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.
Zhang XY, Zhu FX, Robinson NE.We examined the effect of activation of beta 2-adrenoceptor (AR) by isoproterenol (ISO) on acetylcholine (ACh) release evoked by electrical field stimulation (EFS: 20 V, 0.5 Hz, 0.5 msec) from cholinergic nerves in five regions of equine airways. We also tested if the effect of ISO was dependent on epithelium or prostanoids by examining the effect of ISO on ACh release in the presence and absence of epithelium or cyclooxygenase inhibition. Trachealis strips or bronchial rings were preincubated for 60 min with 10(-7) M atropine, 10(-6) M neostigmine, and 10(-5) M guanethidine. The ACh amount wa...
Yamashita K, Yonezawa K, Izumisawa Y, Kotani T.The antagonistic effects of atipamezole (20, 40, 60, 80, and 100 micrograms/kg i.v.) on medetomidine (10 micrograms/kg i.v.)-induced sedation were evaluated in horses. Although 20 and 40 micrograms/kg of atipamezole were not sufficient to reverse the sedation, 60 micrograms/kg did effectively reverse the sedation. Atipamezole at 80 micrograms/kg was more potent, and significantly shortened the duration of sedation without any apparent side effects, but a higher dose of 100 micrograms/kg was not more effective than 80 micrograms/kg. The possible use of atipamezole as a reversal agent may enhanc...
Adler CP, Friedburg H, Herget GW, Neuburger M, Schwalb H.DNA content, ploidy level, cell size and nuclear number were investigated in 54 mammalian hearts from nine species. DNA content was determined biochemically and ploidy level of cells was studied by the means of Feulgen cytophotometry. Nuclear number was calculated by a new method, while cell size was determined by using ocular micrometry. In most mammals diploid cell nuclei predominate. Higher ploidy levels were found in the human and the pig hearts. The total amount of DNA correlated with the myocardial weight. Eight million heart muscle cell nuclei were found in mice (myocardial weight 160 m...
Manohar M, Goetz TE.Exercise-induced pulmonary hemorrhage (EIPH) is a common occurrence in racehorses. The objective of this study was to compare pulmonary vascular pressures of healthy Thoroughbred horses with and without postexertion endoscopically detectable fresh blood in the trachea. The nasopharynx, larynx, and trachea (down to the carina) of horses were examined weekly with an endoscope 55-60 min postexertion, and the diagnosis of EIPH was confirmed by the presence of fresh blood in the trachea. Measurements of heart rate and right atrial, pulmonary arterial, and pulmonary arterial wedge pressures were mad...
Simones P, De Geest JP, Lauwers H.The pectinate ligaments of ten horses, two donkeys, five oxen, five sheep, ten goats, five dogs, five cats, thirty pigs and two rabbits were studied under the stereomicroscope and the scanning electron microscope. In the horse and the donkey, the pectinate ligament was very prominent and was characterized by sturdy interconnected strands and relatively small intertrabecular spaces. The pectinate ligaments of ruminants were composed of shorter strands, separated by relatively larger spaces. Fusion between adjacent strands, resulting in the formation of fenestrated sheets, was regularly observed...
Aurich JE, Kühne A, Hoppe H, Aurich C.Effects of seminal plasma on post-thaw motility and membrane integrity of cryopreserved horse spermatozoa were investigated. Carboxyfluorescein diacetate staining was used for the assessment of sperm membrane integrity. Adding 30% of seminal plasma from stallions with high post-thaw sperm motility to ejaculates from stallions with low post-thaw sperm motility increased progressive motility from 24.0 +/- 1.6 to 34.5 +/- 1.9% (P < 0.05) and membrane integrity from 27.0 +/- 2.1 to 34.3 +/- 2.3% membrane-intact spermatozoa (P < 0.05). Conversely, the addition of seminal plasma from stallions...
Netherwood T, Wood JL, Townsend HG, Mumford JA, Chanter N.A case control study of foal diarrhoea in the United Kingdom was carried out over a 3-year period. Clostridium perfringens was significantly associated with foal diarrhoea (Odds Ratio (OR) = 3.0), being isolated from 57% of 421 animals with diarrhoea but from only 27% of 223 healthy foals. Also, C. perfringens was significantly associated with fatal diarrhoea (OR = 4.5). About half of diarrhoea with a fatal outcome was attributable to this organism. The other pathogens significantly associated with diarrhoea were rotavirus (OR = 5.6), Cryptosporidium spp. (OR = 3.2) and the nematode Strongyloi...
Proudman CJ, Trees AJ.There is increasing interest in the application of serological methods to macro-parasite infections to indicate infection intensity, which in turn is related to pathogenicity. Colic is the single most important cause of mortality in horses and there is evidence that a proportion of colic cases are associated with infection with the intestinal cestode Anoplocephala perfoliata. In order to develop better tools to investigate this association, the correlation between antigen-specific equine IgG and IgG(T) and infection intensity of A. perfoliata was investigated. Affinity purification of a 12/13 ...
Corveleyn S, Deprez P, Van der Weken G, Baeyens W, Remon JP.Six healthy mares ranging in age from 6 to 12 years and weighing from 415 to 540 kg were used to determine the rectal bioavailability of ketoprofen. For the rectal administration, three different formulations, each containing 1 g of ketoprofen, were administered in a fatty and a hydrophilic suppository base and as a liquid suspension. An average elimination half-life of 1.3 h (+/-1.2) was found. The average value for the total plasma clearance (ClT) was 131.9mL/ min.kg (range 95-183.5). The volume of distribution Vd(area) was 255 mL/kg and the mean residence time (MRT) value was 0.47 h. After ...
Wilson SM, Rakhit S, Murdoch R, Pediani JD, Elder HY, Baines DL, Ko WH, Wong PY.Experiments were undertaken using cultured equine sweat gland epithelial cells that express purine receptors belonging to the P2U subclass which allow the selective agonist uridine triphosphate (UTP) to increase the concentration of intracellular free Ca2+ ([Ca2+]i). Experiments using pertussis toxin (Ptx), which inactivates certain guanine-nucleotide-binding proteins (G-proteins), showed that this response consisted of Ptx-sensitive and Ptx-resistant components, and immunochemical analyses of the G-protein alpha subunits present in the cells showed that both Ptx-sensitive (alpha i1-3) and Ptx...
Foreyt WJ, Lagerquist JE.Peripheral blood neutrophils from horses, cattle, and Rocky Mountain bighorn sheep (Ovis canadensis canadensis) were evaluated for susceptibility to cytotoxin-dependent lysis of different biotypes and serotypes of Pasteurella haemolytica of domestic sheep, cattle, bighorn sheep, or mountain goat (Oreamnos americana) origin utilizing a cytotoxicity assay which measures the degree of bacteria cytotoxin-killing of neutrophils. All isolates of P. haemolytica (biotypes A and T) were noncytotoxic to horse neutrophils. Thirteen of 18 R haemolytica biotype A isolates were cytotoxic (> 50% neutrophi...
Yamagata M, Wilkie DA, Gilger BC.Eosinophilic keratoconjunctivitis was diagnosed in 7 horses at The Ohio State University between 1976 and 1994. All horses had moderate-to-severe blepharospasm, chemosis, and conjunctival hyperemia; epiphora; and extensive yellow-to-white caseous mucoid discharge. Corneal ulcers associated with this disease were perilimbal and extended centrally. All ulcers were covered with a white necrotic plaque firmly attached to the underlying cornea. Other ophthalmic abnormalities were not detected. Corneal scrapings examined cytologically contained numerous eosinophils interspersed between epithelial ce...
Sellon DC, Walker KM, Russell KE, Perry ST, Fuller FJ.Equine infectious anemia virus (EIAV) is a lentivirus that replicates predominantly in mature tissue macrophages. Viral expression is strongly influenced by the state of differentiation of the host cell. While blood monocytes can be infected, viral transcription is limited until the cell differentiates into a mature macrophage. Activation of mature macrophages infected with EIAV might also alter viral expression, presumably through binding of cellular transcription factors to viral nucleic acid sequences within the long terminal repeat (LTR). Using DNA amplification techniques, we compared LTR...
Kerr CL, McDonell WN, Young SS.The purpose of this study was to compare and evaluate sedation with intravenous xylazine (1.1 mg/kg bodyweight [BW]) versus intravenous romifidine (100 micrograms/kg BW) followed by induction of anesthesia with intravenous diazepam (0.04 mg/kg BW) and ketamine (2.2 mg/kg BW). Twelve healthy horses were used in a blinded, randomized, cross-over design. Heart rate, presence of 2nd degree atrioventricular heart blocks (2 degrees AVB), respiratory rate, arterial blood pressures, blood gases, packed cell volume, total serum proteins, and duration of anesthesia and recumbency were recorded. Inductio...
Gareis M, Seidel KE, Diehl T.268 diagnostic samples from dogs, cats, horses and cattle were examined in a commercially available blood culture system. Samples of blood, liquor, ascites, thorax punctate, synovia and urine were examined with a blood culture system (Oxoid) over a period of two years in cooperation with the veterinary clinical institutes of internal medicine and surgery, Ludwig-Maximilians-University, Munich and different veterinarians. It was shown that this blood culture system, which has been initially developed for the requirements of human bacteriology, can be used for isolation of clinical important mic...
Rivero JL.To describe an applied method for quantitative estimation of training condition in horses. Methods: 17 sedentary adult (5 to 14 years old) stallions of several breeds endurance trained for 3 months. Methods: Muscle biopsy specimens from 2 depths (20 and 60 mm) of the gluteus medius muscle were obtained before and after training and were analyzed for fiber type distribution, mean cross-sectional area, relative fiber area, and mean number of capillaries in contact with each fiber type relative to their mean area. Fiber types were designated as types 1, 2A, and 2B (high, low, and moderate myosin ...
Thomson CH, Thompson DL, Kincaid LA, Nadal MR.To test the hypothesis that prolactin mediates the increase in seminal volumes induced by sexual stimulation in stallions, semen was collected from six stallions every other day for 26 d. The last eight collection days were treatment days. For each stallion, four treatments were randomly assigned to the first four of the eight treatment collection days, and then repeated in reverse order on the last four collection days; 1) CONTROL: semen collected per normal procedures; 2) Sexually stimulated: stallions were presented to mares in a chute for 10 min before collection; 3) Bromocriptine (dopamin...
Geiser DR, Andrews FM, Rohrbach BW, Provenza MK.To determine normal acid-base status of the CSF and to compare it with changes during acute hypercapnia in equine neonates. Methods: 10 clinically normal foals between 1 and 12 days old. Methods: CSF and arterial and venous blood samples were collected every 15 minutes during 45 minutes of normocapnia and 90 minutes of hypercapnia in isoflurane-anesthetized foals. CSF samples were collected via a subarachnoid catheter placed in the atlanto-occipital space. Results: Comparison of blood and CSF gases during normocapnia indicated that CSF was significantly more acidic than blood. The lower pH was...
Hinchcliff KW, McKeever KH, Muir WW, Sams RA.We theorized that furosemide-induced weight reduction would reduce the contribution of anaerobic metabolism to energy expenditure of horses during intense exertion. The effects of furosemide on accumulated O2 deficit and plasma lactate concentration of horses during high-intensity exercise were examined in a three-way balance randomized crossover study. Nine horses completed each of three trials: 1) a control (C) trial, 2) a furosemide-unloaded (FU) trial in which the horse received furosemide 4 h before running, and 3) a furosemide weight-loaded (FL) trial during which the horse received furo...
Van Hoogmoed L, Snyder JR, Christopher M, Vatistas N.To characterize, in mares, changes in peritoneal fluid that occurred within the first 7 days after routine foaling. Methods: Prospective observational trial. Methods: 15 mares. Methods: Abdominocentesis was performed within 10 days before foaling and again 12 hours, 3 days, and 7 days after each horse foaled. Data recorded for each sample included total nucleated cell count, differential cell count, specific gravity, fibrinogen concentration, and total protein concentration. Smears of each sample were examined by a single clinical pathologist. Results: There were not any significant difference...
Rivero JL, Talmadge RJ, Edgerton VR.The aim of this study was to characterize the myosin heavy chain (MyHC) isoforms present in equine skeletal muscle. Methods: Muscle biopsies were removed from the superficial region of the gluteus medius muscle of five mature horses and analyzed by immunohistochemistry (using a battery of monoclonal antibodies specific for rat MyHC isoforms) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Results: Immunohistochemistry allowed subdivision of three different muscle fiber populations containing a single MyHC, one slow and two fast, and two hybrid populations, one containing slow an...
Gerard MP, Bowman KF, Blikslager AT, Tate LP, Bristol DG.To determine whether complete cecal bypass, by jejunocolostomy or ileocolostomy, is an effective treatment for horses with cecal impaction. Methods: Retrospective analysis of medical records. Methods: 9 horses with cecal impaction managed by jejunocolostomy (3) or ileocolostomy (6) performed with or without typhlotomy for evacuation of cecal contents. Methods: Information on age, breed, gender, duration of medical treatment, preoperative abnormalities, surgical procedure, and postoperative complications was retrieved from the medical records. Follow-up data were obtained via telephone intervie...
Pazzi KA, Kraegel SA, Griffey SM, Theon AP, Madewell BR.Wild type equine p53 was amplified between exons 2 and 9 by the polymerase chain reaction using primers designed from conserved regions in other species. An 828 base pair region, corresponding to codons 25-313 of human p53, was sequenced in both directions. Human and equine amino acid sequences were 87% homologous in this region and 96% homologous in conserved domains II-V. Of eight equine cutaneous or mucocutaneous squamous cell carcinomas directly sequenced from exons 5-8, two had p53 point mutations resulting in single amino acid substitutions.
Holland RE, Grimes SD, Walker RD, Wilson RA.Hemolytic E. coli strain 807-13, O149:NM:K88(STb+, LT+), was isolated from the feces of a neonatal diarrheic foal. E. coli 807-13 was examined for adhesion to brush border membranes (BBM) from foals, adult horses and pigs, and its pathogenicity was assessed in neonatal foals and pigs. E. coli 807-13 did not adhere to equine BBM but adhered to pig BBM. It did not cause diarrhea nor did it colonize the intestinal epithelium of 3 colostrum-deprived and 3 suckled foals challenged at 24 h of age. Acute ulcerative gastritis and acute suppurative gastritis were observed in 2 colostrum-deprived challe...
Holterman WF, de Voogt P, Peereboom-Stegeman JH.Cadmium and zinc were determined in kidney cortex of 63 horses and 51 red deer (Cervus elaphus). Cadmium and zinc were also determined in protein fractions obtained by Sephadex chromatography of kidney cortex from 10 horses and 4 red deer. Histopathological parameters in kidney cortex of horses were compared to cadmium content. The metal contents (on wet weight basis) in kidney cortex of the horses were 0.31 +/- 0.22 mmole Cd/kg (range 0.03-1.21) and 0.63 +/- 0.17 mmole Zn/kg (range 0.36-1.23). The Zn content increased with the Cd content, the Zn increase being less at higher concentrations. N...
Hough ME, Steel CM, Bolton JR, Yovich JV.Four cases of ulceration and stricture of the right dorsal colon were encountered. Ulceration of the right dorsal colon is generally associated with nonsteroidal anti-inflammatory drug (NSAID) toxicosis but there are few reports of stricture following ulceration. All four horses had recent phenylbutazone use: three had been given doses well in excess of the recommended dose and in one the dose was marginally above those recommended but was combined with administration of other NSAIDs. All four horses presented with intermittent low-grade colic, weight loss and ventral oedema. Diarrhoea was als...
McManus CJ, Davison LA, Fitzgerald BP.In a variety of species, glucoprivation results in the suppression of the reproductive axis. Two experiments were performed to test the hypothesis that blockade of glucose metabolism via administration of the glucose inhibitor 2-deoxy-D-glucose (2DG) to mares would cause a modification in gonadotropin and prolactin secretion. Long-term ovariectomized mares (Experiment 1, n=4) or ovary-intact mares during the follicular phase of a synchronized estrous cycle (Experiment 2, n=4 per dose) were treated with 2DG. The dose of 2DG used in Experiment 1 was 100mg 2DG/kg BW, but because severe behavioral...
Frerichs WM.The effect of imidocarb dipropionate [3, 3' bis-(2-imidazolin-2-yl) carbanilide dipropionate] on spermatogenesis in 3 pony stallions was studied. The drug alone had no deleterious effect on spermatogenesis when given intramuscularly 4 times at a dosage level of 4 mg/kg at 72-hour intervals. Hemicastration, with or without subsequent drug treatment, caused almost complete cessation of spermatogenesis 30 days after the operation.
Gasthuys F, Pockelé K, Vervaet C, Weyenberg W, De Prijck K, Pille F, Vlaminck L, Nelis H, Remon JP.The in vivo behaviour of 5% gentamicin sulphate ocular mini-tablets (2-mm diameter, 6.525 mg weight) was compared with gentamicin eye drops in six ponies. Two mini-tablets were inserted on the bulbar conjunctiva of the right eye while a similar dose of gentamicin was administered via eye drops in the left eye. Irritation induced by the mini-tablets and the eye drops was evaluated using a visual analogue scale (0-10). Tears were sampled with ophthalmologic absorption triangles for 1 min for the determination of the concentration of gentamicin sulphate using a microbiological plate diffusion met...
Perillo A, Passantino G, Passantino L, Cianciotta A, Mastrosimini AM, Lacovazzi P, Venezia P, Jirillo E, Troncone A.Among 622 slaughtered horses from eastern Europe, 156 thyroid glands were selected on the basis of macroscopic alterations (e.g., determination of volume and weight). In the 80% of these thyroids, microscopic alterations consistent with a diagnosis of Hashimoto thyroiditis-like disease were found. In particular, a subverted architecture of the thyroid gland with colloid rarefaction, lymphocytic infiltration, and fibrosis was noted. The confirmation of the histopathological diagnosis of an equine Hashimoto thyroiditis-like disease was provided by the increased serum concentration of thyroglobul...
Gilliam LL, Ownby CL, McFarlane D, Canida A, Holbrook TC, Payton ME, Krehbiel CR.Rattlesnake bites in horses are not uncommon and the clinical outcomes are widely variable. Treatment of horses with anti-venom is often cost prohibitive and could have negative consequences; therefore, the development of a quantitative test to determine if anti-venom therapy is indicated would be valuable. The objective of this study was to develop an ELISA to detect rattlesnake venom in biological samples from clinically bitten horses. Nineteen horses were enrolled in the study. Urine was available from 19 horses and bite site samples were available from 9 horses. A double sandwich fluoresce...
Hellyer PW, Bednarski RM, Hubbell JA, Muir WW.Baroreflex sensitivity (BS) was used to quantitatively assess the effects of halothane and isoflurane on the heart rate/arterial pressure relationship during steady-state (10 minutes) and dynamic pressure changes in adult horses. Arterial pressure was decreased in response to nitroglycerin or sodium nitroprusside and increased in response to phenylephrine HCl. Mean (+/- SEM) BS in awake horses was 28.9 +/- 2.6 and 13.2 +/- 2.0 ms/mm of Hg during steady-state decreases and increases in systolic arterial pressure (SAP), respectively. Halothane and isoflurane either significantly (P less than 0.0...
Bukowiecki CF, Bramlage LR.Comminuted middle phalangeal fractures, extending into the proximal and distal portions of the interphalangeal joint, are associated with a poor prognosis for return to athletic performance. An 11-year-old horse with this type of fracture was treated successfully by use of a broad dynamic compression plate.
Magni E, Bertelloni F, Sgorbini M, Ebani VV.To investigate the occurrence of Bartonella sp. infection in asymptomatic horses and donkeys living in Tuscany, Central Italy. Methods: Blood samples were collected from 77 horses and 15 donkeys and tested by indirect immunofluorescent test to detect antibodies against Bartonella sp. and by PCR to detect the pathogen. Results: Fifty-four (58.69%; 95% CI: 47.95%-68.87%) animals, 9 donkeys and 45 horses, were seropositive with antibody titers ranging from 1:64 to 1:512. PCR assays detected 9 horses positive for Bartonella sp. and 3 donkeys for Bartonella henselae genotype I. Conclusions: The det...
Rose RJ, Hartley WJ, Baker W.Bilateral laryngeal paralysis is described in 5 Arabian and part-Arabian foals aged between 23 and 35 days. Tracheotomies resulted in complete relief of dyspnoea. Two cases showed recovery of abductor function of the right arytenoid cartilage after 3 weeks and one of these cases later recovered left abductor function. Four of the foals were autopsied at various times from one week to 6 months after the onset of respiratory obstruction. Histology of the recurrent laryngeal nerves showed active Wallerian degeneration and loss of nerve fibres in many fascicles in cases affected for one to 2 weeks...
Miller CC, Fayrer-Hosken RA, Timmons TM, Lee VH, Caudle AB, Dunbar BS.This study was designed to explore the composition of the equine zona pellucida (EZP) by one- and two-dimensional polyacrylamide gel electrophoresis (1D- and 2D-PAGE), silver staining and immunoblotting techniques. Antral follicles palpable on frozen-thawed equine ovaries were aspirated with a needle and syringe, and the resultant follicular fluid, cellular material and oocytes were pooled. Oocytes were placed in Petri dishes, moved by narrow-bore pipette to droplets of phosphate-buffered saline (PBS) and mechanically cleaned of cumulus cells. The EZP from these collected oocytes was solubiliz...
Fazeli AR, Steenweg W, Bevers MM, van den Broek J, Bracher V, Parlevliet J, Colenbrander B.The hemizona assay (HZA) has been developed as a diagnostic test to predict the fertilisation potential of human spermatozoa. The aim of this study was to develop an HZA for stallion spermatozoa and to investigate a possible relationship between fertility and the outcome of the HZA in this species. Equine oocytes were obtained from ovaries collected at a slaughterhouse and by transvaginal, ultrasound-guided follicle aspiration. They were then denuded from cumulus cells and stored in salt solution at 4 degrees C until use. On the day of the experiments the oocytes were bisected, thus providing ...
Shahkhosravi NA, Son J, Davies HMS, Komeili A.Equine hoof conformation is integral to equine performance and soundness. Consequently, it is a major area of interest within the field of equine health. Researchers have measured several hoof shape parameters to study the hoof conformation. Proximal hoof circumference (PHC) is a primary hoof shape parameter, and its assessment may help to recognize the early stages of the development of changes in hoof morphology or poor hoof shape. Previous studies have mainly used a measuring tape to measure PHC. However, some doubts still exist regarding the reliability, repeatability and accuracy of measu...
Muhonen S, Julliand V.Racing events challenge the fluid balance of athletic horses. The equine large intestine functions as a fluid reservoir, since the properties of dietary forage fibre affect the digesta water content and the milieu of this ecosystem. This study aimed to investigate the effect of grass maturity and legume forage on the faecal water-holding capacity (WHC) and microbial ecosystem, and the fluid balance and body weight (BW) of French trotters in race training. Six geldings were offered three diets with different fibre compositions: concentrate and late-harvested mature grass haylage (35:65 energy r...
Hall JO.Poisoning cases in horses associated with dietary exposures can encompass a wide variety of etiologies that can be caused by natural or man-made components. Feed mixing errors and ingestion of feed formulated for other species are the most common means by which poisonings from man-made materials occur. Ionophore feed additives and antibacterial agents are especially toxogenic to horses. Effects of ionophores in horses include clinical, clinicopathologic, and pathologic changes associated with cardiac, muscular, and neurologic tissues involvement. The acute effects of ionophores, however, can r...
Powers SK, Beadle RE, Lawler J, Thompson D.The O2 deficit-O2 debt relationship in ponies was examined at two levels of treadmill exercise. Five healthy ponies exercised for 8 min at two work rates (WR):(1) 50 m/min at 6% grade and (2) 70 m/min at 12% grade. The O2 deficit and O2 debt were calculated using open-circuit measurement of pulmonary gas exchange during the transition from rest to steady-state exercise and during recovery from exercise. The O2 deficit was significantly lower (P less than 0.05) than the O2 debt at each of the two work rates. The means (+/- SEM) for the deficit and the O2 debt, respectively, in liters were: (1) ...
Johnson AL.Cycling standardbred mares were infused with saline or 20 micrograms gonadotropin-releasing hormone (GnRH) in a pulsatile pattern (one 5-sec pulse/h, 2 h or 4 h) beginning on Day 16 of the estrous cycle. Although serum concentrations of luteinizing hormone (LH) increased significantly earlier in all three GnRH-treated groups (within one day of the initiation of infusion) compared to saline-infused controls, there were no differences in peak periovulatory LH concentrations among treatments (overall mean +/- SEM, 8.98 +/- 0.55 ng/ml). The number of days from the start of treatment to ovulation w...