Immediate Effect of Hoof Trimming on Hoof and Thoracic Joint Angles in Mangalarga Mares.

It is important to understand the effects of hoof trimming on hoof and limb conformation to maximize its benefits on the health of the appendicular skeleton of horses, thus promoting improvements in athletic performance and sporting longevity with regard to athletic horses. There is little information on possible changes in the angulation of the thoracic limb joints after hoof trimming and correlations between the angulation of the thoracic limb joints with hoof measurements. To that purpose, nineteen Mangalarga mares received routine hoof trimming. Visual recordings (photographs) were taken before and after the procedure. Differences (p < 0.05) were found in hoof length, toe angle, heel angle, medial heel height, and metacarpophalangeal angle. Before trimming, correlations were found between frog length and scapulohumeral angle (SH) (r = -0.457; p = 0.049), and between toe length and shoulder-ground angle (SG) (r = -0.553; p = 0.049). A correlation was also seen between the distance from the frog to the lateral wall and the SH angle (r = 0.690; p = 0.001). After trimming, there was a correlation between humeroradial (HR) and SH joint angles (r = 0.669; p = 0.002), and the SG and SH angles (r = 0.488; p = 0.034). This study showed an immediate effect of trimming on the toe angle and heel angle and on the metacarpophalangeal joint angle, in addition to correlations between the hoof and proximal joint angles, following trimming, thus evidencing the relevance of trimming not only in hoof morphology, but also in the conformation of the appendicular skeleton of horses.

Acute phase proteins levels in horses, after a single carbohydrate overload, associated with cecal alkalinization.

Introduction: Horses submitted to carbohydrate overload can develop laminitis due to changes in cecal pH and microbiota, followed by an increase in transmural absorption of luminal content, including bacterial toxins. In response to acute injury there is hepatic overproduction of several proteins known as acute phase proteins (APP). Few studies have evaluated protein fractionation to characterize the inflammatory response in acute laminitis. The aim of this study was to test the viability of an experimental model to induce acute laminitis, using a single carbohydrate overload, and the influence of a buffering solution on the development of the disease; also, study the kinetics of APP during acute laminitis, as well as the correlation between these proteins and clinical signs associated to this syndrome. Methods: Ten healthy horses were divided in a factorial and randomized way into four groups (n = 5): control group (CG), starch group (SG), buffer group (BG), and starch C buffer group (SBG). They were evaluated at seven times (T0h, T4h, T8h, T12h, T24h, T48h, and T72h), which included clinical evaluation and blood sample collection. Total serum protein and albumin concentrations were determined by colorimetry and the other APP by polyacrylamide gel electrophoresis containing sodium dodecyl sulfate and commercial ELISA kits. Data were analyzed by two-way ANOVA, followed by Tukey's test (p < 0.05). The correlation between clinical signs and APP were verified using the Pearson's correlation coefficient. Results and discussion: 40% of the animals from SG and 60% from SBG developed clinical laminitis. A single administration of buffer solution was not able to prevent clinical signs of laminitis. There was no difference between groups on total serum protein, albumin, serum amyloid A and C-reactive protein concentrations (p > 0.05). Transferrin, considered a negative APP, showed a positive response pattern in SG and SBG. Ceruloplasmin had a positive correlation with Obel grade, heart rate on animals from SGB and number of steps on horses submitted to starch overload (SG and SBG). Ceruloplasmin, α-1-antitrypsin and haptoglobin concentrations increased in SBG, suggesting an inflammatory response in animals of this group. Changes in clinical parameters were also more evident in the SBG, corroborating the protein fractionation findings.

Applicability of ARFI elastography in detecting elasticity changes of the equine superficial digital flexor tendon with induced injury.

The objectives of this prospective, experimental study were to describe changes in the stiffness of the equine superficial digital flexor tendon (SDFT) after induced injury, deep digital flexor tendon (DDFT), accessory ligament (AL-DDFT), and suspensory ligament (SL) during 90 days of healing using acoustic radiation force impulse (ARFI) elastography. Eight healthy horses were selected. Preinjury B mode and ARFI evaluations were performed bilaterally in the palmar metacarpal region. Injury was induced only on the left forelimb (G2) by a single injection of collagenase in SDFT, 15 cm distal to the accessory carpal bone. The right forelimb was used as a control (G1). Evaluations were performed at eight timepoints: one before injury (T0) and seven (T1-T7) after injury (3, 15, 30, 40, 60, 75, and 90 days post-induction). Tendinopathies were visualized as hypoechoic areas with loss of parallel tendon fiber pattern. Injured SDFTs presented mainly cool colors (soft) from T1 to T3, and from T4, there was an increase in warm colors (hard), close to the appearance of tendons of G1. In the first four timepoints, there was a decrease in stiffness compared to G1 (P < 0.001). On T1 and T2, a cutoff value <6.21 m/s to determine tendinopathy of the SDFT was established (75.8% sensitivity and 92.03% specificity). Stiffness changes in the DDFT, AL-DDFT, and SL of injured limbs occurred at different timepoints. Tendinopathy significantly altered the stiffness of the injured tendon and the adjacent tissues. ARFI made it possible to detect these changes, helping to monitor the reparation of this injury.

Long-Term Evaluation of Poly(lactic acid) (PLA) Implants in a Horse: An Experimental Pilot Study.

In horses, there is an increasing interest in developing long-lasting drug formulations, with biopolymers as viable carrier alternatives in addition to their use as scaffolds, suture threads, screws, pins, and plates for orthopedic surgeries. This communication focuses on the prolonged biocompatibility and biodegradation of PLA, prepared by hot pressing at 180 °C. Six samples were implanted subcutaneously on the lateral surface of the neck of one horse. The polymers remained implanted for 24 to 57 weeks. Physical examination, plasma fibrinogen, and the mechanical nociceptive threshold (MNT) were performed. After 24, 28, 34, 38, and 57 weeks, the materials were removed for histochemical analysis using hematoxylin-eosin and scanning electron microscopy (SEM). There were no essential clinical changes. MNT decreased after the implantation procedure, returning to normal after 48 h. A foreign body response was observed by histopathologic evaluation up to 38 weeks. At 57 weeks, no polymer or fibrotic capsules were identified. SEM showed surface roughness suggesting a biodegradation process, with an increase in the median pore diameter. As in the histopathological evaluation, it was not possible to detect the polymer 57 weeks after implantation. PLA showed biocompatible degradation and these findings may contribute to future research in the biomedical area.

Anaphylactoid reaction caused by sodium ceftriaxone in two horses experimentally infected by Borrelia burgdorferi.

BACKGROUND: Lyme borreliosis is a disease transmitted by ticks to mammals, especially in horses and humans. Caused by a spirochete Borrelia burgdorferi, it can result in lameness, arthritis, carditis, dermatitis and neurological signs. Anaphylactoid reactions are severe responses caused by direct action of substances (drugs, toxins), which can pose risks to life. Still poorly documented in horses, these reactions are caused by the effects of inflammatory mediators such as histamine, kinins and arachidonic acid metabolites. The last two are the most clinically relevant for the species. CASE PRESENTATION: The simultaneous occurrence of anaphylactoid reaction in two horses experimentally infected by Borrelia burgdorferi undergoing intravenous treatment with ceftriaxone sodium is reported. It was administered 4.7 × 10(8) spirochetes intradermal and subcutaneous applications in both horses to evaluate clinical aspects of the Lyme disease, 95 days before the application of sodium ceftriaxone. During the administration, one horse (a gelding) showed immediate and severe anaphylactoid symptoms such as urticaria, dyspnea, tachycardia, and eyelid edema, which were controlled by injecting dexamethasone. After 1 day, it expressed signs of abdominal discomfort, caused by severe bloat, which was treated surgically via celiotomy. Subsequently, this gelding had piroplasmosis and severe anemia, requiring treatment with an antimicrobial and blood transfusion. Second horse (a mare) showed signs of hypotension during the application of the antibiotic, which disappeared only when the application was interrupted. Days after the event, the mare developed moderate large colon bloat, which was treated with medication only. Subsequently the mare was evolved into the prodromal phase of laminitis in one of the forelimbs, which was treated for 10 days with non-steroidal anti-inflammatory and rheology modifying drugs and cryotherapy. CONCLUSIONS: From the two cases presented here, it does appear that sodium ceftriaxone can induce anaphylactoid reactions in horses infected by Borrelia burgdorferi, which may evolve into colic syndrome, laminitis and the occurrence of opportunistic infections. However, further evidence should be collected in order to draw definite conclusions.

Long-term facial artery catheter implantation for serial arterial blood sampling and invasive arterial blood pressure measurement in horses.

The purpose of this investigation was to evaluate surgical catheter implantation in the facial artery of horses and the long-term maintenance of such arteries using heparin and ascorbic acid as filling solution. Nine horses were implanted with a polyurethane catheter. The catheters were flushed with a heparin/ascorbic acid solution every 8h and remained patent for 25 days. Arterial blood samples were collected twice a day, and one exercise test that included serial blood samples and arterial pressure recordings was performed on a treadmill. Polyurethane catheters surgically implanted in the facial artery can be kept patent by filling with a heparin/ascorbic acid solution and provide convenient invasive arterial access in horses which is suitable for use for serial blood sampling and blood pressure recordings, even during exercise on treadmill.

Anestesia por isofluorano em eqüinos submetidos à infusão contínua de medetomidina ou xilazina / Isoflurane anesthesia in horses during medetomidine or xilazine continuous infusion

Avaliaram-se oito eqüinos sob anestesia geral inalatória com isofluorano (1CAM) e infusão contínua de xilazina (0,35mg kg-1h-1) ou medetomidina (3,5µg kg-1h-1), em relação à freqüência cardíaca, ritmo cardíaco, freqüência respiratória, pressão arterial, hemogasometria arterial e temperatura, nos tempos T0 (imediatamente antes do início da infusão contínua) e T10 ao T60 (intervalos de 10 minutos, após início da infusão contínua). Houve redução da freqüência cardíaca e da temperatura e elevação da pressão arterial média. A paCO2 (no GM) elevou-se e a paO2 mostrou-se maior no GM que no GX. Conclui-se que a infusão contínua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatória, com isofluorano, em eqüinos, promove alterações cardiocirculatórias, respiratórias, térmicas e hemogasométricas discretas e equivalentes.

Eight horses under inhalant general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg kg-1h-1) or medetomidine (3.5µg kg-1h-1) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60). Heart rate and temperature decreased and mean arterial pressure increased. PaCO2 (in GM) increased and GM showed a higher paO2 than GX. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalant general anesthesia with isoflurane in horses promote slight and equivalent cardiocirculatory, respiratory, thermic and arterial blood gases changes.