fungi were isolated from 4 samples, and 7 additional samples were obtained from a mare with active intrauterine infection. Fluid volumes obtained during estrus (means = 40.3 +/- 11 ml) tended to be greater than those recovered during diestrus (means = 36.8 +/- 7.9 ml), but the difference was not significant. Concentrations and yields of protein in reco...
Rebhun WC, Tennant BC, Dill SG, King JM.Renal toxicosis attributable to vitamin K3 (menadione sodium bisulfite) was suspected in 5 young adult horses in which acute renal failure developed following parenteral administration of vitamin K3 at the manufacturers' recommended dosages. Renal disease was subsequently induced experimentally in 5 of 6 horses by administration of vitamin K3 at manufacturers' recommended dosages. Signs of renal disease in the clinical patients as well as in the horses treated experimentally included renal colic, hematuria, azotemia, and electrolyte abnormalities consistent with acute renal failure. Two clinic...
Lavach JD, Severin GA, Roberts SM.Perforating corneal wounds in horses have a better prognosis than wounds that involve both cornea and sclera. Sharp objects tend to produce more isolated corneal wounds and have a better prognosis than do wounds produced by blunt objects. The records of 43 horses that sustained penetrating wounds of the cornea were reviewed. In addition, the surgical approach and postoperative wound management is described. The report attempts to provide more information regarding the management of ocular trauma in horses.
Samuelson DA, Andresen TL, Gwin RM.Conjunctival swab specimens were obtained from both eyes of 43 horses, 25 cows, 50 dogs, and 25 cats without keratitis or other ophthalmologic problems. Fungi were isolated from 95% of the horses, 100% of the cows, 22% of the dogs, and 40% of the cats. Aspergillus spp were isolated from 56% of the horses, 12% of the cows, 8% of the cats, and none of the dogs. Penicillium spp and Cladosporium spp were isolated ubiquitously. Collectively, 28 species from 209 isolants were identified.
Rice DW, Blake CC.Crystals of horse muscle 3-phosphoglycerate kinase have been grown in the presence of a wide variety of substrates using either potassium tartrate or polyethylene glycol as a precipitant. In those grown from polyethylene glycol, two related crystal forms have been obtained by varying the nature of the substrates present in the crystallization medium. In order to obtain one of these forms, form B, the presence of the substrate 3-phosphoglycerate appears to be essential. The two crystal forms are not interconvertible by simple diffusion experiments and the crystals grown in the absence of 3-phos...
Leach DH, Ormrod K, Clayton HM.An investigation was made of the stride characteristics of horses jumping 2 obstacles during a Grand Prix competition. One obstacle was a picket fence and rail 1.3 m high (fence 2), and the other was a coop and rail 1.52 m high (fence 11). Thirteen distance and 22 timing measurements of 17 horses were extracted from high-speed films, using computer-aided analysis. These data were used to compare takeoff and landing of the lead and nonlead legs, the thoracic limbs and pelvic limbs, and fence 2 and fence 11. Paired t-tests were used to compare means and a stepwise regression analysis was done fo...
The Journal of heredityMay 1, 1984
Volume 75, Issue 3 220-224 doi: 10.1093/oxfordjournals.jhered.a109916
Cothran EG, MacCluer JW, Weitkamp LR, Pfennig DW, Boyce AJ.The relationship between inbreeding and both conception and foaling rates in Standardbred horses (trotters and pacers) was examined for 1194 breeding years. There was a statistically significant (P less than 0.05) trend for conception and foaling rates to decrease with increased inbreeding; however, this relationship accounted for less than 2 percent of the variation. Additionally, the relationship between reproductive performance and inbreeding was not consistent between trotters and pacers. For trotters (F = 0.103) there was a trend for an increase in conception and foaling rates with increa...
Rogers PA, Fahey GC, Albert WW.Serum amino acid profiles and other serum characteristics of broodmares and their foals wee studied. Compared with mares, foals had significantly higher concentrations of serum leucine, threonine, aspartic acid, asparagine, glutamic acid, glutamine, proline and tyrosine, glucose, cholesterol, creatinine and phosphorus. Foals had significantly less serum histidine, glycine, cystine, taurine, protein and urea nitrogen. Lysine and/or methionine supplementation of pregnant and lactating broodmare diets were conducted. Changes in serum amino acid profiles caused by dietary amino acid supplemented w...
Breeze RG, Legreid WW, Bayly WM, Wilson BJ.Perilla ketone was assessed for its usefulness as a model of equine restrictive pulmonary disease. Three ponies were given 18 mg/kg bodyweight synthetic perilla ketone in dimethyl-sulphoxide. Within 24 h of administration, respiratory rate, peak inspiratory and expiratory flow rates and minute volume were increased. By 48 h there was a significant decrease in tidal volume, and blood pH and base excess were also decreased but not outside normal limits. At necropsy there was congestion and oedema of the lungs. Histologically there was diffuse alveolar injury but no evidence of significant obstru...
Schamhardt HC, Hartman W, Lammertink JL, Badoux DM.Strain tracings obtained from the tibial cortex of walking ponies reveal peaks in the principal tension and compression strains occurring immediately before and after the support phase. Evidence is presented that the presupport peak is caused by inertial forces.
Allen BV, Blackmore DJ.The relationship between paired plasma and serum viscosity measurements and plasma proteins, including fibrinogen, were compared in 106 horses with both normal and abnormal serum protein levels. There is a highly significant positive correlation between serum viscosity and total serum proteins and total globulin levels. The difference between plasma and serum viscosity correlated well with clottable fibrinogen concentration. Albumin levels showed a negative correlation with plasma and serum viscosity, globulins and fibrinogen. Simultaneous estimation of serum and plasma viscosity improves the ...
DiPietro JA, Todd KS, Reuter-Dallman V.Ivermectin given IM at 200 micrograms/kg, alone or in combination with procaine penicillin G at 600 IU/kg, to 20 randomly selected young horses of various breeds reduced fecal strongyle egg counts from 400-4100 epg (avg greater than 1000) pretreatment to zero 7 days posttreatment. There were no systemic or injection-site reactions, either immediate or delayed, in any of the horses.
Gideon L.Esophageal anastomosis was performed on 2 foals after resecting a midcervical stricture. Nasogastric tube alimentation and antibiotic therapy allowed these foals to recover, and they matured to useful performing horses. These cases demonstrated a feasible and successful surgical management regimen for the strictured esophagus.
Weld JM, Kamerling SG, Combie JD, Nugent TE, Woods WE, Oeltgen P, Tobin T.The effects of naloxone on the cardiovascular, hematologic and metabolic derangements associated with endotoxic and hemorrhagic shock were studied in unanesthetized horses. In the first of 3 experiments blood glucose and lactate levels, hematocrit, white, red and differential white cell counts, rectal temperature and clinical signs were obtained before and after endotoxin (10 micrograms/Kg) administration in 5 horses. In the second experiment, two groups of 3 horses received either intravenous naloxone (0.04 mg/Kg) or saline, 7 minutes prior to endotoxin. In a third experiment two groups of 4 ...
Rugh KS, Garner HE, Hatfield DG, Herrold D.Six adult ponies were trained calmly to assume and maintain left lateral recumbency without the use of sedative or immobilising agents. During a 30 min recumbent period, pHa, arterial oxygen and carbon dioxide tensions (PaO2 and PaCO2) and heart and respiratory rates were monitored at regular intervals to evaluate ventilatory response. Overall, there were no statistically significant differences found between mean control and recumbent or final standing values. When lightweight ponies were compared to heavyweight ponies, only mean PaO2 at 10 mins recumbency was different. This information supp...
Sullins KE, Messer NT, Nelson L.Twenty-one adult horses were randomly assigned into 7 groups of 3 and were treated for 5 days with procaine penicillin G, benzathine penicillin , or phenylbutazone in various combinations and dosage schedules. Serum concentration of penicillin was measured serially over a 7-day period. The highest mean peak serum concentration was 2.06 micrograms/ml. Comparable peak values were seen 2 to 4 hours after administration of 22,000 IU of procaine penicillin G/kg of body weight given once or twice daily. A minimum serum concentration of 0.25 micrograms/ml was selected as adequate for efficacy against...
Zink MC, Johnson JA.Bronchoalveolar lavage was performed 5 times, sequentially, on 3 healthy foals when each was between 2 and 63 days of age. Total and differential counts were performed on recovered cells. The lungs of foals less than 19 days of age contained few alveolar macrophages recoverable by bronchoalveolar lavage. This number increased sharply during the first 2 to 3 weeks of life, but remained relatively constant subsequently. Approximately 86% of the alveolar cells in the lungs of foals up to 3 weeks of age were alveolar macrophages. During the first 2 months of life, this number decreased to approxim...
Brook D.A guarded, sterile swab is used to obtain samples for uterine culture. With the mare in stocks, the tail bandage and the perineum washed, the culture rod is introduced into the vagina with a gloved hand. After the rod is guided through the cervix, the guard cap is dislodged and the swab is rubbed along the endometrium, after which the rod is extracted. Samples for uterine culture should only be obtained during full estrus. Swabs should be directly plated onto agar within 2 hours of collection. Blood agar is appropriate for initial screening, but use of specialized types of agar expedites ident...
Hänni K, Hesford F, Lazary S, Gerber H.Genomic DNA isolated from 20 horses was digested with up to six restriction endonucleases and subjected to southern blot hybridization analysis using various human class II alpha- and beta-chain cDNA probes. A high degree of restriction fragment length polymorphism (RFLP) was found for the DQ alpha, DP beta, DQ beta and DR beta probes, about 20 polymorphic bands being detected for each. DR alpha showed 2-4 polymorphic bands, whereas no evidence for DP alpha-like genes was found. A number of correlations of RFLPs with individual alloantisera were apparent.
Cymbaluk NF, Christison GI, Leach DH.Eighteen Quarter Horse and Paint weanling colts were assigned to two treatments, either limit or ad libitum feeding. Nutrient digestibilities of diets were evaluated between 6 and 12 mo, 12 and 18 mo and 18 and 24 mo of age. From 6 to 12 mo, energy digestibility (64 to 68%) was unaffected by feed intake level. Ad libitum-fed horses had energy digestibilities 9 to 10% greater (P less than .05) than limit-fed horses between 12 and 24 mo of age, but adjustment for DM intake removed these differences. Limit-fed, mature ponies used dietary energy similarly to growing horses from 6 to 18 mo of age, ...
McChesney AE.Since the advent of cell culture techniques, numerous viruses have been shown to be related to respiratory diseases in horses. Although the viruses differ in many ways, they cause disease with some common characteristics. This report is a summary of some of the available material from written sources and from personal observations. It is intended to help explain some of the changes observed in viral-induced respiratory disease.
Steel NL, Ireland JL, McGowan CM.In horses/ponies with pituitary pars intermedia dysfunction (PPID), pergolide mesylate treatment, with monitoring of therapeutic response, is recommended by contemporaneous literature and equine endocrinologists. However, it is unknown whether these recommendations are adhered to in private practice. This clinical audit aimed to compare treatment and monitoring of PPID cases in veterinary practice against available recommendations. Case data and basal plasma adrenocorticotropic hormone (ACTH) concentrations from all equids tested for PPID between 2012 and 2016 from a single veterinary practice...
Mata F.Several growth models are commonly used in the biological sciences, to model the follicle growth occurring in the estrous cycle. The aim of this project was to find the model that best fit the follicular size growth data for Lusitano mares. Retrospective data collected from reproduction book records of n=84 mares and n=124 cycles was used to find the series to be fitted to the models. The exponential, Gompertz, logistic, von Bertalanffy, Richards and Weibull models were used, and the most parsimonious and best fit was achieved with the logistic model (r(2)=0.999). The logistic model fits the L...
McKeever KH, Malinowski K, Christensen RA, Hafs HD.The purpose of this experiment was to test the hypothesis that chronic (89 days) administration of recombinant equine somatotropin (eST) would increase aerobic capacity and improve exercise performance in old mares. Fifteen, healthy, unfit, aged (20-26 year old) mares were randomly assigned to a treatment (eST, 12.5 mg day-1 in 3 ml glycine/manitol buffer, s.c., n = 7) or control (vehicle, 3 ml day-1, s.c., n = 8) group. Aerobic capacity and exercise performance were measured using a standardized exercise test (SET) performed on a high speed treadmill. Tests were conducted before (-21 days), d...
Sepulveda MF, Perkins JD, Bowen IM, Marr CM.Doppler tissue imaging (DTI) is a novel noninvasive method by which myocardial velocity can be assessed directly and it allows regional, rather than global, cardiac function to be evaluated. Objective: That regional differences in myocardial velocities exist within the equine ventricle. Objective: To develop a repeatable examination technique for DTI in horses, describe DTI findings in various regions of the normal equine ventricle, compare colour (CDTI) and spectral (SDTI) techniques of DTI, and document regional differences in myocardial velocity. Methods: Five regions of the ventricles (rig...
Mohammed R, Nader SM, Hamza DA, Sabry MA.Cryptococcosis is an opportunistic mycozoonosis of global significance in a wide variety of host species. In equines, cryptococcosis is uncommon, and sporadic cases have been reported with rhinitis, sinusitis, pneumonia, and meningitis. Cryptococcus spp. represents a potential risk for immunosuppressed and healthy persons. In Egypt, epidemiological data on cryptococcal infection in horses are limited. The current study was carried out to investigate the occurrence of Cryptococcus spp. in horses and its possible role in the epidemiology of such disease in Egypt. A total of 223 samples was colle...
Hendrickson DA.The determination of poor performance in the young or unproven horse can be a difficult experience for the practitioner. This article describes an incremental exercise test that may be helpful in determining the cause of poor performance in horses when a complete physical examination and a lameness examination fail to elucidate the causes of poor performance. Included are values from normal yearling and 2-year-old horses that have undergone the incremental exercise test.
Raeside JI, Christie HL.C(18) neutral steroid formation by cytochrome P450 aromatase has been recorded for several equine and porcine tissues. High activity of P450 aromatase is reflected in the quantities of estrogens in yolk-sac (y-s) fluid of early equine conceptuses. In a previous study of y-s fluid we detected large amounts of androgens by radioimmunoassay (RIA), using an antiserum for androstenedione (A(4)). Here, we report that RIA, following chromatography, gave tentative identification of the major peak as norandrostenedione (19-norA) not as A(4). Furthermore, even greater quantities of 19-norA seemed to be ...
Kirker-Head CA, Kirker-Head RP.Six healthy, adult female horses were administered five times the minimum maintenance dose of an oral low-molecular-weight chondroitin sulfate, glucosamine HCl, and manganese ascorbate chondroprotective agent (Cosequin; Nutramax Laboratories, Inc., Edgewood, MD) daily for 35 days. Hematology, serum biochemistry, and synovial fluid parameters were assessed twice prior to administering the product and again at the end of the treatment period. Physical examinations performed daily throughout the study showed no abnormal clinical changes attributable to the product. All hematologic parameters meas...
Houpt KA.Knowledge of animal behavior is an important asset for the veterinarian; therefore a course in veterinary animal behavior is offered at the New York State College of Veterinary Medicine as an elective. The course emphasizes the behavior of those species of most interest to the practicing veterinarian: cats, dogs, horses, cows, pigs and sheep. Dominance heirarchies, animal communication, aggressive behavior, sexual behavior and maternal behavior are discussed. Play, learning, diurnal cycles of activity and sleep, and controls of ingestive behavior are also considered. Exotic and zoo animal beha...
Serra Bragança FM, Broomé S, Rhodin M, Björnsdóttir S, Gunnarsson V, Voskamp JP, Persson-Sjodin E, Back W, Lindgren G, Novoa-Bravo M, Gmel AI....No abstract available
Manglai D, Wada R, Kurohmaru M, Yoshihara T, Kuwano A, Oikawa M, Hayashi Y.The present study attempted to clarify the characteristics of the guttural pouch mucosa in equines and to evaluate its foreign substance clearance ability. The specimens were collected from nine regions (eight in the guttural pouch mucosa, and one in the nasopharynx mucosa). We first examined the pouch mucosa by light and electron microscopy. We then measured the frequency of goblet cells per 200 epithelial cells, the length of the cilia, the thickness of the epithelial cell layer and lamina propria and statistically analyzed the data. The guttural pouch mucosa consisted of stratified columnar...
Kwok WH, Kwok KY, Leung DK, Leung GN, Wong CH, Wong JK, Wan TS.The positive findings of norbolethone in 2002 and tetrahydrogestrinone in 2003 in human athlete samples confirmed that designer steroids were indeed being abused in human sports. In 2005, an addition to the family of designer steroids called 'Madol' [also known as desoxy-methyltestosterone (DMT)] was seized by government officials at the US-Canadian border. Two years later, a positive finding of DMT was reported in a mixed martial arts athlete's sample. It is not uncommon that doping agents used in human sports would likewise be abused in equine sports. Designer steroids would, therefore, pose...