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.
Art T, Lekeux P.Five healthy, fit Standardbreds (mean +/- SEM, 490.4 +/- 15.0 kg, 4.0 +/- 0.5 years) were studied during a standardized test carried out on a treadmill. The test consisted of an 8-minute warm-up and a 9-minute exercise period (1 minute at 1.7, 4, 7, 8, 9, and 10 m/s; 2 minutes at 4 m/s; and a 1-minute walk at a 6% slope). Respiratory airflow, tidal volume (V(T)), and respiratory frequency (f) were continuously recorded, using 2 ultrasonic pneumotachographs connected to a face mask and mass spectrometer. Oxygen uptake, carbon dioxide output, and expired minute volume (V(E)) were obtained on a b...
Curran S, Ginther OJ.Embryonic heart rate was studied during 87 examinations in 56 mares on Days 25 to 174 post ovulation. Real-time B-mode using a stopwatch and M-mode ultrasonography were compared. For analyses of heart rates, data were grouped into weeks or months. For the stopwatch and M-mode techniques, respectively, heart rates averaged 123 and 133 beats per minute during Month 1, peaked during Month 3 at 172 or 196 beats, then gradually decreased over the duration of the study to 126 and 130 beats during Month 6. There was a significant increase in heart rate from Months 1 to 2 and Months 2 to 3 and a signi...
Nemoto K, Osawa R, Hirota K, Ono T, Miyake Y.Gram-negative tannin-protein complex degrading bacteria (T-PCDB) were first isolated from animals except for the koala. The occurrence of T-PCDB in feces of 15 species of mammals with different feeding habits was investigated. T-PCDB occurred in 7 of 54 horses but they could not be isolated from other mammals tested. These T-PCDB comprised less than 0.1% of the facultative anaerobic microflora in horse feces and it was much less than that previously reported in koala feces ( > 60%). A total of 7 T-PCDB fecal isolates showed a range of phenotypic diversities. They were all Gram-negative rods...
Daels PF, Hughes JP.The purpose of this study was to develop a contraceptive method for feral horses. The feral horse population has increased significantly in recent years despite attempts to control numbers. As in most wild animal population control programs, contraceptive methods must be easy to apply, cause minimal disruption to the social structure and be fully reversible. In the present study, we tested the effectiveness of an intrauterine device (IUD) for fertility control in mares. Six mares were fitted with a silastic O-ring-shaped IUD on July 1 of Year 1. The IUD-treated mares were turned out with 12 no...
Griko YV, Freire E, Privalov G, van Dael H, Privalov PL.The energetics of the temperature-induced unfolding of equine lysozyme was studied calorimetrically and compared with that of two structurally homologous proteins: hen egg white lysozyme and alpha-lactalbumin. The structure of each of these proteins is characterized by the presence of a deep cleft that divides the molecule into two regions called the alpha and beta domains. In equine lysozyme and alpha-lactalbumin the latter domain specifically binds Ca2+. It is shown that, in contrast to hen egg white lysozyme in which the alpha and beta domains unfold as a single cooperative unit, in equine ...
Trostle SS, Hendrickson DA.Suture sinuses formed in 3 horses following closure of ventral midline incisions with size-2 polypropylene. Suture sinuses healed after the suture material was removed. Suture sinus formation following closure with polypropylene may be related to the suture material's mechanical, rather than its chemical, properties. If polypropylene is used to close the linea alba in horses, the amount of tissue incorporated in the suture loops, suture tension, and knot volume should be minimized to decrease the risk of suture sinus formation.
Gauvreau GM, Wilson BA, Schnurr DL, Young SS, McDonell WN.The purpose of this study was to develop a technique to measure the oxygen cost of ventilation and the values of ventilatory parameters in seven normal horses rebreathing carbon dioxide (CO2). All the horses responded to increased inspiratory levels of CO2 by increasing their tidal volume (VT) and frequency of breathing (Vf). The mean (SE) oxygen cost litre-1 of ventilation, measured at rates of ventilation greater than 200 litres min-1 was 1.7 (0.04) ml litre-1, similar to that of normal human subjects ventilating submaximally. It was concluded that the CO2 rebreathing test is a practical, no...
Kaseda Y, Khalil AM, Ogawa H.The stability of relationships between harem stallions and mares (consort relations) was investigated and the durations of inter partum intervals were determined in order to establish if there was any correlation between the stability of consort relation and reproductive success of mares in Misaki feral horses. Thirty-four mares were observed continuously for more than 5 years. The lifetime stability was 80-100% (mean 92.4%) for 16 mares, 60-79% (mean 70.4%) for 10 mares and 0-59% (mean 27.9%) for 8 mares. The continuous length (years) of specific consort relations was 2-10 years and was found...
Middleton SB, Foley SJ, Foy MA.National Hunt jockeys suffer a disproportionate number of clavicular fractures and their return to riding may be considerably delayed by refracture and symptomatic nonunion, with obvious implications. We report six such cases in which excision of the clavicular fragment distal to the fracture was associated with an early return to work and no recurrent injury to the shoulder.
Slater JD, Herrtage ME.Echocardiographic examinations were performed on 41 clinically normal small ponies, large ponies and horses. Using standardised two-dimensional (2-D) echocardiographic images to guide M-mode studies, the interventricular septal thickness, left ventricular internal dimension and left ventricular wall in systole and diastole, and aortic diameter in diastole were measured. Normal values for these echocardiographic dimensions were obtained across a wide range of bodyweights. Although there was a trend for echocardiographic dimensions to increase with bodyweight across the whole range of animals ex...
Eaton MD, Evans DL, Hodgson DR, Rose RJ.We examined the effect of treadmill speed and incline on O2 uptake (VO2), CO2 production, heart rate (HR), plasma lactate concentration, economy of locomotion, stride frequency, and stride length. A further aim was to examine the relationships between HR and VO2 and lactate and VO2 and whether these relationships vary with alterations in treadmill incline. The experiment was a latin square design, using five horses and five treadmill inclines (0, 2.5, 5.0, 7.5, and 10.0%). Fit Thoroughbred horses exercised for 4 min at 3 m/s at 0% slope, after which the treadmill was set to the allocated incli...
Price JS, Jackson B, Eastell R, Wilson AM, Russell RG, Lanyon LE, Goodship AE.In this study we tested the hypothesis that exercise induces an adaptive response in the developing skeleton which may be monitored in vivo by measuring biochemical markers of bone metabolism. The effects of exercise on two biochemical markers of bone formation were determined; the carboxy-terminal propeptide of type I procollagen (PICP), and the bone-specific isoenzyme of alkaline phosphatase (BAP), and one putative marker of resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP). All three markers were measured for a year in 2-year-old thoroughbred horses exerc...
Uboh CE, Rudy JA, Railing FA, Enright JM, Shoemaker JM, Kahler MC, Shellenberger JM, Kemecsei Z, Das DN.Although urine is the sample of choice for drug tests in racehorses, it is rarely obtained following the sudden death of a racehorse on the track while racing. The purpose of this study was to demonstrate the significance of postmortem tissue samples as an alternative to urine and blood samples in equine drug analysis following the sudden death of a racehorse on the track while participating in a competitive race. Postmortem tissue samples were frozen (-80 degrees C) until analyzed. A 30-40-g portion of each organ was homogenized in a 0.1 M phosphate buffer (pH 7.4), deproteinized, hydrolyzed ...
Blissitt KJ, Bonagura JD.Reference values were established for selected Doppler derived variables from a group of 40 normal Thoroughbred and Thoroughbred cross horses. Standard two-dimensional (2-D) images used for guiding the Doppler sampling site allowed accurate alignment with flow. Tricuspid inflow velocities during rapid filling (E) and atrial contraction (A) were significantly higher when recorded from a right parasternal angled view than from a right parasternal long-axis view. In 8 horses the tricuspid inflow peak A velocity was higher than the peak E velocity. The peak acceleration of blood flow was higher (P...
Brinsko SP, Ball BA, Ellington JE.Oocytes were harvested from mare ovaries obtained at slaughter and were divided into 3 groups based on the age of the donor. The age groups consisted of young (2 to 7 yr), middle-aged (8 to 14 yr) and aged (>or=15 yr) mares. There were no differences between age groups in the proportions of follicles available for examination or the proportions of normal, abnormal or total oocytes collected. After 24 h of culture, the overall maturation rate to the second metaphase (MII) was 52.7%. Maturation rates for oocytes obtained from young and middle-aged mares were similar, but oocytes from aged mar...
Mason MW, Skedros JG, Bloebaum RD.The relative importance that certain strain features, including mode (e.g., tension vs. compression) and magnitude, have in affecting adaptive bone remodeling seen in normal skeletally mature bones remains controversial. The equine radius is used as a model because in vivo strain data show that the mid-to-proximal diaphysis receives a consistent history of predominantly cranial-caudal bending loads, in contrast to the distal diaphysis which receives relatively more torsional loading superimposed on cranial-caudal bending. Medial and lateral cortices serve as control regions because they corres...
Stewart F, Charleston B, Crossett B, Barker PJ, Allen WR.An apparently unique protein produced in large quantities by the endometrium of the mare which adheres to, or is incorporated into, the acellular capsule that surrounds the equine conceptus in early pregnancy, has been characterized and partially sequenced. It has a molecular mass of approximately 18 kDa on SDS-PAGE gels and is nonglycosylated as assessed by a sensitive carbohydrate detection kit. Comparison of its first 24 amino-terminal amino acids with all entries in the databases failed to show any significant identity with any other protein sequence. Secretion of the protein appears to be...
Grünig G, Triplett L, Canady LK, Allen WR, Antczak DF.Invading trophoblasts form endometrial cups in the endometrium of the pregnant mare. In the present study we characterized the maternal leucocyte response to endometrial cups from their formation to their regression. The maternal leucocyte response was correlated with the stages of trophoblast development. (1) Aggregates of CD4+ and CD8+ cells were present between the migrating and differentiating endometrial cup trophoblasts and surrounding the forming endometrial cups. (2) Numbers of CD4+ cells within the mature endometrial cups were much reduced. At the periphery of the endometrial cups CD4...
Doxey DL, Tothill S, Milne EM, Davis Z.Three horses suffering from grass sickness were treated successfully but showed clinical signs which varied in severity and duration. They were all characterised by marked and often erratic changes in behaviour and appetite.
Rivero JL, Serrano AL, Henckel P.Biopsies of the gluteus medius muscle were taken at three different depths from 36 endurance horses aged 8.42 +/- 2.85 years and of both sexes. Twenty of the horses were considered to be excellent performers on the basis of the mean speed of their three fastest records in endurance events over the previous two or three years, whereas 16 were moderate performers. The biopsy samples were analysed for the activities of the enzymes citrate synthase (an indicator of citric acid cycle activity), 3-OH-acyl-CoA-dehydrogenase (an indicator of lipid oxidation) and lactate dehydrogenase (an indicator of ...
Wiśniewska A, Janczarek I, Wilk I, Tkaczyk E, Mierzicka M, Stanley CR, Górecka-Bruzda A.Ridden horses have been reported to be fearful of cows. We tested whether cows could provoke behavioural and cardiac fear responses in horses, and whether these responses differ in magnitude to those shown to other potential dangers. Twenty horses were exposed to cow, a mobile object or no object. The time spent at different distances from the stimulus was measured. In a separate test, heart rate (HR), root mean square of successive differences between heartbeats (RMSSD) and the horses' perceived fear were assessed at various distances from the stimuli. The horses avoided the area nearest to a...
Lindsay-McGee V, Sanchez-Molano E, Banos G, Clark EL, Piercy RJ, Psifidi A.The Connemara pony (CP) is an Irish breed that has experienced varied selection by breeders over the last fifty years, with objectives ranging from the traditional hardy pony to an agile athlete. We compared these ponies with well-studied Warmblood (WB) horses, which are also selectively bred for athletic performance but with a much larger census population. Using genome-wide single nucleotide polymorphism (SNP) and whole-genome sequencing data from 116 WB (94 UK WB and 22 European WB) and 36 CP (33 UK CP and 3 US CP), we studied the genomic diversity, inbreeding and population structure of th...
Josseck H, Zenker W, Geyer H.This study involved a macroscopic evaluation of hoof quality in 152 Lipizzaner horses (130 from Austria and 22 from other countries) and a controlled double blind trial of the effects of biotin on hoof horn growth and quality over 19 months in 42 stallions from the Spanish Riding School (SRS) in Vienna. Using a grading system that incorporated evaluation of horn wall, white line, sole and frog, the macroscopic study revealed the following: 90% of the Austrian Lipizzaners had soft white lines and crumbling, fissured horn at the bearing border of the walls; 39% of the stallions of the SRS, > ...
Millard JT, Chuang E, Lucas JS, Nagy EE, Davis GT.A simple and robust biochemistry laboratory experiment is described that uses restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products to verify the identity of a potentially valuable horse. During the first laboratory period, students purify DNA from equine samples and amplify two loci of mitochondrial DNA. During the second laboratory period, students digest PCR products with restriction enzymes and analyze the fragment sizes through agarose gel electrophoresis. An optional step of validating DNA extracts through realtime PCR can expand the experiment to th...
Sherman GB, Lund LA, Bunick D, Winn RJ.The luteinizing hormone (LH) beta subunit gene is expressed in the pituitary glands of all mammals, whereas the closely related chorionic gonadotropin (CG) beta subunit genes have been identified only in primates and equids, and are expressed in placenta. In the case of horses, there is a single-copy equine (e) luteinizing hormone/chorionic gonadotropin hormone beta subunit gene (eLH/CGbeta) that (1) is expressed in both pituitary gland and placenta, (2) encodes a characteristic carboxyl terminal peptide (CTP) extension, and (3) transcribes an atypically elongated 5'-untranslated region (UTR) ...
Ripley AM, Penedo MCT, Grahn RA, Martinez de Andino EV, Walbornn SR, Serafini R, Love CC, Hinrichs K.Fetal genotyping has important applications in the horse, but currently necessitates embryo recovery and biopsy. We investigated whether fetal genotyping could be performed on yolk-sac fluid recovered from pregnant mares via transvaginal aspiration. Fluid was collected before Day 30 to provide results before establishment of the endometrial cups (Day 37). Genotyping and assessment of maternal DNA contamination was performed by analyzing histograms of PCR results for 19 loci. In Exp. 1, mares underwent yolk-sac aspiration on Days 22-28 of gestation. Fluid (0.56-1.02 mL) was recovered from fiv...
Elliott CR, Vasey JR, Russell TM.To report on the outcome of wounds to the hindlimb of racehorses, and horses with the intended use of racing, where both the long digital extensor (LoDE) and lateral digital extensor (LaDE) tendons had been completely transected. Methods: Retrospective case series. Methods: Records of all horses admitted with hindlimb lacerations between 2002 and 2009 were examined for cases where both the LoDE and LaDE tendons in the hindlimb had been severed, and specifically in horses intended to be used for racing. Outcome was assessed via retrieval of race records and via telephone questioning of the owne...
Ayala I, Montes A, Bernal LJ, Sandoval JA, Gutierrez C.The duration of electrocardiograph wave forms and intervals were determined in 179 Spanish-bred (Andalusian) horses aged from 1 month to 17 years. The values were compared with those of other breeds, and the relationship between electrocardiographic data and age was examined. High correlation coefficients were found between PR, ST and QT intervals and the age of the horses, and an inverted relation between heart rate and age was found. A multiple range analysis was made and the results suggest that significant changes in duration values and heart rate occurred at the age of 6 months and in the...
Van Diest TJ, Kogan CJ, Kopper JJ.Hospitalized horses are at risk for colic due to several factors, all of which may reduce voluntary water intake (VWI) further contributing to the development of colic during hospitalization. Our objectives were to determine if using flavored water (sweet feed, peppermint, or apple-flavored electrolyte) increases VWI of hospitalized horses and to determine if horses consumed more flavored water versus plain water. We hypothesized that (1) in hospitalized horses the availability of flavored water results in more VWI than the availability of unflavored water and that (2) average intake of flavor...
Bookbinder L, Schott HC.To describe refeeding syndrome in an equid without a history of recognized risk factors. Methods: Refeeding syndrome with marked hypophosphatemia developed in an aged miniature donkey gelding during treatment of suspected enterocolitis. Hypophosphatemia (manifested clinically as ileus and neuromuscular weakness) developed despite a short (3 day) history of hyporexia, increased body condition (7/9), and adherence to nutritional recommendations for critically ill equids. Nutritional support included nasogastric enteral feeding with a commercial equine nutrition product claiming to provide 100% o...
Sonea IM, Bowker RM, Robinson NE, Broadstone RV.Distribution of pulmonary nerves immunoreactive for either substance P or calcitonin gene-related peptide was determined, using immunohistochemical methods on healthy lungs from adult equids. The overall patterns of distribution of substance P and calcitonin gene-related peptide-like immunoreactivity were similar. Distribution of immunoreactive nerves was not uniform throughout the lungs; nerve fibers immunoreactive for these peptides were more frequently observed near the hilus of the lung than in the caudal lobes or in the periphery of the lung. Nerve fibers immunoreactive for substance P or...
Rutberg AT, Turner JW, Herman K.To be effective and publicly acceptable, management of free-roaming horses and burros in the United States and elsewhere needs a consistent ethical framing of the animals and the land they occupy. In the U.S., the two laws that largely govern wild horse and burro management, the 1971 Wild Free-Roaming Horse and Burro Act and the 1976 Federal Land Policy and Management Act ("FLPMA"), rest on conflicting foundations, the former based on an ethic of care and the latter on largely utilitarian principles. These conflicts specifically fuel debates over the selection of appropriate fertility control ...
Sakamoto T, Fawcett JA, Innan H.Horses have substantial variation in coat color, and the genetic loci responsible for the coat color variations have been well investigated. It has been believed that some color variations should follow a single-locus Mendelian law. Examples include the Gray locus that causes the gray phenotype and the Extension locus that specifies the chestnut phenotype. We reevaluated the roles of the Gray and Extension loci by using a large number of mating records of Thoroughbred racing horses. We showed that the data indeed fits the Mendelian law extremely well for the two loci. Furthermore, we demonstra...
Petrova V, Yonkova P, Simeonova G, Vachkova E.Subcutaneous fat tissue is an accessible and abundant source of multipotent stem cells for cell therapy in regenerative medicine. Successful trilineage differentiation is required to define the stemness features of the obtained mesenchymal cells, and adipogenesis is a part of it. Since indomethacin is bound to serum albumin, replacing foetal bovine serum (FBS) with horse serum (HS) in adipogenic induction protocols would suppress its cytotoxic effect and reveal a better adipogenic potential in equine MSCs. The equine subcutaneous adipose-derived stem cells (ASCs) were separately induced in adi...
Rose NS, Northrop AJ, Brigden CV, Martin JH.The aim of this study was to quantify the effects of two different 8-week stretching regimes on stride length (SL) and range of motion (ROM) in the equine trot. Eighteen horses were divided into three matched groups: a 6 days/week stretching regime (6DSR), a 3 days/week stretching regime (3DSR) and a control no-stretching regime (NSR). SL and ROM data were collected at weeks 0, 2, 4, 6 and 8 for trot in-hand. Stretching had no significant effect on SL. A number of significant differences were found in joint ROM between treatments in the shoulder, stifle and hock, suggesting some negative biome...
Parks CM, Manohar M.In recent years, increasing attention has been focused on the physiological responses of the horse to maximal exercise. Cardiovascular response in near maximally exercised galloping ponies (heart rate 225 +/- 7 beats/min; whole body oxygen consumption 122 +/- 12 ml/min/kg) comprised a marked increase in blood flow to the cerebellum, myocardium, diaphragm and the working muscles, while renal blood flow decreased precipitously. Cerebral and brainstem perfusion did not vary from resting values. Transmural homogeneity of myocardial blood flow persisted during near maximal exercise. It was reported...
Bass LD, Denniston DJ, Maclellan LJ, McCue PM, Seidel GE, Squires EL.Equine embryos (n=43) were recovered nonsurgically 7-8 days after ovulation and randomly assigned to be cryopreserved in one of two cryoprotectants: 48% (15M) methanol (n=22) or 10% (136 M) glycerol (n=21). Embryos (300-1000 microm) were measured at five intervals after exposure to glycerol (0, 2, 5, 10 and 15 min) or methanol (0, 15, 35, 75 and 10 min) to determine changes (%) in diameter over time (+/-S.D.). Embryos were loaded into 0.25-ml plastic straws, sealed, placed in a programmable cell freezer and cooled from room temperature (22 degrees C) to -6 degrees C. Straws were then seeded, h...
McGreevy PD, Richardson JD, Nicol CJ, Lane JG.There is confusion in the veterinary literature concerning the definition of oral based stereotypies in the horse. This study reports the use of fluoroscopy and endoscopy during cribbiting/wind-sucking in afflicted horses. This permitted observations of movements of the pharyngeal and oesophageal tissues and of the air column within during the stereotypic behaviour. The findings reported show that the sequence of events during crib-biting/wind-sucking is not related to deglutition and that air is not swallowed to the stomach. Transient dilation of the upper oesophagus was recorded and the char...
Hales EN, Esparza C, Peng S, Dahlgren AR, Peterson JM, Miller AD, Finno CJ.Equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM) is an inherited neurodegenerative disorder of unknown etiology. Clinical signs of neurological deficits develop within the first year of life in vitamin E (vitE) deficient horses. A genome-wide association study (GWAS) was carried out using 670,000 SNP markers in 27 case and 42 control Quarter Horses. Two markers, encompassing a 2.5 Mb region on ECA7, were associated with the phenotype (p = 2.05 × 10-7 and 4.72 × 10-6). Within this region, caytaxin (ATCAY) was identified as a candidate gene due to its known role ...
Antonioli ML, Canola PA, de Carvalho JRG, Fonseca MG, Ferraz GC.It is important to understand the effects of hoof trimming on hoof and limb conformation to maximize its benefits on the health of the appendicular skeleton of horses, thus promoting improvements in athletic performance and sporting longevity with regard to athletic horses. There is little information on possible changes in the angulation of the thoracic limb joints after hoof trimming and correlations between the angulation of the thoracic limb joints with hoof measurements. To that purpose, nineteen Mangalarga mares received routine hoof trimming. Visual recordings (photographs) were taken b...
Verhaar N, Hoppe S, Grages AM, Hansen K, Neudeck S, Kästner S, Mazzuoli-Weber G.α2 agonists are frequently used in horses with colic, even though they have been shown to inhibit gastrointestinal motility. The aim of this study was to determine the effect of dexmedetomidine on small intestinal in vitro contractility during different phases of ischaemia. Experimental segmental jejunal ischaemia was induced in 12 horses under general anaesthesia, and intestinal samples were taken pre-ischaemia and following ischaemia and reperfusion. Spontaneous and electrically evoked contractile activity of the circular and longitudinal smooth muscles were determined in each sample with a...
Machida N, Yasuda J, Too K.A morphometric study of hearts in 81 equine foetuses, ranging in age from 190 to 330 days of foetal age, and in 26 newborn foals is reported. The mean weight, external dimensions, ventricular wall thickness and circumference of the atrio-ventricular orifice were measured. Features of the main associated vessels of the heart were also recorded. All cardiac measurements of foetuses increased linearly throughout the latter half of pregnancy and were highly correlated with foetal age. This linear growth pattern was also found in the parameters of the associated arterial trunks. The ratio of the ri...
Gradil CM, Uricchio CK, Schwarz A.The present study evaluated a novel intrauterine device for its effect on estrus suppression. The self-assembling intrauterine device (Upod) consists of three 12 mm × 26 mm elliptically shaped units each with a magnetic core and coated with a polymer (total weight 22.5 g). Each magnetic unit is inserted independently from the other. Once inside the uterus, these magnetic elliptical units self-assemble and adapt the lower energy "ring" conformation. In mares, the devices can be inserted at any stage of the estrous cycle without the need for multiple exams. Shatter-proof grade material is u...
Turner JE, Irvine CH.Gonadotrophin-releasing hormone (GnRH) was used in several regimens in anoestrous mares in an attempt to investigate the effects of frequency and dose on follicle-stimulating hormone (FSH) and luteinizing hormone (LH) release, and consequently on ovulation and corpus luteum establishment. Thrice daily injections of GnRH induced development of pre-ovulatory follicles, but hourly injections or constant infusions were required to induce ovulation. Hourly injections induced a much higher LH:FSH ratio in the presence or absence of ovarian hormones. When anoestrous mares were given an implant that r...
Warner A, Mayhew IG.Anhidrosis is loss of the ability to sweat. The problem is seen in horses kept in a hot humid climate, and it may cause severe impairment of thermoregulation in the equine athlete. British Thoroughbreds imported to her tropical colonies are the earliest recorded cases, and since then the syndrome has come to be described as one of Thoroughbreds, usually performance athletes, undergoing acclimatization to heat and humidity. A recent epidemiologic study of cases in Florida has shown, however, that many different breeds, and long time inhabitants of a hot climate, may be affected. Equine sweat gl...
Hall LW, Aziz HA, Groenendyk J, Keates H, Rex MA.To investigate activity in respiratory muscles, insulated wire electrodes were used to record electromyographic activity in the costal diaphragm and in the intercostal, serratus ventralis, internal abdominal oblique, transversalis and rectus abdominis muscles in conscious horses and in the same animals when anaesthetised. Electromyographic activity was related to respiratory phases as recorded by a stethograph around the chest wall. The costal diaphragm showed tonic and inspiratory activity in both conscious and anaesthetised animals. The principal muscle actively involved in expiration was th...
John HA, Laffling AJ, Marrs J, Baird A, Jat PS, Holdstock NB, Rossdale PD.To enable direct testing of a range of potential toxins or pathogens that might be involved in grass sickness, equine thoracic sympathetic chain ganglion cell lines were established from primary cell cultures by retroviral-mediated transduction of the temperature-sensitive mutant of the establishment oncogene encoding SV40 large T antigen. Morphological and behavioral features, temperature dependence, and immunocytochemical characteristics of the cell lines were investigated. The majority of cells were noradrenergic neurons in which dopamine-beta-hydroxylase, the enzyme that catalyzes norepine...
Epstein K, Cohen N, Boothe D, Nieuwoudt C, Chandler J.In many cases of equine infectious disease, long-term administration of antimicrobial drugs is required. Oral agents are preferred because of the relative ease of administration compared with other routes. Enrofloxacin has been shown to be effective against a variety of equine pathogens, but oral administration of this drug has proved difficult in horses. An oral gel formulation made from the injectable cattle product produces blood levels sufficient to resolve infections caused by a variety of common equine pathogens.
Read JE, Cabrera-Sharp V, Offord V, Mirczuk SM, Allen SP, Fowkes RC, de Mestre AM.Equine chorionic girdle trophoblast cells play important endocrine and immune functions critical in supporting pregnancy. Very little is known about the genes and pathways that regulate chorionic girdle trophoblast development. Our aim was to identify genes and signalling pathways active in vivo in equine chorionic girdle trophoblast within a critical 7-days window. We exploited the late implantation of the equine conceptus to obtain trophoblast tissue. An Agilent equine 44K microarray was performed using RNA extracted from chorionic girdle and chorion (control) from equine pregnancy days 27, ...
Mlodawska W, Okólski A.From the ovaries of 256 slaughtered mares a total of 1713 follicles were isolated from which 1641 (95.8%) oocytes were recovered (6.4/mare). A total of 564 follicles and oocytes were evaluated for the degree of vascularisation of the follicle wall, the appearance of the follicular fluid and the location and morphology of the cumulus-oocyte-complex. Follicles with a diameter of >10 mm displayed more numerous, well branched and more pronounced blood vessels than the smaller ones (4-10 mm diameter) and most of them contained clear, yellowish fluid with few granulosa cells. The percentage of oo...
