bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twin embryos in mares II: post fixation embryo reduction
Authors: GINTHER O. J. 
Published: April 2010

SummaryRecent findings on the development and natural outcome of twins from Day 17 (immediately after fixation) to Day 40 are reviewed. Incidence of embryo reduction was increased significantly when the vesicles became fixed unilaterally, rather than bilaterally, and when the vesicles were unequal in diameter. Of 68 mares with twins on the day of fixation, post fixation embryo reduction occurred in 41 (60 per cent). The incidence of reduction was 41 of 48 (85 per cent) following unilateral fixation; reduction occurred in all of 22 mares with vesicles of dissimilar size (4 mm or more difference in diameter) and in 19 (73 per cent) of 26 mares with vesicles of similar size (0 to 3 mm difference). Embryo reductions were complete (vesicle no longer visible ultrasonically) by Day 20 (59 per cent of the reductions), during Days 21 to 30 (27 per cent), or Days 31 to 38 (14 per cent). In 80 per cent of the early reductions (by Day 20) the eliminated vesicle disappeared within one day. Reductions that occurred after Day 20 were preceded by a gradual decrease in size. As the number of days after Day 17 increased, the frequency of reduction decreased and the time required for completion of reduction increased. When the twins were dissimilar in diameter (4 mm or more), they were more likely to undergo reduction by Day 20. In summary, dissimilarity in diameter increased the likelihood of unilateral fixation, increased the incidence of reduction for unilaterally fixed vesicles, hastened the day of occurrence of reduction and shortened the interval from initiation to completion of reduction. The deprivation hypothesis proposes that embryo reduction occurs when a major portion of the three walled area of the yolk sac or the vascularised wall of the yolk sac or allantoic sac is in apposition with the wall of the adjacent vesicle rather than with the endometrium; the vesicle is deprived of adequate embryonal‐maternal exchange and therefore regresses.
Pulmonary vascular reactivity of the newborn pony foal
Authors: DRUMMOND W. H. , SANCHEZ I. R. , KOSCH P. C. , WEBB A. I. 
Published: April 2010

SummaryAdult ponies develop pulmonary hypertension at altitude (Bisgard, Orr and Will 1975), but the neonatal response to acute hypoxaemia is unknown. Seven foals aged five days were instrumented with a systemic and a Swan‐Ganz pulmonary artery catheter while anaesthetised and intubated. Cardiac index, pulmonary (PAP) and systemic (SAP) vascular pressures were measured as the foals breathed gas mixtures with F102 of 8 to 94 per cent. Because foramen ovale or ductus arteriosus shunts might have altered thermodilution cardiac index measurements in the stressed foals, the ratio, PAP/SAP was calculated to define relative circulatory reactivity. Three foals, two of which were full siblings, had very marked elevation of PAP/SAP from 0.6 to 1.41 at low inspired oxygen tensions. Four different foals attained maximal PAP/SAP of only 0.2 to 0.92 at similarly low oxygen tensions (P<0.0001). Thus, pulmonary vascular reactivity to ventilatory hypoxaemia varied greatly in pony foals of the same age. The exaggerated reactivity in related foals suggested that, as in cattle, a genetic predisposition to develop reactive pulmonary hypertension under hypoxaemic stress may exist.
A preliminary investigation of the effect of selected electromagnetic field devices on healing of cannon bone osteotomies in horses
Authors: SANDERS‐SHAMIS MARLENE , BRAMLAGE L. R. , WEISBRODE S. E. , GABEL A. A. 
Published: April 2010

SummaryThe effect of electrical stimulation by means of selected electromagnetic field devices on healing of cannon bone osteotomies in horses was examined. The defects were created as 3 cm × 1 mm longitudinal osteotomies through the dorsal cortices of the mid‐metacarpi/metatarsi of adult horses. This type of defect would asses bone healing in a situation similar to an acute, stable fracture of the cortex. Three electromagnetic devices of different design were tested in three different groups of horses. Healing was evaluated radiographically and histologically. Results showed that osteotomies treated with the electromagnetic devices healed similarly to untreated controls. Our conclusion is that the electromagnetic devices studied did not have a local effect on the repair process of an acute, stable, osseous defect.
Body fluid and endometrial concentrations of ketoconazole in mares after intravenous injection or repeated gavage
Authors: PRADES MARTA , BROWN M. P. , GRONWALL R. , HOUSTON ANN ELIZABETH 
Published: April 2010

SummaryAfter single oral administration of ketoconazole (30 mg/kg bodyweight [bwt]) in 50 ml of corn syrup to a healthy mare, the drug was not detected in serum. Ketoconazole in 0.2 N HC1 was administered intragastrically to six healthy adult horses in five consecutive doses of 30 mg/kg bwt at 12 h intervals. Ketoconazole concentrations were measured in serum, synovial fluid, peritoneal fluid, cerebrospinal fluid (CSF), urine and endometrium. Mean peak serum ketoconazole concentration was 3.76 μg/ml at 1.5 to 2 h after intragastric administration. Mean peak synovial concentration was 0.87 μg/ml 3 h after the fifth dose. Similarly, mean peritoneal concentration peaked 3 h after the fifth dose at 1.62 μg/ml. Mean endometrial concentrations peaked at 2.73 μg/ml 2 h after the fifth dose. Ketoconazole was detected in the CSF of only one of the six mares at a concentration of 0.28 μg/ml 3 h after the fifth dose. The highest measured concentration of ketoconazole in urine was 6.15 μg/ml 2 h after the fifth dose. A single intravenous injection of ketoconazole (10 mg/kg bwt) was given to one of the six mares; the overall elimination rate constant was estimated at 0.22/h and bioavailability after oral administration was 23 per cent.
Rhodococcus equi foal pneumonia: Protective effects of immune plasma in experimentally infected foals
Authors: MARTENS R. J. , MARTENS JUDY G. , FISKE R. A. , HIETALA SHARON K. 
Published: April 2010

SummaryThe immunoprophylactic capacity of specific immune plasma was evaluated in pony foals infected experimentally withRhodococcus equi.Immune plasma, produced by repeated parenteral administration of viableR. equito adult horses, was harvested and frozen. Group I (six control foals) and Group II (six principal foals) received lactated Ringers solution and immune plasma respectively at three and five days of age.R. equiwere aerosolised into a caudal lung lobe of all foals at seven days of age. Clinical signs, haematological alterations, immune responses, thoracic radiographs and technetium99mpulmonary perfusion scans were monitored. All foals were destroyed and complete post mortem examinations performed. All foals developed pneumonia as evidenced by clinical, radiographic and perfusion alterations, but the survival rate of principal foals was significantly (P < 0.01) greater than that of control foals. Five control foals developed terminal disease, whereas all principal foals recovered. There was no significant (P>0.05) difference in temperature response, or peripheral blood leucocyte, neutrophil or fibrinogen concentrations between groups. ELISA values forR. equiantibody were significantly (P<0.001) greater in principal foals following treatment, but there was no significant (P>0.05) difference in IgG or IgM concentrations between groups. Results of the haemolysis inhibition assay indicated that equi factor neutralising antibodies were transferred by immune plasma to the principal foals. Post mortem examinations of five control foals destroyed at approximately three weeks post infection because of terminal disease, revealed severe pyogranulomatous pneumonia. One control and all principal foals were either free of lesions or had resolving lesions and/or minimal scar formation at three months post infection. The results of this investigation document the importance of humoral factors in controlling the disease process, and the capacity of humoral immunoprophylaxis to alter the clinical progression ofR. equipneumonia.
A retropspective study of 100 pelvic fractures in horses
Authors: RUTKOWSKI J. A. , RICHARDSON D. W. 
Published: April 2010

SummaryThe records of 100 horses with clinical or radiographic diagnosis of a pelvic fracture were reviewed to determine prognostic indicators associated with clinical signs or radiographic fracture characteristics. Degree of lameness, soft tissue swelling, crepitis, muscle atrophy, skeletal external assymetry and palpable assymetry on rectal examination were evaluated. There was no significant relationship between the aforementioned clinical signs and the long‐term case outcome. Fracture sites or presence of an acetabular fracture were not related to prognosis. The positive outcome of 77 per cent of horses that were allowed to survive and were available for follow‐up in this study warrants the effort of salvage of valuable individuals.
Ventilation‐perfusion relationships in the anaesthetised horse
Authors: NYMAN G. , HEDENSTIERNA G. 
Published: April 2010

SummaryVentilation‐perfusion relationships were studied by the multiple inert gas elimination technique in seven horses while they were conscious and during inhalation anaesthesia with halothane. A generally good match between ventilation and perfusion was found in the conscious, standing horse. During anaesthesia a huge shunt developed, ie perfusion of completely unventilated lung regions, both in dorsal and left lateral recumbency and whether the horse was breathing spontaneously or mechanically ventilated. The shunt was significantly greater and the arterial oxygen tension (PaO2) significantly lower in dorsal than in left lateral recumbency. Little or no perfusion of low V̇A/Q̇ regions was observed during anaesthesia, whether ventilation was spontaneous or mechanical. Positive end‐expiratory pressure (PEEP) did not significantly improve PaO2or reduce the shunt. Selective mechanical ventilation of dependent lung regions with PEEP reduced the shunt markedly, an effect that was not achieved by conventional mechanical ventilation with general PEEP. The findings seem compatible with alveolar collapse during anaesthesia, causing shunt, whereas the absence of clearly low V̇A/Q̇ regions questions the role of airway closure as the major disturbance of gas exchange.
The arterial supply of the navicular bone in the normal horse
Authors: RIJKENHUIZEN ASTRID B. M. , NEMETH F. , DIK K. J. , GOEDEGEBUURE S. A. 
Published: April 2010

SummaryAn arteriographic and histological study of the arterial blood supply of 35 navicular bones, from 19 adult horses with no clinical or radiographical signs of navicular disease, is described. The arteries enter the navicular bone from four directions: distal, proximal, medial, and lateral. The navicular bone can be divided into areas which receive arteries from one, two, or three directions, whereas the distal supply covers the largest part of the navicular bone. The distal arteries enter the navicular bone through the nutrient foramen which contains loose connective tissue, nutrient vessels and myelinated nerves. At least 77 per cent of the nutrient foramina contains synovial membrane. Twelve per cent of the arteries in the navicular bone show histological changes. Thickening of the intima with or without splitting of the internal elastic membrane and hyalinisation, fibrosis and hypertrophy of the media were observed.
The effect of unilateral resection of segments of both palmar digital arteries on the navicular bone in ponies: An experimental study
Authors: RIJKENHUIZEN ASTRID B. M. , NÈMETH F. , DIK K. J. , GOEDEGEBUURE S. A. , VAN DEN BROM W. E. 
Published: April 2010

SummaryClinical, radiographical, scintigraphical and histological effects on the navicular bone after resection of the medial and lateral palmar digital arteries in the pastern of one forelimb in ponies are evaluated. The acute disruption of the main blood supply of the distal extremity causes lameness due to the suddenness of the resection in which the collateral circulation is insufficiently developed. Because of the compensatory collateral circulation, no permanent symptoms of ischaemia occur despite the partial resection of both palmar digital arteries. Histologically the percentage of relative osteoid volume of the operated limb was significantly higher than in the control limb.
The effect of artificial occlusion of the Ramus navicularis and its branching arteries on the navicular bone in horses: An experimental study
Authors: RIJKENHUIZEN ASTRID B. M. , NÉMETH F. , DIK K. J. , GOEDEGEBUURE S. A. , VAN DEN BROM W. E. 
Published: April 2010

SummaryThe clinical, radiographic, arteriographic, scintigraphic and histological effects of experimental occlusion of the Ramus navicularis (R. Navicularis) and its branching arteries are evaluated. Occlusion of the R. navicularis and its branching arteries creates changes, arteriographically and histologically, which resemble those of navicular disease. The increased bone remodelling, the shift in arterial pattern, the formation of collaterals and the increased connective tissue in the synovial membrane and nutrient foramina, as a reaction to the reduction of the distal arterial supply of the navicular bone, are also pathological features in the navicular bones of horses with navicular disease. The results of the present study support the theory that a reduced distal arterial supply of the navicular bone is important in the pathogenesis of navicular disease.
Changes in circulating equine erythrocytes induced by brief, high‐speed exercise
Authors: SMITH J. E. , ERICKSON H. H. , DEBOWES R. M. , CLARK MARGARET 
Published: April 2010

SummaryFive horses were exercised at 10m/sec at a 3° incline for 2 mins. Packed cell volume, erythrocyte count, haemoglobin concentration, mean corpuscular volume, plasma protein, total white cell count and lymphocytes increased significantly in blood samples taken after exercise, compared with those taken before exercise; but mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration decreased. Erythrocytes were more resistant to osmotic stress after exercise, but their shape and degree of deformity were unaffected by exercise.
A computer‐derived protocol to aid in selecting medical versus surgical treatment of horses with abdominal pain
Authors: DUCHARME N. G. , PASCOE P. J. , LUMSDEN J. H. , DUCHARME G. R. 
Published: April 2010

SummaryIn order to determine which variables are useful in identifying horses with abdominal pain requiring surgery, data were analysed from 219 horses presented at one veterinary teaching hospital. Using multiple stepwise discriminant analysis with a recursive partitioning algorithm, we obtained a decision tree that identifies surgical and non‐surgical patients. The prevalence of surgical patients was 79 per cent in this population. The sensitivity, specificity, and positive and negative predictive values of this decision tree were 99 per cent, 55 per cent, 90 per cent and 99 per cent respectively. Compared to the clinical decision, this decision tree yielded more false positives (11 per cent) but almost eliminated false negatives (1 per cent). This decision tree was validated by the jack‐knife method and also by evaluation using a new sample in a second veterinary teaching hospital in which the prevalence of surgical patients was 55 per cent. This led to sensitivity, specificity and positive and negative predictive values of 93 per cent, 73 per cent, 81 per cent and 89 per cent respectively.
Induction of peritoneal adhesions with small intestinal ischaemia and distention in the foal
Authors: LUNDIN CANDACE , SULLINS K. E. , WHITE N. A. , CLEM M. F. , DEBOWES R. M. , PFEIFFER C. A. 
Published: April 2010

SummaryTwenty‐two foals were divided into groups of intestinal distension and intestinal ischaemia as methods to induce peritoneal adhesions. In the first group, the lumen of a segment of distal small intestine was occluded without extramural vascular compromise and distended with lactated Ringer's solution to a constant pressure of 25 cm H2O for 2 h within the abdomen. The ischaemic group underwent 70 mins total vascular occlusion of identical segments of bowel. Serosal biopsies were obtained before and after each experimental procedure and following 60 mins of reperfusion. Similar biopsies were harvested from a control group of foals with no bowel occlusions. The foals were destroyed 10 days after surgery and tissues collected for histological and ultrastructural evaluation. Experimental and control mesothelial surfaces were denuded histologically immediately after experimental occlusions. Serosal oedema and cellular infiltration were observed following reperfusion of the ischaemic segments but were present immediately after 2 h of distension. All foals had developed bowel‐to‐bowel and bowel‐to‐mesentery adhesions of the experimental segments. Control foals under 30 days old exhibited mesenteric contraction and thickening of the isolated segment whereas those older than 30 days had little or no mesenteric thickening or contraction. Histologically, in the experimental segments, fibrous tissue had formed on the outer boundary of the original serosa, and new mesothelial‐like cells were present on the surface of fibrous tissue in some areas. Some serosal fibrosis was also seen in most of the control segments.
Sequential clinical and synovial fluid changes associated with acute infectious arthritis in the horse
Authors: TULAMO RIITTA‐MARI , BRAMLAGE L. R. , GABEL A. A. 
Published: April 2010

SummaryInfectious arthritis was induced experimentally in one tarsocrural joint of six horses by intra‐articular injection of 1 ml Staphylococcus‐saline suspension containing 9 times 104to 3 times 106organisms. The corresponding contralateral joint was injected with 1 ml of saline and served as a control. The progression of the induced infectious arthritis was assessed over a nine‐day period by clinical examination and sequential synovial fluid analysis with pH and lactate measurements. Changes in synovial fluid were present before clinical signs of infectious arthritis were manifested. The diagnostic value of different synovial fluid parameters at various stages of infection was determined. Cellular changes initially preceded the biochemical changes. Total leucocyte counts showed a significant increase within 24 h (up to 100 times 109/litre) with great variability in subsequent measurements. Neutrophilia over 90 per cent and pH under 6.9 were the most consistent findings in the infected synovia. Increased total protein was also significant and was progressive throughout the experiment. Serum and synovial glucose difference and synovial lactate had more diagnostic value in the acute stages than in the chronic stages. The control joints elicited an inflammatory response manifested by increased leucocyte count, moderate neutrophilia, slightly increased total protein concentration, and slightly decreased pH, but all reactions were minor in comparison to those in the infected joints.
High frequency jet ventilation in horses: an experimental study
Authors: DUNLOP C. I. , HODGSON D. S. , WATSON J. W. , GILLESPIE J. R. , STEFFEY E. P. , JACKSON A. C. 
Published: April 2010

SummaryHigh frequency jet ventilation (HFJV) is a recently developed mode of ventilation that delivers small tidal volumes at frequencies greater than 60 cycles per min via an injection catheter to the animal's airway. The construction of a high frequency jet ventilator suitable for use in adult horses is described. The effectiveness of this ventilator in maintaining normal arterial blood ‐ gas tension was evaluated in five healthy adult horses. The horses were anaesthetised with intravenous acetylpromazine, guaifenesin, and thiamylal, positioned in lateral recumbency and baseline measurements were made during spontaneous ventilation. The horses were then paralysed with succinylcholine and ventilated for at least 20 mins with HFJV. Air was delivered from the ventilator to the animal by a polyethylene tube. The tip of this tube remained within and approximately 30 cm from the cuffed end of a standard 30 mm internal diameter large animal orotracheal tube. Frequency of flow interruption was 3 Hz with a constant source pressure of 275 kPa and an inspiratory to expiratory ratio of approximately 1:2.6. Gas delivery to the horse, as estimated with a resonator system was approximately 2 litres/breath. During HFJV, arterial carbon dioxide tension was significantly reduced and arterial oxygen tension significantly increased above measurements made when the horses were spontaneously breathing air.
Treatment of solar prolapse using the heart bar shoe and dorsal hoof wall resection technique
Authors: EUSTACE R. A. , CALDWELL M. N. 
Published: April 2010

SummaryThis paper describes the treatment of 10 horses suffering from acute laminitis using the heart bar shoe and a dorsal hoof wall resection technique. All cases had progressed to prolapse of the tip of the pedal bone covered by solar corium through the horny sole; in one case the exposed tip of the distal phalanx became visible. Nine cases of distal phalangeal rotation and one case of distal displacement of the distal phalanx (sinking) are described. Two animals were destroyed because of the degree of lameness, one remains slightly lame at the trot and the remaining seven have returned to their previous use at comparable levels of performance.
Visceral prolapse after castration in the horse: a review of 18 cases
Authors: VAN DER VELDEN M. A. , RUTGERS L. J. E. 
Published: April 2010

SummaryDuring a 10 year period, 18 horses were treated surgically because of visceral prolapse after castration. Surgery was successful in six cases of omental prolapse and in eight out of 12 cases of intestinal prolapse. To minimise the risk of visceral prolapse, the authors prefer half‐closed castration, with proper ligation of the parietal vaginal tunic, to open castration. If adequate treatment is started promptly, prognosis in cases of visceral prolapse is favourable.
Pharmacokinetics of amikacin in critically ill neonatal foals treated for presumed or confirmed sepsis
Authors: ADLAND‐DAVENPORT PAMELA , BROWN M. P. , ROBINSON J. D. , DERENDORF H. C. 
Published: April 2010

SummaryFourteen foals less than four days of age were treated with the aminoglycoside, amikacin sulphate, and either penicillin or ampicillin for septicaemia, pneumonia, and/or failure of passive immunoglobulin transfer. Serum amikacin concentrations were determined at three times during an 8 or 12 h dosing interval. A 7.0 mg/kg bodyweight dose of amikacin every 8 h was appropriate. Prematurity did not influence mortality. All seven premature foals survived, whereas four of the seven full term foals died. Uraemia in three foals was caused by urinary bladder rupture; amikacin‐induced nephrotoxicity was not recognised by clinical chemistries (elevations in serum creatinine or blood urea nitrogen concentrations) or post‐mortem findings.
Effect of strenuous exercise stress on chemiluminescence response of equine alveolar macrophages
Authors: WONG C. W. , THOMPSON H. L. , THONG Y. H. , THORNTON J. R. 
Published: April 2010

SummaryBronchoalveolar lavage samples were collected using a fibreoptic endoscope from horses at specified times before and after single bouts of exercise. Lucigenin‐dependent phagocytic chemiluminescence was used to assess the effect of exercise on the alveolar macrophage metabolic activity in response to stimulation by opsonised zymosan. A profound suppressive effect on the chemiluminescence production was present throughout the first three days after exercise. However, the cellular composition of lavage fluids was not altered by the exercise. It is suggested that strenuous exercise may jeopardise the antimicrobial function of alveolar macrophages which may lead to an increase in susceptibility to infection.