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Monitoring variables of cardiac performance in horses is challenging owing to patient size, temperament, and anatomic peculiarities. Blood pressure is a major determinant of afterload, but it is not a reliable surrogate of cardiac performance and tissue perfusion. Cardiac output, together with arterial and venous oxygen content, provides insight as to the adequacy of delivery of blood and oxygen to the body as a whole and can be used to gauge the fluid responsiveness and cardiovascular status of the patient. Measurement of intracardiac pressures serves to assess cardiac filling pressures, myocardial performance, and vascular resistance., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The equine gut harbours complex microbial populations which influence physiology, metabolism, nutrition and immune functions, while disruption to the gut microbiota has been linked with conditions such as lameness, diabetes and obesity. Therefore, the present study was conducted to determine the association between microbial dysbiosis, sex, age and body condition scores (BCS) of horses (Equus equus caballus) in Maiduguri and its environs. Forty horses were assessed by convenient sampling, while faecal samples were collected and analyzed to determine the microbiomes in the various age groups with variable BSC in stallions and mares. The present study revealed that there was strong and not significant association between the microbial populations in the gut of horses and the various age groups (Chi-Squared test = 11.809; df = 18; P = 0.8570). There were significant (p < 0.0001) differences in the microbiome population in the guts of the horses. There were significant (p < 0.05) differences in the microbiomes in the various body scores. There were significant (P < 0.047) differences in the microbiomes of the mares and stallions. E. coli had the highest burden of microbial populations with 30.38*10 3 ± 1.04*10 3 in the guts of horses in the study area, while statistically there were no differences in the populations of Corynebacterium, Klebsiella, Salmonella, Staphylococcus and Streptococcus in the gut of horses in the study area relative to E. coli. This study provides information on the nature of bacterial population present in horses in Maiduguri and its Environs. Therefore, further high-throughput characterization of the faecal bacteria microbiome of horses is essential to enable comparison to disease state and thus develop diagnostic tests, prophylactic measures and appropriate treatments., (Copyright © 2018. Published by Elsevier Ltd.)

Reduction of the hyperinsulinaemic response to feeding is central to the management of insulin dysregulation (ID). The aim of this study was to compare insulinaemic and glycaemic responses to soaked hay, dry hay and haylage in ponies. Twelve ponies of mixed breeds were maintained under identical management conditions. A randomised four-way crossover trial was conducted, in which fasted animals were fed a meal of 0.25% body weight as dry matter intake soaked hay, dry hay or haylage, or administered an oral glucose test (OGT). Blood glucose and serum insulin concentrations were measured before and at 2h following OGT, and regularly for 5h following forage meals. Median and interquartile range (IQR) area under the curve (AUC) for insulin (AUC i ) was greater for haylage (median 6495; IQR 17352) vs. dry hay (2932; IQR 5937; P=0.019) and soaked hay (1066; IQR 1753; P=0.002), and greater for dry hay vs. soaked hay (P=0.002). The AUC for glucose (AUC g ) was lower for soaked hay (1021; IQR 99) vs. dry hay (1075; IQR 105; P=0.002) and haylage (1107; IQR 221; P=0.003). Six ponies were classified as having ID based on the OGT. AUC i was greater in ID vs. non-ID ponies after all forages. In contrast, there was no detectable effect of ID status on AUC g . On an equivalent dry matter basis, soaked hay produced the lowest insulinaemic and glycaemic responses to feeding, while haylage produced the highest responses. The insulinaemic effects of all forages were greater in ponies with ID. These data support the practice of soaking hay with water to reduce postprandial insulinaemic responses in ponies., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Endocrine diseases, such as equine metabolic syndrome and pituitary pars intermedia dysfunction, are common in domesticated horse populations, and the frequency with which these diseases are encountered and managed by equine veterinary practitioners is expected to increase as the population ages. As clinicians learn more about the effects of these diseases on equine reproductive physiology and efficiency (including effects on reproductive seasonality, ovulation efficiency, implantation, early pregnancy loss, duration of pregnancy, and lactation), strategies and guidelines for improving fertility in affected animals continue to evolve. It is hoped that further research will establish these recommendations more firmly., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Synovitis of the navicular bursa is common in performance horses. The objective of this study was to describe an ultrasound-guided technique to inject a distended navicular bursa and to evaluate its feasibility for use by a clinician not trained in the technique. Twenty distal limbs of horses of various breeds and sizes were used. To produce synovial distension, the navicular bursa of each limb was injected with contrast medium using a lateral approach and radiography was performed to confirm that the contrast medium was distending the bursa. The digit was positioned with the distal interphalangeal joint in hyperextension. A microconvex ultrasound probe was placed in the hollow of the pastern, palmar to the middle phalanx and the region was assessed in a transverse plane slightly oblique to the horizontal plane. The ultrasound probe was rotated to visualize both the lateral and medial recesses and to select which side was more distended to inject. A 21G 0.8 × 50 mm needle was inserted abaxially to the probe in the plane of the ultrasound beam into the proximal recess of this navicular bursa and a methylene blue solution was injected. Following injection, dissection was performed to assess whether the navicular bursa had been successfully injected. This ultrasound-guided technique was reliably performed with a success rate of 68%. The success of injection is influenced by hyperextension of the foot, quality of ultrasound images and degree of distension of the bursa., (© 2015 Blackwell Verlag GmbH.)

Several studies have shown that there is a high prevalence of ill-fitting saddles. Many riders do not have saddle fit professionally assessed on at least an annual basis. Back dimensions can change considerably over the period of a year and therefore saddle fit should be assessed several times yearly, especially if work intensity has been altered. Saddle fit should be evaluated before and after exercise because back dimensions can change during work. Ideally, horses should be ridden in individual purpose-fitted saddles, rather than the same saddle being used on several horses. There remains little scientific rationale for the use of pads and numnahs under a saddle, except to temporarily improve saddle fit, and the use of numnahs that exert pressure on the spinous processes can be detrimental to performance. Although saddle slip consistently to one side can be associated with poor saddle fit or asymmetry of the horse's back, the most common cause is hindlimb lameness., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: Rapid and precise measurement of total and differential nucleated cell counts is a crucial diagnostic component of cavitary and synovial fluid analyses., Objectives: The objectives of this study included (1) evaluation of reliability and precision of canine and equine fluid total nucleated cell count (TNCC) determined by the benchtop Abaxis VetScan HM5, in comparison with the automated reference instruments ADVIA 120 and the scil Vet abc, respectively, and (2) comparison of automated with manual canine differential nucleated cell counts., Methods: The TNCC and differential counts in canine pleural and peritoneal, and equine synovial fluids were determined on the Abaxis VetScan HM5 and compared with the ADVIA 120 and Vet abc analyzer, respectively. Statistical analyses included correlation, least squares fit linear regression, Passing-Bablok regression, and Bland-Altman difference plots. In addition, precision of the total cell count generated by the VetScan HM5 was determined., Results: Agreement was excellent without significant constant or proportional bias for canine cavitary fluid TNCC. Automated and manual differential counts had R(2)  < .5 for individual cell types (least squares fit linear regression). Equine synovial fluid TNCC agreed but with some bias due to the VetScan HM5 overestimating TNCC compared to the Vet abc. Intra-assay precision of the VetScan HM5 in 3 fluid samples was 2-31%., Conclusions: The Abaxis VetScan HM5 provided rapid, reliable TNCC for canine and equine fluid samples. The differential nucleated cell count should be verified microscopically as counts from the VetScan HM5 and also from the ADVIA 120 were often incorrect in canine fluid samples., (© 2015 American Society for Veterinary Clinical Pathology.)

Summary Alphaviral equine encephalomyelitis is a mosquito-borne infection that causes severe neurological disease and fatalities in horses and humans in the Americas. Consequently, the equine alphaviruses (Eastern, Western and Venezuelan) are of considerable concern worldwide and are notifiable to the World Organisation for Animal Health. In addition, these diseases are considered a potent potential biological weapon, emphasising the need to develop an effective vaccine. Alphaviral equine encephalomyelitis is caused by Eastern equine encephalomyelitis virus (EEEV), Western equine encephalomyelitis virus (WEEV) or Venezuelan equine encephalomyelitis virus (VEEV), which are related members of the Alphavirus genus in the Togaviridae family. Although related, the three viruses are genetically and antigenically distinct. The disease is characterised by fever, anorexia, depression and clinical signs of encephalomyelitis, and may be fatal in up to 90% of cases, for both humans and horses, particularly in the case of EEE. Surviving horses develop lifelong immunity but may have permanent neuropathology. The aim of this paper is to analyse the scientific information available on the evolution of EEE, WEE and VEE, and any potential vaccines.

Reasons for Performing Study: There is limited information about risk factors and survival associated with disorders of the small colon requiring surgical management., Objectives: 1) To document the types of surgical lesion in horses where pathology of the small (descending) colon was the primary cause of abdominal pain, 2) to describe the short- and long-term survival of these cases and identify factors associated with survival and 3) to identify preoperative variables associated with localisation of a lesion to the small colon., Methods: Clinical data and long-term follow-up were obtained for horses that underwent exploratory laparotomy over a 10-year period. Descriptive data were generated for short- and long-term survival and survival analysis performed to identify factors associated with reduced survival. Univariable and multivariable relationships were explored using a Cox proportional hazards model. Preoperative factors associated with increased likelihood of a small colon lesion were explored, using controls randomly selected from horses undergoing exploratory laparotomy for treatment of colic unrelated to the small colon., Results: The study population included 84 horses. Of horses with small colon lesions recovered from anaesthesia, the percentage that survived until discharge, one year and 2 years following surgery, was 91.0, 81.0 and 73.5%, respectively. Median survival time for horses in which a resection had been performed was 1029 vs. 3072 days in the nonresection group. Small colon cases were more likely to have shown a longer duration of colic signs prior to admission (P<0.001) and to develop post operative diarrhoea (P = 0.001) when compared with surgical controls., Conclusions: Lesions of the small colon carry a good prognosis for survival following surgery. Resection and anastomosis was the only factor associated with reduced long-term survival., Potential Relevance: This study provides information about lesion types and post operative survival that may be used to assist informed decision-making when managing these cases., (© 2012 EVJ Ltd.)

Reasons for Performing Study: Anecdotal evidence collected by a variety of organisations has highlighted poor welfare in horses transported long distances to slaughter within the European Union., Objective: To investigate welfare of horses being transported long distances within the EU to slaughter., Methods: Data on transported horses were recorded at 2 assembly centres in Romania and at 4 abattoirs in Italy over an 8 month period in 2008., Results: A total of 1519 horses in 64 separate shipments were observed in Romania prior to transport of which 212 horses were deemed unfit for transport and only 3 shipments (5%) complied with Council Regulation (EC) no. 1/2005 with respect to both horse and vehicle compliance. The destination most commonly stated for the horses from these assembly centres was Italy. A total of 1271 horses in 63 separate shipments were observed after transport in Italy, of which 86 horses in 4 shipments had also been observed prior to transport in Romania. The majority of the horses observed at these abattoirs originated from Poland (51%) and Romania (44%). On arrival in Italy at the time of unloading, 471 of 1271 horses (37%) were deemed unfit for transport in accordance with Council Regulation (EC) no. 1/2005 and none of the shipments were compliant with respect to both vehicle and horse requirements. An average of 6 horses per shipment (28% of each shipment) had at least one acute injury on arrival in Italy. A significantly higher prevalence of severe injuries and lameness was found in animals on arrival In Italy compared with animals leaving Romania. Horses examined on arrival in Italy were twice as likely to have 1-3 acute contusions or excoriations as horses examined in Romania. There was also a 2-fold increase in the number of animals deemed unfit for transport., Conclusion: This study has identified evidence of poor welfare in horses being transported long distances to slaughter, including severe lameness and injuries, and a high level of noncompliance with Council Regulation (EC) no. 1/2005 on the Protection of Animals during Transport., (© 2010 EVJ Ltd.)

Disease of the paranasal sinuses of the horse is common and treatment often involves lavage and sometimes surgery. The development of minimally-invasive, sinus-specific treatments, such as balloon sinuplasty, requires a thorough understanding of this complex anatomical region. To improve this understanding, 10 heads from dead horses of various ages were grossly dissected. The heads were transected sagittally and each half was dissected to expose the left and right nasomaxillary apertures and associated structures which were then photographed and measured. Entrances from the rostral and caudal maxillary sinuses into the maxillary aperture were found that led to a common exit at the middle nasal meatus. The caudal and rostral maxillary sinuses had their own, completely distinct outlets (entrances into the nasomaxillary aperture). There was no significant effect of side on measured variables., (Copyright © 2009 Elsevier Ltd. All rights reserved.)

Reasons for Performing Study: Welfare concerns over the reasons for interruption or termination of a sporting career in horses have been expressed., Objectives: To study the career of competition horses and factors that influence career length., Methods: In 2004, 46,576 rider-horse combinations were registered with the Dutch National Equestrian Federation (KNHS) in dressage, show jumping, eventing and endurance. From this population, approximately 1% of horses in each discipline were selected at random and all recorded competition data from the KNHS registration system collected and supplemented by detailed rider/owner telephone enquiry, carried out in July 2009., Results: A total of 520 horses were included aged 7.1 ± 3.2 years; endurance horses were on average slightly older than horses in the other 3 disciplines. A total of 334 horses (64.2%) ended their competition career with their initial rider during the study period; the mean total career time was 3.8 ± 2.8 years. Reasons for this included being sold on (51.5%), veterinary reasons (23.9%), being used for breeding (8.7%), changing to a recreational career (8.1%), rider-related issues (6.3%) and retirement (1.5%). No follow-up was available for horses sold. Orthopaedic problems accounted for the majority of the veterinary career-ending decisions (63.7%). A total of 385 horses (74.0%) had one or more career breaks; main reasons were rider-related issues (39.2%), others included temporary withdrawal from competition (21.6%), veterinary problems (21.8%), breeding (9.1%) and miscellaneous (8.3%)., Conclusions: Veterinary reasons for career breaks or termination of career accounted for 21.8 and 23.9% over the period investigated. They formed the second reason (after selling) why horses stopped competing with their initial rider/owner. Veterinary reasons were the third important cause for a temporary career break., Potential Relevance: Further in depth research of the reasons for interruption or termination of an equine career may be useful for the improvement of equine welfare., (© 2010 EVJ Ltd.)

This report describes previously unreported upper airway abnormalities encountered in a 5-month-old American miniature horse colt presented for elective surgery. Caution should be exercised when administering general anesthesia or heavy sedation to individuals of this breed that present with multiple congenital abnormalities.

Reasons for Performing Study: Genomics using cDNA microarrays could provide useful information about physiological adaptations and metabolic disorders in endurance horses., Objectives: In order to show that genes are modulated in leucocytes in relationship with performance and clinical status of the horses, gene expression in leucocytes, haematological and biochemical parameters were compared between successful and disqualified endurance horses., Methods: Blood samples were collected at rest (TO) and just after a 140-160 km endurance race (T1) in 2 groups of horses: 10 continuing successful (S) and 10 disqualified horses stopped at a vet-gate for metabolic disorders (D). Total RNA was extracted from the blood cells (leucocytes), checked for purity, amplified and hybridised using mouse cDNA microarrays including 15,264 unique genes. Differential gene expressions were studied by hybridisation of each sample T1 vs. a control sample collected at TO (pool of 20 sound horses)., Results: Some significant differences were observed in the haematology and biochemistry of the 2 groups (S vs. D). In Group D, rhadomyolysis was confirmed with CK 13,124 u/l and AST 1242 u/l. The list of 726 (including 603 annotated genes) significant genes was filtered according to a high P-value cut-off (P<0.00001). Among them, 130 were upregulated (expression ratio>1.5) and 288 were down-regulated (<1/1.5). Analysis of variance revealed 62 genes differentially expressed (P<0.05) in Groups D and S. The expression levels of 28 and 50 genes were significantly correlated (r>0.75) with CK and AST level in Group D, respectively. The gene ontology classification showed that more genes were up-regulated in S than in the D. More genes were down-regulated in the disqualified horses., Conclusions: Long exercise induced many significant gene modulations in leucocytes. Some genes were expressed in relationship with the clinical phenotype observed in Group D: rhabdomyolysis and haemolysis., Potential Relevance: Some of these genes could be candidates to explain poor performance or pathologies. Further association studies with a greater number of genes should be conducted.

Morphologic assessment of spermatozoa is one of the most objective measures in a Breeding Soundness Examination of a stallion. There are different systems for morphologic assessment of spermatozoa. The objectives of this article are to review spermatogenesis, describe clinical sample preparation, discuss previous methods of morphologic classification and explain the use of a differential spermiogram. The advantages of the differential spermiogram method of analysis are discussed, along with its use in delineating intrinsic and extrinsic disturbances in spermatogenesis. Case examples of specific cellular associations and their diagnostic relevance are discussed.

We used the sperm chromatin structure assay (SCSA) to study the change in stallion sperm DNA susceptibility to denaturation after exposure of extended semen to three different storage temperatures (5, 20, or 37 degrees C) at 7, 20, 31, and 46 h. In addition, we compared the rates of sperm DNA denaturation in fertile and subfertile stallions. Among fertile stallions, spermatozoa stored at 20 and 37 degrees C showed a significant (P < 0.05) rise in the SCSA measures (Mean(alpha1), S.D.(alpha(t)), and percent cells outside the main population-COMP(alpha(t))) overtime, with the degree of rise being more dramatic at 37 degrees C. Over all stallions, samples stored at 5 degrees C showed no significant (P > 0.05) changes in the SCSA values measured over time, indicating maintenance of chromatin quality for up to 46 h. The COMP(alpha(t)) from stallions classified as subfertile showed an increased susceptibility to denaturation or decline in chromatin quality between 20 and 31 h when stored at 5 degrees C; however, spermatozoa from fertile stallions did not change during the time intervals analyzed. These data suggest that sperm DNA from some subfertile stallions may decline at a greater rate than spermatozoa from fertile stallions when exposed to similar storage conditions.

The activities of the enzymes related to the malate-aspartate shuttle, which convert cytosolic NADH into mitochondrial NADH, were measured in red and white blood cells from thoroughbred horses undergoing continuous training (race horses) and compared with those in blood cells from riding horses. The activities of malate dehydrogenase (MDH), a rate-limiting enzyme for the malate-aspartate shuttle, were significantly elevated in the white blood cells (WBC) from race horses compared with those from riding horses. There were no significant differences in the activities of the enzymes in the red blood cells between race horses and riding horses. This increase in the MDH activity in their WBC is considered to reflect the increased metabolic activity in the race horses resulting from the training.

Over the last 30 years, the increase in interest in horses for racing and riding activities has stimulated scientific research in equine locomotion. This paper presents a review of the measurement methods and their applications used to assess equine locomotion. After describing gaits and velocity-related changes in stride variables, the current applications of gait analysis are presented. The economic consequences of lameness justifies the great effort now being put into lameness quantification and prevention. To improve breeding and reduce the costs of training, early performance evaluation tests for each discipline are proposed. After extensive fundamental and methodological research on the various aspects of equine locomotion, the horse industry should benefit from the applications of gait analysis by improving the profitability of racing and riding activities.

The Spanish sheep and horse strains of Echinococcus granulosus possess several differential characteristics in their metacestode stage. Cysts from sheep vary widely in size and fertility, but they usually have a thin cyst wall and, when fertile, a whitish hydatid sand formed by brood capsules and protoscoleces. Two types of infections have been observed in horses: one resembling that of sheep, caused by small, non-fertile cysts with a thin wall, and a second type caused by medium to large, always fertile cysts with a thick wall. In this latter case, hydatid sand is always dark brown in color and formed mainly by brood capsules (with almost no free protoscoleces) and abundant calcareous corpuscles. These characteristics of the fertile equine cysts, which were identified in other studies by genetic, biochemical, immunological and physiological criteria as belonging to the horse strain, have not been previously described nor observed in cysts from other host species. It is considered that the horse strain possesses a strong intermediate host specificity.

Eighty Standardbred horses, originating from 5 training campuses, with decreased athletic performance in association with symptoms such as intermittent fever and mild pharyngitis were examined. As control animals, 10 horses from a stable with normally performing horses were used. Virus isolation and clinico-chemical and serological tests were performed. Lymphocyte proliferation tests were carried out to evaluate the capacity of the cell-mediated immunity. In addition, a bioassay for equine type I interferon, as a marker for early viral infections, was established. No specific microbe could be linked to these symptoms, but there was a temporary suppression of the cell-mediated immunity, which might be explained by the serological evidence of an EHV-2 and/or rhinovirus infection.

A clinical material of 133 Standardbred horses with palmar/plantar osteochondral fragments (POF) in the metacarpo- and metatarsophalangeal joints were studied. All horses had their fragments removed with arthroscopic surgery. 102 of the horses were 3 years old or younger when surgery was performed. Anatomical localisations of the fragments were in agreement with earlier reports. There was no statistical significant difference in month of birth in the POF--group compared to the total population. Eighty % of the horses that had raced before surgery came back to racing. The racing performance relative to their contemporaries remained the same after the POF operation. 65% of the horses that had not raced before surgery raced after the operation. The breeding index BLUP (Best Linear Unbiased Prediction) was used to evaluate if the POF-horses differed genetically in racing ability from the total population. The average BLUP value of the POF group was 103.4 (+/- 0.65), while the mean BLUP value of the total population was 98.9. This difference was highly significant and indicated that these POF horses belonged to a selected group. A homogeneity test of allele frequencies in blood type systems was performed to evaluate if any genetic difference was persistent between POF horses compared to the total population. The statistical analysis of gene frequencies for alleles in blood type systems indicated a genetic discrimination in blood type systems D and Tf.

Three groups of foals were raised under different management programs in this study: Group 1 (n = 6) and Group 2 (n = 6) were raised with their dams on pasture; Group 3 foals (n = 5) were raised under parasite-free conditions. Mares and foals of Group 1 received daily pyrantel tartrate (PT) treatment with their pelleted feed ration, whereas mares and foals of Groups 2 and 3 received only the pelleted ration. Pasture-reared foals were weaned and moved to a heavily contaminated pasture for 5 weeks. Group 1 foals continued to receive daily PT treatment whereas Group 2 foals received only the pelleted feed ration. Following this period, all foals were moved into box stalls. Half of each group was challenged with 10(3) Strongylus vulgaris infective third-stage larvae (L3), 5 x 10(3) Strongylus edentatus L3 and 10(5) mixed cyathostome L3; the remaining half served as unchallenged controls. Necropsy examinations were performed 6-week post-challenge for evaluation of parasite burdens and lesions. Daily PT treatment of Group 1 reduced the patent cyathostome infections of both mares and foals and was effective in reducing pasture burdens of infective larvae. Daily treatment of Group 1 foals during weaning continued to suppress EPG levels; however, it did not prevent large strongyle infections during the weaning period. Group 1 foals were more sensitive to challenge than Group 2 foals, which did not exhibit any post-challenge disturbances. Group 1 foals were equally susceptible to challenge as parasite-free foals.

The functional properties of different immunoglobulin isotypes in equine recurrent uveitis (ERU) has not been investigated yet. Here, we describe the quantitative determination of total immunoglobulin levels and isotype differentiation in the vitreous of four horses with ERU as compared to that of seven healthy horses. In contrast to almost equal amounts of total immunoglobulin in the vitreous of both groups, remarkable differences were found: All four of the horses with ERU had significantly higher IgA contents in their vitreous as compared to the control group. However, the other isotypes monitored (IgM, IgGa, IgGb, IgGc and IgG(T)) indicated no differences between both groups. Comparing the individual ratios of immunoglobulin isotypes in the vitreous and the autologous serum of two horses with ERU and two control animals provided informative results: IgM was only detected in serum but not at all in vitreous of all horses investigated. All four IgG isotypes monitored in the diseased animals as well as these IgG isotypes and the IgA in healthy animals were present in the same ratios in serum and in vitreous of the individual horses. In general, the content of such isotypes in the vitreous was about 1000 fold lower then the respective isotypes in the autologous serum. These results are compatible with a transfer of the IgG and IgA isotypes from the serum into the vitreous in healthy individuals. All four horses with ERU, however, had a selectively increased relative IgA content in the vitreous as compared to their serum. This argues for a preferential local IgA production within the framework of a local immunological reaction to antigens located within the eyes of horses with ERU.

Objective: To determine normal CSF electrophoresis patterns in horses, and to determine whether the electrophoretic scans from horses with cervical compression differ from those of neurologically normal horses., Animals: 32 horses assigned to 1 of 2 groups: neurologically normal (n = 18) or cervical compression (n = 14)., Procedure: CSF was collected from 18 neurologically normal horses referred to the Marion duPont Scott Equine Medical Center, and protein electrophoresis was performed to describe the normal equine CSF electrophoretogram. Results of CSF electrophoresis from 14 horses with cervical compression were then compared with results for the neurologically normal horses., Results: Horses with cervical compression had decreased beta-globulin fraction, and 1 or 2 prominent post-beta 2 peak(s). When the presence of post-beta peaks was used as a diagnostic criterion for cervical compression, the test had sensitivity of 71.4% and specificity of 81.8%. The positive and negative predictive values were 83.3 and 69.2%, respectively., Conclusion and Clinical Implications: Electrophoresis of CSF may be a useful diagnostic aid in evaluation of horses with neurologic disease.

Objective: To determine whether laryngeal hemiplegia would increase transmural pulmonary artery pressure (TPAP)., Animals: 6 horses., Design: Horses were studied under 5 conditions: control conditions, after induction of left laryngeal hemiplegia, during obstruction of the left nostril, after placement of an instrumented tracheostomy, and after placement of an open tracheostomy. Horses were evaluated after being given saline solution and after being given furosemide., Procedures: Horses were exercised on a high speed treadmill, using a maximum speed of 13 m/s. During each exercise, airway pressures, airflow, esophageal and pulmonary artery pressures, and blood gas partial pressures were measured., Results: When adjusted for horse, speed, and obstruction condition, mean TPAP (pulmonary artery pressure-esophageal pressure) and minimum TPAP were significantly lower after administration of furosemide than after administration of saline solution. In horses given saline solution, respiratory obstruction that increased intrapleural pressure significantly increased mean TPAP, and respiratory obstruction that decreased intrapleural pressure significantly decreased minimum TPAP., Conclusions: Changes in intrapleural pressure appear to play an important role in pulmonary artery pressure and TPAP., Clinical Relevance: Because induction of laryngeal hemiplegia did not increase TPAP, laryngeal hemiplegia is unlikely to contribute to development of exercise-induced pulmonary hemorrhage.

The collagenolytic activity and its sensitivity to doxycycline inhibition in tracheal aspirates (TA) of horses with chronic obstructive pulmonary disease (COPD) was analyzed with SDS-PA gel electrophoresis (SDS-PAGE), using Type 1 collagen as the substrate. Both autoactive and total collagenase activities were significantly higher in TAs of horses with symptomatic COPD than in TAs of healthy horses. Doxycycline inhibition studies suggest that most of the TA collagenase is of the neutrophil type (MMP-8), but some is derived from other cells such as fibroblasts and monocyte/macrophages (MMP-1) and bacteria (bacterial collagenases). Drugs inhibiting collagenases in the respiratory tract might be worth a trial in the treatment of COPD in horses.

Cryptosporidium parvum and Giardia duodenalis are now recognized as primary enteric pathogens in animals and humans. Regulatory agencies, such as the Environmental Protection Agency are under increasing pressure to reduce the concentration of these protozoa in surface waters. Given the popularity of recreational riding of horses on public land in California backcountry, concerns have been raised by various regulatory agencies as to whether horses used for backcountry recreation are a significant source of C. parvum and G. duodenalis for the environment. The prevalence of fecal shedding of Cryptosporidium and Giardia in horses with a history of being ridden in California backcountry during 1993 and 1994 was estimated. Using both direct fluorescent antibody and levitation centrifugation tests, none of 91 single-collection fecal samples from throughout California had Cryptosporidium oocysts or Giardia cysts. Horses ranged from 4 to 24 years of age. Because none of the 91 samples, collected 1 time from each horse, were positive and assuming that the sensitivity and specificity of the test methods employed were 100%, the highest probable prevalence of shedding for either protozoal pathogen was < 3.2% for the cohort of horses studied.

Chronic synovitis may cause recurring lameness in competing race horses. Forty-five standardbred horses with recurring lameness secondary to chronic synovitis were studied. Arthroscopic synovectomy was performed in 32 metacarpo-/metatarsophalangeal joints and in 28 intercarpal joints of horses that had previously been treated unsuccessfully with commonly used intraarticular medication The outcome of the synovectomy was evaluated by comparing racing performance before and after surgery. The synovial membrane was microscopically characterized as chronic synovitis of varying severity. Racing performance was expressed by racing results including average earnings/race, place 1-3, best time and racing index. Fourteen of 19 horses with chronic synovitis of the intercarpal joint performed at an equal or higher racing level after synovectomy. Twenty-one of 26 horses with lameness secondary to chronic synovitis in the fetlock joint had an equal or higher racing capacity after synovectomy. The results of this study indicates that arthroscopic synovectomy in combination with rest is an effective method in the treatment of chronic synovitis when conventional intraarticular medication has failed.

The efficacy of treatment with cambendazole was tested in 1-year-old horses on a farm in Dubrovka, Ukraine. Thirty-five horses were treated. Their egg output was compared on the day of treatment and 14 days later with that of 33 untreated horses. Before treatment the mean number of eggs g-1 faeces was 614 in the controls and 766 in horses that had been treated. After 14 days the mean egg output in the controls was 580 and in the treated horses 369. This means a reduction of 54.5%. Only cyathostome larvae could be cultured from faeces collected after treatment. It can be concluded that benzimidazole resistance in cyathostomes is present in the Ukraine.

This review compromises data about endogenous cortisol and its physiological variations in horses. The influence of synthetic glucocorticoids on the endogenous cortisol concentrations is discussed as well. The second part of the review summarizes detection times of therapeutically used glucocorticoids (dexamethasone, betamethasone, triamcinolone, prednisone, prednisolone, methylprednisolone and hydrocortisone) in the horse and their implication for doping control.

The tumour suppressor protein p53 enhances the genetic stability of the cell and plays a critical role in tumour suppression. Equine p53 was analysed by sequencing exons 5 to 9, a region which includes most known mutations and all the mutational hotspots in the species that have been investigated. The fragment was amplified, cloned and sequenced from genomic and complementary DNA. A comparison of the predicted amino acid sequences between the horse and other species resulted in identities between 66 per cent with the clawed frog and 92 per cent with the cat. Using the single strand conformation polymorphism technique, exons 5 to 8 amplified from sarcoid tissue and peripheral leucocytes of 28 sarcoid-affected and 11 healthy horses were screened for mutations. No mutations were identified, suggesting that the frequency of p53 mutations in equine sarcoid might be low. However, the high incidence of bovine papillomavirus (BPV) infection in equine sarcoid may indicate the functional inactivation of p53 by BPV-encoded E6 protein.

Carbohydrate-induced laminitis has been associated with decreased platelet survival, decreased blood flow to the hoof wall and with the deposition of platelets and microthrombi within venules in the dermal laminae. To evaluate further the systemic prothrombotic events occurring in the prodromal stages of laminitis, plasma samples from control and laminitis-affected ponies and horses were tested for the presence of thrombin-antithrombin (TAT) complexes and fibrin fragment D (D-dimer). No statistically significant differences between the control and laminitis-affected animals were observed for either the D-dimer or the TAT complexes. Few of the values for individual animals exceeded the reference ranges for control animals. These data indicate that the prothrombotic events observed in carbohydrate-induced laminitis may not be associated with systemic activation of the coagulation or fibrinolytic systems.

Exercise has been recognized as a stress, which can significantly alter the host's immune response and, therefore, its susceptibility to disease. Whereas research in this area has previously focused primarily on human subjects and laboratory animals, it has more recently extended to domestic animals, especially the equine athlete. Despite several studies, defining the relationship among exercise, the immune response, and disease has proven difficult due to a number of factors, including the complexity of the immune system and the variable nature of exercise itself. It now appears that exercise has dual effects on the immune system. Suppressive effects, such as a decline in the ratio of CD4+ to CD8+ cells, diminished lymphocyte function, and a decline in the number and cytolytic activity of natural killer cells have been observed in response to brief high-intensity exercise, prolonged exhaustive exercise, and overtraining. In contrast, moderate training generally has beneficial effects on host defense mechanisms. The mechanisms for regulating the dual effects of exercise are complex, involving a network of neuroendocrine hormones and cytokines.

Objective: To evaluate selected shoe characteristics as risk factors for fatal musculoskeletal injury (FMI) and specifically for suspensory apparatus failure (SAF) and cannon bone condylar fracture (CDY) of Thoroughbred racehorses in California., Design: Case-control study., Animals: Thoroughbred racehorses (n = 201) that died of were euthanatized at California racetracks between August 1992 and July 1994., Procedure: Shoe characteristics were compared between case horses affected by FMI (155), SAF (79), and CDY (41) and control horses that died for reasons unrelated to the appendicular musculoskeletal system (non-FMI; 46). Multivariable logistic regression was used to estimate odds ratios for FMI, SAF, and CDY., Results: Toe grabs were identified as possible risk factors for FMI, SAF, and CDY. The odds of FMI, SAF, and CDY were 1.8, 6.5, and 7.0, respectively, times greater for horses shod with low toe grabs than for horses shod without toe grabs on front shoes. Horses shod with regular toe grabs on front shoes had odds 3.5, 15.6, and 17.1 times greater (P < 0.05) for FMI, SAF, and CDY, respectively, compared with horses shod without toe grabs. The odds of horses shod with rim shoes were a third (P < 0.05) of those shod without rim shoes for either FMI or SAF. The apparent association between toe grab type and CDY may, in part, be attributable to concurrent SAF and CDY injuries in many horses., Clinical Relevance: Avoiding the use of toe grabs should decrease the incidence of FMI, especially SAF, in Thoroughbred racehorses. The use of rim shoes that are more consistent with natural hoof shape may decrease injury risk.

Objective: To analyze in vitro lymphocyte-mediated immune responses of horses with sarcoids against allogeneic sarcoid cells containing endogenous retrovirus but not expressing major histocompatibility complex antigens., Design: Lymphocyte-mediated immune reactions were assessed by means of proliferative responses in mixed lymphocyte tumor cell culture (MLTC) assay and lymphocyte-mediated cytotoxicity against various equine target cells., Animals: 12 horses with sarcoid tumors and 15 control horses., Procedure: Blood lymphocytes were cocultured in MLTC with allogeneic sarcoid cells (Mc-1, BayMc-1), equine testis cells, or normal equine dermal fibroblasts. Lymphocytes were assayed for proliferative responses by [3H]thymidine uptake and for cytotoxicity against the same targets by 51Cr release assay. The lymphocyte populations were analyzed for some common surface markers., Results: Lymphocytes from horses with sarcoids exerted an anamnestic proliferative response in MLTC against Mc-1 cells, but this procedure never generated cytotoxic lymphocytes. However, lymphocytes from all horses cultured in medium with 10% allogeneic serum only had selective. natural cytotoxicity against Mc-1 that was generated without DNA synthesis. Approximately 80% of the lymphocytes disappeared during culture; however the remaining population of small, viable lymphocytes indicated a decrease of CD4+ T lymphocytes, but numbers of T cells with receptors for Helix pomatia A hemagglutinin were unaffected. Few lymphocytes had Fc-receptors for IgG, were complement-reactive positive cells or were B cells expressing surface immunoglobulin., Conclusions: Results may indicate a natural defense system, which preferentially recognizes and lyses tumor cells that are deficient in surface expression of major histocompatibility complex antigens, without intervention of conventional T-cell receptors or antibodies.

The secondary constituents accompanying calcite and vaterite (crystalline forms of calcium carbonate) in the sabulous deposits from 140 vesical samples and one renal sample of equine urine were studied by infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Apatitic calcium phosphate, present in 12 per cent of the samples, generally appeared in the form of spherulites with smooth and rough surfaces. Calcium sulphate, clearly detected by IR in 12.7 per cent of the samples, did not have a characteristic structure under SEM, although EDX detected sulphur in the samples. Amorphous silica was observed in one case and had a nodular appearance. Organic fibres were not as common as might have been expected in equine urinary deposits.

Objective: To evaluate the distribution of mepivacaine hydrochloride after distal interphalangeal (DIP) joint injection in horses., Design: Prospective, uncontrolled study., Animals: 10 adult horses., Procedure: 30 minutes before euthanasia, 8 ml of 2% mepivacaine hydrochloride was injected into the dorsal pouch of a forelimb DIP joint. Synovial tissue from the DIP joint and podotrochlear (navicular) bursa and bone tissue from the medullary cavity of the distal sesamoid (navicular) bone were taken from both forelimbs immediately after death. All synovial and bone specimens were analyzed for tissue concentration of mepivacaine by high-performance liquid chromatography. Synovial tissue and bone specimen concentrations from the injected forelimb were compared with corresponding specimens from the noninjected forelimb. All synovial tissue and bone specimen concentrations were compared with an estimated effective tissue concentration of mepivacaine (0.3 microgram/mg) for local anesthesia., Results: Specimen concentrations of mepivacaine from the injected forelimb were significantly greater (P < 0.05) than those in the corresponding tissues of the contralateral noninjected forelimb. All DIP joint and navicular bursa synovial tissue specimens from the injected forelimb had greater than the estimated effective tissue concentration of mepivacaine for local anesthesia. Of the 10 navicular bone specimens from the injected forelimb, 4 were higher and 2 were within 20% of the estimated effective tissue concentration of mepivacaine for local anesthesia., Conclusions: Mepivacaine hydrochloride deposited into the DIP joint should anesthetize pain arising from navicular bursa synovia and may decrease pain arising from the medullary cavity of the navicular bone., Clinical Relevance: DIP joint injection of mepivacaine hydrochloride is not specific for DIP joint pain.

Objectives: To adapt and characterize a human ELISA kit to quantify thrombin-antithrombin III (TAT) complexes in horses, and to evaluate TAT as a marker for hypercoagulation in horses., Animals: 29 clinically normal horses used as controls, and 4 ill horses used to evaluate assay for known causes of hypercoagulation., Procedure: A commercially available human sandwich-type ELISA kit with 2 antibodies against human thrombin and antithrombin III that bind selectively to their corresponding TAT antigenic sites was used. Equine TAT standards were made from purified equine thrombin and antithrombin III. Proteins diluted in a phosphate-buffered saline solution containing 0.1% Tween and 1 U of heparin/ ml were used to establish standard curves. Reference intervals for TAT concentration in citrated equine plasma, and intra- and interassay coefficients of variation were determined., Results: Mean +/- SD values were 3.95 +/- 1.93 micrograms/L, with median of 3.18 micrograms/L and range of 1.95 to 9.03 micrograms/ L. One horse with cecal perforation had TAT concentration of 174.30 micrograms/L, and a horse infused IV with endotoxin had TAT concentration of 62.98 micrograms/L 12 hours after infusion., Conclusions: The data suggest that human TAT ELISA kits can be used to measure TAT concentration in citrated equine plasma, and that TAT is a marker for hypercoagulation in horses., Clinical Relevance: Assays for equine TAT many help to further characterize the hypercoagulable state in horses.

Serotype, biotype, antibiogram, hemolysin production, fimbrial hemagglutinins, select toxin genes (STb, STaP, LT, slt1 and slt2) and the attaching effacing (eae) gene were determined for 99 foal strains of E. coli. E. coli from diarrheic and normal foals could not be distinguished by serotype, biotype, or antibiogram. Differences (P < or = 0.05) were observed in hemolysin production (11.5% vs 0%) and the expression of mannose-resistant hemagglutinins (23% vs 13%) among E. coli from diarrheic and healthy foals, respectively. Three of the E. coli strains from diarrheic foals were positive with probes for slt genes and one was positive for STb and LT genes. One strain from a healthy foal possessed the STb gene. As determined by the polymerase chain reaction, 8 strains possessed the eae gene. Seven of the 8 strains were from diarrheic foals and one eae-positive strain was from a healthy foal. The slt-positive strains did not possess eae genes and the eae-positive strains did not possess slt genes. These results indicate that enterotoxigenic strains of E. coli are not implicated in any substantial degree in sporadic foal diarrhea. However, the identification of slt-positive and eae-positive strains in foal feces indicate the presence of potentially virulent strains among foals.