Comparison of subarachnoid administration of low-dose bupivacaine and lidocaine in healthy goats.

OBJECTIVE: This study aimed to compare the effects of low-dose subarachnoid injections of 2% lidocaine (LIDO) and 0.5% bupivacaine (BUPI) in goats. ANIMALS: 6 healthy, privately owned female goats. METHODS: In this randomized blind crossover clinical trial, each goat received 0.05 mL/kg-1 of LIDO, BUPI, or sterile saline solution into the lumbosacral subarachnoid space, with a seven-day washout. Cardiorespiratory variables, rectal temperature, and somatosensory (pinprick) and motor (ataxia) functions were recorded at baseline (time 0) and 2, 5, 10, 15, and 30 minutes after injection, then every 20 minutes until the goat was standing and able to walk. Time to regain somatosensory and motor functions was compared between treatments using Kaplan-Meier survival curves and the Cox proportional hazards model. Linear mixed-effects models were used to compare cardiorespiratory variables between treatments and over time. A P value ≤ .05 was considered significant. RESULTS: Somatosensory recovery was longer with BUPI, though not statistically significant. The median time to stand was 50 (50, 67) minutes after LIDO injection and 104 (101, 156) minutes after BUPI injection (P = .031). The median time to walk was 72 (54, 85) minutes after LIDO versus 225 (220, 245) minutes after BUPI injection (P = .031). Cardiovascular and respiratory variables showed no significant differences between treatments. CLINICAL RELEVANCE: Despite prolonged ataxia with BUPI, pinprick sensation recovery did not differ. At reduced doses, both LIDO and BUPI are deemed acceptable for short procedures of the flank, pelvic limb, or tail in healthy goats.

Pharmacokinetics and tolerability of single-dose enteral cannabidiol and cannabidiolic acid rich hemp in horses (Equus caballus).

The pharmacokinetics and tolerability of cannabinoids and their metabolites were determined in eight horses after enteral administration of a commercial CBD/CBDA-rich hemp oil product. Each horse was administered 2 mg/kg or 8 mg/kg CBD/CBDA or no treatment in a randomized cross-over design. Serial serum samples collected over 48 h were analyzed by high performance liquid chromatography with tandem mass spectrometry. Plasma chemistry analysis was performed at 0 h and 24 h. Vital parameters, pedometry, and blinded mentation and gait evaluations were recorded at intervals up to 24 h. Manure production and gastrointestinal transit time were tracked for 48 h after oil administration. The median maximal concentration of CBD and CBDA were 5.2 and 36.95 ng/mL in the 2 mg/kg group, respectively; and 40.35 and 353.56 ng/mL in the 8 mg/kg group. The median half-life of elimination was not calculated for the 2 mg/kg CBD treatment due to lack of time points above the lower quantifiable limit beyond the Cmax while it was 7.75 h in the 8 mg/kg group. CBDA absorption was biphasic. Pharmacokinetic parameters for tetrahydrocannabinol, tetrahydrocannabinolic acid, cannabigerolic acid, and 7-carboxy cannabidiol are also reported. No significant differences in any of the measured tolerability parameters were demonstrated between treatment groups. Single-dose enteral administration of CBD/CBDA-rich hemp extract up to 8 mg/kg does not appear to produce neurologic, behavioral, or gastrointestinal effects in horses.

Efficacy of treatment of equine anhidrosis with acupuncture and Chinese herbs is low but higher in treated horses compared with placebo.

OBJECTIVE: To assess the therapeutic efficacy of acupuncture in combination with Chinese herbs for treatment of horses affected with anhidrosis. ANIMALS: 44 horses affected with anhidrosis for up to 3 years' duration were enrolled. Inclusion required both compatible clinical signs and results of a quantitative intradermal terbutaline sweat test. METHODS: Study horses were randomly allocated into 2 groups. Group 1 (n = 19) was treated with daily Chinese herbs and 4 weekly acupuncture sessions. Group 2 (n = 25) was given daily hay powder as a placebo and 4 weekly sham acupuncture sessions. Horses were tested by quantitative intradermal terbutaline sweat test within 2 days after treatment completion and again 4 weeks following treatment. RESULTS: Terbutaline-induced sweat responses (mg) were not different between groups within 2 days and 4 weeks after treatment. Two days after treatment, ratios of sweat responses (compared to baseline) were higher (P < .05) in the treatment group compared to the placebo group at terbutaline concentrations of 1.0, 100, and 1,000 µg/mL. The number of horses responding to treatment was higher in the treatment group (5/19 [26%]), compared to horses in the placebo group (1/25 [4%]) for 1 of 5 terbutaline concentrations 2 days (10 µg/mL) or 4 weeks (0.1 µg/mL) after treatment. CLINICAL RELEVANCE: Ratios of sweat responses were higher in treatment horses 2 days after treatment, compared to baseline, but not 4 weeks later. The efficacy of a traditional Chinese veterinary medicine protocol for anhidrosis treatment with acupuncture and Chinese herbs was low but higher in treated horses compared with placebo.

The effects of orally administered trazodone on ambulation and recumbency in healthy horses.

BACKGROUND: Trazodone, a serotonin receptor antagonist and reuptake inhibitor, might be a useful adjunctive treatment in the initial management of horses with acute laminitis if it minimizes ambulation or encourages recumbency. OBJECTIVES: (1) Evaluate the effects of PO trazodone on ambulatory activity and recumbency in healthy horses; and (2) assess the pharmacokinetics of multiple PO doses of trazodone. ANIMALS/METHODS: In a randomized cross-over design, 8 healthy horses received placebo or trazodone at 2 doses (2.5 and 7.5 mg/kg) PO q12h for 48 hours with a 14-day washout period between treatments. Forelimb step frequency was measured using a hoof-mounted accelerometer and continuous video monitoring was used to detect recumbency. Groups were compared using repeated measures analysis of variance with Tukey's post hoc test. Trazodone and m-chlorophenylpiperazine (m-CPP) plasma concentrations were determined by ultra-high performance liquid chromatography-tandem mass spectrometry and pharmacokinetics were analyzed using noncompartmental methods. RESULTS: Step frequency was lower in horses receiving 7.5 mg/kg trazodone than in the control group (mean step reduction: 44% ± 11%). Steps-area under the curve were significantly lower in the 7.5 mg/kg group (mean ± SD: 3375 ± 525 steps × hour) as compared to the 2.5 mg/kg group (mean ± SD: 5901 ± 2232; P = .02) and compared to control (mean ± SD: 6590 ± 1241; P = .001). No difference was found in the number of recumbent episodes (P = .92) or total duration of recumbency (P = .9). Trazodone and m-CPP achieved steady-state concentrations, with an accumulation ratio of 1.45 ± 0.2. CONCLUSIONS AND CLINICAL IMPORTANCE: Although it did not affect recumbency, trazodone at 7.5 mg/kg q12h decreased step frequency by approximately 44%.

Plasma l-indospicine and 3-nitropropionic acid in ponies fed creeping indigo: Comparison with results from an episode of presumptive creeping indigo toxicosis.

BACKGROUND: Creeping indigo (Indigofera spicata) toxicosis is an emerging problem among horses in Florida and bordering states. OBJECTIVES: To quantify the putative toxins l-indospicine (IND) and 3-nitropropionic acid (NPA) in creeping indigo collected from multiple sites and to measure plasma toxin concentrations in ponies fed creeping indigo and horses with presumptive creeping indigo toxicosis. STUDY DESIGN: Experimental descriptive study with descriptive observational field investigation. METHODS: Air-dried creeping indigo was assayed for IND and NPA content. Five ponies were fed chopped creeping indigo containing 1 mg/kg/day of IND and trace amounts of NPA for 5 days, then observed for 28 days. Blood samples from these ponies and from horses involved in a presumptive creeping indigo toxicosis were assayed for IND and NPA. RESULTS: IND in creeping indigo plants was 0.4-3.5 mg/g dry matter whereas NPA was <0.01 to 0.03 mg/g. During creeping indigo feeding, clinical and laboratory signs were unchanged except for significant weight loss (median 6%, range 2%-9%; p = .04) and significant increase from baseline plasma protein concentration (median 16 g/L, range 8-25 g/L; p < .001). These changes could not definitively be ascribed to creeping indigo ingestion. Plasma IND rose to 3.9 ± 0.52 mg/L on day 6. Pharmacokinetic modelling indicated an elimination half-life of 25 days and a steady state plasma concentration of 22 mg/L. Plasma IND concentration in sick horses during an incident of creeping indigo toxicosis was approximately twice that of clinically normal pasture mates. Plasma NPA was <0.05 mg/L in all samples. MAIN LIMITATIONS: Creeping indigo used in the feeding trial may not be representative of plants involved in creeping indigo toxicosis. There was no control group without creeping indigo in the feeding trial. CONCLUSIONS: Indospicine can be detected in blood of horses consuming creeping indigo and the toxin accumulates in tissues and clears slowly. The role of NPA in the neurological signs of this syndrome is unclear.

Ion Channel and Ubiquitin Differential Expression during Erythromycin-Induced Anhidrosis in Foals.

Macrolide drugs are the treatment of choice for Rhodococcus equi infections, despite severe side-effects temporary anhidrosis as a. To better understand the molecular biology leading to macrolide induced anhidrosis, we performed skin biopsies and Quantitative Intradermal Terbutaline Sweat Tests (QITSTs) in six healthy pony-cross foals for three different timepoints during erythromycin administration-pre-treatment (baseline), during anhidrosis and post-recovery. RNA sequencing of biopsies followed by differential gene expression analysis compared both pre and post normal sweating timepoints to the erythromycin induced anhidrosis episode. After Bonferroni correction for multiple testing, 132 gene transcripts were significantly differentially expressed during the anhidrotic timepoint. Gene ontology analysis of the full differentially expressed gene set identified over-represented biological functions for ubiquitination and ion-channel function, both biologically relevant to sweat production. These same mechanisms were previously implicated in heritable equine idiopathic anhidrosis and sweat gland function and their involvement in macrolide-induced temporary anhidrosis warrants further investigation.

Genomic Association of Chronic Idiopathic Anhidrosis to a Potassium Channel Subunit in a Large Animal Model.

Similar to humans, the horse relies predominantly on the evaporation of sweat from the skin surface to dissipate excess body heat. Loss of the sweat response or anhidrosis can result in life-threatening hyperthermia. Anhidrosis occurs more frequently in some breeds as well as occurs at an increased frequency among individuals with a family history, suggesting a heritable component to the pathology. Given the natural occurrence and indications of genetic components in the etiology, we utilized genomics to better understand the molecular mechanisms involved in sweat response. We performed a case-control (n = 200) GWAS targeting cases of chronic idiopathic anhidrosis in a controlled genetic background to discover the contributing regions and interrogated gene function for roles in the sweating mechanism. A region containing the KCNE4 gene, which encodes the ß-subunit of a potassium channel protein with a possible function in sweat gland outflow, was associated (P = 1.13 × 10-07) with chronic idiopathic anhidrosis through GWAS. A candidate mutation (NC_009149.3:g.11813731A > G, rs68643109) disrupting the KCNE4 protein structure could explain the disease but requires further investigation in larger populations. We show the potential role of ion channels and cellular damage in sweat response, correlating anhidrosis as a possible effect of congenital channelopathy.

Evidence for anti-inflammatory effects of firocoxib administered to mares with experimentally induced placentitis.

PROBLEM: Minimal evidence exists supporting therapeutic selections for equine placentitis. The goal of this study was to characterize the anti-inflammatory effects of firocoxib when administered to mares with placentitis. METHODS: Mares (gestation D270-300) were assigned to: INFECT (n = 6; placentitis, no treatment), FIRO (n = 6; placentitis, firocoxib, 0.1 mg/kg, PO, daily), and NORM (n = 6; no infection/treatment). Allantoic fluid (8 hours, 24 hours, birth) and amniotic fluid (birth) were collected from mares after infection. Concentrations of IL-1ß, IL-6, TNF-α, IL-10, PGF2α , and PGE2 in fluids were measured by ELISA. mRNA expression of IL-1ß, IL-6, TNF-α, IL-8, IL-10, matrix metalloproteinases (MMPs) -1, 3, and 9 in fetal membranes/fetuses was quantified using real-time PCR. RESULTS: Allantoic TNF-α concentrations were lowest in FIRO at 8 hours and 24 hours post-infection; IL-6 concentrations were lower in FIRO than NORM at 8 hours, lower in FIRO than INFECT at 24 hours post-inoculation, and lower in NORM than FIRO or INFECT at birth. Marginal mean allantoic IL-ß and IL-10 concentrations were lower in FIRO and NORM than INFECT. Amniotic fluid cytokines were lowest in NORM with all measurements in that group being below the limit of detection. Allantoic PGF2α concentrations were lower in FIRO and INFECT than NORM at 8 hours post-inoculation, and lower in FIRO than INFECT or NORM at 24 hours post-inoculation. Allantoic PGE2 concentrations were lower in FIRO than INFECT. Amniotic PGF2α and PGE2 concentrations were lower in NORM than INFECT. In fetal membranes, group differences with respect to IL-1ß, IL-6, IL-8, and MMP1 were dependent on tissue type. CONCLUSIONS: Data suggest a suppressive effect of firocoxib administration on cytokine and prostaglandin production in mares with placentitis.

Metabogenomics reveals four candidate regions involved in the pathophysiology of Equine Metabolic Syndrome.

An analogous condition to human metabolic syndrome, Equine Metabolic Syndrome (EMS) is defined by several clinical signs including obesity, hyperinsulinemia, and peripheral insulin dysregulation (ID). Affected horses may also exhibit hypertension, hyperlipemia and systemic inflammation. Measures of ID typically comprise the gold-standard for diagnosis in veterinary care. Yet, the dynamic nature of insulin homeostasis and complex procedures of typical assays make accurate quantification of ID and EMS challenging. This work aimed to investigate new strategies for identification of biochemical markers and correlated genes in EMS. To quantify EMS risk within this population, we utilized a composite score derived from nine common diagnostic variables. We applied a global liquid chromatography/mass spectroscopy approach (HPLC/MS) to whole plasma collected from 49 Arabian horses, resulting in 3392 high-confidence features and identification of putative metabolites in public databases. We performed a genome wide association analysis with genotypes from the 670k Affymetrix Equine SNP array utilizing EMS-correlated metabolites as phenotypes. We discovered four metabolite features significantly correlated with EMS score (P < 1.474 × 10-5). GWAs for these features results (P = 6.787 × 10-7, Bonferroni) identified four unique candidate regions (r2 > 0.4) containing 63 genes. Significant genomic markers capture 43.52% of the variation in the original EMS score phenotype. The identified genomic loci provide insight into the pathways controlling variation in EMS and the origin of genetic predisposition to the condition. Rapid, feasible and accurate diagnostic tools derived from metabogenomics can be translated into measurable benefits in the timeline and quality of preventative management practices to preserve health in horses.

Use of principle component analysis to quantitatively score the equine metabolic syndrome phenotype in an Arabian horse population.

Equine metabolic syndrome (EMS), like human metabolic syndrome, comprises a collection of clinical signs related to obesity, insulin dysregulation and susceptibility to secondary inflammatory disease. Although the secondary conditions resulting from EMS can be life-threatening, diagnosis is not straightforward and often complicated by the presence of other concurrent conditions like pituitary pars intermedia dysfunction (PPID). In order to better characterize EMS, we sought to describe the variation within, and correlations between, typical physical and endocrine parameters for EMS. Utilizing an unsupervised statistical approach, we evaluated a population of Arabian horses using a physical examination including body measurements, as well as blood plasma insulin, leptin, ACTH, glucose, and lipid values. We investigated the relationships among these variables using principle component analysis (PCA), hierarchical clustering, and linear regression. Owner-assigned assessments of body condition were one full score (on a nine-point scale) lower than scores assigned by researchers, indicating differing perception of healthy equine body weight. Rotated PCA defined two factor scores explaining a total of 46.3% of variation within the dataset. Hierarchical clustering using these two factors revealed three groups corresponding well to traditional diagnostic categories of "Healthy", "PPID-suspect", and "EMS-suspect" based on the characteristics of each group. Proxies estimating up to 93.4% of the composite "EMS-suspect" and "PPID-suspect" scores were created using a reduced set of commonly used diagnostic variables, to facilitate application of these quantitative scores to horses of the Arabian breed in the field. Use of breed-specific, comprehensive physical and endocrinological variables combined in a single quantitative score may improve detection of horses at-risk for developing EMS, particularly in those lacking severe clinical signs. Quantification of EMS without the use of predetermined reference ranges provides an advantageous approach for future studies utilizing genomic or metabolomics approaches to improve understanding of the etiology behind this troubling condition.

Update on Streptococcus equi subsp equi infections.

There are few diseases that ignite as much fervor among horse owners as strangles. Streptococcus equi subsp equi (strangles) infections frequently require the treating veterinarian to manage not only the clinical cases but also the biosecurity and provision of information to all involved parties. Although the disease is typically characterized by low mortality and high morbidity, restrictions of horse movement that result from appropriate quarantine procedures often frustrate the involved parties. The aims of this article are to provide clinically relevant information for diagnosis, treatment, and biosecurity management of strangles infection.