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Topic:Equine Health

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.
Penicillin-induced hemolytic anemia and acute hepatic failure following treatment of tetanus in a horse.
The Cornell veterinarian    January 1, 1991   Volume 81, Issue 1 13-18 
Step DL, Blue JT, Dill SG.Acute, severe hemolytic anemia occurred in a horse being treated for tetanus with intravenous penicillin and tetanus antitoxin. During treatment, the horse developed a positive direct antiglobulin test and a high titer (maximum 1:1024) of IgG anti-penicillin antibody. The horse recovered from the tetanus and penicillin induced hemolytic anemia, but later developed acute hepatic failure, probably resulting from the administration of equine origin tetanus antitoxin.
Evaluation of an electronic device used as a quick screening method to detect changes in the red cell content of the blood in horses participating in endurance trail rides.
Veterinary research communications    January 1, 1991   Volume 15, Issue 4 309-314 doi: 10.1007/BF00430036
de Waal A, Potgieter FJ.Dehydration, to varying degrees, will inevitably occur in horses participating in endurance trail rides. This water loss is directly related to the amount of body water lost through evaporative cooling, that in turn being related to the amount and rate of work performed, and to the environmental temperature and humidity. An electronic apparatus that can substitute for the conventional and time-consuming venous haematocrit was developed to measure the animals' hydration status. The mechanism of this electrometer is based upon the relationship between the red cell content and the electrical cond...
Equine testicular aromatase: substrates specificity and kinetic characteristics.
Comparative biochemistry and physiology. B, Comparative biochemistry    January 1, 1991   Volume 100, Issue 1 107-115 doi: 10.1016/0305-0491(91)90092-r
Gaillard JL.1. In the stallion, estrogens were synthesized and sulfated in vivo by the testis. 2. The equine testicular enzyme aromatized androgens and 19-norandrogens with similar velocity, but not 16 alpha-hydroxytestosterone or epitestosterone in contrast to the human placental aromatase. 3. One single enzyme was implicated in the aromatization of androstenedione, testosterone, 19-norandrostenedione and 19-nortestosterone by ETMES. 4. During the process of androstenedione aromatization by ETMES, 19-hydroxyandrostenedione and 19-oxoandrostenedione were released and 4-hydroxyandrostenedione was a competi...
Influence of pregnancy and lactation on diurnal and seasonal changes in lactic acid and pyruvic acid levels and in values of pH, pCO2 and pO2 in the mare blood.
Comparative biochemistry and physiology. A, Comparative physiology    January 1, 1991   Volume 98, Issue 3-4 497-501 doi: 10.1016/0300-9629(91)90437-h
Flisińska-Bojanowska A, Gill J, Komosa M.1. The diurnal changes in the levels of lactic (LA) and pyruvic (PA) acids and in values of pH, pO2 and pCO2 were studied in the blood of barren and later on in pregnant and lactating mares, throughout three subsequent years. 2. Blood samples were taken every 4 hr, for one day, each month, throughout 3 years. 3. The mares were kept and fed in the same conditions, lighting was natural. 4. In barren mares, diurnal rhythm in LA, PA, pO2 and pCO2 was found. 5. The pregnancy as well as lactation masked diurnal rhythms in parameters studied, except the LA level during lactation but then the acrophas...
Relationship between the fertility of fresh and frozen stallion semen and semen quality.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 107-114 
Samper JC, Hellander JC, Crabo BG.Studies were designed to investigate whether sperm motility determined with a Hamilton-Thorn HTM-2000 motility analyzer (HTM), or the percentage of spermatozoa that passed through glass wool (GW), Sephadex (S), or glass wool/Sephadex (GWS) filters could be used to predict the fertilizing potential of fresh or frozen semen. In the fresh semen study, 10 randomly selected ejaculates from 4 stallions exclusively used for A.I. breeding were assayed during the season. The 521 mares used were inseminated with 500 x 10(6) motile spermatozoa after gynaecological examination every 2 days. In the frozen ...
Measurements of glucose metabolism in single equine embryos during early development.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 419-425 
Brück I, Hyland JH.The contributions of 2 biochemical pathways to the total metabolism of glucose (the Embden-Meyerhof pathway [EMP] and the pentose phosphate pathway [PPP]), were assessed for equine embryos recovered on Day 4.5, 7.5 and 11.5 post ovulation. At all developmental stages studied, glucose was metabolized through both pathways. Through the EMP, the amounts of glucose metabolized per nl embryo volume per hour were 4.0, 9.9 and 3.1 pmol, whereas via the PPP, amounts were 0.9, 1.7 and 0.07 pmol for Day-4.5, -7.5 and -11.5 embryos, respectively. The ratio of EMP:PPP with age was 9.7 for Day -4.5 embryos...
A preliminary study of immunological castration in colts.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 183-190 
Dowsett KF, Pattie WA, Knott LM, Jackson AE, Hoskinson RM, Rigby RP, Moss BA.This study tested the effectiveness of a conjugated GnRH vaccine for stimulating antibody production, suppressing testosterone secretion and depressing testicular development in yearling colts. Two colts were allocated to each of three groups, (1) control, (2) subcutaneous and (3) intramuscular vaccinations. Two injections of the vaccine were given 11 weeks apart. Liveweight gain was not affected by vaccination but plasma testosterone concentrations in the treated colts were suppressed and their antibody titres to GnRH were greater than 1:1000. Testicular development in the treated colts also ...
Osteochondral fracture of the proximal palmar middle phalanx in a Thoroughbred.
Equine veterinary journal    January 1, 1991   Volume 23, Issue 1 67-69 doi: 10.1111/j.2042-3306.1991.tb02717.x
Welch RD, Watkins JP.No abstract available
Post-partum ovarian activity in Finnhorse mares with special reference to seasonal effects.
Acta veterinaria Scandinavica    January 1, 1991   Volume 32, Issue 3 313-318 doi: 10.1186/BF03546960
Koskinen E.In a previous study, times from parturition to the first ovulation were followed in 55 Finnhorse mares on the basis of milk progesterone determinations. Ninety-six per cent of mares had ovulated by day 20 post-partum. If intervals of more than 19 days are excluded from the data, the time from parturition to 1st ovulation was 117 days. However, in cases of foaling before and after the beginning of June the times were 13.0 days and 8.8 days, respectively (p less than 0.001). Long intervals (over 16 days) occurred mainly before 1st May (in 6 out of 7 cases). In a 2nd study, 25 post-partum Finnhor...
Diagnosis of locomotor incoordination in horses.
Polskie archiwum weterynaryjne    January 1, 1991   Volume 31, Issue 3-4 15-28 
Modrakowski A, Siembieda J, Szymonis-Szymanowski W.Four horses manifesting locomotor incoordination were used in the research. Precise localization of the compression of cervical spinal cord due to malforming lesions or instability of the vertebral column was determined by means of radiography and myelography. The results, particularly those obtained by means of myelography, appeared to be of decisive diagnostic importance to planned surgical operation to remove the compression of the spinal cord.
A negative feedback role for the ovaries of the mare on tonic LH secretion before the first ovulation of the breeding season.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 241-247 
Affleck KJ, Conboy HS, Fitzgerald BP.Eleven anoestrous mares were assigned randomly to Group A (intact, n = 6) or Group B (ovariectomized in January, n = 5). Jugular blood samples were collected during February to April. Ovarian activity was assessed by ultrasound and ovulation was confirmed by progesterone analysis. Intact mares ovulated between 2 and 28 April. Mean diameter of the largest follicle was less than 20 mm on 17 or 18 March (Period 3), but increased to 29 mm by 31 March or 1 April (Period 4). During Periods 1 and 2 (14 or 15 February and 3 or 4 March) mean luteinizing hormone (LH) concentrations were similar in both ...
Studies of bone marrow and leucocyte counts in peripheral blood in fetal and newborn foals.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 603-608 
Chavatte P, Brown G, Ousey JC, Silver M, Cottrill C, Fowden AL, McGladdery AJ, Rossdale PD.Clinical and pathological records of 124 foals were studied. The foals were assigned to six groups; normal, premature, dysmature, bacterially infected, neonatal maladjustment syndrome and Equid herpesvirus type 1 (EHV-1) infected. Also, 6 pony fetuses were sampled via catheters in the umbilical vein and artery between 280 and 310 days gestation. Bone marrow aspiration was performed on a further 14 foals. Premature foals had significantly lower neutrophil counts than normal foals up to 5 h. Foals with bacterial infections had significantly lower neutrophil counts up to age 12 h. EHV-1 infected ...
Equine herpesvirus: new approaches to an old problem.
Equine veterinary journal    January 1, 1991   Volume 23, Issue 1 6-7 doi: 10.1111/j.2042-3306.1991.tb02703.x
Onions D.No abstract available
Effect of pulsatile or continuous administration of GnRH on reproductive function of stallions.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 145-154 
Blue BJ, Pickett BW, Squires EL, McKinnon AO, Nett TM, Amann RP, Shiner KA.Gonadotrophin-releasing hormone (GnRH) was administered subcutaneously to reproductively normal stallions, either in a pulsatile manner (10 micrograms GnRH/2 h; n = 6) or as a continuous infusion (10 micrograms GnRH/2 h; n = 6), and in a pulsatile manner to 9 reproductively abnormal stallions, from February to July, 1988. Hormonal secretion patterns, testicular parameters and semen characteristics were monitored before and during treatment. In general, pulsatile GnRH caused a significant increase (P less than 0.05) in luteinizing hormone (LH) concentrations in the peripheral blood of normal st...
Maturation of oocytes from normal and atretic equine ovarian follicles as affected by steroid concentrations.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 385-392 
Okolski A, Bézard J, Magistrini M, Palmer E.The ovaries of 23 mares were collected at slaughter during April-June and follicles (4-40 mm in diameter) were dissected and punctured to obtain oocytes for culture. The follicles were grouped according to histology: (a) normal, (b) showing primary and (c) secondary atresia. Antral fluid was analyzed for steroid content; oestradiol and testosterone (but not progesterone or androstenediol) were closely correlated with follicle size and histological state. Oocytes were cultured early after slaughter in Medium 199 (Difco OSI, France) or Medium B2, the highest percentage of oocytes reaching Metaph...
Effect of constant light exposure on circulating gonadotrophin levels and hypothalamic gonadotrophin-releasing hormone (GnRH) content in the ovariectomized pony mare.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 259-266 
Cleaver BD, Grubaugh WR, Davis SD, Sheerin PC, Franklin KJ, Sharp DC.Melatonin is thought to play a role in relaying photic information to the central nervous system as part of the seasonal reproductive cycle of the mare. However, the mechanisms by which melatonin may act are unknown. Therefore, this study was designed to determine whether exposure to constant light would, by reducing circulating melatonin concentrations, have any effect on hypothalamic gonadotrophin-releasing hormone (GnRH) content and circulating levels of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Blood samples were collected for 12 h at 15-min intervals from 8 ovariect...
Protection against naturally acquired Rhodococcus equi pneumonia in foals by administration of hyperimmune plasma.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 571-578 
Madigan JE, Hietala S, Muller N.A 2-year field study was performed to determine the capability of increasing Rhodococcus equi specific antibody in foals via plasma transfusion or mare vaccination, to determine the kinetics of R. equi (ELISA) antibody decay and to assess the protective effects of these procedures in foals on a farm endemic for R. equi. Plasma donors were vaccinated with a killed R. equi bacterin and produced high levels of anti-R. equi antibodies, which were harvested by plasmapheresis. In Experiment 1, 68 foals were given 1 litre of hyperimmune plasma intravenously (i.v.) between 1-60 days of age. Foal plasm...
An oestrogen conjugate enzyme immunoassay for monitoring pregnancy in the mare: limitations of the assay between days 40 and 70 of gestation.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 37-44 
Stabenfeldt GH, Daels PF, Munro CJ, Kindahl H, Hughes JP, Lasley B.A direct enzyme immunoassay was developed to measure conjugated oestrogens in the plasma of pregnant mares. The antibody was produced in rabbits using oestrone-3-glucuronide (E1G) conjugated to bovine serum albumin. The enzyme conjugate was E1G conjugated to horseradish peroxidase. A sharp increase in plasma E1G concentrations occurred between Days 35 and 40 of gestation. Values declined slightly to Day 45, remained relatively constant to around Day 70 and rose sharply thereafter. Fetal death before Day 35 had no effect on plasma concentrations of E1G. Fetal death after Day 35 in conjunction w...
Comparison of bronchoalveolar lavage and respiratory secretion cytology in horses with histologically diagnosed pulmonary disease.
Schweizer Archiv fur Tierheilkunde    January 1, 1991   Volume 133, Issue 3 123-130 
Winder NC, Grünig G, Hermann M, von Fellenberg R.Equine bronchoalveolar lavage (BAL) fluid collected from 70 horses and respiratory secretions (RS) obtained from 61 of these horses were evaluated cytologically and grouped according to the histological diagnosis of the lungs from which they were obtained. The histological categories included: normal lung (8 horses); pulmonary eosinophilic infiltration (9 horses); interstitial pneumonia (5 horses); pulmonary hemorrhage (5 horses); and mild (12 horses), moderate (7 horses) and severe (24 horses) chronic small airway disease. In horses with pulmonary disease, all BAL samples and all but one RS s...
The influence of metabolic alkalosis upon exercise metabolism in the thoroughbred horse.
European journal of applied physiology and occupational physiology    January 1, 1991   Volume 63, Issue 2 129-134 doi: 10.1007/BF00235182
Greenhaff PL, Harris RC, Snow DH, Sewell DA, Dunnett M.Six thoroughbred horses exercised on a motorised treadmill on two separate occasions at a speed of 11 or 12 m.s-1 for up to 2 min. 4 h prior to exercise each horse was given a 21 test solution of sodium bicarbonate (NaHCO3; 0.6 g.kg-1 body mass) or a control solution of water by nasogastric intubation, the order of administration of the two solutions was randomised. Blood samples (n = 15) were obtained before and during the 4 h after intubation, during exercise and for 30 min after exercise. NaHCO3 ingestion resulted in changes in pre-exercise acid-base status. The changes in blood lactate and...
Evaluation of measures taken by ultrasonography and caliper to estimate testicular volume and predict daily sperm output in the stallion.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 99-105 
Love CC, Garcia MC, Riera FR, Kenney RM.The semen of 26 stallions, 2-20 years of age, was collected once a day for 7 consecutive days to determine daily sperm output (DSO). After the last collection, 17 stallions were castrated. Testicular volume was estimated using two methods. Length, width, height, of each testis were measured by caliper. Length, width, height, cross-sectional area and circumference at the widest point of the testis were measured by ultrasonography. Both caliper and ultrasound measurements were first made in the live animal, and again in vitro. There were no differences in these measurements because of method or ...
A review of the pathophysiology of exercise-induced pulmonary haemorrhage in the equine athlete.
Veterinary research communications    January 1, 1991   Volume 15, Issue 3 211-226 doi: 10.1007/BF00343226
Donaldson LL.In the United States, more than 75% of equine athletes are reported to suffer from exercise-related haemorrhage of the respiratory tract (Voynick and Sweeney, 1986; Sweeney et al., 1990). Fiberoptic endoscopy has traced the source of blood to beyond the bifurcation of the trachea. In 1981, the term exercise-induced pulmonary haemorrhage (EIPH) was introduced (Pascoe et al., 1981). Racehorses of all breeds, polo ponies and three-day event horses of mixed heritage, even foxhunters, may 'bleed' (Voynick and Sweeney, 1986; Pascoe et al., 1981; Sweeney and Soma, 1983; Hillidge, 1986). Any horse wor...
[CEA test in domestic animals].
Schweizer Archiv fur Tierheilkunde    January 1, 1991   Volume 133, Issue 7 311-313 
Hässig M, Casal M, Von Beust B, Nussbaumer M, Rüsch P.In human cancer treatment, CEA (carcino embryonic antigen) testing is a routine procedure, even though the test is of low sensitivity (40%) and low specificity (70%). Since tests with polyclonal antibodies render no reproducible results with animal sera, the applicability of a recently available monoclonal CEA test designed for human sera was evaluated. We were able to show that the latter test was of supplemental diagnostic value when testing animal sera. The upper normal limit for dogs is 1.65 ng/ml, for cats 2.81 ng/ml, for cows 2.85 ng/ml, for sheep 2.85 ng/ml and for horses 1.61 ng/ml.
Mycotic keratitis in a horse caused by Aspergillus fumigatus. The first reported case in Finland.
Acta veterinaria Scandinavica    January 1, 1991   Volume 32, Issue 3 373-376 doi: 10.1186/BF03546967
Aho R, Tala M, Kivalo M.The first identified Finnish case of equine mycotic keratitis caused by Aspergillus fumigatus is described. The clinical picture, the sampling method, the macro- and micromorphology of the causative fungus and the therapy applied are reported in detail. Therapy with natamycin (Pimafucin 2.5% eyedrops. Gist-Brocades) was successful. Mykotisk keratit hos häst orsakad av beskrivs första gången i Finland. Klinisk bild, provtagning, makroskopisk och mikroskopisk morfologi av svampen samt terapi rapporteras i detalj. Terapin med natamycin (Pimafucin® 2.5 % ögondroppar, Gist-Brocades) var effek...
Direct effects of free and conjugated steroids on GnRH stimulated LH release in cultured equine anterior pituitary cells.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 327-332 
Baldwin DM, Roser JF, Muyan M, Lasley B, Dybdal N.Enzymatically dispersed anterior pituitary cells from donor mares were cultured for 48 h in alpha-modified Eagles' medium containing 10% steroid-free horse serum. The cells were then incubated for 24 h in fresh medium oestrogen followed by a 4-h incubation with or without GnRH. Media and cell extracts were analyzed for LH by radioimmunoassay. In the first series of experiments, pituitary cells from Day-3 dioestrous mares were preincubated with ethanol (control) or different concentrations of E2 (10(-11) to 10(-7) M) for 24 h prior to a 4-h incubation without (basal) or with 1.0 nM GnRH. E2 inc...
Follicular and endocrine responses of anoestrous mares to administration of native GnRH or a GnRH agonist.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 227-233 
McCue PM, Troedsson MH, Liu IK, Stabenfeldt GH, Hughes JP, Lasley BL.Thirty-seven seasonally anoestrous mares were divided into treatment and control groups and given 10 micrograms of native GnRH (GnRH) per hour using a peristaltic pump, or 10 micrograms GnRH agonist (GnRHa) twice daily, beginning on either 13 January, 13 February or 14 March. Treatment with GnRH was equally effective in inducing ovulation in January (4/5), February (4/5) and March (3/4). GnRHa treatment was more effective in inducing ovulation in February (4/5) and March (4/4) than in January (2/8). Peak luteinizing hormone (LH) concentrations in mares induced to ovulate with GnRH (7.4 +/- 1.5...
The effect of acute exercise on the secretion of corticotropin-releasing factor, arginine vasopressin, and adrenocorticotropin as measured in pituitary venous blood from the horse.
Endocrinology    January 1, 1991   Volume 128, Issue 1 65-72 doi: 10.1210/endo-128-1-65
Alexander SL, Irvine CH, Ellis MJ, Donald RA.We have used the technique which we have developed for collecting pituitary venous blood from conscious, undisturbed horses to study the effect of acute vigorous exercise on the secretion of CRF, arginine vasopressin (AVP) and ACTH. Pituitary venous (pit) blood was collected every 1-5 min from nine trained racehorses at rest in the stable. The horses then trotted quietly for 10 min, after which they galloped as fast as possible for 4-6 min, before returning to the stable where sampling continued. In Exp 1 (n = 5) no blood samples were taken during exercise, whereas in Exp 2 (n = 4), pit blood ...
Ovarian activity in fillies treated with anabolic steroids prior to the onset of puberty.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 351-356 
Skelton KV, Dowsett KF, McMeniman NP.This study investigated the effects of zero, low (0.55), medium (1.1) and high (2.2 mg/kg LW) boldenone undecylenate on the reproductive physiology of sixteen fillies from the ages of 7 to 11 months until 2 years. Ovarian activity measured by cross-sectional area, total number of ovulations, total number of follicles and the number of large follicles (greater than 30 mm in diameter) was significantly reduced by steroid treatments. Of fillies that ovulated during the first breeding season, the age of first ovulation and the second breeding season was significantly delayed in the high dose group...
Renal clearance, urinary excretion of endogenous substances, and urinary diagnostic indices in healthy neonatal foals.
Journal of veterinary internal medicine    January 1, 1991   Volume 5, Issue 1 28-33 doi: 10.1111/j.1939-1676.1991.tb00927.x
Brewer BD, Clement SF, Lotz WS, Gronwall R.Urine (U) and serum (S) were obtained every 2 hours during a 12- or 24-hour period from eight healthy 96-hour-old pony or horse foals. Dams' milk samples were obtained concurrently. Urine volume was measured during this 12- or 24-hour period. The mean amount of urine produced was 148 +/- 20 ml/kg/day. Baseline urinalyses were evaluated on all foals at two days of age, before any manipulation. Urine generally was dilute (less than 1.008) but the specific gravity was as high as 1.027 in one normal foal. Continuous (12 or 24 hour) urinary catheterization resulted in bacteriuria but not white bloo...
Plasma progestagens in the mare, fetus and newborn foal.
Journal of reproduction and fertility. Supplement    January 1, 1991   Volume 44 517-528 
Holtan DW, Houghton E, Silver M, Fowden AL, Ousey J, Rossdale PD.This study used gas chromatography/mass spectrometry (GC/MS) to identify and measure plasma progestagens. The method included deuterated internal standards, e.g. [17,21,21,21-2H]-5 alpha-pregnane-3,20-dione, solid-phase extraction, derivatization (methoxime/t-butyldimethylsilyl) and GC/MS. Full-scan screening identified 3 5-pregnenes, 2 4-pregnenes and 7 5 alpha-pregnanes (no 5 beta-pregnanes). The selected ion mode was used for routine quantitation from calibration curves; response was linear (r greater than 0.98) from 2 to 2000 ng equivalents/ml (0.5 ng/ml method sensitivity) and intra- and ...