bluuebunny/crossref_metadata_2025 huggingface dataset:
A Theoretical Model for Design in Management Science
Authors: de Mozota Brigitte Borja
Published: June 2010

Design management has changed greatly since Peter Gorb's definition in 1990. The purpose of this paper is to synthesize the various models of design management and to explain their limitations, given the paradigm shift within the design profession from an activity to a knowledge‐based profession.

The territory of design in management science is developed in detail within the limits of these diverging forces. A convergent model of design‐value management, based not on practices but on management science models, is developed and applied. This is pertinent to the emerging trend in design leadership and to the potential for design thinking input ahead of the new challenges facing contemporary managers—sense building, complexity, innovation, and the socially responsible organization.
Building Fences: Undocumented Immigration and Identity in a Small Border Town
Authors: Martinez Adriana E. , Hardwick Susan W.
Published: June 2010

They could build [the fence] to the heavens and we will still jump it. And if not, we will go underneath, like groundhogs, (Undocumented migrant en route from Mexico to Texas, Piedras Negras, 2009).
Magnetic resonance imaging features of a benign peripheral nerve sheath tumour with ‘ancient’ changes in the tongue of a horse
Authors: Schneider A. , Tessier C. , Gorgas D. , Kircher P. , Mamani J. , Miclard J.
Published: June 2010

A 12‐year‐old Selle Français mare was presented because of inspiratory stridor, hypersalivation and dysphagia. A mass at the base of the tongue could be visualised by upper airway endoscopy, oral cavity examination and radiographs of the head. The exact localisation, extent of the mass and extent of tissue infiltration could only be defined by magnetic resonance imaging (MRI). This Case Report illustrates the usefulness of MRI to assess the characteristics and extent of such a lesion and describes the appearance of peripheral nerve sheath tumour in the tongue of a horse.
Use of experimental embryo transfer to study the role of the immune system in embryonic death
Authors: CROY B. A.
Published: June 2010

Animal model systems of pregnancy failure are necessary for critical assessment of the mechanisms that are important to the success of pregnancy because experimental manipulations of the important elements should be able to reverse the outcome of these pregnancies. Most models of pregnancy failure have been described in interspecies pregnancies. This review describes an easily manipulated interspecies pregnancy system that has been developed between two species of mice, Mus caroli and Mus musculus, that do not interbreed. Using the techniques of embryo transfer and embryo surgery, this system has given new insight into the cellular and immunological mechanisms involved in embryonic death. M caroli embryos, transferred to the M musculus uterus, implant and develop to mid‐gestation but then die. However, failure of the xenogeneic M caroli embryonic cells can be prevented by the production of interspecies chimaeras in which the foetal trophoblast layer matches that of the recipient's uterus. Thus, trophoblast is the cellular component that determines success or failure of xenogeneic pregnancy. In failing M caroli pregnancies, anti‐foetal cytotoxic cells are demonstrable in the resorbing embryos. These resorptions can be inhibited by treatment with the immunosuppressive drug, cyclosporin A, and enhanced by preimmunisation. However, M caroli embryos transferred to tolerant or other immunosuppressed recipients resorb at mid‐gestation, thereby suggesting that specific anti‐M caroli immune responses are not essential to M caroli failure and that trophoblast‐uterine interactions alone may be sufficient to cause foetal death in the absence of immune effectors.
Pregnancy in ovariectomised mares achieved by embryo transfer: A preliminary study
Authors: HINRICHS KATRIN , SERTICH P. L. , CUMMINGS M. R. , KENNEY R. M.
Published: June 2010

Four ovariectomised mares were used as recipients for embryo transfer. They were given 300 mg progesterone in oil intramuscularly daily for five days before transfer and were subsequently maintained on this treatment. Embryos were recovered and transferred non‐surgically seven or eight days after the donor mares had ovulated. A total of seven embryos were transferred and pregnancy was established in three of the four recipients. At the time of writing, these pregnancies have developed normally to Days155, 92 and 82 of gestation, respectively.
Recent studies relating to early embryonic death in the mare
Authors: WOODS G. L. , BAKER C. B. , HILLMAN R. B. , SCHLAFER D. H.
Published: June 2010

Early pregnancy loss was studied by sequential ultrasound examinations of 404 pregnancies in commercial brood mares. Overall, the rate of early pregnancy loss was 11.1 per cent. More pregnancies were lost at two to four weeks post ovulation than at four to six or six to eight weeks post ovulation (23 of 45 versus nine of 45 or 10 of 45). The mean (±se) number of days from detection of pregnancy loss until the subsequent ovulation was higher for mares in which pregnancy loss was detected at six to eight weeks post ovulation than at the earlier stages (21.1 ± 3.90 versus 12.0 ± 1.59 or 9.5 ± 1.05, respectively). Thirty‐one of 45 mares that lost pregnancies were subsequently mated; 20 (60 per cent) became pregnant but eight of these pregnancies (40 per cent) were again lost.

In a second study a total of 84 embryo collection attempts were made from 14 maiden and 14 subfertile mares. More uterine flushes from maiden mares yielded embryos than from subfertile mares (29 of 42 versus 17 of 42). There were more flushes in which one or more normal embryos were recovered from maiden mares than from subfertile mares (28 of 42 versus eight of 42). There were fewer flushes in which only abnormal embryos were recovered from maiden mares than from sub‐fertile mares (one of 42 versus nine of 42).
Review of pathogenesis and treatment of degenerative joint disease
Authors: McILWRAITH C. W. , VACHON ANNE
Published: June 2010

Treatment of degenerative joint disease (osteoarthritis) is discussed in relationship to pathogenesis of five clinical entities, defined to facilitate discussion:‐ 1) occurring in high motion joints and associated with synovitis; 2) associated with low motion joints; 3) “non‐progressive” articular cartilage erosion; 4) secondary to other identified problems (intra‐articular fractures, ligamentous damage, wounds, septic arthritis, osteochondrosis); and 5) chondromalacia of the patella. In addition to direct damage to articular cartilage, synovitis and capsulitis and depletion of matrical glycosaminoglycans and proteoglycans play important roles. The natural healing response in damaged articular cartilage is inadequate. The principles of treatment are divided into: 1) prevention or treatment of primary causes. These include the effects of track surface, shoeing, and the appropriate resolution of intra‐articular fractures, septic arthritis and osteochondritis dissecans. 2) treatment of active soft tissue disease contributing to articular cartilage degeneration, including rest, physical therapy, synovectomy and administration of anti‐inflammatory drugs, sodium hyaluronate and polysulfated glycosaminoglycans. 3) attempts at treatment of articular cartilage loss or degeneration, including articular cartilage curettage, subchondral bone drilling, osteophyte removal, articular cartilage grafting and arthrodesis.
Ultrasonic transmission velocity and single photon absorptiometric measurement of metacarpal bone strength: An in vitro study in the horse
Authors: McCARTHY R.N. , JEFFCOTT L.B. , McCartney R.N.
Published: June 2010

Ten pairs of third metacarpal bones from Thoroughbred horses aged two to 12 years were used to estimate bone strength. Measurements of transverse cortical ultrasound velocity, cortical cross sectional area and bone mineral content were made using ultrasonic transmission velocity and single photon absorptiometry. These data were used to determine bone mineral density, compact bone density and modulus of elasticity. The results were compared with those measured by direct means or chemical analysis and satisfactory correlations were obtained between estimated and measured values. Single photon absorptiometry was found to be more accurate than dual photon absorptiometry. The estimated modulus of elasticity in the transverse direction correlated well with the measured longitudinal value obtained by compression testing. This investigation confirmed the value and precision of using a combined ultrasonic and photon absorptiometric technique for non‐invasive measurement of bone strength.
Monitoring the effects of treadmill exercise on bone by non‐invasive means during a progressive fitness programme
Authors: McCARTHY R.N. , JEFFCOTT L.B.
Published: June 2010

Six Standardbred horses underwent a 14‐week training programme on a treadmill. The training schedule consisted of five weeks of slow work of six to 12 km/day at 5 m/sec. This was followed by a nine week interval programme increasing in its intensity so that for the last three weeks the horses did three to four intervals/day from 600 to 1000 m at or above maximum heart rate. Ultrasound velocity through the third metacarpus showed a significant increase as a result of training. There was also a significant increase in modulus of elasticity, but no change in bone mineral content, bone mineral density or compact bone density. A decrease in ultrasound velocity was noted immediately after a session of trotting on the treadmill for 6 km. These changes reflected the potential to alter the viscoelastic properties of cortical bone through treadmill exercise, but did not explain the mechanism involved.
Is an interferon‐like protein involved in the maternal recognition of pregnancy in mares?
Authors: SHARP D. C. , McDOWELL K. J. , WEITHENAUER J. , FRANKLIN K. , MIRANDO M. , BAZER F. W.
Published: June 2010

To investigate the possibility that an interferon‐like protein similar to ovine trophoblast protein 1 (oTP‐1) is involved in the maternal recognition of pregnancy in the horse, conceptus membranes were cultured in the presence of a radioactive protein precursor to examine the incorporation of amino acids into proteins similar to oTP‐1. There were no proteins of similar isoelectric point or molecular weight range prior to Day 15, the time when maternal recognition of pregnancy should be completed. In addition, there was no immunological cross‐reactivity of conceptus‐conditioned media from equine conceptus cultures in an oTP‐1 radioimmunoassay. Furthermore, bioassay of equine uterine flushings, as well as conceptus‐conditioned media did not reveal any antiviral activity, although there was a small amount of antiviral activity measured in yolk sac fluid from a Day 15 equine conceptus. These data do not provide strong evidence for the existence of an oTP‐1‐like protein from the equine conceptus.
A monoclonal antibody specific for equine trophoblast
Authors: ORIOL J. G. , POLEMAN J. C. , ANTCZAK D. F. , ALLEN W. R.
Published: June 2010

A monoclonal antibody specific for horse trophoblast was produced after immunisation of mice with isolated chorionic girdle cells. When tested using an indirect immunoperoxidase assay, this antibody (F102.1) labelled both the non‐invasive trophoblast of the allantochorion and the invasive trophoblast of the chorionic girdle, as well as the mature endometrial cup cells which secrete equine chorionic gonadotrophin. Antibody F102.1 failed to label any of 18 adult and 6 foetal horse tissues, or any cells in the foetus or placenta with the exception of the trophoblast. Longitudinal studies demonstrated that the molecule identified by antibody F102.1 is expressed between Day 12 and term. There is no evidence that the molecule recognised by antibody F102.1 is antigenic in pregnancy, and no function has yet been ascribed to the molecule.
The effects of steroids on nutrients in yolk sac fluid of Day 18 pony conceptuses
Authors: WEITHENAUER J. , SHARP D. C. , SHERRIN P. C.
Published: June 2010

In the mare, there is a high incidence of early embryonic mortality which corresponds to early conceptus development and the time of maternal recognition of pregnancy. The need for synchrony between the developing conceptus and the uterine environment emphasises the delicate processes of establishment and maintenance of pregnancy. Further research is necessary to investigate the environments of the conceptus and uterus, and their interaction, for a better understanding of these processes and ultimately a reduction in early embryonic loss.
Influence of donor parity and age on the success of commercial equine embryo transfer
Authors: VOGELSANG S. G. , VOGELSANG M. M.
Published: June 2010

Data were compiled regarding the success of commercial embryo recovery rate, transfer pregnancy rate, and embryonic loss in recipients, with respect to influence of donor parity and age, between 1985 and 1988. There were significant differences between maiden and subfertile mares for embryo recovery rate (40/66 versus 81/282), transfer pregnancy rate (34/49 versus 38/78), and embryonic loss in recipients (4/34 versus 13/38). There were also significant differences between recently foaling and subfertile mares (146/276 versus 81/282) and for younger mares (two to eight and nine to 17‐year‐old) compared with older mares (18 to 28‐year‐old) for embryo recovery rates (80/132, 94/183 and 93/309, respectively). Transfer pregnancy rates differed signifiantly between mares aged two to eight‐years‐old compared with those aged nine to 17 and 18 to 28‐years‐old (59/84, 50/97 and 50/90 respectively). No differences were observed among any of the age groups regarding embryonic loss in recipients. There was an effect of year on embryo transfer pregnancy rate in 1985 compared with subsequent years that could have been attributed to any of a wide variety of external factors.
Methods and comparative aspects of embryo cryopreservation in domestic animals
Authors: SEIDEL G. E.
Published: June 2010

The most important principle of cryopreservation is that most of the water must be removed from cells before they freeze intracellularly. This is usually achieved by slow cooling after extracellular ice forms; dehydration occurs because the high concentration of salts in the medium remaining between the ice crystals draws water out of the cells. Cryoprotectants improve survival rates of frozen cells. However, osmotic damage must be minimised when cells are removed from cryoprotectant solutions after thawing. Successful methods of cryopreservation take these principles into account. Tolerance by embryos of cryopreservation procedures varies according to species and stage of embryonic development. Pig embryos are killed when cooled below 15°C. Of particular relevance is the finding that equine embryos less than 300 μm in diameter can by cryopreserved with current methods much more successfully than those larger than 300 μm. Further research is required to improve cryopreservation procedures for equine embryos.
Recent studies on in vivo fertilisation of in vitro matured horse oocytes
Authors: ZHANG J. J. , BOYLE M. S. , ALLEN W. R. , GALLI C.
Published: June 2010

Fresh horse oocytes dissected from slaughterhouse ovaries were allocated to two groups depending on the degree of development of the cumulus investment. In Group I, the cumulus was fully compact whereas in Group II it was partially expanded. Basic culture medium (M199) was supplemented either with 20 per cent late oestrus mare serum (M199a) or 10 per cent foetal calf serum plus gonadotrophins (M199b). At the start of the culture, 70 per cent of Group I and 28 per cent of Group II oocytes were at germinal vesicle, or germinal vesicle breakdown stages. During culture in M 199a, the proportion of oocytes reaching metaphase of second meiosis (M II) was at a maximum after 30 h in culture for Group I oocytes (61 per cent) and after 24 h in culture for Group II oocytes (68 per cent). After culture in M199b, a higher proportion of Group I oocytes (89 per cent) displayed full expansion and mucification of the cumulus than when cultured in M199a (13 per cent), although the same proportion reached M II in each medium (63 per cent and 64 per cent respectively). Fluorographs of 1‐dimensional gels of oocyte protein showed an accumulation of a polypeptide (MW 34 kDa) during culture. A total of 29 in vitro matured oocytes were transferred to the oviducts of four recently mated recipient mares judged to be at the point of ovulation. Uterine flushing of these mares eight days after surgery resulted in the recovery of seven blastocysts, two of which were then transferred surgically to the uteri of synchronised recipient mares and one pregnancy resulted.
The morphology of the equine iridocorneal angle: a light and scanning electron microscopic study
Authors: DE GEEST J. P. , LAUWERS H. , SIMOENS R. , DE SCHAEPDRIJVER L.
Published: June 2010

The present investigation of 20 equine eyes shows that the iridocorneal angle of the horse is characterised by a very distinct pectinate ligament and a large ciliary cleft. The pectinate ligament consists of long and broad pigmented trabeculae which form a firm, flat and dense network that encircles the eye. On meridional sections, the ciliary cleft is visible as a wide triangular space comprising the trabecular meshwork which consists of two parts. The inner part is the larger and forms a three‐dimensional network of large pigmented trabeculae with very wide intertrabecular spaces. The outer part occupies a much smaller area and fills the posterior angle of the ciliary cleft. It is a compact annular network consisting of small non‐pigmented circularly orientated trabeculae. They enclose very narrow spaces which contain glycosaminoglycans. External to the outer network lies the angular aqueous plexus, which is rudimentary. This discontinuous plexus runs circularly and is composed of small slit‐like vessels. The intrascleral venous plexus is also very weakly developed, whereas the internal collector channels and the episcleral venous plexus are clearly visible. The large ciliary cleft is supported by the strong trabeculae of both the pectinate ligament and the inner part of the trabecular meshwork, making collapse of the ciliary cleft practically impossible. This morphology of the equine iridocorneal angle helps to explain the rarity of glaucoma in the horse.
The equine fundus III: pathological variants
Authors: MATTHEWS A. G. , CRISPIN SHEILA M. , PARKER J.
Published: June 2010

A wide range of ophthalmoscopic variants are encountered during routine examination of the horse. Some result from minor anatomical anomalies, cause no significant effect on vision and may be considered to lie within the limits of ‘biological normality’. Others are a consequence of pathological disruption of the anatomical integrity of the fundus, and may directly or indirectly affect the neurosensory retina and produce some degree of visual deficit. This paper illustrates the ophthalmoscopic appearance of a number of pathological variants of the anatomic fundus, and discusses their possible effect upon vision. Among the abnormalities discussed is peripapillary chorioretinitis, which commonly presents as the so‐called peripapillary ‘butterfly lesion’. It is concluded that, although this lesion may occur in conjunction with signs of more generalised posterior segment disease, eg posterior capsular cataract, in the absence of concurrent signs of anterior uveitis there is no reason to associate the lesion with equine recurrent uveitis (periodic ophthalmia).
Horner's syndrome in the horse: a clinical, experimental and morphological study
Authors: SIMOENS P. , LAUWERS H. , DE MUELENARE C. , MUYLLE E. , STEENHAUT M.
Published: June 2010

A clinical case of Horner's syndrome is described in a Standardbred horse, and the various symptoms of cranial sympathetic denervation are studied in two ponies after experimental transection of the left cervical sympathetic trunk and vagosympathetic trunk, respectively. The most prominent symptoms of equine Horner's syndrome were ptosis, local sweating and increased cutaneous temperature in the denervated area. Enophthalmos, miosis and increased lacrimation were also observed but these symptoms were mild, variable and difficult to ascertain. Prolapse of the third eyelid was not noticed. Concomitant laryngeal hemiplegia was present in the clinical case and was provoked experimentally in one pony by transection of the left vagosympathetic trunk. The aetiology of each of these symptoms is discussed by comparing the results of pharmacological tests and histological findings in the three horses with the data from the literature.
Follow‐up report of a case of surgical aphakia with an analysis of equine visual function
Authors: FARRALL H. , HANDSCOMBE M. C.
Published: June 2010

More work is necessary to establish corneal dimensions and retinal structure and neural organisation in the equine eye. This paper reports a case of surgical management of bilateral cataracts in a pony and the results of a survey of refractive error in normal horses. Aspects of accommodation are discussed. It is suggested that a difference in retinal receptor organisation between horse and human eyes could explain the good visual performance of the aphakic pony; and that the degree of blurring of vision in the aphakic situation is less, both in absolute terms and in proportion to presumed normal levels of vision, in the horse than in man. It would not seem necessary to consider intra‐ocular implants for horses at this stage. The authors feel it is unwise to extrapolate too freely from human data. More information is needed on the optics and retinal topography of many species, particularly horses and dogs, before routine implant surgery on eyes is undertaken.
The physiological basis of training the skeleton
Authors: LANYON L. E.
Published: June 2010

The skeleton consists of a series of elements with a variety of functions. In locations such as the skull, where shape or protection are of prime importance, the bone's architecture is achieved during growth under predominant genetic control. In locations such as the limbs, where the ability to withstand repetitive loading is important, only the general form of the bone will be achieved as a result of growth alone, the remaining characteristics resulting from an adaptive response to functional load bearing. In the horse, this functional loadbearing will be provided by the animal's natural activity pattern in box or paddock supplemented by the specific activities of the training regimen. It is the adaptive response to the total activity pattern that influences bone modelling and remodelling and so determines the bone's architecture. The objective of the training regimen is to ensure that this response achieves an appropriate match between bone architecture and the loads it is required to withstand during both training and athletic performance. We propose that for the match between architecture and load‐bearing to be established, and maintained, subsequently, bone cells must be able to ‘assess’ directly or indirectly the functional strains produced within the bone tissue. Because these strains are used as feedback they are both the objective of functionally adaptive modelling and remodelling, and the stimulus for its control. The mechanisms whereby bone cells control skeletal modelling and remodelling to produce a functionally competent skeleton are unknown although some of the factors and sequence of events involved are presented here. The extent to which variation in training regimen affects bone architecture has not been studied systematically in any species.
Kinetics of V̇O2 and V̇CO2 in the horse and comparison of five methods for determination of maximum oxygen uptake
Authors: ROSE R. J. , HODGSON D. R. , BAYLY W. M. , GOLLNICK P. D.
Published: June 2010

To determine whether maximum oxygen uptake (VO2max) in the horse is influenced by type of exercise test, five different protocols were evaluated in eight untrained Thoroughbreds exercised on a treadmill. With all protocols, horses were given a 5 min warm‐up on a 10 per cent treadmill slope. Three protocols were at a 10 per cent slope and included: 1) increasing the running speed by 1 to 2 m/sec every 60 sees from 4 m/sec to a maximum of 12 m/sec; 2) running at 12 m/sec until fatigue; and 3) running for 3 to 4 mins at speeds ranging from 6 to 12 m/sec with rest pauses between exercise bouts. The fourth protocol employed a 24 per cent slope where animals exercised for 5 mins at 2 m/sec followed by 3 mins at 5 m/sec, and 2 mins at 6 m/sec. The fifth test involved running at 11 m/sec while the slope of the surface was increased every 2 mins until the horses could not maintain the pace. A plateau in V̇O2 occurred in all protocols except when exercise was performed on a 24 per cent slope. Slow speed exercise at a steep grade (24 per cent) produced the highest V̇O2 (P<0.05) even though there was no plateau in the V̇O2. A steady state for V̇O2 and V̇CO2 existed 90 secs after the onset of exercise with all protocols which involved 2 mins or more at each speed. The V̇O2 and V̇CO2 values at all speeds of the rapid incremental exercise test were not different to those found at steady state in the third exercise protocol.
Some factors influencing plasma AST/CK activities in Thoroughbred racehorses
Authors: HARRIS PAT A. , SNOW D. H. , GREET T. R. C. , ROSSDALE P. D.
Published: June 2010

Sixty‐six Thoroughbred horses in training (2 or 3 years of age) were studied during one flat racing season, to investigate the relationship between age, sex, time of year, dietary electrolyte imbalances and plasma aspartate aminotransferase/creatine kinase (AST/CK) activities. Management and training variations were minimised. Between February to October, monthly 24 h post exercise samples were collected and analysed for AST and CK activities. Sex and/or age were shown to have a significant effect on the occurrence of high CK (>100 iu/litre) and AST (> 300 iu/litre) activities. Fillies were more likely to have elevated CK and AST than colts. Two‐year‐olds tended to have higher AST activities than three‐year‐olds. Time of year had no significant effect on the number of animals with high or low activities. Fourteen animals had consistently raised plasma AST activities (median >300 iu/litre). Eight of these raced and seven won at least one race. The average daily intake of calcium, sodium, phosphorus and potassium was determined at each sampling time. In eight of the horses, the fractional electrolyte excretion (FE) of phosphate (PO4) and sodium (Na) was determined monthly. FE values were also determined in three horses which had suffered repeated attacks of the equine rhabdomyolysis syndrome. The FE, PO4 and Na values reflected dietary intake of calcium, phosphorus and sodium respectively. It was not possible to determine any effect of training or a predisposition to equine rhabdomyolysis. No obvious differences were found between the resting thyroxine values of three animals with consistently low AST activities, six of those with consistently raised AST and three animals which had suffered repeated attacks of rhabdomyolysis.
The effect of an acute angulation of the hind hooves on diagonal synchrony of trotting horses
Authors: CLAYTON HILARY M.
Published: June 2010

High speed cinematography was used to measure the timing and distance characteristics of the trot in the five sound horses. Two farriery treatments were compared: (1) normal, in which the dorsal hoof wall was aligned with the pastern axis in all four feet and (2) acute hind hoof angulation, in which the hind toes were allowed to grow relatively longer than the heels, so that the angulation was approximately 10° lower than the normal hind hoof angle for the individual animal. Comparison between the two treatments showed that the acute hind hoof angulation was associated with significant increases in hind limb breakover time (P=0.001), overreach distance (P=0.001) and overreach duration (P=0.017), whereas stride length, forelimb breakover and diagonal distance did not change (P>0.05). In the majority of horses, limb movements at the start and end of the diagonal stance phase were slightly asynchronous, so that when the hooves were trimmed normally the hind limb more often preceded the diagonal forelimb at impact and lift off. The prolongation of hind limb breakover due to the acute hind hoof angulation was associated with a tendency for the hind limb to lift off later than the forelimb. The difference in lift off sequence between the two farriery treatments was highly significant (P=0.001). During the swing phase the normal coordination was restored and there was no significant difference in the impact sequence with the normal and acute hind hoof angulations (P>0.05).
Follow‐up of 28 horses with third metacarpal unicortical stress fractures following treatment with osteostixis
Authors: HANIE E. A. , SULLINS K. E. , WHITE N. A.
Published: June 2010

The results of 31 intracortical dorsal metacarpal stress fractures in 28 horses following unicortical osteostixis were reviewed. The incidence was predominately in the middle third of the lateral aspect of the left metacarpus, and males were affected more commonly. Approximately half of the surgical procedures were perfomed with the horse in the standing position. The mean times to return to training and racing were 4.25 and 6.9 months respectively. There was no correlation between time taken to return to racing and position of surgery. Complications experienced included lack of suture removal and one case with a seroma.
A comparison of injectable anaesthetic regimens in mules
Authors: MATTHEWS NORA S. , TAYLOR T. S. , SKROBARCEK CINDY L. , WILLIAMS J. D.
Published: June 2010

Three combinations of injectable anaesthetic agents were compared in nine adult mules. The combinations were xylazine/ketamine (X/K), xylazine/butorphanol/ketamine (X/B/K), and xylazine/tiletamine‐zolazepam (X/T). Measured variables were heart rate, respiratory rate, systolic blood pressure, arterial blood pH, PCO2and PO2, recumbency time and number of attempts to stand. Quality of induction and recovery, muscle relaxation and response to stimulus were evaluated subjectively. Recumbency time was significantly (P<0.05) longer with X/B/K and X/T than with X/K. Mules required significantly more attempts to stand under the influence of X/T than X/K or X/B/K. No statistically significant (P<0.05) differences in heart rate, respiratory rate, blood pressure or arterial pH, PCO2and PO2were detected between groups.
The pharmacology and pharmacokinetics of high‐dose methocarbamol in horses
Authors: III W.W. MUIR , SAMS R.A. , ASHCRAFT SUSAN
Published: June 2010

The haemodynamic, respiratory and behavioural effects and pharmacokinetics of methocarbamol were studied in eight healthy, adult horses after intravenous (iv) and oral administration of large dosages. Heart rate, cardiac output, mean pulmonary arterial blood pressure, systolic, diastolic and mean aortic blood pressure, respiratory rate and arterial blood gases did not change after either iv (30 mg/kg bodyweight [bwt]) or oral (50 and 100 mg/kg bwt) dosages of methocarbamol. Mild to moderate depression was observed in five of eight horses administered iv methocarbamol, and in all horses administered oral methocarbamol. Plasma methocarbamol concentration declined very rapidly during the initial or rapid disposition phase after iv administration; the terminal elimination half‐life ranged from 59 to 90 mins. Peak plasma methocarbamol concentrations following oral administration occurred within 15 to 45 mins and oral bioavailability ranged from 50.7 to 124 per cent.
Pharmacokinetics and metabolism of intravenous doxapram in horses
Authors: SAMS R. A. , DETRA R. L. , III W. W. MUIR
Published: June 2010

The pharmacokinetics and metabolism of doxapram in horses administered intravenous (iv) doses of 0.275, 0.55 and 1.1 mg doxapram/kg bodyweight (bwt) were investigated. Plasma doxapram concentrations decreased rapidly after drug administration and the disappearance of doxapram from plasma was best described by a polyexponential equation. Median values of total body clearance were 10.9, 10.6 and 10.9 ml/min/kg bwt for the three doses and were independent of dose. The steady‐state volume of distribution was approximately 1,200 ml/kg bwt and the median biological half‐life ranged from 121 to 178 mins. Plasma protein binding of doxapram ranged from 76.0 to 85.4 per cent. The blood:plasma doxapram concentration ratio was approximately 0.8 and the affinity of the red blood cells for doxapram ranged from 2.0 to 2.8 indicating sequestration of doxapram in erythrocytes. Renal clearance of doxapram was a minor route of elimination. Metabolic clearance of doxapram appeared to be a major route of elimination. Four metabolites of doxapram were isolated from urine and were identified. The metabolites were: a) 1‐ethyl‐4‐[(2‐hydroxyethyl) amino]ethyl‐3,3‐diphenyl‐2‐pyr‐rolidinone, b) a glucuronic acid or sulphuric acid conjugate of 1‐ethyl‐3‐(hydroxyphenyl)‐4‐(2‐morpholinoethyl)‐3‐phenyl‐pyr‐rolidinone, c) 3,3‐diphenyl‐4‐(2‐morpholinoethyl)‐2‐pyr‐rolidinone and d) 1‐(2‐hydroxyethyl)‐3,3‐diphenyl‐4‐(2‐morpholinoethyl)‐2‐pyr‐rolidinone. The rapid disappearance of doxapram from plasma immediately after iv administration was attributed to redistribution of the drug from plasma to other tissues. The short duration of clinical effect from doxapram may be attributed to redistribution of the drug from plasma and other well‐perfused tissues, such as the brain, to less well‐perfused tissues such as the skeletal muscles and adipose tissue. Continuous or repeated administration of doxapram could prolong the duration of clinical effect because re‐distribution is less important as steady‐state conditions are approached.
Sympatho‐adrenal activity and the clinical sedative effect of detomidine in horses
Authors: RAEKALLIO MARJA , LEINO ANNE , VAINIO O. , SCHEININ MIKA
Published: June 2010

Thirty‐nine horses were given detomidine 10 μg/kg bodyweight (bwt) intravenously (iv) and six horses were given a corresponding volume of saline solution before minor procedures. Venous blood samples were collected for catecholamine and cortisol determination immediately before the detomidine or saline injection and 20 mins after it. The behaviour of the horse at the time of detomidine injection and the extent of sedation were evaluated. Plasma adrenaline, noradrenaline and the catecholamine metabolites, 3,4‐dihydroxyphenylglycol (DHPG) and 3,4‐dihydroxyphenylacetic acid (DOPAC), and cortisol concentrations decreased significantly after administration of detomidine, but they remained unchanged in the control group. A high plasma adrenaline concentration before detomidine injection, indicative of a high level of stress, seemed to correspond with a reduced sedative effect of detomidine. The extent of sedation also was related to the concentrations of adrenaline, noradrenaline and DHPG in plasma after the detomidine injection. The reductions in the plasma catecholamine concentrations may have been caused, in part, by decreased secretion of catecholamines due to the sedative effects of detomidine; but detomidine also influences the plasma catecholamine concentrations by reducing directly sympatho‐adrenal activity.
Pharmacokinetics of tolfenamic acid in the horse
Authors: JAUSSAUD P. , GUIEU D. , BELLON C. , BARBIER B. , LHOPITAL M. C. , SECHET R. , COURTOT D. , TOUTAIN P. L.
Published: June 2010

The pharmacokinetics of tolfenamic acid were studied in five ponies after an intravenous (iv) administration (2 mg/kg bodyweight [bwt]) and in four horses after an oral administration (30 mg/kg bwt) of tolfenamic acid. The plasma levels were determined by high pressure liquid chromatography (HPLC) and gas chromatography‐mass spectrometry (GC‐MS). For the iv administration, a three‐compartment model was used to represent the plasma concentration‐time curve of the drug. The elimination half‐life of the compound was 6.1 ± 1.5 h, the total body clearance was 72.4 ± 16.7 ml/kg bwt/h and the steady‐state volume of distribution 0.32 ± 0.11 litres/kg bwt. For the oral administration, absorbtion was delayed with a mean lag‐time to absorption of 32 ± 28 mins. The peak plasma concentration 11.1 ± 0.69 μg/ml was observed after a highly variable delay ranging from 1.9 to 6.5 h post administration. The terminal half‐life (4.2 ± 0.48 h) was very similar; to that obtained after iv administration. Tolfenamic acid could not be detected in equine plasma with the described analytical methods more than 48 h after drug administration.
Investigations into the incidence of field colic
Authors: Uhlinger Christine
Published: June 2010

This investigation was undertaken to compare the accuracy of different methods of collecting data on the incidence of colic. The results of an historical cohort technique and a questionnaire survey were compared with those obtained from a prospective cohort study. In a separate analysis, the practical application of the historical cohort method was used to estimate the incidence of colic in horses owned by regular clients of a general equine practice.

Horses from 14 herds were used in Part 1 of the study, to gather the prospective cohort, historical cohort and questionnaire data. The prospective cohort method recorded 91 episodes of colic in 349.1 horse years, generating an incidence of 0.26 cases/horse‐year at risk. The historical cohort method, based on an analysis of billing records, identified 82 colic cases in 370 horse‐years at risk, under‐counting colic cases and overestimating the population at risk. However, the summary estimate of 0.22 cases/horse‐year at risk did not differ significantly from that generated by the prospective cohort study (P / 0.18). The questionnaire based survey identified 112 colic cases in 313 horse‐years at risk, over‐counting cases and under‐counting the population at risk. The incidence estimate was 0.36, which differed significantly from that found in the prospective cohort survey (P = 0.008).

The second part of this investigation used the validated historical cohort method to estimate the incidence of colic in animals owned by clients of a University field service practice. The incidence estimated in this population was 0.19 cases/horse year at risk. This incidence may be generalised to groups of mature performance and pleasure horses using veterinary services regularly for herd health activities.
Identification of tumour necrosis factor in the blood and peritoneal fluid of horses with colic
Authors: May S. A. , Spiers Susan , Carter S. D. , Bennett D. , Edwards G. B.
Published: June 2010

Tumour necrosis factor was detected both in the blood and peritoneal fluid of 14 horses with various types of gastrointestinal obstruction. In comparison, tumour necrosis factor was not present in these fluids in 6 normal horses and ponies. The median endotoxin concentration was increased in the blood of horses with colic, but the median interleukin‐1 concentration was not altered in the blood and peritoneal fluid of colic cases in comparison with the normal horses and ponies. This preliminary work supports the hypothesis that tumour necrosis factor is involved in the endotoxaemia which is a consequence of severe gastrointestinal obstructions, and that it is a potential target for medical therapy in such cases.
Duration of antisecretory effects of oral omeprazole in horses with chronic gastric cannulae
Authors: Jenkins Christine C. , Blackford J. T. , Andrews F. , Frazier Donita L. , Mattsson H. , Olovsson S.‐G. , Peterson A.
Published: June 2010

Eight female horses with chronic gastric cannulae were given omeprazole as enteric‐coated granules (1.4 mg/kg bwt) via nasogastric tube once daily for 6 days. The effects on basal and pentagastrin‐stimulated gastric acid secretion were determined 5 h after dosing on Days 1 and 5 ofadministration. A third gastric secretion test was done on Day 7, 24 h after the dose on Day 6. Gastric juice volume, pH, acidity, and acid output were determined during a 1‐h basal secretion test followed by a 2‐h pentagastrin‐stimulated (6 μg kg−1 h−1) test.

When compared with placebo controls, omeprazole significantly inhibited basal gastric acid output by 72% and pentagastrin‐stimulated acid output by 86% on Day 5. Gastric juice pH was also significantly increased. On Day 7, basal gastric acid output was significantly decreased by 90% and pentagastrin‐stimulated secretion was decreased by 72%. The effect of omeprazole administration on gastric juice volume was variable.

Once daily administration of 1.4 mg omeprazole/kg bwt significantly inhibited basal and stimulated gastric acid secretion in horses by the 5th dose. Gastric acid secretion was significantly inhibited for at least 27 h after omeprazole treatment, indicating a long duration of antisecretory effect of the drug in horses.
Placentas and foetal health
Authors: COLLINS MARGARET H.
Published: June 2010

The placenta provides many critical services to the developing foetus. Proper placental implantation, growth and function are necessary for normal foetal growth and development. Placental structure varies widely among species but all mammalian placentas have a convoluted materno‐foetal interface that may be quite simple or highly complex; the more complicated interdigitations tend to characterise smaller placentas that have limited areas of contact between the placenta and the endometrium. The intimacy of the contact between maternal and foetal tissue varies from apposition only, as in the equine placenta, to invasion of maternal vessels by foetal cells, as in man. Abnormalities identified in the human placenta provide insight into maternal and foetal diseases that affect pregnancy outcome.
Endoderm cells of the equine yolk sac from Day 7 until formation of the definitive yolk sac placenta
Authors: ENDERS A. C. , SCHLAFKE S. , LANTZ K. C. , LIU I. K. M.
Published: June 2010

On Day 7 of pregnancy, when the inner cell mass coalesces to one side of the blastocyst, a discontinuous layer of cells is present underlying the inner cell mass and isolated cells were found around the mural trophoblast. As early as Day 8, these cells that were scattered around the blastocyst cavity unite to form a continuous endodermal layer, resulting in a bilaminar blastocyst. The endodermal cells have slightly bulging apical surfaces towards the cavity of the blastocyst, but in many areas have flanges and projections that form complex basolateral compartments within the endoderm and especially between the endoderm and trophoblast. These cells also develop an extensive series of unusual apical ridges. With the development of the primitive streak and the trilaminar blastocyst, angiogenesis proceeds from the forming embryo into the yolk sac. At first the anastomotic vessels form a simple mesh, but by Day 20, erythroblasts are present in the newly formed sinus terminalis. The loss of the capsule (Day 21) and the development of the embryonic circulation establish the relationships of the definitive yolk sac. There is a bilaminar region with endodermal cells showing basolateral compartmentalisation and a specialised sinus terminalis region bordering the choriovitelline placenta. The largest endodermal cells are associated with the choriovitelline placenta, but a substantial cuboidal lining also covers the splanchnopleuric portion of the vascular yolk sac. The allantochorion rapidly assumes predominance in respiratory exchanges, and the choriovitelline placenta not only decreases in relative area but increases in thickness. However, the 3 major regions of the yolk sac persist for several weeks after their formation, and both the vasculature and especially the endodermal cells remain robust despite the decrease in size of the yolk sac. It is concluded that the pleomorphic endodermal cells of the equine yolk sac differentiate in response to local signals. By Day 25 the allantochorion is an increasingly significant exchange unit, and the continued robustness of the vascular portions of the yolk sac and especially its endodermal layer suggests that synthetic and metabolic activities of the endodermal cells will be the dominant function of the yolk sac subsequently.
Embryonic and early foetal development in donkeys
Authors: GASTAL E. L. , SANTOS G. F. , HENRY M. , PIEDADE H. M.
Published: June 2010

Embryo and early foetal development was studied until Day 60 (ovulation = Day 0) in 25 Brazilian jenny donkeys. The occurrence of ovulation and embryonic development was assessed by daily examinations using realtime ultrasonography. An embryonic vesicle, first detected at Day 10.9 ± 0.1 after ovulation, remained mobile within the uterine lumen until Day 16.0 ± 0.5 when it had a diameter of 21.8 ± 1.5 mm. Until immobilised the vesicle was detected in the left horn, right horn and body of the uterus 49.2, 41.8 and 9% of the time respectively. There was a temporal relationship between vesicle expansion, increase in uterine tone and immobilisation of the vesicle.

The mean diameter of the embryonic vesicle or conceptus was 3.5, 28.0, 30.9, 45.3 and 59.2 mm on Days 10, 20, 30, 40 and 50, respectively, after ovulation. The vesicle remained spherical up to Day 17.8 ± 0.4 but thereafter became irregular in outline. The embryo was first detected on Day 19.9 ± 0.2 and heart beats were noted on Day 21.8 ± 0.3. The mean values for width x crown‐rump length of the embryo/foetus were 3 times 4, 8 times 12, 11 times 17, 13 times 32 and 19 times 47 mm on Days 20, 30, 40, 50 and 60, respectively. The allantoic sac was first detected between Days 19 and 23 and it occupied approximately 25, 50 and 75% of the embryonic vesicle on Days 30, 33 and 38 respectively. The embryo was situated in the dorsal pole of the vesicle by Day 34.8 ± 0.7 and an umbilical cord was first observed on Day 41.1 ± 0.8, coincident with descent of the foetus.
PGE2 secretion by the conceptus and binding by non‐pregnant endometrium in the horse
Authors: VANDERWALL D. K. , WOODS G. L. , WEBER J. A. , LICHTENWALNER A. B.
Published: June 2010

Conceptus PGE2secretion was determined by incubating equine conceptuses (7/day)in vitrofor 24 h. Day‐11, ‐13 and ‐15 conceptuses secreted (mean ± sem) 91.2 ± 23.7, 92.8 ± 15.9 and 170.8 ± 24.9 ng PGE2/24 h, respectively. Day‐15 conceptuses secreted more (P<0.05) PGE2than Day‐11 or Day‐13 conceptuses. Conceptus diameter and PGE2secretion were positively correlated (R2= 0.52; P<0.001). Endometrial membrane preparations from non‐pregnant mares (6/day) were incubated with [3H]PGE2and nonradioactive PGE2. The concentrations of unoccupied endometrial PGE2binding sites on Days 11, 13 and 15 were 116.2 ± 17.7, 93.3 ± 12.4 and 57.2 ± 7.3 fmol/mg protein, respectively. The binding site concentration was higher (P<0.05) on Day 11 than Day 15. The dissociation constant of the binding reaction on Days 11, 13 and 15 was 1.94 ± 0.35, 1.55 ± 0.11 and 1.64 ± 0.25 nM, respectively. There was no difference (P>0.10) in the dissociation constant between days. These results demonstrate that equine conceptuses secrete PGE2, and non‐pregnant equine endometrium specifically binds PGE2during the period of maintenance of the corpus luteum.
Oviduct flushing as a treatment for infertility in the mare
Authors: ZENT W. W. , LIU I. K. M. , SPIRITO M. A.
Published: June 2010

The oviducts of 8 infertile mares (12–21 years) were flushed from the uterotubal junction to the fimbria in an attempt to clear the oviduct of any oviductal masses that might have been interfering with migration and/or fertilisation of the ovum. None of them had been diagnosed as pregnant for at least 3 consecutive years and the uteri were grade II or III. Flushing was successful (masses extruded) in 5 mares and 3 of these became pregnant. This procedure has the potential of correcting a possible cause of infertility, but it is a major surgical undertaking and should not be attempted unless all other diagnostic procedures have failed to produce a reason for the inability to conceive.