RESUMO
OBJECTIVE: To clarify the anti-inflammatory effect of platelet lysate (PL) on equine persistent synovitis by using a model of synovitis induced by monoiodoacetic acid (MIA). METHODS: Nonseptic synovitis was induced by administering MIA into both antebrachiocarpal joints of 6 clinically healthy horses on day 0. On days 23, 30, and 37, carpal circumference measurement and synovial fluid collection for assays (leucocytes, LDH, tumor necrosis factor-α, and TGF-ß1) were performed, after which PL was injected into 1 antebrachiocarpal joint and saline into the contralateral joint. Synovium and synovial fluid were obtained on day 44 for histological analysis and quantification of inflammation-related genes (matrix metalloproteinase-13, a disintegrin and metalloproteinase with thrombospondin motifs 4, receptor activator of nuclear factor κ-Β ligand, and collagen type I α2 chain) and the abovementioned proteins. RESULTS: The LDH level on day 44 was significantly lower in the PL-injected joint than in the saline-treated one. However, no significant differences were found in the other indices quantified, including osteoclast counts on the synovium. CONCLUSIONS: Multiple IA administration of PL does not exert anti-inflammatory effects on the equine persistent synovitis induced by MIA. CLINICAL RELEVANCE: Intra-articular PL administration did not alter many inflammatory biomarkers, suggesting that PL does not have a direct anti-inflammatory effect. However, the reduction in synovial LDH levels suggests that PL promoted joint tissue repair and may consequently alleviate inflammation at the site of administration.
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Retraining retired racehorses for various purposes can help correct behavioral issues. However, ensuring efficiency and preventing accidents present global challenges. Based on the hypothesis that a simple personality assessment could help address these challenges, the present study aimed to identify genetic markers associated with personality. Eight genes were selected from 18 personality-related candidate genes that are orthologs of human personality genes, and their association with personality was verified based on actual behavior. A total of 169 Thoroughbred horses were assessed for their tractability (questionnaire concerning tractability in 14 types of situations and 3 types of impressions) during the training process. Personality factors were extracted from the data using principal component analysis and analyzed for their association with single nucleotide variants as non-synonymous substitutions in the target genes. Three genes, CDH13, SLC6A4, and MAOA, demonstrated significant associations based on simple linear regression, marking the identification of these genes for the first time as contributors to temperament in Thoroughbred horses. All these genes, as well as the previously identified HTR1A, are involved in the serotonin neurotransmitter system, suggesting that the tractability of horses may be correlated with their social personality. Assessing the genotypes of these genes before retraining is expected to prevent problems in the development of a racehorse's second career and shorten the training period through individual customization of training methods, thereby improving racehorse welfare.
Assuntos
Comportamento Animal , Caderinas , Monoaminoxidase , Personalidade , Polimorfismo de Nucleotídeo Único , Animais , Cavalos/genética , Monoaminoxidase/genética , Personalidade/genética , Polimorfismo de Nucleotídeo Único/genética , Comportamento Animal/fisiologia , Caderinas/genética , Genótipo , Masculino , Feminino , Proteínas da Membrana Plasmática de Transporte de Serotonina/genéticaRESUMO
Effects of different winter paddock management of Thoroughbred weanlings and yearlings in Hokkaido, Japan, which is extremely cold in winter, on physiological function, endocrine function and growth were investigated. They were divided into two groups; those kept outdoors for 22 hr in the paddock (22hr group) and those kept outdoors for 7 hr in daytime with walking exercise for 1 hr using the horse-walker (7hr+W group), and the changes in daily distance travelled, body temperature (BT), heart rate (HR), HR variability (HRV), endocrine function and growth parameters were compared between the two groups from November at the year of birth to January at 1 year of age. The 7hr+W group could travel almost the same distance as the 22hr group by using the horse-walker. The 22hr group had a lower rate of increase in body weight than the 7hr+W group in January. In addition, lower in BT and HR were observed, and HRV analysis showed an increase in high frequency power spectral density, indicating that parasympathetic nervous activity was dominant. And also, changes in circulating cortisol and thyroxine were not observed despite cold environment. On the other hand, the 7hr+W group had higher prolactin and insulin like growth factor than the 22hr group in January, and cortisol and thyroxine were also increased. Physiological and endocrinological findings from the present study indicate that the management of the 7hr+W group is effective in promoting growth and maintaining metabolism during the winter season.
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Criação de Animais Domésticos , Sistema Endócrino , Cavalos , Japão , Cavalos/crescimento & desenvolvimento , Criação de Animais Domésticos/métodos , Estações do Ano , Sistema Endócrino/fisiologia , Temperatura Baixa , Frequência Cardíaca , Masculino , Feminino , Animais , Hormônios/sangue , Aumento de Peso/fisiologia , Condicionamento Físico AnimalRESUMO
This study investigated age-related radiographic changes in the distal parts of the forelimbs by radiographic evaluation and identified the radiographic changes associated with diseases specific to foals. The hoof angle (HA), distal phalanx angle (P3A), distal phalanx palmer angle (P3PA), distal interphalangeal joint angle (DIPJA), and metacarpophalangeal joint angle (MPJA) on lateromedial radiographs of forelimbs were measured on the day after birth (Day 1); at 1, 2, 4, 6, and 8 weeks of age; and then at monthly intervals until 12 months of age. HA and P3A significantly increased from 1 day to 4 weeks and 4 weeks to 3 months of age. The P3PA increased dramatically from 1 day to 1 week, 1 week to 2 weeks, and 2 weeks to 8 weeks of age, and then decreased after 3 months of age. DIPJA significantly decreased from 1 day to 2 weeks of age before increasing from 3 to 5 months of age. MPJA increased with age until 4 weeks, slightly decreased from 2 to 4 months of age, and then gradually decreased from 4 to 6 months of age. The findings indicate that foals' forelimbs typically show flexion of the fetlock and a broken backward hoof-pastern axis just after birth, an upright fetlock until 4 months of age, and a change to a mature conformation after 6 months of age. Physiological variants were correlated with the occurrence of common foal diseases during the radiographic evaluation periods.
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Casco e Garras , Cavalos , Animais , Casco e Garras/diagnóstico por imagem , Membro Anterior/diagnóstico por imagem , Radiografia , Extremidades , Osso e OssosRESUMO
Throughout the Plio-Pleistocene, climate change has impacted tropical marine ecosystems substantially, with even more severe impacts predicted in the Anthropocene. Although many studies have clarified demographic histories of seabirds in polar regions, the history of keystone seabirds of the tropics is unclear, despite the prominence of albatrosses (Diomedeidae, Procellariiformes) as the largest and most threatened group of oceanic seabirds. To understand the impact of climate change on tropical albatrosses, we investigated the evolutionary and demographic histories of all four North Pacific albatrosses and their prey using whole-genome analyses. We report a striking concordance in demographic histories among the four species, with a notable dip in effective population size at the beginning of the Pleistocene and a population expansion in the Last Glacial Period when sea levels were low, which resulted in increased potential coastal breeding sites. Abundance of the black-footed albatross dropped again during the Last Glacial Maximum, potentially linked to climate-driven loss of breeding sites and concordant genome-derived decreases in its major prey. We find very low genome-wide (π < 0.001) and adaptative genetic diversities across the albatrosses, with genes of the major histocompatibility complex close to monomorphic. We also identify recent selective sweeps at genes associated with hyperosmotic adaptation, longevity, and cognition and memory. Our study has shed light on the evolutionary and demographic histories of the largest tropical oceanic seabirds and provides evidence for their large population fluctuations and alarmingly low genetic diversities.
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Evolução Biológica , Ecossistema , Animais , Variação Genética , AvesRESUMO
Persistent synovitis damages the articular cartilage in horses. To evaluate the effectiveness of treatment for synovitis using a model induced by intra-articular administration of monoiodoacetic acid (MIA), it is necessary to identify inflammatory biomarkers characteristic of the MIA model. Synovitis was induced by administering MIA into the unilateral antebrachiocarpal joints of five horses, and saline was injected into the contralateral joints as a control on day 0. Clinical and ultrasonographic examinations and synovial fluid collection were performed on days 0, 1, 2, 7, 14, 21, 28, and 35. Leukocyte, lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6), and transforming growth factor-ß1 (TGF-ß1) concentrations in the synovial fluid were measured. Synovium was obtained after euthanasia on day 42 and histologically examined before quantification of the gene expression of inflammatory biomarkers by real-time PCR. Acute inflammatory symptoms persisted for approximately 2 weeks before returning to control levels. However, some indicators of chronic inflammation remained elevated until day 35. On day 42, synovitis continued histologically, with osteoclasts. The expressions of matrix metalloproteinase 13 (MMP13), a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4), receptor activator of nuclear factor kappa-Β ligand (RANKL), and collagen type I α2 chain (Col1a2) were significantly higher in the MIA model than in the control. In the MIA model, representative inflammatory biomarkers in the chronic inflammatory stage were persistently expressed in both synovial fluid and tissue, suggesting that they may be useful for the assessment of the anti-inflammatory effect of drugs.
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Doenças dos Cavalos , Sinovite , Cavalos , Animais , Ácido Iodoacético/efeitos adversos , Sinovite/induzido quimicamente , Sinovite/tratamento farmacológico , Sinovite/metabolismo , Sinovite/veterinária , Colágeno Tipo I/efeitos adversos , Biomarcadores , Doenças dos Cavalos/induzido quimicamente , Doenças dos Cavalos/tratamento farmacológico , Doenças dos Cavalos/metabolismoRESUMO
A pharmacokinetics/pharmacodynamics (PK/PD) approach was used to determine the best empirical dosage regimen of cefazolin (CEZ) after intramuscular (IM) administration of CEZ in horses. Seven horses received a single IM or intravenous (IV) administration of CEZ of 5 mg/kg bodyweight (BW) according to a crossover design. CEZ plasma concentrations were measured using LC-MS/MS. The plasma concentrations in these seven horses and those of six other horses obtained in a previous study with an IV CEZ dose of 10 mg/kg were modelled simultaneously using NonLinear Mixed-Effect modelling followed by Monte Carlo simulations to establish a rational dosage regimen. A 90% Probability of Target Attainment (PTA) for a PK/PD target of a free plasma concentration exceeding MIC90 (fT > MIC ) for 40% of the dosing interval was set for selecting an effective dosing regimen. The typical half-life of absorption and bioavailability after IM administration were 1.25 h and 96.8%, respectively. A CEZ dosage regimen of 5 mg/kg BW q12h IM administration achieved therapeutic concentrations to control both Streptococcus zooepidemicus and Staphylococcus aureus. For the same dose, the fT > MIC after IM administration was significantly longer than after IV administration, and the IM route should be favoured by clinicians for its efficiency and convenience.
Assuntos
Antibacterianos , Cefazolina , Animais , Cavalos , Cefazolina/farmacologia , Método de Monte Carlo , Cromatografia Líquida/veterinária , Espectrometria de Massas em Tandem/veterinária , Testes de Sensibilidade Microbiana/veterináriaRESUMO
Late-term fetal loss in horses is a major problem in the horse-breeding industry globally. Abnormal pregnancies should be diagnosed as early as possible to prevent abortions and other gestational problems. According to our previous longitudinal study in healthy pregnant mares, the plasma activin A concentration increases as pregnancy progresses. The aim of the present study was to compare plasma activin A concentrations in healthy pregnant Thoroughbred mares (n=40) with those in pregnant mares that suffered fetal loss or showed abnormal symptoms (n=30) during late gestation. This field study found that plasma activin A concentrations were higher in the abnormal group (pregnancy loss, red bag delivery, premature udder development, and vaginal discharge) than the normal group (P < 0.001; cutoff value: ≥ 138.2 pg/mL; sensitivity, 74.4%; specificity, 77.5%). More specifically, plasma activin A concentrations in the "symptom" and "abnormal delivery" subgroups were higher than those in gestational-age-matched normal groups (P < 0.001). Nevertheless, the plasma activin A concentration in the "normal delivery" subgroup was not different from that in the "abnormal delivery" subgroup in samples collected within 10 days before delivery. In conclusion, this study is the first to demonstrate a significantly earlier increase in plasma activin A concentration in abnormal pregnancies of Thoroughbred mares during late gestation.
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Ativinas , Gravidez , Animais , Cavalos , Feminino , Idade GestacionalRESUMO
Cephalothin (CET) concentrations in body fluids (plasma, synovial fluid, pleural fluid, peritoneal fluid, and aqueous humor) and tissue samples (bone, lung, jejunum, hoof, and subcutaneous tissue) were investigated to consider the treatment of infectious diseases in horses. CET 22 mg/kg body weight was intravenously administered to 12 horses. Samples were collected from four different horses at 1, 3, and 5 hr after administration. The CET concentration in body fluids other than aqueous humor was maintained above the MIC90 values of Streptococcus zooepidemicus and Staphylococcus aureus until 5 hr, but it was not maintained above that of S. aureus in bone. CET (22 mg/kg twice a day) is effective for septic arthritis, pleuritis, and peritonitis caused by gram-positive bacteria but ineffective for osteomyelitis.
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In drug metabolism studies in horses, non-targeted analysis by means of liquid chromatography coupled with high-resolution mass spectrometry with data-dependent acquisition (DDA) has recently become increasingly popular for rapid identification of potential biomarkers in post-administration biological samples. However, the most commonly encountered problem is the presence of highly abundant interfering components that co-elute with the target substances, especially if the concentrations of these substances are relatively low. In this study, we evaluated the possibility of expanding DDA coverage for the identification of drug metabolites by applying intelligently generated exclusion lists (ELs) consisting of a set of chemical backgrounds and endogenous substances. Daprodustat was used as a model compound because of its relatively lower administration dose (100 mg) compared to other hypoxia-inducible factor stabilizers and the high demand in the detection sensitivity of its metabolites at the anticipated lower concentrations. It was found that the entire DDA process could efficiently identify both major and minor metabolites (flagged beyond the pre-set DDA threshold) in a single run after applying the ELs to exclude 67.7-99.0% of the interfering peaks, resulting in a much higher chance of triggering DDA to cover the analytes of interest. This approach successfully identified 21 metabolites of daprodustat and then established the metabolic pathway. It was concluded that the use of this generic intelligent "DDA + EL" approach for non-targeted analysis is a powerful tool for the discovery of unknown metabolites, even in complex plasma and urine matrices in the context of doping control.
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Dopagem Esportivo , Animais , Cromatografia Líquida/métodos , Cavalos , Espectrometria de Massas/métodos , Preparações Farmacêuticas , Detecção do Abuso de Substâncias/métodosRESUMO
The creation of genetically modified horses is prohibited in horse racing as it falls under the banner of gene doping. In this study, we developed a test to detect gene editing based on amplicon sequencing using next-generation sequencing (NGS). We designed 1012 amplicons to target 52 genes (481 exons) and 147 single-nucleotide variants (SNVs). NGS analyses showed that 97.7% of the targeted exons were sequenced to sufficient coverage (depth > 50) for calling variants. The targets of artificial editing were defined as homozygous alternative (HomoALT) and compound heterozygous alternative (ALT1/ALT2) insertion/deletion (INDEL) mutations in this study. Four models of gene editing (three homoALT with 1-bp insertions, one REF/ALT with 77-bp deletion) were constructed by editing the myostatin gene in horse fibroblasts using CRISPR/Cas9. The edited cells and 101 samples from thoroughbred horses were screened using the developed test, which was capable of identifying the three homoALT cells containing 1-bp insertions. Furthermore, 147 SNVs were investigated for their utility in confirming biological parentage. Of these, 120 SNVs were amenable to consistent and accurate genotyping. Surrogate (nonbiological) dams were excluded by 9.8 SNVs on average, indicating that the 120 SNV could be used to detect foals that have been produced by somatic cloning or embryo transfer, two practices that are prohibited in thoroughbred racing and breeding. These results indicate that gene-editing tests that include variant calling and SNV genotyping are useful to identify genetically modified racehorses.
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Edição de Genes , Miostatina , Animais , Sequenciamento de Nucleotídeos em Larga Escala , Cavalos/genética , Miostatina/genética , Nucleotídeos , Análise de Sequência de DNARESUMO
BACKGROUND: Vadadustat, a hypoxia-inducible factor prolyl hydroxylase (HIF-PHD) inhibitor, is a substance which carries a lifetime ban in both horse racing and equestrian competition. A comprehensive metabolic study of vadadustat in horses has not been previously reported. OBJECTIVE: Metabolism and elimination profiles of vadadustat in equine plasma and urine were studied for the purpose of doping control. METHODS: A nasoesophageal administration of vadadustat (3 g/day for 3 days) was conducted on three thoroughbred mares. Potential metabolites were comprehensively detected by differential analysis of full-scan mass spectral data obtained from both in vitro studies with liver homogenates and post-administration samples using liquid chromatography high-resolution mass spectrometry. The identities of metabolites were further substantiated by product ion scans. Quantification methods were developed and validated for the establishment of the excretion profiles of the total vadadustat (free and conjugates) in plasma and urine. RESULTS: A total of 23 in vivo and 14 in vitro metabolites (12 in common) were identified after comprehensive analysis. We found that vadadustat was mainly excreted into urine as the parent drug together with some minor conjugated metabolites. The elimination profiles of total vadadustat in post-administration plasma and urine were successfully established by using quantification methods equipped with alkaline hydrolysis for cleavage of conjugates such as methylated vadadustat, vadadustat glucuronide, and vadadustat glucoside. CONCLUSION: Based on our study, for effective control of the misuse or abuse of vadadustat in horses, total vadadustat could successfully be detected for up to two weeks after administration in plasma and urine.
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Glicina , Fígado , Cavalos , Animais , Feminino , Espectrometria de Massas , Cromatografia Líquida/métodos , Glicina/metabolismo , Fígado/metabolismoRESUMO
Cervical vertebral stenotic myelopathy (CVSM), a common cause of cervical spinal cord compression, is a neurological disease characterized by general proprioceptive ataxia and weakness of hindlimbs that tends to develop in young adult Thoroughbred horses. Although male horses seem to be at increased risk for CVSM, the mechanism for the occurrence of sex differences in the prevalence of CVSM is still poorly understood. Hence, we hypothesized that sex differences in the development of cervical spinal cord and spinal canal would affect the development of CVSM. This study aimed to evaluate sex differences in the development of cervical spinal cord and spinal canal in Thoroughbred horses. A total of 29 Thoroughbred horses underwent computed tomographic myelography. Thereafter, the volumes of cervical spinal cord and spinal canal were calculated. Accordingly, male horses had significantly lager cervical spinal cord volume and cervical spinal cord-to-spinal canal volume ratio than those of female horses (P<0.05). Sex differences in the cervical spinal cord-to-spinal canal volume ratio gradually decreased until around 1,400 days of age. Younger male horses have narrower interspace between the cervical spinal cord and spinal canal than younger female horses, suggesting that an imbalanced cervical spinal cord and spinal canal growth is one of the causes of CVSM.
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Medula Cervical , Doenças dos Cavalos , Compressão da Medula Espinal , Doenças da Medula Espinal , Estenose Espinal , Animais , Medula Cervical/diagnóstico por imagem , Feminino , Doenças dos Cavalos/etiologia , Cavalos , Masculino , Caracteres Sexuais , Canal Medular/diagnóstico por imagem , Compressão da Medula Espinal/etiologia , Compressão da Medula Espinal/veterinária , Doenças da Medula Espinal/veterinária , Estenose Espinal/complicações , Estenose Espinal/veterináriaRESUMO
Thoroughbred horses appear to be particularly predisposed to cervical vertebral stenotic myelopathy (CVSM), also known as wobbler syndrome. We hypothesized that variations in the cervical vertebral volumes can affect the dynamic instability of the cervical vertebrae. This observational study aimed to clarify whether cervical vertebral volume could be considered as a contributing factor in CVSM in Thoroughbred horses. Computed tomography (CT) was used to investigate a total of 21 male Thoroughbred horses (age range, 217-1,002 days; mean, 542.3 days). The study population comprised 17 CVSM horses (age range, 217-1,002 days; mean, 549.8 days) and 4 non-CVSM horses (age range, 244-682 days; mean, 510.5 days). The cervical vertebral volumes of three-dimensional CT were measured using the image-processing software. A significant difference in the variation of cervical vertebral volumes among C2 to C4 and C3 to C5 was identified in the CVSM group (P<0.05). While no significant differences were found in the variation in cervical vertebral volumes among C4 to C6. C3 demonstrated a significantly smaller cervical vertebral volume than C2 and C4 (P<0.05). In the non-CVSM group, no significant differences were found in the variation of cervical vertebral volume among C2 to C4, C3 to C5, and C4 to C6. Our findings suggest that variations in cranial cervical vertebral volume in CVSM male horses can be considered as an important contributing factor in CVSM development.
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Doenças dos Cavalos , Doenças da Medula Espinal , Estenose Espinal , Animais , Vértebras Cervicais/diagnóstico por imagem , Doenças dos Cavalos/diagnóstico por imagem , Cavalos , Masculino , Doenças da Medula Espinal/diagnóstico por imagem , Doenças da Medula Espinal/veterinária , Estenose Espinal/diagnóstico por imagem , Estenose Espinal/veterinária , Tomografia Computadorizada por Raios X/veterináriaRESUMO
BACKGROUND: We aimed to investigate the recent incidence of carpal fractures and the risk factors for recurrent ipsilateral fractures after arthroscopic removal of clinically active unilateral carpal chip fracture fragments in Thoroughbred racehorses. METHODS: The findings for horses managed under the Japan Racing Association that developed carpal bone fractures between 2014 and 2018 were retrospectively reviewed. The proportion of cases that developed a recurrent carpal fracture in the originally affected joint was calculated, and the risk factors for recurrent fractures were analysed. RESULTS: In total, 2858 carpal fractures were recorded in the study period (incidence, 0.8%). Of the 554 horses that resumed racing after the treatment of the unilateral major carpal chip fracture, 144 had a recurrent fracture (26.0%). Chip fractures of the third carpal bone (odds ratio [OR]: 3.7) or a combination of the distal end of the radius and intermediate carpal bone (OR: 3.0) were associated with a significantly higher risk of recurrent fractures than the distal aspect of the radial carpal bone. CONCLUSIONS: The incidence of carpal fractures remained similar to that reported in Japan in the 1990s. The rate of recurrent ipsilateral fractures differed among lesion sites.
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Ossos do Carpo , Fraturas Ósseas , Doenças dos Cavalos , Animais , Ossos do Carpo/cirurgia , Fraturas Ósseas/epidemiologia , Fraturas Ósseas/etiologia , Fraturas Ósseas/cirurgia , Fraturas Ósseas/veterinária , Doenças dos Cavalos/epidemiologia , Doenças dos Cavalos/etiologia , Doenças dos Cavalos/cirurgia , Cavalos , Incidência , Estudos Retrospectivos , Fatores de RiscoRESUMO
The purpose of this observational study was to determine the characteristic computed tomographic (CT) myelography findings of cervical vertebral stenotic myelopathy (CVSM) lesions in Thoroughbred horses. A total of 23 Thoroughbred horses (age range, 155-717 days on CT examination; mean, 410.9 days) were analyzed. All 23 Thoroughbred horses underwent unenhanced radiography, radiographic myelography, and CT myelography. Unenhanced radiographs were observed the presence of cervical vertebral malalignment and osseous lesions. Radiographic myelograms were observed for signs of cervical spinal cord compression; additionally, CT myelograms were used to detect cervical vertebral osseous lesions. Ventral compressions were frequently observed in the cranial cervical vertebrae (C2-C4), whereas dorsal compressions were frequently observed in the caudal cervical vertebrae (C5-C7). Furthermore, osseous lesions of the caudal articular process developed more frequently than those of the cranial articular process. CT myelography in Thoroughbred horses is a useful method for detecting CVSM changes.
Assuntos
Doenças dos Cavalos , Doenças da Medula Espinal , Estenose Espinal , Animais , Vértebras Cervicais/diagnóstico por imagem , Vértebras Cervicais/patologia , Doenças dos Cavalos/diagnóstico , Cavalos , Mielografia/veterinária , Doenças da Medula Espinal/veterinária , Estenose Espinal/patologia , Estenose Espinal/veterinária , Tomografia Computadorizada por Raios X/veterináriaRESUMO
BACKGROUND: Computed tomographic myelography can be a useful tool for evaluating vertebral canal stenosis. However, an index of spinal cord compression is yet to be established. OBJECTIVES: This observational descriptive study aimed to establish an index for spinal cord compression using computed tomography (CT). METHODS: Twenty-three Thoroughbred horses (age, 155-717 days; weight, 205-523 kg) with suspected cervical vertebral malformation were subjected to computed tomographic myelography in dorsal recumbency using large-bore gantry CT to define the entire cervical vertebrae from C1 to C7. Subsequently, the height of the spinal cord was measured in the sagittal plane reformatted using curved multi-planar reformation (MPR), thereby comparing it with stenotic ratio (i.e. dividing the area of spinal cord by that of the subarachnoid space) measured in the transverse plane. The measurement was performed at the level of each of six intervertebral spaces, for a total of 138 sites. Accordingly, the appropriate cut-off value for spinal cord height was determined using the receiver-operating characteristic curve, from which the area under the curve with 95% confidence interval was estimated. RESULTS: The spinal cord compression cut-off value was 7.06 mm, with an area under curve of 0.84. A weak relationship was observed between spinal cord height and stenotic ratio (R2 = 0.08, p < 0.05). CONCLUSIONS: Following curved MPR, a cut-off value of 7.06 mm may serve as an index for spinal cord compression.
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Doenças dos Cavalos , Compressão da Medula Espinal , Estenose Espinal , Animais , Doenças dos Cavalos/diagnóstico por imagem , Cavalos , Mielografia/veterinária , Compressão da Medula Espinal/diagnóstico por imagem , Compressão da Medula Espinal/veterinária , Estenose Espinal/diagnóstico por imagem , Estenose Espinal/veterinária , Tomografia Computadorizada por Raios X/veterináriaRESUMO
BACKGROUND: For medication control in several jurisdictions, withdrawal time is the period of refrain from racing after drug administration. It is set by adding a safety period to an experimental detection time. However, there are no reports of statistical analyses of detection time for the determination of withdrawal time in flunixin meglumine-treated horses. OBJECTIVE: To analyse the population pharmacokinetics of flunixin in horses through the generation of a dataset for detection time statistical analysis and predictions via Monte Carlo simulation. STUDY DESIGN: Experimental study. METHODS: Drug plasma and urine concentrations following single intravenous administration of flunixin 1.1 mg/kg bodyweight (BW) in 10 horses and multiple administration of q 24 hours for 5 days in 10 horses were measured using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Data were modelled using a nonlinear mixed effect model followed by Monte Carlo simulation. Irrelevant plasma concentration (IPC) and irrelevant urine concentration (IUC) were calculated using the Toutain approach. Detection times were obtained considering the time after the last administration for selected quantiles of 5000 hypothetical horses under the international screening limit (ISL) proposed by the International Federation of Horseracing Authorities (plasma: 1 ng/mL, urine; 100 ng/mL). RESULTS: For a regimen of 1.1 mg/kg BW q 24 hours, the IPC and IUC values were 2.0 and 73.0 ng/mL respectively. Detection times in plasma above the ISL for 90% of simulated horses were estimated as 74 hours after a single 1.1 mg/kg dose administration, 149 and 199 hours after multiple doses over 5 days at either 24- or 12-hour intervals respectively. Corresponding detection times in urine were 46, 68 and 104 hours respectively. MAIN LIMITATION: Only female horses were investigated. CONCLUSIONS: Statistical detection times for different flunixin meglumine regimens indicated a delay of detection time in plasma after multiple administrations under ISL.
Assuntos
Clonixina , Espectrometria de Massas em Tandem , Animais , Anti-Inflamatórios não Esteroides , Cromatografia Líquida/métodos , Cromatografia Líquida/veterinária , Clonixina/análogos & derivados , Feminino , Cavalos , Método de Monte Carlo , Espectrometria de Massas em Tandem/veterináriaRESUMO
The shape of the white line of the hoof is closely related to the shape of the notch on the dorsal distal bearing border of the distal phalanx (P3). In this study, a radiographic survey of the P3 of both forelimbs of 163 Thoroughbred yearling horses was conducted. The correlation of the depth and width of the notch were analyzed with the toe white line separation grades (0 to 3). As a result, the toe white line separation grade increased, the depth and the width of the notch also increased significantly. Radiographic examination of the P3 of the forelimbs might be useful for deciding whether to implement hoof care to prevent onset of toe white line separation.
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Casco e Garras , Doenças dos Cavalos , Animais , Membro Anterior/diagnóstico por imagem , Casco e Garras/diagnóstico por imagem , Doenças dos Cavalos/diagnóstico por imagem , Cavalos , Radiografia , Dedos do PéRESUMO
Many studies have reported that advancing age in broodmares has a negative impact on the reproductive performance of horses. However, although the ages at first and last mating vary among broodmares, it is unknown how this variation affects the correlation between age and reproductive performance in mares. Here, in order to examine the effects of the ages at first and last mating, we analyzed all recorded mating events for Thoroughbreds in Japan from 1997 to 2017. We found that the live foal birth rate of mares with a younger age at first mating indeed declined at an earlier age than those with an older age at first mating and that the number of years since the first mating also contributes to the decline in the birth rate. We also found that the live foal birth rate and mean earnings of the produced foals are much higher for mares with an older age at last mating compared with mares with a younger age at last mating. Our results should aid breeders in assessing the value of broodmares and designing breeding strategies.