Tumor Necrosis Factor and Interleukin-6 Activity and Endotoxin Concentration in Peritoneal Fluid and Blood of Horses with Acute Abdominal Disease

The purpose of this study was to evaluate the diagnostic and prognostic significance of tumor necrosis factor-alpha (TNF) and interleukin-6 (IL-6) activities and endotoxin concentration in blood and peritoneal fluid of 155 adult horses with acute abdominal disease (colic). Samples also were obtained from 20 healthy adult horses. Blood and peritoneal fluid supernatant TNF and IL-6 activities and endotoxin concentration were significantly greater in horses with colic, compared with healthy horses. In horses with colic, the peritoneal fluid endotoxin concentration and TNF and IL-6 activities were significantly greater than those in blood. Within the colic group, peritoneal fluid IL-6 activity was the analyte that was most frequently increased. Blood and peritoneal fluid supernatant TNF and IL-6 activities were significantly greater when endotoxin was detected in the same sample. Blood and peritoneal fluid IL-6 activity was significantly greater in horses with inflammatory or strangulating lesions, compared with horses having nonstrangulating or noninflammatory lesions. Compared with all other data categories, diagnostic accuracy for nonsurvival was greatest (80%) when blood IL-6 activity exceeded 60 units/mL. The results of this study indicate that endotoxin was present in the peritoneal cavity of at least one third of horses with any acute disease of the abdomen. In horses presented for colic, blood or peritoneal fluid IL-6 activity was more useful than either TNF activity or endotoxin concentration for distinguishing lesion type. Although diagnostic accuracy for the prediction of nonsurvival was good for all of the analytes, negative values were more useful in the prediction of a favorable outcome than were abnormally increased values in the prediction of mortality.     

Effects of Lidocaine Infusion during Experimental Endotoxemia in Horses

Background: The clinical efficacy of IV infusion of lidocaine for treatment of equine endotoxemia has not been studied. Hypothesis: Lidocaine infusion after exposure to lipopolysaccharide (LPS) will inhibit the inflammatory response and have inhibitory effects on the hemodynamic and cytokine responses to endotoxemia. Animals: Twelve horses. Methods: Two equal groups (n = 6): saline (GI) and lidocaine (GII). In all animals, endotoxin (500 ng/kg body weight [BW]) was injected intraperitoneally over 5 minutes. Twenty minutes later, animals received a bolus of GI or GII (1.3 mg/kg BW) over 5 minutes, followed by a 6‐hour continuous rate infusion of GI or GII (0.05 mg/kg BW/min). Treatment efficacy was judged from change in arterial blood pressure, peripheral blood and peritoneal fluid (PF) variables (total and differential cell counts, enzyme activities, and cytokine concentrations), and clinical scores (CS) for behavioral evidence of abdominal pain or discomfort during the study. Results: Compared with the control group, horses treated with lidocaine had significantly lower CS and serum and PF tumor necrosis factor‐α (TNF‐α) activity. At several time points in both groups, total and differential cell counts, glucose, total protein and fibrinogen concentrations, and alkaline phosphatase, creatine kinase, and TNF‐α activities were significantly different from baseline values both in peripheral blood and in PF. Conclusions and Clinical Importance: Lidocaine significantly decreased severity of CS and inhibited TNF‐α activity in PF.     

多黏菌素对雏鸡不同组织中SOD活性及丙二醛含量的影响

以口服给药方式给雏鸡喂服不同剂量多黏菌素B，测定了不同组织中SOD活性和MDA的含量。结果表明，低剂量组雏鸡；肝脏和心脏在给药后第8天，肾脏在第4天，脾脏和大脑在第12天SOD活性显著升高；肝脏，脾脏和心脏于第8天，肾脏于第4天，大脑于第12天MDA含量显著降低。高剂量组雏鸡；肝脏，肾脏和心脏中SOD活性在给药后第1天极显著升高，脾脏和大脑在给药后第4天，胰腺和十二指肠于第12天SOD活性显著升高；肝脏于给药后第1天MDA含量显著降低，脾脏，肾脏和心脏于给药后第4天及胰腺和十二指肠子第12天MDA含量显著降低。SOD活性升高后随之下降而MDA含量下降后则随之升高，毒性反应主要表现为肝毒性，肾毒性，脾毒性，心脏毒性和神经毒性。     

Tensions used on girths on thoroughbred racehorses

OBJECTIVE: To determine commonly used girth tensions in Thoroughbred racehorses in the Melbourne metropolitan area. DESIGN: A prospective industry survey. METHODS: Strappers were instructed to tension girths, using the same saddle, under-saddle packing and girth, sufficiently to hold the saddle for racing. These tensions were continuously recorded by an in-line load cell in the girth. Seventeen strappers from five stables participated in the study, which was conducted on 91 horses. RESULTS: Resting girth tensions varied considerably. The mean tension on inhalation was 13 +/- 0.4 kg. Male strappers recorded higher tensions than females for all indices measured. Age and girth size of the horse did not significantly influence results. CONCLUSION: This study confirms that there is no standard for application of a girth and saddle in the Thoroughbred racing industry and the range of tensions applied was large. Strappers were unable to reliably apply the same tensions between horses. Values recorded at the extremes of the range seem inappropriate for racing conditions as low values would result in slippage of the saddle and higher values may result in girth galls and possible reduction in athletic performance. Further work is necessary to determine the point at which girth tension affects performance.     

不同处理方法对水牛同期发情效果的观察

[目的]为筛选一套高效且适宜于生产推广的水牛同期发情处理方案。[方法]借助便携式兽用B超观察,用PGc一次注射法、PMSG＋PGc法和GnRH＋PGc＋GnRH法对水牛进行同期发情处理。[结果]发情率和排卵率分别为58.33%、84.21%、83.90%和54.17%、50.00%、75.42%,平均发情率为77.94%,平均排卵率为65.69%,GnRH法处理水牛同期发情获得较高的排卵率。黄体影响同期发情处理效果,对PGc、PMSG影响较大,对GnRH处理影响较小。[结论]GnRH法处理结束48h内有72.88%（86/118）的受体排卵,排卵时间高度集中,具有较好的推广应用前景。     

Clinical and immunomodulating effects of ketamine in horses with experimental endotoxemia

Background: Ketamine has immunomodulating effects both in vitro and in vivo during experimental endotoxemia in humans, rodents, and dogs. Hypothesis: Subanesthetic doses of ketamine will attenuate the clinical and immunologic responses to experimental endotoxemia in horses. Animals: Nineteen healthy mares of various breeds. Methods: Experimental study. Horses were randomized into 2 groups: ketamine‐treated horses (KET; n = 9) and saline‐treated horses (SAL; n = 10). Both groups received 30 ng/kg of lipopolysaccharide (LPS, Escherichia coli, O55:B5) 1 hour after the start of a continuous rate infusion (CRI) of racemic ketamine (KET) or physiologic saline (SAL). Clinical and hematological responses were documented and plasma concentrations of tumor necrosis factor‐α (TNF‐α) and thromboxane B₂ (TXB₂) were quantified. Results: All horses safely completed the study. The KET group exhibited transient excitation during the ketamine loading infusion (P < .05) and 1 hour after discontinuation of administration (P < .05). Neutrophilic leukocytosis was greater in the KET group 8 and 24 hours after administration of LPS (P < .05). Minor perturbations of plasma biochemistry results were considered clinically insignificant. Plasma TNF‐α and TXB₂ production peaked 1.5 and 1 hours, respectively, after administration of LPS in both groups, but a significant difference between treatment groups was not demonstrated. Conclusions and Clinical Importance: A subanesthetic ketamine CRI is well tolerated by horses. A significant effect on the clinical or immunologic response to LPS administration, as assessed by clinical observation, hematological parameters, and TNF‐α and TXB₂ production, was not identified in healthy horses with the subanesthetic dose of racemic ketamine utilized in this study.     

Effects of transport, lairage and stunning on the concentrations of some blood constituents in horses destined for slaughter

The aim of the present study was to determine, in horses destined to slaughter, the effects of transport, lairage and stunning on some blood constituents related to stress. Twenty one horses culled from a race track due to poor athletic performance, transported weekly to a nearby slaughterhouse were used. Each horse was canulated through venipuncture of the right jugular vein with a central venous catheter which remained permanently until after the exsanguination. Through the catheter, blood samples were taken at 6 sampling times: one hour before loading of the horses, immediately after loading, at the end of the journey, immediately after unloading, after lairage, in the stunning box before stunning and during exsanguination. Blood samples were analyzed for the following variables: plasma lactate concentration, plasma creatine phosphokinase activity (CK), plasma glucose concentration, plasma cortisol concentration and packed cell volume (PCV). Time in the stunning box, number of stunning attempts, presence of return to consciousness signs and time between stunning and sticking were also recorded. The results for pre-mortem variables were: mean time in the stunning box 9 min 48 sec, 85.7% of the horses fell at the first stunning attempt, 57.2% of the horses showed signs of returning to consciousness after stunning and the most frequent interval between stunning and sticking was 1.01 to 2 min. Mean values for the blood variables showed a significant rise (P < 0.05) in the concentrations of lactate, glucose and cortisol, as well as CK activity and PCV during transport. The highest values for these blood constituents were seen before stunning and during exsanguination, except for cortisol concentration, which showed the highest values during the transport process.     

Immunological response and markers of cell damage in seropositive horses for Toxoplasma gondii

Toxoplasmosis is an important parasitic disease affecting several species of mammals, but little is known about this disease in horses. This study aimed to investigate the levels of several immunological variables and markers of cell damage in the serum of seropositive horses for Toxoplasma gondii. Sera samples of adult horses from the Santa Catarina State, Brazil used on a previous study were divided into groups according to their antibody levels for T. gondii determined by immunofluorescence assay, i.e. 20 samples from seronegative horses (Group A – control), 20 samples from horses with titers of 1:64 (Group B), 20 samples of horses with titers of 1:256 (Group C), and five samples from horses with titers of 1:1024 (Group D). Positive animals (Groups B, C, and D) had higher levels of immunoglobulins (IgM and IgG), pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1, IL-4, and IL-6) and protein C-reactive protein, as well as lower levels of IL-10 (anti-inflammatory cytokine) when compared to seronegative horses (Group A). The nitric oxide levels were also elevated in seropositive horses. Therefore, we have found humoral and cellular immune responses in seropositive horses, and a correlation between high antibody levels and inflammatory mediators. Markers of cell injury by lipid peroxidation (TBARS) and protein oxidation (AOPP) were elevated in animals seropositives for T. gondii when compared to seronegatives. Therefore, seropositive horses to T. gondii can keep active immune responses against the parasite. As a consequence with chronicity of disease, they show cellular lesions that may lead to tissue damage with the appearance of clinical disease.     

Linseed oil supplementation in diet for horses: Effects on palatability and digestibility

Feed palatability and in vivo apparent digestibility of nutrients were compared in horses fed concentrates in which barley was, or not, partially substituted by 8% linseed oil. According to a cross-over design, three geldings and one stallion were fed at near maintenance level hay plus low or high fat diet (50/50). The last days of each 3-months sub-periods, partial faeces collections were performed and concentrate intake rate was measured to estimate the digestibility and the palatability of the diet. The inclusion of linseed oil did not affect the palatability of the diet and increased significantly (P < 0.05) the apparent digestibility of DM (66.5 vs 64.1%), CF (83.7 vs 57.3%) and NDF (53.0 vs 50.7%) but not of CP and ADF.     

Effect of the microclimate on horses during international air transportation in an enclosed container

OBJECTIVE: To determine if the microclimate is detrimental to horses during international air transportation in an enclosed container. PROCEDURE: On each of two 12 h and two 24 h flights three horses were transported in an enclosed container designed to prevent exposure to insect vectors. Heart rates were monitored throughout and blood samples were collected periodically. Air in the container was sampled for bacteria and fungal spores and the temperature and relative humidity were recorded inside and outside the container periodically during the flight. On the two 12 h flights similar observations were made on three horses transported in regular open containers, which were used as controls. RESULTS: Heart rates during the flights reflected any agitation of the horses. Agitation was only mild and generally associated with take-off and landing. There were no changes in haematological or blood biochemical values that suggested any detrimental effects of the flights. The temperature in the Airstable was relatively constant during each flight (means ranged from 18.7 to 23.4 degrees C) and was significantly warmer than in the cargo hold (range 13.9 to 18.3 degrees C). Relative humidity fluctuated more widely and reflected the ambient humidity during airport stops. The numbers of bacteria and fungal spores in the Airstable air varied during the flights but were of no apparent significance to the horses' health. CONCLUSION: The Airstable proved a convenient means to transport horses on international flights and caused no discernible ill effects on the horses studied.     

Risk Factors for Equine Postoperative Ileus and Effectiveness of Prophylactic Lidocaine

Background: Postoperative ileus (POI) is a frequent and often fatal complication of colic surgery. Reliably effective treatments are not available.
Objectives: To determine risk factors and protective factors associated with POI, and to assess the effect of lidocaine IV on short-term survival.
Animals: One hundred and twenty-six horses that underwent small intestinal colic surgery and that survived for at least 24 hours postoperatively.
Methods: Retrospective cross-sectional study. The association of 31 pre-, intra-, and postoperative variables with POI and the association of lidocaine treatment with short-term survival were investigated. Associations were evaluated with univariable logistic regression models, followed by multivariable analysis.
Results: Significant associations of high heart rate (odds ratio [OR] = 1.05, 95% confidence interval [CI] 1.03–1.08), the presence of more than 8 L of reflux at admission (OR = 3.02, 95% CI 1.13–8.02) and the performance of a small intestinal resection (OR = 2.46, 95% CI 1.15–5.27) with an increased probability of POI were demonstrated. Prophylactic lidocaine treatment was significantly associated with a reduced incidence of POI (OR = 0.25, 95% CI 0.11–0.56). Lidocaine treatment was also significantly associated with enhanced short-term survival (OR = 0.30, 95% CI 0.09–0.98).
Conclusions and Clinical Importance: The variables associated with an increased risk of POI can be useful in identifying horses at risk of POI and in providing a more accurate prognosis. The results are supportive for lidocaine IV as an effective prokinetic treatment after small intestinal colic surgery.     

Effects of Density and Rest Stops on Movement Rates of Unrestrained Horses during Transport

The goal of this study was to provide estimates of how much loose (unrestrained) horses move during transport. Data were collected from six shipments of slaughter horses that were transported in a 16.2-m, single-deck semi-trailer in June and July of 2004 for 18 to 20 hours as part of an earlier project. Usable video was obtained from five groups of mature horses transported at “low” density (five to seven horses per group averaging 216.5 kg/m²) and three groups of horses transported at “moderate” density (10–11 horses per group averaging 345.5 kg/m²). Three low-density and two moderate-density groups had access to six water bowls inserted through the sides of the compartments during 1-hour rest stops occurring after 8 hours and at the end of transport. Twelve cameras, one mounted in each corner of the three compartments, were used to record behavior. Distance and rate of movement by individual horses during transport and during two 1-hour rest periods were determined by analysis of 206 hours of usable video footage of individual horses. Mean movement rate tended to be higher during travel (4.23 m/hour) than during the 1-hour periods when the truck was stopped (2.75 m/hour), but it did not seem to be influenced by group density. Movement was stimulated by the availability of water during the rest stops. In general, movement was strongly influenced by one or two horses causing disruption of the group, and not by independent actions of members of the group.     

Studies on the experimental induction of ptosis in horses

The precise appearance of ptosis due to lesions at different sites was investigated in experimental ponies. The angles of the eyelashes to the head was used as an objective measurement of ptosis after local anaesthesia of the sympathetic trunk or the palpebral nerve and the administration of an ocular alpha agonist or antagonist. It was shown that ptosis is not an inevitable consequence of palpebral nerve pathology, that ocular alpha antagonists can induce ptosis, and that alpha agonist eyedrops have an inconsistent effect on the equine pupil, but are consistent at reversing ptosis induced by sympathetic denervation in unsedated horses.