bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonography of the equine triceps muscle before and after general anaesthesia and in post anaesthetic myopathy
Authors: SMITH R. K. W. , DYSON SUE J. , HEAD M. J. , BUTSON R. J.
Published: April 2010

The ultrasonographic appearance of the equine triceps muscle of clinically normal horses, before and after general anaesthesia, was investigated and compared with 5 cases of post anaesthetic myopathy. The triceps muscle areas were examined bilaterally using a 7.5 MHz linear array probe in 2 different planes, with each limb both weightbearing and nonweightbearing. The triceps muscles of 4 unanaesthetised horses were scanned twice, 24 h apart. Six horses underwent general anaesthesia and were scanned pre‐anaesthesia and at 1 and 24 h intervals after recovery. Blood samples were obtained in the unanaesthetised group at each scan time and, in the anaesthetised group, pre‐anaesthesia and at 10 min, 5 and 24 h after recovery. Creatine kinase (CK) and aspartate aminotransferase (AST) concentrations were measured. Anaesthetic details and recovery were related to the ultrasonographic and muscle enzyme findings. Five horses with post anaesthetic myopathy were scanned at intervals after the onset of clinical signs.

In normal horses, the triceps muscle appeared ultrasonographically as echoic striations separated by anechoic areas. The fascia dividing muscle bellies was visible as an echoic line. Ultrasonographs obtained with the limb nonweightbearing had no change or a slight overall increase in echogenicity. The scans of control unanaesthetised horses were unchanged on successive days. All anaesthetised horses had uncomplicated anaesthesia and recoveries and did not exhibit any clinical signs of post anaesthetic myopathy. Elevated CK and AST values were found up to 342 and 195%, respectively, of the pre‐anaesthetic values but no significant alterations in the ultrasonographic appearance of the muscles were detected.

Clinical cases of post anaesthetic myopathy had disruption of the normal ultrasonographic pattern. There was an overall increase in echogenicity with a loss of the normal striated pattern. In 3 cases, there was localised increased echogenicity within the muscle. One of these horses was humanely destroyed for other reasons and histological examination of the affected muscle revealed a necrotic area correlating with the hyperechoic region. Two horses had bilateral involvement of the triceps musculature. Four horses recovered clinically from the myopathy and the ultrasonographic appearance returned to normal except in 1 horse where focal hyperechoic regions remained 10 weeks after the onset of the clinical signs.
Character and duration of pharmacological effects of intravenous isoxsuprine
Authors: HARKINS J. D. , MUNDY G. D. , STANLEY S. , WOODS W. E. , SAMS R. A. , RICHARDSON D. R. , TOBIN T.
Published: April 2010

Isoxsuprine is a therapeutic medication used to treat navicular disease and other lower limb problems in horses and is one of the more frequently detected therapeutic agents in racing horses. In a crossover study, horses were administered isoxsuprine i.v. to determine the character and duration of its pharmacological effects. Isoxsuprine significantly increased heart rate 5–150 min following injection. Unrestrained activity following isoxsuprine treatment was significantly greater than control activity for 105 min after treatment. There was an apparent, although statistically nonsignificant, increased cutaneous blood flow resulting in visible water vapour and sweat production 5–60 min after administration. Initially, there was no difference in skin temperature between control and isoxsuprine treatment values; however, skin temperature decreased below control values 45–120 min after injection. Concurrently, there was a significant decrease in rectal temperature reflecting a decrease in body core temperature. Using infrared thermography, a significant decrease in superficial skin temperature of the front legs occurred 30–240 min after treatment. Isoxsuprine also reduced smooth muscle tone, which was apparent by decreased tone of the internal anal sphincter 10–180 min after treatment. It was concluded that the measurable pharmacological effects of i.v. isoxsuprine are short lived, since none of the above responses were apparent 4 h or more after i.v. administration.
Use of a virulence‐associated protein based enzyme‐linked immunosorbent assay forRhodococcus equiserology in horses
Authors: PRESCOTT J. F. , FERNANDEZ A. S. , NICHOLSON V. M. , PATTERSON M. C. , YAGER J. A. , VIEL L. , PERKINS G.
Published: April 2010

An enzyme‐linked immunosorbent assay (ELISA) was developed againstRhodococcus equiusing Triton X‐114 detergent extracted whole cell material, in which the virulence associated protein (VapA) predominated. Enzyme‐linked immunosorbent assay titres corresponded to antibody reacting with VapA on Western blots. There was considerable variation in antibody titres of nonimmunised mares and in the time when the colostrally derived antibody of their foals had declined to low or undetectable titres. In general, antibodies in foals declined to their lowest levels at age 4–8 weeks. Seroconversion occurred in foals age 8–10 weeks, but the precise time depended on maternal titre and the month in which the foal was born. Foals reaching age 8 weeks in late summer showed more marked seroconversion than foals born earlier. The ELISA was used to follow the response to immunisation with the same Triton X‐114 extracted material. Six mares immunised before parturition with the antigen in aluminium hydroxide adjuvant developed high titres, up to >102,400 and transferred them to their foals through colostrum. Their foals responded to immunisation with 0.5‐1.0 mg antigen 3, 5, 7 and 9 weeks after birth. Antibody titres following immunisation with similar dosage reached up to >102,400 in a separate group of foals of nonimmunised mares. Nonvaccinated control foals seroconverted at age 6–8 weeks. The VapA based ELISA is useful to follow the course of natural infection withR. equior immunisation with VapA based antigen.
Palmaroproximal approach for arthrocentesis of the proximal interphalangeal joint in horses
Authors: MILLER S. M. , STOVER SUSAN M. , TAYLOR K. T. , ZARUCCO LAURA A.
Published: April 2010

A technique was developed for arthrocentesis of the palmaroproximal pouch of the pastern joint. The landmark for percutaneous puncture is a ‘V’ shaped depression formed by the palmar aspect of the proximal phalanx (P1) dorsally, an eminence associated with the attachment of the collateral ligaments to P1 and the middle phalanx distally and the insertion of the lateral branch of the superficial digital flexor tendon palmarodistally. Comparison of arthrocentesis between the palmaroproximal approach and the traditional dorsal approach in 8 cadavers and 8 horses demonstrated that the palmaroproximal approach was associated with less needle manipulation, greater injection volume (horses) and frequent synovial fluid flow.
Prerace venous blood acid‐base values in Standardbred horses
Authors: SOMA L. R. , UBOH C. E. , NANN L. , GERBER AMY L.
Published: April 2010

The administration of sodium bicarbonate (NaHCO3) or ‘milk shakes’ to Standardbred horses before racing is widespread. This study analysed nonrace day (CTL) and prerace venous acid‐base values from Standardbred horses racing in Pennsylvania (PA) and New Jersey (NJ). Mean ± s.d. CTL bicarbonate (HCO3−) and base excess (BE) values, for a group of horses stabled during the 1993 racing season at Pocono Downs, Pennsylvania, were 28.6 ± 1.9 and 2.6 ± 1.7 mmol/1, respectively. In the same population of horses, mean ± s.d. values for prerace HCO3−and BE values were 33.1 ± 2.8 and 7.0 ± 23 mmol/1, respectively, for horses administered frusemide (F) 4 h before race time and 31.5 ± 2.4 and 5.5 ± 2.0 mmol/1 for the horses not administered frusemide (NF). There were differences (P<0.05) in pHv, PvCO2, HCO3−and BE values between the CTL and prerace samples. The venous acid‐base values of the CTL horses were normally distributed. The prerace acid‐base values measured during 1993 were not normally distributed, indicating changes due either to the administration of alkalising substances or other manipulations of the horses on race day. Changes in all acid‐base values were observed during the subsequent 1994 racing season with further changes observed when horses were placed in a secured stable 8 h before the race.

The criteria used in some racing jurisdictions for disqualifying a horse were the elevations in HCO3−, Na+and pH. The correlation coefficients (r2) for the least squares regression for HCO3−vs. pH and HCO3−vs. Na+in prerace venous blood samples were 0.31 and 0.21, respectively, indicating a poor relationship between the 3 acid‐base values.

To discourage the administration of NaHCO3to horses before a race, the use of a BE value of ≥10 mmol/1 for NF and ≥12 mmol/1 for F was adopted as a single index for the disqualification of horses from a race. The results of this study indicate that the use of a single index and, in this case BE, has curtailed the prerace administration of NaHCO3to horses.
Influence of chronic degenerative endometritis (endometrosis) on placental development in the mare
Authors: BRACHER VERENA , MATHIAS SUSANNA , ALLEN W. R.
Published: April 2010

Placentation between 80 and 220 days of gestation was studied by measurement of fetal dimensions and gross, light and transmission and scanning electron microscopic examinations of the allantochorion and endometrium from 4 fertile mares with no, or very mild, endometrial histopathology and 6 subfertile Thoroughbred mares suffering varying degrees of age‐related chronic degenerative endometritis (endometrosis). Spontaneously occurring twin gestation was observed in 3 animals. Several of the subfertile mares had endometrial cysts which showed 2 distinct features during pregnancy: those located near the lumenal surface of the endometrium showed no sign of microcotyledon development in both the endometrium and the opposed, flat and smooth allantochorion, whereas endometrial cysts located deeper in the stroma were covered by apparently normal glands and microcotyledons. Fetal dimensions were lower in the subfertile mares, but still within the reference range. Microcotyledon development appeared to be delayed and the chorionic macro‐ and microvilli looked shorter and blunter between 80 and 120 days in the 2 subfertile mares compared to the 2 fertile mares at the same gestational ages. At 120 days, the subfertile mare had significantly less microvilli per surface area than her fertile counterpart and her fetus weighed only half that from her counterpart, despite a similar crown‐rump length. However, between 160 and 220 days the difference in microcotyledon development between the young fertile and old subfertile mares was much less marked, despite the continued existence of considerable numbers of distended 'gland nests' in the endometrium of the latter group.
Ultrasonographic assessment of fetal well‐being during late gestation: development of an equine biophysical profile
Authors: REEF VIRGINIA B. , VAALA WENDY E. , WORTH LEILA T. , SERTICH PATRICIA L. , SPENCER PAMELA A.
Published: April 2010

Mares with complicated pregnancies (illness, problems at parturition or delivery of an abnormal foal, n = 30) were scanned transabdominally from 298 days gestation to term in order to measure fetal size, evaluate fetal well‐being and characterise the intrauterine environment. The results of the last scan obtained prior to parturition were compared to normal data obtained from fetuses of comparable gestational age to develop a biophysical profile specific for the equine fetus. Twelve mares produced a normal foal (positive outcome) and 18 mares delivered 19 abnormal foals (negative outcome). Both fetuses that were inactive throughout the entire scan and 4 of 5 fetuses with heart rate abnormalities were abnormal at birth. Three of 4 fetuses surrounded by decreased allantoic fluid quantities had a negative outcome. All mares with large anechoic spaces between the uterus and placenta (n = 3) and/or thickened uteroplacental units (n = 5) delivered abnormal foals. There was a significant correlation between fetal aortic diameter and neonatal foal weight in these complicated pregnancies (P<0.0001, r = 0.85). Fetal aortic diameters were predicted from maternal weight and 6 fetuses had smaller than predicted aortic diameters, all with negative outcomes.

A biophysical profile of the equine fetus from 298 days gestational age to term was developed that included 6 factors related to pregnancy outcome: fetal heart rate, fetal aortic diameter, maximal fetal fluid depths, uteroplacental contact, uteroplacental thickness and fetal activity. The profile proved informative about fetal well‐being, perinatal morbidity and perinatal mortality. A low score was a definite indication of an impending negative outcome; however, a high score was not assurance of a positive outcome. The utility of such a biophysical profile and future directions for research are discussed.
Penetrating wounds of the thorax in 15 horses
Authors: LAVERTY SHEILA , LAVOIE J.‐P. , PASCOE J. R. , DUCHARME N.
Published: April 2010

Clinical features, treatment and outcome of 15 horses with penetrating thoracic wounds are described. The most common cause of trauma was collision with an object (10 horses). Concurrent clinical findings included subcutaneous emphysema (12 horses), pneumothorax (12 horses), haemothorax (5 horses) and pneumomediastinum (6 horses). Axillary wounds were present in 5 horses. Foreign bodies were identified and removed from 2 horses. Wounds were sutured (6 horses) or packed (7 horses). Air was evacuated from the pleural cavities of 11 horses. Eleven horses (73%) were discharged from the hospital. All horses subjected to euthanasia had severe trauma to structures outside the thoracic cavity including perforation of the colon (2 horses), renal trauma (1 horse) and a luxated thoracolumbar vertebra (1 horse). From this study, it can be concluded that 1) the prognosis for horses with penetrating thoracic wounds, without extrathoracic injury, is favourable; 2) a thorough evaluation including the abdominal cavity should be performed and 3) horses with axillary wounds should be monitored closely for respiratory distress until the wound has completely healed.
Development of subchondral cystic lesions after articular cartilage and subchondral bone damage in young horses
Authors: RAY C. S. , BAXTER G. M. , McILWRAITH C. W. , TROTTER GAYLE W. , POWERS BARBARA E. , PARK R. D. , STEYN P. F.
Published: April 2010

The objective of this study was to determine if damage to the articular cartilage alone or articular cartilage plus subchondral bone of the distal medial femoral condyle of young, exercised horses resulted in the formation of subchondral cystic lesions. Twelve Quarter Horses (age 1–2 years), free of clinical and radiographic signs of osteochondrosis and lameness were used. In 6 horses(Group 1), a 15 times 1 mm linear full thickness defect in the articular cartilage was made arthroscopically on the weightbearing surface of the distal aspect of the medial femoral condyle. In the other 6 horses(Group 2), a 15 times 3 mm full thickness elliptical cartilage defect was made, followed by burring a 5 mm diameter, 4 mm deep hole into the subchondral bone. Three weeks after surgery, all horses were hand walked and trotted for 2 weeks and then exercised for 6 min daily, 5 days a week for the next 14 weeks on a treadmill. They were then turned onto a small paddock for 6 weeks (6 months total). The development of subchondral cystic lesions was determined using radiography. Bone activity in the femoral condyle was monitored with nuclear scintigraphy. All horses that developed subchondral cystic lesions radiographically were subjected to euthanasia for gross and histological examination of the lesions.

No subchondral cystic lesions and no clinical abnormalities were detected in the horses inGroup 1.Subchondral cystic lesions developed radiographically in 5 of 6 horses in(Group 2).Scintigraphic findings of horses with subchondral cystic lesions were inconsistent. Histological examination of lesions revealed variable quantities of fibrous connective tissue, fibrocartilage and bone, with evidence of bone remodelling adjacent to the subchondral cystic lesion. The results suggest that damage to articular cartilage plus subchondral bone, but not articular cartilage alone, of the distal medial femoral condyle may lead to the development of subchondral cystic lesions. These findings indicate that all subchondral cystic lesions in horses may not be osteochondrosis‐type lesions and that trauma to weightbearing articular surfaces of young horses may be a predisposing factor.
Cardiorespiratory responses to exercise in horses with different grades of idiopathic laryngeal hemiplegia
Authors: CHRISTLEY R. M. , HODGSON D. R. , EVANS D. L. , ROSE R. J.
Published: April 2010

The relationship between different grades of laryngeal function, as assessed by endoscopy at rest, and the measurements of indices of gas exchange and exercise capacity was assessed during a standardised treadmill exercise test in 149 horses. Horses with abnormalities other than idiopathic laryngeal hemiplegia (ILH) were excluded from the study and laryngeal function was graded according to an established system. There were no significant differences in age, weight, maximum oxygen uptake, maximum carbon dioxide production, maximum respiratory exchange ratio, maximum oxygen pulse and run time between the grades. Blood lactate concentration at 10 m/s was greater (P<0.01) in horses withgrade5 laryngeal function than other grades. Minimum PaO2(P<0.001) and SaO2(P<0.01) were lower and maximum PaCO2(P<0.001), higher in horses withgrades 4and5laryngeal function than other grades. Horses withgrade 4function had a lower minimum CaO2(P<0.01) than horses with other grades. Minimum PAO2decreased fromgrades 1and2togrades 4and5(P<0.05). The minimum alveolar ventilation was lower (P<0.05) in horses withgrades 4and 5 laryngeal function compared to other grades.

The results of this study indicate that endoscopic assessment of laryngeal function at rest, using a simple grading system, provides an indication of dynamic changes in ventilation and the effects on blood gases during exercise. From the data, we suggest that horses that have some movement of the left arytenoid cartilage but are unable to achieve full abduction have similar ventilatory effects and blood gas responses during maximal exercise to those with complete paralysis. Some horses withgrade 3laryngeal function had blood gas results similar to those of horses withgrades 4and5laryngeal function, indicating that discrepancies may occur between the resting assessment and laryngeal function during strenuous exercise.
Radiation hazards from horses undergoing scintigraphy using technetium−99m
Authors: WHITELOCK R. G.
Published: April 2010

This paper quantifies the extent of the radiation hazard to personnel from horses undergoing scintigraphy using technetium99mmethylene diphosphonate (99Tcm‐MDP). From the data produced it is possible to derive safe working protocols which are comfortably within the legislated limits for whole body doses as set out in the Ionising Radiations Regulations 1985. Measurements were made of the surface and environmental activities which result from individuals undergoing scintigraphic evaluation and also from urine contaminated bedding. The use of both high and low activities in the assessment of the radiation hazard to personnel and owners is considered.
Nitric oxide production by equine articular cellsin vitro
Authors: FREAN S. P. , BRYANT CLARE E. , FRÖLING INGA‐LILL , ELLIOTT J. , LEES P.
Published: April 2010

Recent research in several species has suggested nitric oxide (NO) as a mediator of articular cartilage damage and an inhibitor of cartilage matrix neosynthesis. This study investigated NO production by cultured equine articular chondrocytes in response to 2 arthritogenic molecules, namely lipopolysaccharide (LPS) and interleukin‐1β (IL‐1β), and compared NO production by cultured equine synoviocytes stimulated with LPS. Synoviocytes exhibited a low basal level of NO synthesis (measured as nitrite, a NO metabolite) that was neither significantly increased nor decreased by exposure to LPS. Basal NO synthesis by synoviocytes was not significantly reduced by competitive inhibitors of nitric oxide synthase (NOS). In contrast, chondrocytes treated with LPS or IL‐1β synthesised nitrite in a dose‐related manner. Inhibitors of NOS suppressed nitrite production to below the basal levels of release of unstimulated cells. Dexamethasone, an inhibitor of induction of the inducible isoform of NOS (iNOS), reduced nitrite synthesis by LPS‐stimulated chondrocytes. Western blot analysis revealed expression, in response to LPS, of protein in the same molecular weight range as iNOS identified in other species. This work demonstrates that equine chondrocytes have the capacity to synthesise NO, although its exact roles in cartilage metabolism have yet to be determined.
Inflammatory markers in bronchoalveolar lavage fluid of Standardbred racehorses with inflammatory airway disease: response to interferon‐alpha
Authors: MOORE B. R. , KRAKOWKA S. , MCVEY D. S. , CUMMINS J. M. , ROBERTSON J. T.
Published: April 2010

Protein and eicosanoid concentrations and procoagulant activity were determined in bronchoalveolar lavage fluid (BALF) from 32 Standardbred racehorses with inflammatory airway disease (IAD) and 6 control horses. Total protein, albumin and immunoglobulin G (IgG) concentrations were high (P<0.05) in the BALF from horses with IAD, a finding consistent with exudation of plasma protein into the airway. Immunoglobulin A (IgA) concentrations also were increased (P<0.05) which may signify local immunoglobulin production. Difference was not detected in prostaglandin E2and 6‐ketoprostaglandin F1αconcentrations in BALF of IAD‐affected and control horses. Procoagulant activity was identified in the majority (66%) of BALF samples from IAD‐affected horses and was not detected in control horses. Natural human interferon‐alpha (nHuIFNα) (placebo, 50, 150, or 450 units) was administered orally for 5 days to IAD‐affected horses in a double‐blind, randomised block design. Total protein, IgG, and IgA concentrations in BALF were reduced (P<0.05) 8 days after administration of 50 u and 150 u nHuIFNα, and 15 days after administration of 50 u nHuIFNα. Procoagulant activity and albumin concentrations in BALF were lower 8 days after administration of 50 u nHuIFNα. Oral administration of low‐dose nHuIFNα appeared to ameliorate these parameters of lower respiratory tract inflammation in Standardbred racehorses with IAD.
The relationship between the concentration of ionised calcium and parathyroid hormone‐related protein (PTHrP[1–34]) in the milk of mares
Authors: CARE A. D. , ABBAS S. K. , OUSEY J. , JOHNSON L.
Published: April 2010

Once lactation is established in mares, there is little change in the ionised calcium concentration in their milk. In contrast, the concentration of PTHrP(1–34) in the milk increases to a maximum level by the end of the second week of lactation, near which it remains for the rest of the lactation. As found in other species, the concentration of PTHrP(1–34) in mare's milk is considerably higher than that in plasma, sampled at the same time. No significant correlation could be demonstrated between the concentrations of PTHrP(1–34) and ionised calcium in the milk except during the last 10 weeks of lactation.
A light microscopic and ultrastructural examination of calcified dental tissues of horses: 1. The occlusal surface and enamel thickness
Authors: KILIC S. , DIXON P. M. , KEMPSON S. A.
Published: April 2010

Gross and microscopic examinations were undertaken on 46 cheek (molar and premolar) and 4 incisor equine teeth that were fractured, or sectioned either with a lathe or diamond saw. Specimens were examined without treatment, after decalcification or acid etching, utilising light, and scanning and transmission electron microscopy. In some horses, the occlusal surface of the teeth were covered with an organic pellicle. The occlusal surface of the underlying equine enamel contained different wear patterns, including polished areas, local fractures, wedge‐shaped pits, striations and depressions. Occlusal dentine showed depressions whose depth was related to its occlusal surface area, with larger surface areas having deeper depressions. The thickness of equine enamel varied greatly throughout its folds in the transverse plane, and was thickest in areas where folds were parallel to the long axis of the maxilla and mandible. Enamel thickness remained constant in the longitudinal plane (throughout the length of the tooth). Peripheral enamel was more deeply infolded in lower than in upper cheek teeth and this appeared to compensate for the absence of infundibula (deep, cup‐like enamel indentations that are partially filled with cement) in the lower cheek teeth.
A light microscopic and ultrastructural examination of calcified dental tissues of horses: 2. Ultrastructural enamel findings
Authors: KILIC S. , DIXON P. M. , KEMPSON S. A.
Published: April 2010

Ultrastructural examinations defined 3 equine enamel types termed equine (Eq.) Types 1,2 and 3 enamel, according to the transverse appearances of their enamel prisms and the amount and appearance of their interprismatic enamel. Eq. Type 1 enamel contained alternating rows of oval shaped prisms and thick interprismatic enamel plates, and was found adjacent to the amelodentinal junction. Eq. Type 2 enamel consisted of circular, ‘keyhole’ to ‘horseshoe’ shaped prisms with little or no interprismatic enamel and was located adjacent to the amelocemental junction. Eq. Type 3 enamel was composed of rounded prisms surrounded by large amounts of interprismatic enamel and was inconsistently present in a thin layer at the amelodentinal and amelocemental junctions. Prism decussation was seen in the thickest peripheral enamel of the upper cheek teeth but was present throughout incisor enamel therefore making incisors highly resistant to cracking. Scanning electron microscopic examination showed enamel crystals to be cylindrical shaped on transverse section; however, on transmission electron microscopic examination these crystals had shapes, ranging from near oval to rectangular and formed small subunits, with crystals diverging from each other at various angles.
Abdominal surgery in foals: a review of 119 cases (1977–1994)
Authors: CABLE CHRISTINA S. , FUBINI SUSAN L. , ERB HOLLIS N. , HAKES JEANNE E.
Published: April 2010

The case records of 119 young horses (all less than age one year) that underwent an exploratory celiotomy during a 17 year period were examined to determine the surgical findings, short‐ and long‐term outcome, and prevalence of small intestinal disease compared to previous reports in the mature horse. Physical and laboratory values were compared for long‐term survivors vs. nonsurvivors and the frequency of post operative intra‐abdominal adhesions was determined. The most common cause for exploratory celiotomy was small intestinal strangulation, followed by enteritis and uroperitoneum. Six horses died during surgery, 23 were subjected to euthanasia at the time of surgery due to a grave prognosis, and 17 horses died or were destroyed after surgery, prior to discharge from the hospital; the short‐term survival was 61%. Nine horses were lost to follow‐up. Forty‐one horses survived long‐term (at least 6 months after surgery), 15 died or were subjected to euthanasia after discharge for reasons related to the prior abdominal surgery, and 8 died or were destroyed after discharge due to unrelated reasons, making the long‐term survival 45%. Fifty‐three (45%) of the horses presented as neonates, and 66 (55%) presented age 3–12 months. Uroperitoneum and meconium impaction were the most common disease in the neonate. Intussusception and enteritis were the most common diseases in older foals. The overall prevalence of small intestinal disease was 44%. Significant elevations in packed cell volume, heart rate, nucleated cell counts and total protein in abdominal fluid and rectal temperature were observed in nonsurvivors compared to survivors. Nonsurvivors had significantly decreased serum bicarbonate, chloride, sodium, and venous pH values. There was no evidence that location of the lesion affected long‐term survival. Horses with a simple obstruction had a higher survival percentage than those with a strangulating obstruction, and horses that underwent an intestinal resection had a lower long‐term survival than those horses undergoing only intestinal manipulation. Nineteen (33%) of the foals examined after the original surgery had evidence of intra‐abdominal adhesions. Nine of these (16%) had adhesions that caused a clinical problem.
Causes of natal dispersal and emigration and their effects on harem formation in Misaki feral horses
Authors: KASEDA Y. , OGAWA H. , KHALIL ASHRAF M.
Published: April 2010

Misaki feral horses were separated into 2 herds and the difference between dispersal from natal group (natal dispersal) and dispersal from natal area (natal emigration) was studied. The causes of dispersal and emigration and their effects on harem formation were studied 1979–1994. The number of horses ranged from 73 (mature males: 8, mature females: 26, young males: 8, young females: 3, colt foals: 6, filly foals: 10 and geldings: 12) in 1979 and 86 (mature males: 14, mature females: 37, young males: 12, young females: 7, colt foals: 5, filly foals: 7 and geldings: 4) in 1994 when the present study ended. All 29 males which survived to age 4 years and 58 females which survived to age 3 years left their natal or mother groups at age one to 3. Seventeen of 22 dispersing males and 29 of 39 dispersing females left their natal groups around the birth of their siblings and significant correlations were found between natal dispersal and birth of a sibling. The number of emigrating young males correlated negatively and significantly with the total number of young males in another herd and the number of emigrating young females correlated positively and significantly with the total number of young females in the natal herd. All 13 emigrating stallions which survived to age 5 years formed stable harem groups and a significant correlation was found between natal emigration and harem formation. Twenty‐three of 35 resident mares formed stable consort relations with harem stallions and a significant correlation was found between residence and formation of stable consort relations.
Clinical evaluation of the serodiagnostic value of enzyme‐linked immunosorbent assay forRhodococcus equiinfection in foals
Authors: HIGUCHI T. , HASHIKURA S. , GOJO C. , INUI T. , SATOH S. , YOSHIDA M. , ISHIYAMA T. , YAMADA H. , TAKAl S.
Published: April 2010

An enzyme‐linked immunosorbent assay (ELISA) for detection of serum IgG antibodies against Tween 20‐extracted antigen of strain ATCC 6939 was applied in Hidaka, Japan to a total of 752 sick foals showing a variety of signs of infectious disease. An optical density (OD) value of more than 0.3 was tentatively fixed to be positive on the basis of readings made of healthy horse sera in previous studies. During a 2 year study, 138 of the 752 sick foals showed an OD value of 0.3 or higher and were designated as ‘suspected ofR. equiinfection’. Age distribution during the initial medical examination of the 138 seropositive foals was significant in that most (64%) foals were age 31–60 days, with a sharp decrease in subjects beyond that age. Of the 138 foals suspected of havingR. equiinfection, 34 foals (25%) showed OD values of over 0.9 at the initial medical examination, in addition to high blood leucocyte counts and serum fibrinogen and alpha‐globulin values. The infectious foals had been treated with antibiotics just before and after serodiagnosis and 126 foals (91%) recovered from the disease. However, no clinical improvement was observed in 12 foals (9%). At necropsy, these foals revealed suppurative pneumonia and lymphadenitis of gut associated lymph nodes accompanied by abdominal abscesses. All isolates from the pulmonary and abdominal abscesses revealedR. equi. These results suggest that OD readings in the high range are associated with severe disseminated infection withR. equi.
Prostaglandin F2αrelease associated with an embryo transfer procedure in the mare
Authors: KASK K. , ODENSVIK KRISHNA , KINDAHL H.
Published: April 2010

The pattern of the main metabolite of prostaglandin (PG) F2αwas recorded following a nonsurgical embryo transfer technique in 9 mares under field conditions in Estonia. Three patterns were observed. Two of them were characterised by PG release, thereas the third was not. A tendency towards a shortened cycle was seen in 3 mares. Observations were made regarding the manipulation of the uterus as being normal or difficult to perform. In general, mares where the procedure was considered difficult were also found to have a PG release.;
Effects of triamcinolone acetonide on anin vivoequine osteochondral fragment exercise model
Authors: FRISBIE D. D. , KAWCAK C. E. , TROTTER G. W. , POWERS B. E. , WALTON R. M. , McILWRAITH C. W.
Published: April 2010

The objective of this study was to determine the effects of intra‐articularly administered triamcinolone acetonide (TA) in exercised equine athletes with carpal osteochondral fragmentation. Eighteen horses were randomly assigned to each of 3 groups. An osteochondral chip fragment was created in one randomly chosen intercarpal joint of each horse. Both intercarpal joints in the placebo control group (CNT) horses were injected with intra‐articular administration (IA) of polyionic fluid. Both joints in the TA control group (TA CNT) horses were treated with 12 mg of TA in the intercarpal joint without an osteochondral fragment, and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. The TA treated group (TA TX) horses were treated with 12 mg of TA in the joint that contained the osteochondral fragment and the opposite intercarpal joint was injected with a similar volume of polyionic fluid. All horses were treated IA on days 13 and 27 after surgery and exercised on a high speed treadmill for 6 weeks starting on Day 14.

Horses in the TA TX group were significantly less lame than horses in the CNT and TA CNT groups. Horses in either TA CNT or TA TX groups had lower total protein, and higher hyaluronan, and glycosaminoglycan concentrations in synovial fluid than did those in the CNT group. Synovial membrane collected from subjects in TA CNT and TA TX groups had significantly less inflammatory cell infiltration, subintimal hyperplasia and subintimal fibrosis compared to the CNT group. Articular cartilage histomorphological parameters were significantly better from the TA CNT and TA TX groups compared to the CNT group.

In conclusions, results from this study support favourable effects of TA on degree of clinically detectable lameness, and on synovial fluid, synovial membrane, and articular cartilage morphological parameters, both with direct intra‐articular administration and remote site administration as compared to placebo treatment. The clinical use of IA administered TA in horses may be therapeutically beneficial in selected cases of osteochondral fragmentation and osteoarthritis.
Estimation of performance potential of Standardbred trotters from blood lactate concentrations measured in field conditions
Authors: COUROUCÉ ANNE , CHATARD J. C. , AUVINET B.
Published: April 2010

The purpose of this study was to examine the relationship between V4 (velocity which results in a blood lactate concentration of 4 mmol/1), age and racing performance of Standardbred trotters and to establish V4 normal values to select good and poor performers. The specific influence of racing (RT) and training (T1 and T2) tracks was also examined. A total of 159 horses were divided into 5 age‐groups from 2 to 6 and over and performed 330 standardised exercise tests of 3 steps performed at increasing speeds. The velocity of the horses was measured with a tachometer on the sulky. Blood lactate concentrations were measured from the jugular vein after each step. For the 5 age‐groups, mean V4 values increased significantly (P<0.05) with age between 2 and 4 years. After 5 years, this increase was reduced and became nonsignificant. The highest V4 values were obtained on the racing track (RT) and the lowest on the training tracks (T1; P<0.05). No significant difference was found between RT and T2 nor between T1 and T2. Horses were defined as good performers (GP) when finishing between the first and the fifth place in a race or poor performers (PP) when finishing lower than fifth. V4 was significantly higher for GP than for PP (P<0.05). Normal value of V4 were established for good and poor performers taking into account the 95% confidence interval of the data.

Therefore, V4 depends on age and track and can be considered an important parameter to evaluate trotters' racing potential.
Influence of antigen challenge on platelet responsiveness in horses with chronic obstructive pulmonary disease
Authors: ABLETT J. M. , FAIRBAIRN S. M. , PAGE C. P. , LEES P. , CUNNINGHAM F. M.
Published: April 2010

A role for platelets in allergic airways disease has been postulated and changes in the responsiveness of circulating platelets have been demonstrated following antigen challenge of asthmatic human subjects. In this study agonist‐induced aggregation of equine platelets in vitro has been compared before and after exposure of horses to a controlled hay and straw challenge. Prior to challenge the response of platelets, from horses with chronic obstructive pulmonary disease (COPD) and normal animals, to adenosine diphosphate (ADP) and platelet activating factor (PAF) did not differ. Five hours after initiation of the challenge, there was a modest but significant decrease in the response of platelets from the COPD horses to PAF, but not to ADP. Platelets from normal horses were not less sensitive to either agonist at this time. Twenty four hours after challenge the responses of platelets from COPD horses to both agonists were the same as pre‐challenge values. These results demonstrate that antigen challenge alters the responsiveness of platelets from allergic horses to PAF and this change is suggestive of PAF release accompanying allergen exposure in the horse.
Some effects of multiple administrations of detomidine during the last trimester of equine pregnancy
Authors: LUUKKANEN L. , KATILA T. , KOSKINEN E.
Published: April 2010

Detomidine was given to 11 pregnant mares at 3 week intervals during the last trimester of pregnancy. Maternal and fetal electrocardiographs were recorded and fetal activity studied by transabdominal ultrasonography, before and 2 h (2, 5, 10, 20, 30, 60, 90 and 120 mini after injection. After parturition, the foals were examined and weighed. Maternal and fetal hearts rate showed an initial decline after detomidine administration. Maternal heart rate in the treatment group were lower already 2 min after injection, but a reduction in fetal heart was first seen 5 min after detomidine administration. Mean fetal heart rate at 2 min after detomidine injection was 109, 104, 95 and 89 beats/min, whereas at 5 min it was 80,76,72 and 66 beats/min in the 2nd, 3rd, 4th and 5th examination session, respectively. The heart rates did not revert to the control values during follow‐up. Decline and recovery patterns were quite similar during all examination sessions. The mares exhibited conductive disturbances 2 min after detomidine administration, but fetal heart rhythm remained regular. Fetal activity was decreased at 5 min but had reverted to control values about 90 min after detomidine administration. Administration of detomidine (0.015 mg/kg) to healthy pregnant mares at 3 week intervals during the last trimester had no measurable detrimental effects on the outcome of pregnancy.
Expression of transforming growth factor‐β1 in normal and dyschondroplastic articular growth cartilage of the young horse
Authors: HENSON FRANCES M. D. , SCHOFIELD P. N. , JEFFCOTT L. B.
Published: April 2010

This study describes the distribution pattern of transforming growth factor‐β1 (TGF‐β1) mRNA and protein in normal pre‐and post natal growth cartilage and alterations present in lesions of dyschondroplasia (osteochondrosis). TGF‐β1 expression and immunoreactivity have been investigated byin situhybridisation and immunolocalisation in the articular/epiphyseal growth cartilage of the lateral trochlear ridge of the distal femur. Cartilage was obtained from 19 normal Thoroughbred horses (5 prenatal and 14 post natal horses) and 15 post natal horses with dyschondroplasia (DCP).

TGF‐β1 mRNA expression and immunoreactivity were detected in the proliferative and upper hypertrophic zones in both pre‐ and post natal normal articular/epiphyseal cartilage. However, mRNA itself was only detected in the mid‐ and lower hypertrophic zones. Immunoreactivity was identified intracellularly with some nuclear staining observed. In focal lesions of DCP mRNA expression and immunoreactivity were reduced compared to normal cartilage, but strong mRNA expression was observed in the chondrocyte clusters immediately surrounding a lesion of DCP. The results described in this study demonstrate alterations in TGF‐β1 in dyschondroplastic lesions and indicate that it could be involved in the pathogenesis of this condition in the horse.
Prospective study of equine colic incidence and mortality
Authors: TINKER MARY K. , WHITE N. A. , LESSARD P. , THATCHER C. D. , PELZER K. D. , DAVIS BETTY , CARMEL D. K.
Published: April 2010

A prospective study of one year was conducted on 31 horse farms to obtain population based estimates of incidence, morbidity and mortality rates of equine colic. Farms with greater than 20 horses were enrolled by randomly selecting horse owners from 2 adjacent counties of Virginia and Maryland. Descriptive information for 1427 horses was collected at the initiation of the study and updated at 3 month intervals. Time on the farm during the study was tabulated for each horse. When colic was reported by the owner, investigators visited the farm to obtain information about the colic. The crude incidence density rate of colic was 10.6 colic cases/100 horse‐years, based on 104 cases/358,991 horse‐days. The median farm specific incidence density rate was 7 cases/100 horse‐years, and the range for individual farms varied from 0 to 30 colic cases/100 horse‐years. A specific diagnosis was not made for 84 (81%) of colic episodes. Seventy colic episodes (67%) were treated by a veterinarian. Drugs were used in 83 (80%) colic episodes, and 78 (75%) of colic cases were mild, requiring no treatment or resolving after only one treatment. Four horses required colic surgery. Fourteen (13%) horses had more than one episode of colic during the year. Mortality from all causes of death was 2.5 deaths/100 horse‐years, mortality rate for colic was 0.7 deaths/100 horse‐years. Proportional mortality rate of colic, 28%, was higher than for any other cause of death. Horses less than age 2 years or greater than age 10 years had lower incidence than horses age 2–10 years. No difference in colic risk between genders was identified. Arabian horses had the lowest and Thoroughbreds the highest breed specific incidence rates. Horses used for eventing, or in training had a statistically significant higher incidence rate of colic compared to mature horses with no use (pets, retired, on pasture with no stated purpose). Horses used for lessons or with no use had the lowest incidence rates.
Surgical treatment of subchondral cystic lesions of the third metacarpal bone: results in 15 horses (1986–1994)
Authors: HOGAN PATRICIA M. , McILWRAITH C. W. , HONNAS C. M. , WATKINS J. P. , BRAMLAGE L. R.
Published: April 2010

Subchondral cystic lesions (SCLs) in the condyle of the third metacarpal bone (MCIII) were surgically treated in 15 horses. The median age at presentation was 18 months (range 10 months‐12 years) with 10 of 15 horses less than age 2 years. The SCLs were confined to the front limbs in all cases with 2 horses having bilateral lesions. Lesions were isolated to the medial condyle(s) of MCIII in 13 of 15 horses; a cystic lesion occurred in the lateral condyle in one horse and in the sagittal ridge in one horse. One horse with bilateral lesions had an additional cystic lesion located in the right medial femoral condyle. Fourteen of 15 horses had a history of moderate lameness attributable to the metacarpophalangeal joint; the lesion was an incidental finding in one horse. Duration of lameness ranged from 4 weeks to 8 months and was either acute in onset, or occurred intermittently and was associated with exercise. Fetlock flexion significantly exacerbated the lameness in all cases. Synovial effusion was absent in 8 (53%) cases.

Cystic lesions were curetted arthroscopically in 12 horses, and through a dorsal pouch arthrotomy in 3 horses. Concurrent osteostixis of the cystic cavity was performed in 7 horses. Two horses were treated arthroscopically for osteochondral fragmentation of the proximodorsal aspect of the proximal phalanx one year following surgical curettage of the SCL.

Twelve of 15 horses (80%) were sound for intended use following surgical treatment. Two horses did not regain soundness and follow‐up information was unavailable for one horse. Total period of follow‐up was 1–6 years. Follow‐up radiographic examinations were available for 9 horses. Mild periarticular osteophyte formation and enthesiophyte formation at the dorsal joint capsular attachments was present in 5 of the 9 horses. Bony ingrowth of the cystic lesion was detectable in 8 horses and enlargement of the cystic cavity was observed in one horse. Based on the information gained from this study, it would appear that surgical treatment of SCLs in the distal metacarpus can result in a favourable outcome for athletic use.
Stress response to chronic inflammation in the horse
Authors: MILLS P. C. , NG J. C. , KRAMER H. , AUER D. E.
Published: April 2010

Five clinically healthy Thoroughbred geldings were injected with Freund's adjuvant 3 times to induce a chronic inflammatory response. Blood was collected at various times before and after adjuvant administration. Clinical responses (rectal temperature and general demeanour) were also monitored. Adjuvant injection induced increases in rectal temperature and plasma fibrinogen concentration (maximum levels measured were mean ± s.d. 39.7 ± 0.5°C and 8.2 ± 03 g/l, respectively), indicative of an inflammatory response. A mild clinical depression was also observed in the horses for 24 h after the first injection of adjuvant only. Plasma Cortisol levels decreased significantly from control levels of mean ± s.d. 187.7 ± 24.3 nmol/l to a minimum of 80.2 ± 22.1 nmol/l (P<0.01) 9 days after the first injection of adjuvant. Conversely, plasma insulin levels increased after the first injection of adjuvant to a maximum (96.7 ± 15.2 iu/ml; P<0.01) 12 days later, while plasma glucose concentrations tended to decline. A control group of horses to rule out contemporary environmental influences on the physiological and biochemical indices measured was not included in this study. The results show that chronic inflammation in the horse depressed resting plasma Cortisol concentrations.