bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of intramuscular omeprazole on gastric acid secretion in horses over a twenty‐four hour period
Authors: SANDIN A. , ANDREWS F. M. , NADEAU J. A. , DOHERTY T. J. , NILSSON G.
Published: June 2010

The effect of intramuscular (i.m.) omeprazole (0.25 or 1.0 mg/kg bwt; LD and HD), respectively, on volume, total acid output (TAO) and pH of the gastric juice was studied during 24 h in 5 horses with a chronically implanted gastric cannula. Whether secretion in controls was basal or stimulated with pentagastrin (8 μg/kg bwt/h), volume (NS) and TAO (P<0.01, NS) gradually decreased and pH increased (P<0.05, NS).

Omeprazole significantly reduced the average basal TAO by 49 ± 6% (LD) and 88 ± 3% (HD) and the stimulated TAO by 64 ± 2% and 97 ± 1%. Basal pH in controls was 2.1–4.2 and after omeprazole treatment, pH 2.8–4.1 (LD) and 2.4–6.6 (HD). After stimulation, the corresponding pH values were 2.6–3.3, 3.9–4.9 and 5.4–7.2. The biological availability of omeprazole was 70–80%. Due to the simplicity of the administration technique and the higher biological availability, intramuscular administration may offer a practical and less expensive way of treating gastric ulcers in horses.
Comparison of the antisecretory effects of omeprazole when administered intravenously, as acid‐stable granules and as an oral paste in horses
Authors: HAVEN MICHELLE L. , DAVE K. , BURROW J. A. , MERRITT A. M. , HARRIS DEBORAH , ZHANG D. , HICKEY G. J.
Published: June 2010

The antisecretory activity of omeprazole on gastric acid when administered i.v., intragastrically orper os, was evaluated in 2 female and 3 castrated male horses. Each horse had been prepared with a chronic indwelling gastric cannula. A single i.v. administration of omeprazole (1.5 mg/kg bwt) was effective in abolishing basal and pentagastrin (PG)‐stimulated acid secretion. Once daily, nasogastric administration of omeprazole in acid‐stable granules for 5 days inhibited acid secretion in a dose‐ dependent manner: 57% (1.5 mg/kg bwt) and 98% (5.0 mg/kg bwt) reduction of PG‐stimulated acid secretion. The degree of inhibition was maintained over a 19 day treatment period with once daily dosing. A prototype oral paste formulation containing either acid‐stable omeprazole granules or uncoated omeprazole powder was equipotent when compared to a similar dosage of acid‐stable omeprazole granules administered by nasogastric tube. A dose‐dependent inhibition was seen with the oral paste formulation containing omeprazole powder: 55% (1.5 mg/kg bwt) and 77% (3.0 mg/kg bwt) reduction of PG‐stimulated acid secretion after 5 days. Therefore, a paste formulation of omeprazole powder may offer an effective, easily administered, once daily acid inhibitory treatment for gastric ulcer disease in horses.
Effect of omeprazole paste on gastric acid secretion in horses
Authors: DAURIO C. P. , HOLSTE J. E. , ANDREWS F. M. , MERRITT A. M. , BLACKFORD J. T. , DOLZ F. , THOMPSON D. R.
Published: June 2010

In a multicentre trial, 13 cannulated horses were treated orally once daily with a paste that delivered omeprazole at a dose of 4 and 5 mg/kg bwt in a 2‐period crossover design to evaluate steady state gastric acid suppression. In each period, basal (unstimulated) and pentagastrin‐stimulated gastric output were evaluated at 5–8 h after 5 doses, at 13–16 h after 10 doses, and at 21–24 h after 15 doses. Baseline data for gastric acid secretion were collected once for each horse in the month prior to initiation of omeprazole treatment. The inhibition of gastric acid secretion relative to baseline values, following treatment with omeprazole, were calculated and expressed as per cent. Pharmacokinetic data were also collected in this trial. At 4 mg/kg bwt, the oral paste formulation of omeprazole inhibited both basal and pentagastrin‐stimulated gastric acid secretion by 99% at 5–8 h after treatment and by 83% (basal) and 90% (pentagastrin‐stimulated) at 21–24 h. Inhibition following the administration of omeprazole at a dose of 5 mg/kg bwt was not significantly greater than when given at 4 mg/kg bwt. The results from this study could possibly lead to the development of an effective and practical antisecretory treatment of ulcer disease in horses.
Safety of omeprazole paste in foals and mature horses
Authors: PLUE R. E. , WALL H. G. , DAURIO C. , ATTEBERY D. K. , COX J. L. , WALLACE D. H.
Published: June 2010

Omeprazole has been shown to promote healing of spontaneously occurring gastric ulcers in horses when administered for 28 days at a dose of 4 mg/kg bwt/day and to prevent recurrence of ulcers in almost all horses when treatment is continued at a dose of at least 2 mg/kg bwt/day. The purpose of the 3 studies reported here was to 1) evaluate the evolution of potential effects of omeprazole paste (GastroGard)1, at a dose of 20 mg/kg bwt/day (5x the recommended dose) for 91 days in mature Thoroughbred horses; 2) evaluate the safety in young horses of omeprazole paste when dosed at 4 mg/kg bwt/day (1x), 12 mg/kg bwt/day (3x) or 20 mg/kg bwt/day (5x) for 91 days in Tennessee walking horse foals; and 3) evaluate the safety of omeprazole paste when dosed at 40 mg/kg bwt/day (10x) for 21 days in mature Thoroughbred horses. Within each study, horses were allocated randomly to the control or omeprazole paste treatment group. Clinical examinations, serum biochemistry and haematology were performed at regular intervals until necropsy at the end of the study. There were no treatment‐related clinical signs in any treated horse and serum biochemistry and haematology were normal. In conclusion, omeprazole paste is safe for use in horses as demonstrated in studies with foals and mature horses.
Safety, acceptability and endoscopic findings in foals and yearling horses treated with a paste formulation of omeprazole for twenty‐eight days
Authors: MURRAY M. J. , EICHORN EVELYN S. , HOLSTE J. E. , COX J. L. , STANIER W. B. , COOPER W. L. , COOPER VALERIE A.
Published: June 2010

A paste formulation of the H+,K+‐ATPase inhibitor omeprazole was evaluated in Thoroughbred foals and yearlings for its safety and acceptability. Twenty foals age 11–16 weeks and 20 yearling horses age 15–17 months were included and gastroscopic examinations performed 1–3 days before and at the end of each trial. Lesions were scored on a scale of 0 to 3 and animals allocated based on endoscopic lesion score and sex, with 4 animals in each of 5 replicates. Dosages of 4 mg omeprazole/kg bwt or sham treatment were administered once daily for 28 days, from a syringe graduated in 50 lb (22.68 kg) increments, the amount of paste administered being rounded up to the nearest corresponding weight in pounds. Acceptability of the paste or sham treatment was assessed and recorded by the individual administering the treatment on the basis of the tolerance or resistance to insertion of the syringe into the mouth, administration of the paste and if the paste was swallowed or actively expelled by the animal. Safety was determined on the basis of daily observation recordings and physical examination findings during and at the conclusion of the trial.

Treatment was judged to have been accepted for all 420 doses of omeprazole paste and all 140 sham doses given to foals during the trial and for 418/420 doses of paste and all 140 sham doses given to yearlings. Two doses of paste were entirely rejected by yearlings.

On the initial endoscopic examination, lesions were observed in the gastric squamous epithelial mucosa in 4 foals and 3 yearlings, and single small, superficial erosions were seen in the gastric glandular mucosa of 2 foals. On the second examination there were small, superficial erosions in the squamous mucosa in 3 foals and 2 yearlings, multi‐focal superficial erosions in 1 foal and 1 yearling, and 1 foal had large areas of erosion extending from themargo plicatustoward the dorsal fundus. No lesions in the glandular mucosa were seen in foals or yearlings. There were no significant differences (P < 0.05) in lesion scores between the beginning and the end of the trials in the omeprazole‐treated or sham‐treated groups of foals or yearlings. A paste formulation of omeprazole, administered at a dose of 4 mg/kg bwt once daily for 28 days, was determined to be highly acceptable to the foals and yearlings we studied, and no adverse effects attributable to the medication were noted
Acceptability of a paste formulation and efficacy of high dose omeprazole in healing gastric ulcers in horses maintained in race training
Authors: VATISTAS N. J. , SNYDER J. R. , NIETO J. , THOMPSON D. , POLLMEIER M. , HOLSTE J.
Published: June 2010

Gastric ulceration has been found to occur in 80–90% of Thoroughbreds in active race training. Previously, variable success has been reported using mucosal surface protectants and H2receptor antagonist. Omeprazole, a substituted benzimidazole, has been shown to inhibit gastric acid secretion in both man and animals. Fourteen horses, in active race training and with endoscopic evidence of moderated to severe gastric ulceration were divided into 2 groups:Group 1(7 horses) were given placebo paste orally once daily for 28 days;Group 2(7 horses) received 1.54 g active omeprazole in the placebo once daily for 28 days. Logs detailing administration and acceptability of the paste, and the horse's feeding and training regime were maintained by the trainer of each horse. Endoscopic examination of the stomach occurred at the beginning of the trial, and at 13–17 days and 27–31 days following commencement of the trial. Those horses that were free of ulceration on Days 27–31 were reexamined on Days 35–49.

Acceptability of the paste, whether with or without active omeprazole, was deemed excellent in all horses except on one occasion, when one horse swallowed the paste following initial mild reluctance. Of the horses given the placebo (Group 1), 3 were withdrawn after the 13–17 day endoscopic examination: 1 horse to be given a H2receptor antagonist, 1 horse was removed from training due to aryepiglottic entrapment and 1 horse had a greater than 10% fall in bodyweight from the start of the trial. Of the horses given active omeprazole (Group 2), one horses was relocated to another race track following the 13–17 day endoscopic examination. For the horses given placebo (Group 1), there was no change in the severity of ulceration. In contrast, the severity of ulceration in the horses given active omeprazole was significantly reduced at 13–17 days and 27–31 days. In 2Group 2horses, ulcers that had been completely eliminated subsequently returned when reexamined at 35–49 days. The results of this study suggest that omeprazole, employing a once daily dosing schedule, is effective at reducing the severity or eliminating gastric ulcers in Thoroughbreds in active race training.
Effects of omeprazole paste on healing of spontaneous gastric ulcers in horses and foals: a field trial
Authors: MacALLISTER C. G. , SIFFERMAN R. L. , McCLURE S. R. , WHITE G. W. , VATISTAS N. J. , HOLSTE J. E. , ERICCSON G. F. , COX J. L.
Published: June 2010

A multicentre, blinded, randomised complete‐block, field trial was conducted with 140 horses and foals age 4 weeks‐28 years to determine if omeprazole paste is effective and safe in promoting healing of spontaneous gastric ulcers under a variety of field conditions and in different breeds and ages of horses. Horses in the study had gastric ulceration as determined by gastroscopy and were divided into replicates of 4 or 5 animals. One horse in each replicate was assigned randomly to receive an empty omeprazole syringe (sham‐dosed control) and the remaining horses received omeprazole paste once daily for 28 days. Gastroscopy was repeated at the end of the study. Horses treated with omeprazole had significantly (P<0.01) more improvement in ulcer scores at the end of the study compared with controls. Ulcers were improved in 32.4 and 99.0% of the control and omeprazole groups, respectively. Ulcers were completely healed in 8.9 and 86.7% of the control and omeprazole groups, respectively. Under typical field conditions, omeprazole was effective at enhancing healing of spontaneous gastric ulcers in horses of a variety of ages and breeds.
The effect of exercise on the distribution and manifestation of osteochondrotic lesions in the Warmblood foal
Authors: van WEEREN P. R. , BARNEVELD A.
Published: June 2010

Osteochondrosis (OC) in the horse has been defined as a disturbance in the process of endochondral ossification which is of multifactorial origin, becoming evident in a large number of joints. Exercise is one of the environmental factors that may influence the clinical manifestation of the disorder, but has never been thoroughly investigated. In this study we investigated the influence of exercise during the first 5 months on the development and distribution of OC lesions in foals of age 5 and 11 months.

Forty‐three foals, all from sires having OC in either the femoropatellar or tibiotarsal joint, were reared to weaning at 5 months under similar conditions except for the type and amount of exercise. Fifteen foals remained at pasture, 14 were kept in box stalls and 14 foals were kept in the same box stalls but daily given an increasing number of gallop sprints. After weaning, 8 foals from each group were subjected to euthanasia. The remaining 19 animals were given identical light exercise regimen for an additional 6 months to euthanasia at 11 months. After euthanasia all major diarthrodial joints were inspected for macroscopic lesions. Histological sections were made from the lesions and from all distal tibial sagittal ridges. Lesions were scored according to severity on a scale of 0 to 4, and a total OC score per joint was calculated.

In the 5 month group, lesions were found in all foals (mean number of lesions 5.5, range 1–14). Frequency was highest in the tibiotarsal (1.9 lesions/foal), the femoropatellar/femorotibial (1.0), the cervical intervertebral (1.0), and the metatarsophalangeal joints (0.6). At 11 months the prevalence of lesions had significantly decreased (mean number of lesions 3.1, range 0–7). This decrease was most evident in the femoropatellar/femorotibial joint, but was negligible in the tibiotarsal joint. Exercise did not significantly influence numbers of lesions, but at 5 months there was a tendency towards more severe lesions in the box‐rested foals. In the femoropatellar/femorotibial joint, lesions were found mainly in the femoral condyles of the box‐rested foals and at the lateral trochlear ridge of the femur in the trained foals.

It is concluded that OC may become manifest in many joints. Many lesions regress and do not become clinically evident, making the number of horses with lesions at mature age into an underestimation of the total amount of animals that have suffered from the condition. The period during which a lesion develops and possibly regresses is limited and variable per site. Exercise at the level given in this study may have some influence on the appearance and the distribution of the lesions, but did not appear to have an aetiological role.
The influence of birth weight, rate of weight gain and final achieved height and sex on the development of osteochondrotic lesions in a population of genetically predisposed Warmblood foals
Authors: van WEEREN P. R. , van OLDRUITENBORGH‐OOSTERBAAN MARIANNE M. SLOET , BARNEVELD A.
Published: June 2010

The influence of inherent variables (sex, birth weight, final achieved height, monthly weight gain rates and osteochondrosis (OC) status of the parents) on the occurrence of osteochondrotic lesions in the femoropatellar and tarsocrural joints in a group of foals was investigated as part of a research project aimed at the study of the development of osteochondrosis and the influence of exercise on the development of the musculoskeletal system in Warmbloods. The foals were genetically predisposed to develop OC, being offspring of sires that all had radiographically proven OC in either the femoropatellar or the tarsocrural joint. In the mare population the incidence of femoropatellar OC was 16% and of OC in the tarsocrural joint 7%.

Foals (n = 43) were weighed at birth, and thence every second week until euthanasia at 5 (n = 24) or 11 (n = 19) months. Height at the withers was taken twice, at birth and at euthanasia. Weight gain rates were calculated for months 1, 2, 3, 4, 5, 7, 9 and 11 and for the entire 5 or 11 month period. Osteochondrosis status of the parents in the 2 joints with respect to the distal tibial sagittal and lateral femoral trochlear ridges was determined radiographically. In all foals, radiographs were taken from the same sites prior to euthanasia. After euthanasia the joints were examined macroscopically and histologically for the presence of osteochondrotic lesions and classified as OC positive (OC+) or negative (OC‐).

No influence of sex on the prevalence of OC in either of the joints could be established. Also, no relationship between the prevalence of tarsocrural OC and any of the growth variables was found. Foals positive for femoropatellar OC had a significantly higher weight gain rate in the third and fifth month. Animals killed at 11 months that were OC+ in the femoropatellar joint had a significantly higher weight gain rate over the 11 month period, weighed more at 11 months, and were taller at the withers and at the croup than non affected animals. Offspring of tarsocrural OC‐ parents did not have a lower number of lesions in this joint than foals of which at least one of the parents was affected, but no foals that were offspring of femoropatellar OC‐ parents themselves showed lesions.

It was concluded that, in this selected group, sex had no influence on the occurrence of OC lesions. Even in this relatively homogenous group weight gain rate affected the occurrence of lesions in the femoropatellar joint, but not in the tarsocrural joint. This corresponds with the different time‐frames in which the lesions develop in the various joints and with the existence of windows of ‘susceptibility’.
Changes in proteoglycan metabolism in osteochondrotic articular cartilage of growing foals
Authors: van den HOOGEN BIANCA M. , van de LEST C. H. A. , van WEEREN P. R. , van GOLDE L. M. G. , BARNEVELD A.
Published: June 2010

In osteochondrosis (OC) the process of endochondral ossification is impaired. Proteoglycans form one of the major components of the extracellular matrix of cartilage and are able to bind calcium. For this reason, proteoglycans are thought to play an important role early in the mineralisation process and may, therefore, be important in the pathogenesis of OC. To investigate possible differences in proteoglycan metabolism, normal and osteochondrotic articular‐epiphyseal cartilage was harvested from the hock and stifle joints of 43 foals age 5 and 11 months. The samples were cultured as explants in which 35S‐[sulphate]‐incorporation, release of newly synthesised and endogenous proteoglycans and content of DNA and proteoglycans were measured ex vivo and after a 4 day period of serum stimulation.

In osteochondrotic cartilage of foals age both 5 and 11 months synthesis of proteoglycans was less stimulated by serum than in normal cartilage. Furthermore, only in the foals age 11 months, ex vivo proteoglycan production was decreased and an increase in the turnover of newly synthesised proteoglycans was detected in osteochondrotic cartilage, without a change in release of endogenous proteoglycans. The reduced response to serum stimulation in osteochondrotic cartilage indicates that osteochondrotic chondrocytes are less vital. The increase in turnover of newly synthesised proteoglycans reflects a change in composition of the proteoglycan pool. Considering the late changes in proteoglycan synthesis, an aberrant proteoglycan synthesis pattern is more likely to be a sequence than a primary cause of the impaired endochondral ossification of osteochondrotic lesions.
Hormones, growth factors and other plasma variables in relation to osteochondrosis
Authors: van OLDRUITENBORGH‐OOSTERBAAN MARIANNE M. SLOET , MOL JAN A. , BARNEVELD A.
Published: June 2010

Osteochondrosis (OC) is a multifactorial disorder with endocrinological dysfunction and mineral imbalance having a role in pathogenesis. The present study focused on a possible relationship between insulin‐like growth factor I (IGF‐I), insulin‐like growth factor II (IGF‐II), parathyroid hormone (PTH), 1,25‐dihydroxy‐vitamin D (1,25(OH)2D), cortisol, copper, zinc, calcium, ionised calcium, magnesium and phosphorus and 5 differentpostmortemand radiographical osteochondrosis scores of hock and ***stifle joints in foals age 0–11 months. Osteochondrosis‐positive foals showed a significantly lower IGF‐I activity than osteochondrosis‐negative foals. PTH, 1,25(OH)2D, cortisol, copper, zinc and calcium also showed significant differences between osteochondrosis‐positive and osteochondrosis‐negative foals.
Influence of different exercise levels and age on the biochemical characteristics of immature equine articular cartilage
Authors: BRAMA P. A. J. , TEKOPPELE J. M. , BANK R. A. , van WEEREN P. R. , BARNEVELD A.
Published: June 2010

This study aimed to examine whether biochemical characteristics of juvenile articular cartilage are changing during the first yearpost partumand whether they can be influenced by exercise at young age.

Water, glycosaminoglycan (GAG), DNA, total collagen, hydroxylysine and hydroxylysylpyridinoline (HP) content were measured in articular cartilage of 43 foals that were subdivided into 3 groups (n = 15, 14 and 14) which were subjected to different exercise regimens from one week after birth to age 5 months. At the age of 5 months all foals were weaned and 8 foals were selected randomly from each exercise group and subjected to euthanasia. The remaining foals (n = 19) were grouped and subjected to a similar exercise regimen for an additional 6 months. Differences were tested by student'sttest (P<0.01).

No effect of exercise on the water or DNA content was found. GAG content increased with increasing exercise in the 5 months group. These differences had disappeared after 6 months of similar exercise. No influence of exercise could be demonstrated on any of the collagen parameters. When comparing 5 months with 11 months group, all parameters except hydroxylysine changed significantly during these 6 months. Water, DNA and GAG content decreased during maturation. Collagen and HP content increased.

It is hypothesised that juvenile equine articular cartilage may be seen as a dynamic, continuously remodelling tissue that is gradually taking on the biochemical characteristics it will have during the rest of the life of the animal. Moderate exercise does not influence the collagen component of the extracellular matrix. It has a beneficial, but reversible, effect on the glycosaminoglycan component.
Effect of exercise on the proteoglycan metabolism of articular cartilage in growing foals
Authors: van den HOOGEN BIANCA M. , van den LEST C. H. A. , van WEEREN P. R. , van GOLDE L. M. G. , BARNEVELD A.
Published: June 2010

In this study, the effect of different exercise regimens on proteoglycan metabolism of articular cartilage was examined in 43 newborn foals randomly divided into 3 groups: a) box‐rest, b) box‐rest with training and c) free pasture exercise. They were subjected to these exercise regimens from ages 1 week to 5 months and at 5 months, 24 foals (8 from each group) were sacrificed to assess short‐term exercise effects. The remaining 19 foals were subjected to the same regimen of light exercise for an additional 6 months before being sacrificed to evaluate possible long‐term effects. Articular cartilage explants were cultured and proteoglycan synthesis, bothex vivoand after 4 days of serum stimulation, release of endogenous and newly synthesised proteoglycans, and DNA‐and GAG contents were measured to determine the metabolic state of the cartilage.

Cartilage metabolic parameters in the box‐rest group at 5 months indicated a retardation in development of the cartilage but, after an additional 6 months, this retardation had almost completely disappeared. The training regimen induced an increase in proteoglycan synthesis at 5 months in cartilage that was, however, accompanied by an increase in proteoglycan release. In the training group at the long‐term, the ability of cartilage to increase proteoglycan synthesis when stimulated was severely reduced. We consider this extra proteoglycan synthesis capacity of great importance to repair small injuries and hence as essential to prevent an early onset of degenerative disorders such as osteoarthritis. Therefore, although extrapolation ofin vitrodata to thein vivosituation always should be done with the utmost care, it is concluded that pasture exercise is best for the development of healthy cartilage resistant to injury and other exercise protocols may carry harmful long‐term effects.
Early changes in the distal intertarsal joint of Dutch Warmblood foals and the influence of exercise on bone density in the third tarsal bone
Authors: BARNEVELD A. , van WEEREN P. R.
Published: June 2010

It was hypothesised that imposition of different exercise levels at a young age would lead to differences in bone density in the third tarsal bone and to difference in the prevalence of pathological lesions that might contribute to the development of bone spavin later in life. Furthermore, based on earlier literature, it was hypothesised that such lesions could be classified as a manifestation of osteochondrosis.

Changes in bone density in the third tarsal bone and early pathological changes in the articular cartilage of the distal intertarsal joint were studied in the offspring of sires with radiographic evidence of osteochondrosis in either stifle or hock. Twenty‐four foals were studied at age 5 months after having been subjected to different exercise programmes (box‐rest, box‐rest with sprint training, pasture exercise) from age one week. Nineteen other foals that originally belonged to the same exercise groups were studied at age 11 months, after they had been weaned, housed together and subjected to an identical low level exercise regimen for an additional 6 months. Bone density was quantified using a microscopic technique. Histomorphological analysis was performed semiquantitatively and using high detail radiography techniques.

At age 5 months, mean ± s.d. bone density in the compact bone of the third tarsal bone was significantly lower in the box‐rested foals (37 ± 4%) than in both the trained and pastured foals (48 ± 7% and 52 ± 11%, respectively). After 6 months of identical exercise the previously box‐rested foals showed an increase in bone density (53 ± 12%) which became similar to the value found in the formerly pastured foals (52 ± 8%). Major pathological lesions (chondrocyte necrosis, fragmentation and chondrone formation) of the articular cartilage of the third and central tarsal bones were already present at age 5 months, but were significantly more numerous at 11 months. There was no relation between the number of cartilage lesions and the osteochondrosis status of the foals. Only 2 lesions in 11‐month‐old foals had histological characteristics compatible with osteochondrosis, all other lesions were degenerative in nature.

It is concluded that bone density of the compact bone of the subchondral bone plate in the third tarsal bone reacts strongly to variations in exercise at a very young age. Low bone density, caused by lack of exercise, can be compensated for when exercise is later increased. Pathological changes in the distal intertarsal joint are common at 5 months and increase to 11 months. These lesions are degenerative in nature and seem not to be related to osteochondrosis. Although the clinical relevance of these abnormalities is uncertain, they may be relevant for the development of osteoarthritic processes in this region later in life.
Postnatal muscle fibre composition of the gluteus medius muscle of Dutch Warmblood foals; maturation and the influence of exercise
Authors: DINGBOOM ELIZABETH G. , DIJKSTRA GRIETJE , ENZERINK E. , van OUDHEUSDEN H. C. , WEIJS W. A.
Published: June 2010

The fibre type composition of the deep gluteus muscle was studied in biopsies of Dutch Warmblood foals from birth until age 48 weeks. Half the foals were given box‐rest, the other half received exercise consisting of an increasing number of gallop sprints. The muscle fibre types were determined using monoclonal antibodies discriminating against the following myosin heavy chain (MHC) isoforms: types I, IIa, IId, Cardiac‐α and Developmental. During the first 48 weeks there was a consistent increase of fibres expressing types IIa MHC, replacing fibres expressing IId MHC. This change was reflected in the presence of a quite large population of fibres co‐expressing MHC IIa and IId. The difference between the exercised (training) and nonexercised (box‐rest) groups was small but suggested that the increase of type IIa fibres was larger in the training group. It appeared that after birth a significant number of fibres coexpress either Developmental and type IIa‐MHC or Cardiac‐α and type I‐MHC. The Developmental isoform disappears during the first 10 weeks after birth and almost all the α isoform expression during the first 22 weeks. It is concluded that a fast turnover of fibre types takes place in the deep gluteus medius in the first months postpartum. Potentially, exercise could have an effect on the rate of change of these fibre types.
Effects of training on the concentration of Na+, K+‐ATPase in foal muscle
Authors: SUWANNACHOT PISIT , VERKLEIJ CYNTHIA B. , WEIJS W. A. , van WEEREN P. R. , EVERTS MARIA E.
Published: June 2010

We investigated the effect of training on the Na+, K+‐ATPase concentration in foal skeletal muscle by measurement of [3H]ouabain binding. From the 7th day after birth, 12 foals were divided in 3 groups: a) staying in a box stall (Box); b) staying in a box stall with a training regimen of an increasing number of sprints per day (Training); and c) staying on pasture (Pasture). Euthanasia was performed after 5 months. Insemitendinosusmuscle, the concentration of [3H]ouabain binding sites (pmol/g wet wt) was 181 ± 6 in theBox, 220 ± 15 in theTraining, and 197 ± 8 in thePasturegroup (all n = 6;Boxvs.Training, P<0.05). Ingluteus medius, the concentration of [3H]ouabain binding sites was 168 ± 9 in theBox, 219 ± 12 in theTraining, and 175 ± 4 in thePasturegroup (all n = 6;BoxorPasturevs.Training, P<0.02). Scatchard analysis of saturation curves showed that the difference in [3H]ouabain binding sites between the 3 groups could not be ascribed to differences in the Kdfor ouabain. Both forsemitendinosusandgluteus mediusmuscle, the concentration of [3H]ouabain binding sites increased in the orderBox < Pasture < Training(a total increase of around 20%). This suggests a specific effect of the amount and intensity of exercise on the Na+, K+ ‐ATPase concentration in horse skeletal muscle, and may lead to a better performance during exercise.
Prognostic indicators in a Danish hospital‐based population of colic horses
Authors: THOEFNER M. B. , ERSBØLL A. K. , HESSELHOLT M.
Published: June 2010

A prospective survey of 528 colic horses, referred to the Large Animal Hospital at the Royal Veterinary and Agricultural University of Copenhagen, Denmark, during the period August 1994 to December 1998, was undertaken to develop a predictive model for application in the clinical assessment of prognosis. In the multivariate logistic regression analysis, 357 colic cases were used in the elaboration of a simple clinical‐practical model consisting of degree of pain, packed cell volume, capillary refill time and rectal temperature. The relationship between rectal temperature and outcome (survival/death) has been regarded as linear. It has also been reported to be nonsignificant. The present study suggests a strong U‐shaped relation, which is easily transformed into a linear association and readily interpretable in the clinical situation if treated as a deviation from 38°C. Several other clinical and laboratory variables were strongly related to outcome in the bivariate analysis. The changes in sensitivity and specificity of the multivariate model, when applied as a prognostic test, were presented with changing cut‐off values. The cut‐off value is the level, of predicted probability of death, at which the clinical decision to treat or subject to euthanasia is taken. The predictive performance of the model was further illustrated using a mortality of 19%. The optimal accurate classification for both survival and death was 87%, which was attained when a cut‐off value of 86% was selected. To minimise the number of horses unnecessarily subjected to euthanasia, the cut‐off value was increased. However, this simultaneously increased the number of misclassified survivors, i.e. the number of horses that would die despite treatment. Outcome was especially poorly predicted in 4 horses, as was indicated by extreme deviance residuals. In 2 of these horses the large residuals were attributable to sudden and severe changes in the course of disease. All 4 horses had changes in variable values towards abnormality prior to death. Repeated measurements are therefore suggested in order to increase the test performance in general. The prerequisites of clinical application of prognostic models are critically discussed. The main findings of the present study indicate that degree of pain, packed cell volume, capillary refill time and temperature deviation from 38°C, used in a logistic regression model, offer a strong model for clinical assessment of prognosis.
Hypercoagulation and hypofibrinolysis in horses with colic and DIC
Authors: MONREAL L. , ANGLÉS A. , ESPADA Y. , MONASTERIO J. , MONREAL M.
Published: June 2010

Changes in haemostasis in horses with colic were assessed by using specific and sensitive markers of coagulation and fibrinolysis activity. Blood samples from 41 horses with severe colic and from 30 healthy control horses were tested. Diagnosis of DIC was based on the findings of at least 3 of 6 abnormalities: thrombocytopenia, prolonged clotting times (PT and APTT), increased polyclonal FDPs, decreased fibrinogen and decreased AT‐III activity. Plasma thrombin‐antithrombin III complexes (TAT), monoclonal fibrin degradation products fragment D (D‐dimer) and monoclonal fibrinogen degradation products (FgDP) were also tested by using ELISA kits.

DIC was diagnosed in 16 of 41 horses with colic. Compared to control and non‐DIC colic values, TAT was significantly (P<0.000) greater in horses with colic and DIC (Control group, mean ± s.d. 2.6 ± 2; non‐DIC colic group, 7.5 ± 9, and DIC colic group, 30.9 ± 36 ng/ml). Also, D‐dimer was significantly (P<0.000) less in the DIC group when compared to control and non‐DIC colic values (mean ± s.d. 677 ± 119, 682 ± 220 and 399 ± 234 ng/ml, respectively). Compared to non‐DIC colic values, FgDP was significantly (P<0.05) lower in the DIC group (363 ± 111, 437 ± 230 and 293 ± 187 ng/ml respectively). Both PT and APTT showed a significant positive correlation with TAT. DIC was more common among nonsurvivors and horses with ischaemic bowel. We conclude that a hypercoagulative state was detected in horses with colic, which was stronger in horses with colic and DIC. Hypofibrinolysis was present only in horses with DIC. Therefore, marked hypercoagulation together with hypofibrinolysis are associated with DIC in horses.
Effect of eltenac in horses with induced endotoxaemia
Authors: MacKAY R. J. , DANIELS C. A. , BLEYAERT H. F. , BAILEY J. E. , GILLIS K. D. , MERRITT A. M. , KATZ T. L. , JOHNSON J. C. , THOMPSON K. C.
Published: June 2010

Ten horses were used in a crossover study to evaluate the effectiveness of eltenac against endotoxaemia. Eltenac (0.5 mg/kg bwt) or saline control was given i.v. then 15 min later, intravenous infusion of endotoxin was begun and continued for 120 min (total dose 100 ng/kg bwt). Horses were monitored for heart and respiratory rates, pulmonary and carotid arterial pressure and core body temperature. Blood was sampled at intervals for measurement of haematological variables and plasma concentrations of lactate, prostanoid metabolites, tumour necrosis factor (TNF) and stress hormones.

In comparison with saline‐treatment, use of eltenac significantly protected against endotoxin‐induced changes in respiratory rate, core temperature, systemic arterial blood pressure (SAP), pulmonary arterial pressure, PCV, and plasma protein, 6‐keto prostaglandin F1α, thromboxane B2, epinephrine, and cortisol concentrations. Despite statistical effect of eltenac on SAP, values in both treatment groups remained well above baseline throughout the evaluation period. Significant protective effect of eltenac was not found for heart rate, white blood cell count, plasma lactate concentration or TNF activity. On the basis of these results, it is expected that use of eltenac will provide clinical benefit in horses with naturally occurring endotoxaemia.
Short‐ and long‐term survival and prevalence of postoperative ileus after small intestinal surgery in the horse
Authors: FREEMAN D. E. , HAMMOCK P. , BAKER G. J. , GOETZ T. , FOREMAN J. H. , SCHAEFFER D. J. , RICHTER R.‐A. , INOUE O. , MAGID J. H.
Published: June 2010

The records of 74 horses that recovered from anaesthesia after surgery for a small intestinal lesion from 1994 to 1999 were reviewed. Sixty‐three horses (85%) had a strangulating lesion and 43 of these (68%) had a resection and anastomosis. Four of 11 horses (36%) without a strangulating lesion had a resection and anastomosis. Sixty‐three horses (85%) survived to discharge, with a survival rate of 53/63 in horses with a strangulating lesion (84%) and 10/11 (91%) in others. For all lesions, short‐term survival for all end‐to‐end anastomoses (91%; 21/23) and for no resection (92%; 23/25) were superior (P<0.05) to survival for jejunocaecal anastomosis (76%; 19/25). Fourteen horses (19%) had a repeat abdominal surgery during hospitalisation; 9 of these (64%) survived short‐term. Postoperative ileus developed in 7/70 horses (10%) after surgery for a problem other than proximal enteritis, and all had a strangulating lesion. Postoperative ileus (POI) was more likely after a jejunocaecostomy than after other procedures, and did not develop after a jejunojejunostomy. Survival >7 months was 52/69 (75%) and for >12 months was 39/57 (68%). The estimated prevalence of adhesions was 13%.

Short‐term survival was poorest in horses that had a jejunocaecostomy, but long‐term survival was less affected by the anastomosis used. The sharpest decline in survival was during the first postoperative week and postoperative mortality then declined over time after surgery. A postoperative protocol that allowed early postoperative feeding was well tolerated. The results confirm that the overall prognosis after small intestinal surgery in horses is improved over earlier findings.
The role of cyclooxygenase inhibitors in repair of ischaemic‐injured jejunal mucosa in the horse
Authors: CAMPBELL N. B. , BLIKSLAGER A. T.
Published: June 2010

Cyclooxygenase inhibitors are administered to horses to prevent endotoxin‐induced elaboration of prostaglandins. However, PGE2and PGI2stimulate repair of injured intestine. There are 2 isoforms of cyclooxygenase: COX‐1, which constitutively produces prostaglandins and COX‐2, which is induced by inflammation. We hypothesised that the nonspecific cyclooxygenase inhibitor flunixin meglumine would retard repair of ischaemic intestinal injury by preventing production of reparative prostaglandins, whereas the selective COX‐2 inhibitor, etodolac, would permit repair as a result of continued COX‐1 prostaglandin production. Segments of equine jejunum were subjected to ischaemia for 1 h, and recovered for 4 h in Ussing chambers. In ischaemic tissue, treated with the nonspecific cyclooxygenase inhibitor, flunixin meglumine (2.7 times 10−5mol/1), production of PGE2and PGI2was inhibited, and there was no evidence of recovery based on measurements of transepithelial resistance. Conversely, untreated ischaemic tissues or tissues treated with the specific COX‐2 inhibitor etodolac (2.7 times 10−5mol/1) had significant elevations in PGE2and PGI2, and significant recovery of transepithelial resistance. These studies suggest that specific COX‐2 inhibitors may provide an advantageous alternative to nonspecific cyclooxygenase inhibitors in horses with colic.
Muscle thickness and neuron density in the caecum of horses with chronic recurrent caecal impaction
Authors: SCHUSSER G. F. , SCHEIDEMANN W. , HUSKAMP B.
Published: June 2010

In this study, the hypothesis that caecal smooth muscle layers would be thinner and the linear neuron density of myenteric plexus greater was tested in normal horses compared to those with chronic recurrent caecal impaction. Four normal horses and 18 horses with chronic recurrent caecal impaction were subjected to euthanasia and 7 tissue samples were collected from each horse at different regions of the caecum (apex, dorsal body, cranial base, dorsal base, caudal base, caudal body, ventral body). Twelve horses with chronic recurrent caecal impaction were treated surgically. Only one tissue sample of the cranial part of the caecal base close to the caecocolic orifice was taken during surgery. The thickness of the circular muscle layer of all caecal regions measured in killed horses with chronic recurrent caecal impaction was significantly increased compared to the equivalent caecal region of normal horses. On the other hand, the longitudinal muscle layer was significantly thicker only in the cranial and caudal caecal base and in the dorsal region of the caecal body. The linear neuron densities of all caecal base areas and 2 caecal body regions, the caudal body region and of the apex, of killed horses with chronic recurrent caecal impaction were significantly lower compared with those in clinically normal horses. The circular muscle layer of all caecal regions was thickened (hypertrophied) probably as a consequence of chronic uncoordinated hypercontractility due to neuron deficit in the myenteric plexus of the caecal base.
Caecal impactions managed surgically by typhlotomy in 10 cases (1988–1998)
Authors: ROBERTS C. T. , SLONE D. E.
Published: June 2010

Surgical management of caecal impactions has included several different procedures suggested over the years. Complete bypass of the caecum through an ileocolic or jejunocolic anastomosis has become common practice for first time caecal impaction management, especially when dysfunction is suspected. In our practice, however, caecal impactions have been managed surgically by typhlotomy alone and of the 10 cases (July 1988‐June 1998), 9 underwent surgery for first time caecal impactions, received a typhlotomy, and had survived an average of 43 months at time of case review. At the time of surgery, all were considered to have a dysfunctional caecum. All horses received routine postoperative care with the addition of anthelmintics as recovery ofAnoplocephala perfoliataoccurred in several cases. Typhlotomy should be considered an acceptable technique for surgical management of first time caecal impactions. Postoperative pyrantel pamoate and larvicidal anthelmintics should also be considered.
Caecocaecal and caecocolic intussusceptions associated with larval cyathostomosis in four young horses
Authors: MAIR T. S. , SUTTON D. G. M. , LOVE S.
Published: June 2010

This report describes the clinical and pathological features of 4 horses affected by caecocaecal or caecocolic intussusceptions associated with larval cyathostomiasis. In each case, there was clinical and/or pathological evidence of concurrent larval cyathostomosis. They all demonstrated variable signs including diarrhoea, pyrexia, weight loss and subcutaneous oedema and cyathostome larvae were identified in the faeces of 3 of the horses. These cases highlight the need to consider caecal intussusceptions as a possible complication in horses affected by larval cyathostomosis, especially where signs of abdominal pain are severe or persistent.
Segmental eosinophilic colitis: A review of 22 cases
Authors: EDWARDS G. B. , KELLY D. F. , PROUDMAN C. J.
Published: June 2010

Twenty‐two horses with colic, referred to the University of Liverpool Equine Hospital (1992–1998), were found at laparotomy to have a partial obstruction of the large colon caused by a segmental mural lesion located in the left dorsal colon. The decision to take the horses to surgery was based on rectal examination findings of secondary impaction and mural oedema of the large colon and turbid peritoneal fluid containing large numbers of neutrophils obtained by paracentesis. The affected segment of colon showed oedema and serosal changes varying from erythema to well‐defined necrosis. These pathological changes were considered to be sufficiently severe in 16 horses to merit partial resection of the left colon. Histology revealed varying degrees of mucosal necrosis, marked submucosal oedema and infiltration with large numbers of eosinophilic leucocytes. No cause was identified for the lesions. Sixteen of the 18 horses discharged from the hospital were alive 3 months to 7 years after surgery and have returned to their previous type of work and level of performance. The remaining 2 horses were subjected to euthanasia because of a recurrence of colic but no autopsy was performed.
Nephrosplenic entrapment in the horse: A retrospective study of 174 cases
Authors: HARDY J. , MINTON M. , ROBERTSON J. T. , BEARD W. L. , BEARD L. A.
Published: June 2010

The clinical findings and outcome of 161 horses diagnosed with 174 episodes of nephrosplenic entrapment (NSE) were reviewed retrospectively. The median age at presentation was 5 years (9 months to 24 years), and duration of colic was 2–92 h. Nasogastric reflux was present in 49 of 113 horses (43.4%) and was significant (≥ 21) in 32 (28.3%) horses. The recurrence rate was 13/161 (8.1%). Thirteen horses (13/174, 7.5%) had other lesions including small intestinal obstruction (4), 360° large colon torsion (5), gastric rupture (2), thromboembolic colic (1) and small colon infarction (1). Of 115 cases, in 107 horses treated by surgery alone, 2 horses required a large colon resection, and 8 (8/107, 7.5%) horses died or were subjected to euthanasia. Twenty‐six of 35 horses (74%) were successfully corrected by rolling under general anesthesia and, of the 9 horses taken to surgery after rolling, 4 had other lesions and 2 were corrected at surgery. Phenylephrine was used in 20 of 35 horses that were rolled and 2 horses required surgery after rolling with phenylephrine. Five horses were jogged after phenylephrine administration and all were successfully corrected. Eleven horses presented with the left colon located between the spleen and the body wall were treated successfully by fasting and/or i.v. fluids. One horse had a gastric rupture after rolling. The overall success rate was 92.5%. In conclusion, NSE is a condition associated with a good prognosis for medical or surgical correction. A small number of horses may have additional gastrointestinal lesions, which may affect outcome.
Celiotomy closure via permanent implantation of polyamide in horses
Authors: BEROZA G. A. , PERRY R. W. , COTTER D. M.
Published: June 2010

Permanent implantation of nonabsorbable materials is appropriate in many surgical circumstances but is not commonly used to close equine celiotomies. This paper describes a simple method of continuous nonabsorbable implantation of polyamide suture used successfully to close 48 equine celiotomies.

Forty‐eight clean or clean‐contaminated celiotomies were successfully performed over 5 years using this technique. The postsurgical survival observation period ranged from 1–6 years (median 3.5 years). There were 45 long‐term survivors (93.75%). Only 2 minor implant complications (4.4%) were observed and successfully corrected. This study demonstrates that appropriately prepared nonabsorbable polyamide suture can be used for safe and cost effective closure of clean and clean‐contaminated equine celiotomies.