Equine health encompasses the study and management of diseases, disorders, and overall well-being of horses. It involves understanding various physiological systems, preventive care, and treatment strategies to maintain optimal health in equine populations. Common areas of focus include nutrition, infectious diseases, orthopedic conditions, and reproductive health. Research in equine health aims to advance knowledge on diagnostic methods, therapeutic interventions, and management practices that improve horse welfare and performance. This page collects peer-reviewed research studies and scholarly articles that explore the diverse aspects of equine health, offering insights into current findings and advancements in the field.
Frolov VA, Derx H, Riguer P.Guinea pigs were sensitized by three subcutaneous injections of 0.1 ml native horse serum at 2-day intervals, 21 days after the third injection the animals developed marked sensitization to this antigen which was manifested by anaphylactic reaction to the subcutaneous challenge with this antigen. At this time, the myocardium of the sensitized animals showed signs of extra- and intracellular oedema, a sharp increase in the number of lysosomes, damage of their membranes, 2 1/2 months after sensitization the animals showed no anaphylactic reaction to the challenge dose of the antigen. There were ...
Bryans JT, Hendricks JB.Contagious equine metritis, introduced by importation of 2 comtaminated stallions from France, affected 54 Thoroughbred brood mares during the 1978 breeding season in Kentucky. The infection was diagnosed bacteriologically and by the use of a complement fixation test. Although lateral spread to stallions, and probably to a few mares, occurred through human agency in the breeding sheds of 2 stud farms, control measures instituted early in the epidemic confined the disease to brood mares bred by stallion on only these farms.
Bielański W, Kaczmarski F.Semen samples were collected from 3 fertile stallions by means of an 'open' artificial vagina and examined under scanning and transmission electron microscopy. The stallion spermatozoon has many features in common with that of other mammals but differs specifically in that it has an asymmetric head, an abaxial position of the tail and an acrosome of small volume. The presence of microtubules in the neck is also a characteristic of stallion spermatozoa.
Tatarov G, Martinov S, Panova M.It was established that the complement binding reaction (CBR) is a suitable and very fast method for horse rhino-pneumonitis diagnostics. Cell cultural virus produced in cell cultures of pig kidneys was used as antigen. The antigen lots tested have no anticomplementary properties. Highest complement binding activity was evident in the non-diluted antigen, which discovered specific antibodies in immune serums. The CBR specificity was tested by the aid of homologous and heterologous serums and antigens. The titers of complement binding antibodies in the serums of 255 horses recovered from the di...
Pascoe RR.An instrument has been designed to measure the effective length (l) and angle of declination (a) of the vulva in the mare. The product, la, provides an index (Caslick Index) suitable for determining the necessity for Caslick's operation in mares not exhibiting the classical symptoms associated with pneumovagina. The value l showed a significant increase (P less than 0.05) with increased age in breeding mares. Studies on 9020 mares revealed that all caslicked mares, and mares with a Caslick Index of less than 150, had a significantly higher pregnancy rate than non-caslicked mares of similar age...
Peaker M, Rossdale PD, Forsyth IA, Falk M.Small samples of mammary secretion were taken for analysis from Thoroughbred mares during the last 3 weeks of pregnancy up to the time of foaling. The concentrations of sodium and chloride decreased while those of lactose, potassium, citrate, phosphate, calcium, magnesium and protein increased. The time-course of these changes showed marked variation between animals. The concentration of whey proteins began to increase about 10 days before parturition. The appearance of the secretion and the size of the mammary glands increased in the last few days of pregnancy. It is suggested that the concen...
Jeffcott LB, Rossdale PD.The position, posture and presentation of the fetus were studied by serial radiography of the abdomen in 18 crossbred Pony mares near term and during first- and second-stage labour. In 3 mares the fetal position was assessed before and after induction of parturition with the synthetic prostaglandin, fluprostenol. In late gestation and up to the time of first-stage labour the fetus lay in ventral position with the forelimbs and poll flexed or partly flexed. At this time fetal movements were confined to flexion and extension of neck and forelimbs, but at parturition the head and limbs gradually ...
McDonell WN, Hall LW, Jeffcott LB.Studies in conscious and anaesthetised ponies demonstrated that starvation, anaesthesia and changes in body position influence the radiographic appearance of the lungs in the lateral and dorsoventral views. Radiographic appearances could not be closely correlated with blood gas values, but they suggested that the volume of the lowermost lung of the laterally recumbent animal is greatly reduced.
Oldenkamp EP.A suspension based on the antibiotic, natamycin, was applied by sponging to 83 horses of various breeds and ages with signs of clinical ringworm. A number of different causative agents were involved of which Trichophyton equinum was the most common. Treatment successfully eliminated the disease within 4 weeks. After treatment the recovered animals did not show any evidence of re-infection for up to 6 months. The mycological clearance rate was 97 per cent and apart from the efficacy against ringworm, the preparation had the advantage of being non-irritant and odourless. It was also useful for t...
Shin SJ, Lein DH, Aronson AL, Nusbaum SR.A total of 19 pathogenic bacterial species was isolated from uterine swabs of 498 out of 1539 mares over 4 years. The swabs were taken by 5 veterinary clinicians using 2 different techniques. Bacterial contamination during swabbing was minimized by scrupulous attention to cleansing of the external genitalia and the perineal area, and in the handling of the culture specimen. The most prevalent organisms isolated were beta-haemolytic streptococcus (39%), Escherichia coli (27%) and Klebsiella pneumoniae (7%). Interpretation of microbiological findings correlated well with clinical findings when n...
Sherman J, Mitchell WR, Martin SW, Thorsen J, Ingram DG.The outbreaks of upper respiratory tract infections in horses at Standardbred racetracks were investigated over a three year period. The most serious epidemics of respiratory disease occurred in the winter and spring seasons. Both influenza viruses and equine herpesvirus 1 were shown to be present in the horse population. The herpesvirus was associated with respiratory disease particularly in the winter but the equine influenza viruses apparently were responsible for the major epidemics of respiratory disease at these tracks. Younger horses, two or three years of age, were particularly suscept...
Pashen RL, Allen WR.The effects of fetal gonadectomy on steroid production and the maintenance of pregnancy in the mare were studied. Removal of the fetal gonads resulted in an immediate fall in maternal plasma concentrations of conjugated and unconjugated oestrogens whereas progestagen levels remained unchanged. Hormone profiles in mares carrying sham-operated fetuses remained similar to those in unoperated control mares. Plasma levels of 13,14-dihydro-15-oxo-PGF-2 alpha (PGFM) were much lower, and uterine contractions weaker, during labour in mares carrying gonadectomized foals than in control mares. Pregnancy ...
Trommershausen-Smith A, Hughes JP, Neely DP.Gonadal dysgenesis in the mare is associated with several different karyotypes, including sex chromosome aneuploidy (63,X; 63,X/64,XX; 63,X/64,XY or 65,XXX), the normal male complement (64,XY) and autosomal deletion (64,XX?del2q-). The 63,X is the most common karyotype found in gonadal dysgenesis. Aneuploid cases probably represent spontaneous chromosome non-disjunction during oogenesis, spermatogenesis or early embryonic development. Cases with XY or autosomal deletion may be inherited defects or of spontaneous origin.
Hershman L, Douglas RH.Two experiments were performed to deterine the critical time at which the equine blastocyst must be present within the uterus of the mare to prevent regression of the corpus luteum, and thus establish the critical time for the maternal recognition of pregnancy. A non-surgical blastocyst collection technique was developed to study this relationship between the blastocyst and the maternal ovary. Results from these experiments demonstrated that the cyclic life-span of the corpus luteum is not affected by the presence of the blastocyst within the mare's uterus until after Day 14 after ovulation. L...
Seeger K, Thurow H, Haede W, Knapp E.A simple enzyme immunoassay (EIA) for the measurement of progesterone is described. Antibody against 11-OH-hemisuccinate-BSA is bound to polystyrene tubes. 11-OH-hemisuccinyl-beta-D-galactosidase is used as enzyme-coupled antigen and methylumbelliferyl-beta-D-galactoside as substrate. Concentrations down to 0.156 ng/ml plasm or amounts of 93 pg/tube are detectable. Probit analysis gave a linear relationship between log concentration and percentage of binding. A comparison of EIA and radioimmunoassay gave a correlation coefficient of 0.81. The assay is sufficiently sensitive to estimate progest...
Stefani M, Berti A, Camici G, Manao G, Cappugi G, Ramponi G.The use of sodium selenite as a catalyst in the presence of oxygen was a suitable technique to obtain in good yield an interchain S-S dimeric form of horse muscle acylphosphatase. The dimer so obtained possesses kinetic properties very similar to those of the native enzyme. On the other hand the dimer has shown a generally lower stability in respect of the thermal inactivation, particularly in the acidic environment, to the lyophilization and to the proteolytic attack. As regards the 8 M urea inactivation, the dimer is not able to completely regain its activity by dilution, showing a behaviour...
Karasek M, Marek K, Kunert-Radek J.The influence of gonadotropic hormones on the ultrastructure of rat pinealocytesin short-term organ culture was studied. Human chorionic gonadotropin (HCG), as well as pregnant mare serum gonadotropin (PMSG), caused a marked activation of pinealocytes. An hypothesis is discussed implying the presence of a feedback mechanism between the pineal organ and the hypothalamo-hypophysial system.
Parry DA, Craig AS, Barnes GR.A study has been made of the ultrastructural organization of the collagen fibrils and elastic fibres in tendons and ligaments from horses of ages ranging from 2 months premature to 19 years. Diameter distributions of the collagen fibrils in the common digital extensor tendon, the superficial flexor tendon and the suspensory ligament are unimodal in the foetal tissue and at birth, and at these stages of development the three collagenous tissues are virtually indistinguishable. However, at maturity, the ligament and flexor tendon have bimodal distributions similar to that found for rat-tail tend...
Jörg A, Portmann P, Fellay G, Dreyer JL, Meyer J.An improved and short method is described for the isolation of intact eosinophilic leukocytes from horse blood with high yield (1--1.5 g/20 l). Viability and purity of the preparations were verified by light and electron microscopy and by the trypan blue exclusion test. Isolated eosinophils were 98--100% pure, intact and viable, and they could be shown to phagocytise immune-complexes.
Fernandez CJ, Scott DW, Erb HN.A retrospective study was performed on skin biopsy specimens from horses and cats having eosinophilic granulomas with 'collagen degeneration', eosinophilic skin diseases without 'collagen degeneration' and pyogranulomas without 'collagen degeneration'. Neither the appearance of collagen fibres nor the dominant polymorphonuclear cells, as seen in H & E-stained sections, were predictive of Masson's trichrome findings. Hence, a Masson's trichrome staining abnormality of collagen fibres was no more likely to be present in lesions with 'collagen degeneration' than in those lesions without 'collagen...
van Niekerk FE, van Niekerk CH.Pregnant Anglo-Arab and Thoroughbred mares (n = 24) were divided randomly according to age and breed into 4 groups of 6 mares each from approximately 6 weeks before their expected foaling date. Diets received by the 4 groups varied in essential amino-acid and total protein contents. Serum progestagen, FSH and LH concentrations were determined from the day of parturition until foal heat and during the 1st oestrous cycle following foal heat. Serum progestagen, FSH and LH concentrations did not differ between the treatment groups. Progestagen concentrations were high (mean = 7.0: 5.2-16.4 ng/ml) ...
Wong DM, Vo DT, Alcott CJ, Peterson AD, Brockus CW, Hsu WH.Arginine vasopressin (AVP) has received increased attention in equine critical care but there is minimal information of AVP concentration in foals. The clinical usefulness of measuring AVP in ill foals depends on knowledge of age-related changes in AVP concentrations in healthy foals. Objective: Plasma AVP concentrations will be significantly different when measured from birth to 3 months of age in healthy foals. Methods: Thirteen healthy university-owned foals. Methods: Prospective, observational study. Blood was collected from healthy foals at birth and 3, 5, 7, 10, 14, 21, 28, 42, 56, and 8...
Valverde A, Boyd CJ, Dyson DH, Pascoe PJ.Dantrolene, a drug used in the prevention and treatment of malignant hyperthermia, was believed responsible for prolonged postanesthetic recumbency in a horse. Prophylactically, dantrolene was given orally before induction of anesthesia. Dantrolene has been recommended for use in horses at risk of developing postanesthetic myopathy. Side effects, including ataxia, may result from dantrolene administration.
Lyons ET, Drudge JH, Tolliver SC.Thirteen critical tests were conducted in horses naturally infected with helminths and bots. Single doses of thiabendazole (44 mg/kg of body weight) and trichlorfon (40 mg/kg of body weight) powder formulations were administered as suspensions sequentially given via stomach tube to evaluate the efficacy of the combination against the large parasites of horses. Parasite removal efficacies were 100% against 2nd instar Gasterophilus intestinalis and 2nd and 3rd instar Gasterophilus nasalis and 82 to 100% against 3rd instar G intestinals. There were complete removals of mature and immature Parasca...
Huricha , Kawai M, Ninomiya S.In this study, we investigated suckling behavior and the distance between a foal and its mare as indicators of foal growth in Hokkaido native horses (HKD) during the first 40 days of life. Direct observations were made of 22 mare and foal pairs from two consecutive days 1 and 2, 5 and 6, 10 and 11, 20 and 21, 30 and 31, and 40 and 41 after birth by focal animal sampling for 3 h per day. Suckling behavior was continuously recorded, along with the terminator. The distance between the foal and its mare was determined using the instantaneous sampling method (1 min), and the percentage was calc...
Baracca A, Bucchi L, Ghelli A, Lenaz G.A method to prepare coupled submitochondrial particles from horse platelets is described. The method allowed us to study the protonophoric activities of both complex I and complex V following the fluorescence quenching of the monoamine 9-amino-6-chloro-2 methoxyacridine (ACMA), a probe highly sensitive to the generation of a transmembrane delta pH. We carried out a kinetic analysis of each enzyme complex studying the proton translocation and the electron transfer activities of complex I as well as the proton translocation and the ATP hydrolytic activities of complex V. A micromethod to prepare...
Guimarães T, Miranda C, Pinto M, Silva E, Damásio L, Costa AL, Correia MJ, Duarte JC, Cosinha C, Lopes G, Thompson G, Rocha A.A possible role of breeding activities in the composition of the microbial population in stallions' external genitalia (EG) and the relationship between micro-organisms colonizing the skin of the abdomen and the ones colonizing the EG have not been studied. In experiment 1, EG microbiological samples were collected from 41 stallions used for both natural cover and semen collection (BST) and from 18 non-breeding stallions (NBST). A higher (p < 0.05) frequency of isolation of potentially pathogenic species was found for BST. Age did not influence number of micro-organism species isolated both in...
Harris P, Geor RJ.The feeding of "low carbohydrate" or "low glycemic" diets has been recommended for management of horses with metabolic and endocrine disorders in which insulin resistance is a component. A "low carbohydrate" diet is a misnomer, however, because horses require that a significant proportion of their daily ration comprises structural carbohydrates (fiber/forage) to maintain gut health and mental wellbeing. This article provides a detailed description of the different carbohydrates in equine feeds. It also reviews the terminology used to describe glucose and insulin responses to the ingestion of c...
Rauws AG, van Schothorst M, Frik JF.The protein binding, the plasma half-life and the residue depletion of sulfamonomethoxine (SMM) after intramuscular administration were investigated in pigs, horses and cattle. Protein binding was weakly concentration-dependent. The bound fraction in plasma in the therapeutic range amounted to approximately 45, 40 and 50% for pigs, horses and cattle respectively, and the plasma half-lives were approximately 5.1, 5.7 and 3.1 hours respectively. SMM levels were less than 1 mug/g in muscle tissue after 36, 20 and 12 hours in pigs, horses and cattle respectively. In the kidney SMM levels were not ...
Caron JP.Laparoscopic removal of the gonads from male and female horses is regularly performed for a variety of reasons. In female horses, common indications for ovariectomy include behavioral problems and signs of abdominal pain that are linked to estrus. Another indication is an abnormal, enlarged ovary, typically due to ovarian neoplasia, the most common being granulosa thecal cell tumor. Ovariectomy is also a treatment option for ovarian hematomas and other abnormalities. In addition, ovariectomy is used to sterilize mares intended for artificial insemination or embryo transfer programs.
Jung H, Lee G, Kim J, Lee JW, Yoon M.The endocrine system is critical to the maintenance of testicular function. The homeostasis of sex hormone levels is orchestrated by positive and negative feedback systems controlled by the hypothalamic-pituitary-gonadal axis. This study investigated the long-term effects of hemicastration on testicular size and function in stallions. Four Thoroughbred stallions, 4-6 years of age, were included in this study. Several parameters, including testicular weight and volume, plasma testosterone concentrations, VASA-positive germ cell populations and cross-sectional areas of the seminiferous tubules ...