Transient glucose malabsorption in two horses fact or artefact?

Two horses, presented for investigation of chronic weight loss despite normal to increased feed intake, had flat oral glucose absorption curves, suggesting malabsorption. The cause of the apparent malabsorption was not evident grossly or on light microscopic examination of the intestinal tract. Both horses survived long term and at follow-up examination had regained weight and their capacity to absorb glucose. These cases illustrate that flat glucose absorption curves may occur in horses with no obvious intestinal lesions, that they may revert to normal and that the results of these tests should be interpreted with caution.     

用线性回归法测定生长母猪内源钙、磷排泄量和豆粕钙、磷真消化率的研究

本文旨在用线性回归法(又称梯度回归法,regression analysis technique,REG)测定生长母猪钙、磷内源排泄和豆粕钙、磷真消化率。选择6头大白×长白二元杂交生长母猪,平均初始体重为(27.6±3.0)kg。采用6×6拉丁方设计,以玉米淀粉-豆粕为基础配制6个不同钙(0.04%、0.09%、0.13%、0.17%、0.22%和0.26%)和磷(0.09%、0.18%、0.27%、0.35%、0.44%和0.53%)水平的半纯合日粮,试验共6期,每期8d,预试期6d,正试期2d。结果得出,以日粮干物质采食量(DMI)为基础,粪钙的排泄量随日粮钙摄入量的增加而线性增加(P<0.01),用回归曲线法得出内源钙排泄量为0.43g/kg DMI,豆粕钙的真消化率为23.41%。以DMI为基础,粪磷总排泄量随日粮磷摄入量的增加而线性增加(P<0.01),内源磷排泄量为0.89g/kg DMI,豆粕磷真消化率为41.44%。钙平均表观消化率比真消化率低28.77%,磷平均表观消化率比真消化率低29.24%。结果显示,不同钙、磷水平的豆粕日粮,钙、磷的表观消化率变化比较大,而真消化率相对稳定。用表观消化率进行饲料配方,会导致钙、磷生物学效价的低估,造成钙、磷过量添加和猪粪钙、粪磷的增加。用真消化率评定钙、磷的生物学效价,比表观消化率更准确,因此在配制动物日粮时更能接近动物实际生产需要量,既不造成浪费也不会出现缺乏。     

线性回归法测定生长猪内源磷排泄量及鱼粉磷真消化率

本研究采用线性回归法测定生长猪内源磷排泄量及鱼粉磷的真消化率.选用5头健康大白×长白阉公猪为试验动物,平均体重为(27.17±0.28)kg.采用5×5拉丁方设计,设5个磷水平(0.08%、0.12%、0.17%、0.21%和0.25%),日粮以葡萄糖和玉米淀粉等为基础原料,鱼粉为磷唯一来源.日粮中添加0.1%TiO2作为外源指示剂.试验分5个试验期,每期6 d,4 d适应期,2 d收粪期.结果表明,生长猪粪磷的排出量与日粮磷的摄入量呈线性关系(y=0.292 7x-0.052 8,R2=0.99,P<0.01),回归法测得生长猪内源磷的排泄量为0.798 5 g/kg,鱼粉磷的真消化率为71.12%.分析粪磷来源发现,内源磷排泄量基本不变(P>0.05),而粪磷随日粮磷含量的增加而增加(P<0.01).由结果可知,线性回归法可用于测定猪内源磷排泄量及鱼粉磷真消化率.     

Cytokine dysregulation in aged horses and horses with pituitary pars intermedia dysfunction

BACKGROUND: Equine pituitary pars intermedia dysfunction (PPID) is the result of a loss of dopaminergic inhibition of the pars intermedia secondary to neurodegeneration of periventricular hypothalamic neurons. The pathologic events contributing to development of neurodegeneration or clinical signs in equids with PPID are unknown. Chronic inflammation may contribute to initiation or progression of PPID. HYPOTHESIS: Horses with PPID have a distinct systemic cytokine profile compared with that of normal adult or aged horses. The cytokine profile of healthy aged horses differs from that of adult horses. ANIMALS: Aged horses with PPID, healthy aged-matched controls, and adult controls (n = 14 per group). METHODS: Total leukocyte cytokine expression was determined by quantitative polymerase chain reaction (PCR), and tumor necrosis factor (TNF)-alpha plasma concentration was determined by enzyme-linked immunosorbent assay (ELISA). Peripheral blood mononuclear cell (PBMC) TNF-alpha response after endotoxin (lipopolysaccharide [LPS]) treatment was assessed by ELISA. RESULTS: Aged healthy horses had increased expression of interleukin (IL)-6, IL-8, and interferon-gamma as well as PBMC TNF-alpha release after LPS stimulation compared with healthy adult horses. In contrast, aged horses with PPID had increased IL-8 expression, but expression of other cytokines was similar to that of healthy adult horses, not age-matched controls. CONCLUSIONS AND CLINICAL IMPORTANCE: Aged horses show evidence of a proinflammatory state that may contribute to development of age-associated diseases. Horses with PPID have increased expression of IL-8, which may influence the ability of horses with PPID to respond to bacterial pathogens. The general decrease in proinflammatory cytokine expression observed in horses with PPID may be the outcome of high plasma concentrations of anti-inflammatory hormones.     

Plasma homocysteine concentrations in healthy horses and horses with atrial fibrillation

Introduction

Homocysteine (HCY) is an amino acid produced from methionine metabolism. Plasma homocysteine concentrations ([HCY]_p) are elevated (>13 μmol/L) in people with atrial fibrillation (AF) and can predict the recurrence of AF after cardioversion. This study aimed to validate a commercially available human HCY assay for use in horses to develop reference intervals for [HCY]_p and compare [HCY]_p in healthy horses and horses with AF.

Fragmentation of intravenous catheters in three horses

Fragmentation of an intravenous, polytetrafluoroethylene catheter occurred in three horses. The retained fragment was identified in the cervical region by radiography and in the jugular vein by ultrasonography. The retained fragment was removed successfully by jugular venotomy.     

二元线性回归法测定生长猪内源磷排泄量及麦麸和豆粕磷的真消化率

本研究采用二元线性回归法测定生长猪内源磷排泄量及麦麸和豆粕磷的真消化率.选用6头健康大白×长白阉公猪为试验动物,平均体重为(34.42±0.64)kg.采用6×6拉丁方设计,设6个总磷水平(0.12%、0.25%、0.28%、0.35%、0.47%和0.54%),日粮以豆粕、葡萄糖、玉米淀粉等为基础原料,麦麸和豆粕为磷来源.日粮中添加0.1%TiO2作为外源指示剂.试验分6个试验期,每期6 d,4 d适应期,2 d收粪期.结果表明,生长猪粪磷的排出量与日粮磷的摄入量呈线性关系(y=0.515 7x-0.0133,R2=0.97,P<0.01),回归法测得生长猪内源磷的排泄量为0.933 0g/kg,麦麸和豆粕磷的真消化率分别为48.07%和47.50%.分析粪磷来源发现,内源磷排泄量基本不变(P>0.05),而粪磷随日粮磷含量的增加而极显著增加(P<0.01).由结果可知,线性回归法可用于测定猪内源磷排泄量及麦麸和豆粕磷的真消化率.     

Emerging outbreaks associated with equine coronavirus in adult horses

The purpose of this study was to describe clinical, hematological and fecal PCR results from 161 horses involved in outbreaks associated with ECoV. The outbreaks happened at four separate boarding facilities between November 2011 and April 2012 in the States of CA, TX, WI and MA. Following the molecular detection of ECoV in the feces from the initial index cases, the remaining herdmates were closely observed for the development of clinical signs. Fecal samples were collected from sick and healthy horses for the PCR detection of ECoV. All four outbreaks involved primarily adult horses. Fifty-nine horses developed clinical signs with 12–16 sick horses per outbreak. The main clinical signs reported were anorexia, lethargy and fever. Four horses from 3 different outbreaks were euthanized or died due to rapid progression of clinical signs. The cause of death could not be determined with necropsy evaluation in 2 horses, while septicemia secondary to gastrointestinal translocation was suspected in 2 horses. Blood work was available from 10 horses with clinical disease and common hematological abnormalities were leucopenia due to neutropenia and/or lymphopenia. Feces were available for ECoV testing by real-time PCR from 44 and 96 sick and healthy horses, respectively. 38/44 (86%) horses with abnormal clinical signs tested PCR positive for ECoV, while 89/96 (93%) healthy horses tested PCR negative for ECoV. The overall agreement between clinical status and PCR detection of ECoV was 91%. The study results suggest that ECoV is associated with self-limiting clinical and hematological abnormalities in adult horses.     

Brainstem auditory-evoked responses in horses with temporohyoid osteoarthropathy

Background: Facial and vestibulocochlear nerve dysfunction occurs commonly in horses with temporohyoid osteoarthropathy (THO); however, auditory dysfunction has not been thoroughly assessed.
Objective: To determine if auditory abnormalities occur in horses with THO.
Animals: Eleven diseased and 8 control horses.
Methods: This is a prospective study in which brainstem auditory-evoked responses (BAER) were recorded in 11 horses diagnosed with THO through neurologic, endoscopic, radiographic, or computed tomographic examinations. BAER findings were compared with those recorded from 8 adult control horses.
Results: All horses with THO were found to have BAER abnormalities that included complete unilateral BAER loss (82%, n = 9/11), partial unilateral BAER loss (18%, n = 2/11) on the most affected side, and contralateral partial BAER loss (46%, n = 5/11). Nine horses had bilateral THO based on diagnostic imaging findings; of these, 5 (56%) horses also had bilateral BAER abnormalities. The complete absence of BAER in affected horses was most consistent with peripheral sensorineural hearing loss. There was a significant association between complete BAER loss and neurologic and diagnostic abnormalities.
Conclusions and Clinical Importance: Auditory abnormalities such as complete or partial BAER loss are common in horses with THO. The BAER test is an objective diagnostic tool that can aid along with other diagnostic modalities in the assessment, management, and follow-up of horses with THO. Furthermore, BAER studies may help to elucidate the pathophysiology of THO in horses.     

Comparison of a 2-step insulin-response test to conventional insulin-sensitivity testing in horses

Equine insulin resistance is important because of its association with laminitis. The insulin-response test is described to diagnose insulin resistance in clinical settings. Practitioners may be reluctant to perform this test because of the time needed for the test and the fear of inducing hypoglycemia. The objective of the study was to compare a 2-step insulin-response test with a complete insulin-response test. A complete insulin-response test was performed on 6 insulin-resistant horses and 6 controls. A 2-step insulin-response test consisting of an intravenous injection of 0.1 IU/kg human insulin and blood glucose determination at 0 and 30 min after injection was performed on the same horses. Times to reach a 50% reduction of glucose baseline were compared between tests and horses. All the horses tolerated both tests well. No significant difference was observed between baseline glucose concentrations of insulin-resistant horses and controls (P = 0.09). Time to reach 50% reduction of glucose baseline for controls was not significantly different with the use of the complete insulin-response test or the 2-step test (P = 0.98). For insulin-resistant horses, the time to reach 50% reduction of glucose baseline with the use of the 2-step test was significantly longer than for controls (P = 0.004). With a cut-off time of 30 min, the 2-step test had the same characteristics as the complete test. The 2-step test provided a safe, rapid, and low-cost method to diagnose insulin resistance in horses in a clinical setting.     

生长猪对饲料原料中磷的消化率

磷是生长猪的一种重要营养素,但它总是不能被猪完全利用,因为其经常与植酸结合在一起。使用标准全肠道消化率（Standard Total Tract Digestibility,STTD）概念,可以更好地测定饲料原料中磷的准确营养价值。豆粕是猪饲料中一种优质蛋白质原料,由于全球猪鸡的饲养规模不断扩大,大豆的需求量快速增加,大大超过了其供应量。因此,一些其它来源的蛋白质原料有时会用于饲料中,以向动物提供一些必需氨基酸。     

Models to quantify excretion of dry matter,nitrogen, phosphorus and carbon in growing pigs fed regional diets

Modern pig production contributes to many environmental problems that relate to manure, especially in areas with highly intensive production systems and in regions like Asia where the regulative control is not effective. Therefore, the objective of this study was to use three different pig diets varying in dietary protein, fibre and fat as representative for Danish (DK), Thai (TH) and Vietnamese (VN) pig production to develop and evaluate different approaches to predict/calculate excretion from growing pigs in comparison with the experimentally determined values.Nine female growing pigs were used in a digestibility and balance experiment. Excretion of dry matter (DM), nitrogen (N), phosphorus (P) and carbon (C) of the experimental diets were determined.Due to the highest dietary fibre content, VN had the lowest digestibility of N, P and C (73, 49, and 73%, respectively) compared with the DK and TH pig diets. From the known diet composition using standard table values on chemical and nutrient digestibly, high accuracy (bias) and low variation was found and the results could be used for prediction on chemical composition and excretion in faeces and urine in growing pigs. Calculation based on standard values regarding nutrient retention in the pig body as used in the Danish manure normative system (DMNS) showed likewise to be quite useful for quantifying the total excretion of N and P.Overall, the results demonstrate that simple models that require cheap and normally available information on dietary nutrients can give useful information on nutrient excretion in growing pigs.     

Models to quantify excretion of dry matter,nitrogen, phosphorus and carbon in growing pigs fed regional diets

Modern pig production contributes to many environmental problems that relate to manure, especially in areas with highly intensive production systems and in regions like Asia where the regulative control is not effective. Therefore, the objective of this study was to use three different pig diets varying in dietary protein, fibre and fat as representative for Danish （DK）, Thai （TH） and Vietnamese （VN） pig production to develop and evaluate different approaches to predict/calculate excretion from growing pigs in comparison with the experimentally determined values. Nine female growing pigs were used in a digestibility and balance experiment. Excretion of dry matter （DM）, nitrogen （N）, phosphorus （P） and carbon （C） of the experimental diets were determined. Due to the highest dietary fibre content, VN had the lowest digestibility of N, P and C （73, 49, and 73%, respectively） compared with the DK and TH pig diets. From the known diet composition using standard table values on chemical and nutrient digestibly, high accuracy （bias） and low variation was found and the results could be used for prediction on chemical composition and excretion in faeces and urine in growing pigs. Calculation based on standard values regarding nutrient retention in the pig body as used in the Danish manure normative system （DMNS） showed likewise to be quite useful for quantifying the total excretion of N and P. Overall, the results demonstrate that simple models that require cheap and normally available information on dietary nutrients can give useful information on nutrient excretion in growing pigs.     

Pharmacokinetics and bioavailability of cefazolin in horses

The pharmacokinetics and bioavailability of cefazolin given (IV, IM) to horses at the dosage of 11 mg/kg were investigated. The disposition of cefazolin given by IV route was characterized by a rapid disposition phase with a half-life of 5 to 10 minutes and a subsequent slower elimination phase with a half-life of 35 to 46 minutes. The total plasma clearance of cefazolin averaged 5.51 ml/min/kg and was due mainly to renal clearance (5.39 ml/min/kg) of unchanged drug. The volume of distribution at steady-state averaged 188 ml/kg. Plasma protein binding of cefazolin at a concentration of 10 micrograms/ml averaged 8.1 +/- 1.9%. Given by the IM route, cefazolin was rapidly absorbed; the extent of bioavailability was 78.4 +/- 18.8%, and the terminal half-life ranged from 49 to 99 minutes. Thus, cefazolin was extensively absorbed, but was eliminated more slowly than after IV administration.     

Rapid calcitonin response to experimental hypercalcemia in healthy horses

Calcium has important physiological functions, and disorders of calcium homeostasis are frequent in horses. We have made important progress understanding equine calcium homeostasis; however, limited information on equine calcitonin (CT) is available, in part because of the lack of validated CT assays. To determine the CT response to high ionized calcium (Ca²⁺) concentrations in healthy horses, we induced hypercalcemia in 10 healthy horses using a calcium gluconate 23% solution (5 mg/kg; 120 mL/500 kg horse) infused over 4 min. Four horses were infused with 120 mL of 0.9% NaCl and used as controls. We validated a human-specific CT radioimmunoassay for use in horses. Serum Ca²⁺ concentrations increased from 6.2 ± 0.3 mg/dL to 9.9 ± 0.5 mg/dL (4 min; P < 0.01). Serum CT increased from 16.7 ± 8.0 pg/mL to 87.1 ± 55.8 pg/mL at 2 min, and 102.5 ± 51.1 pg/mL at 4 min (P < 0.01). Serum CT returned to baseline by 20 min, whereas serum Ca²⁺ returned to baseline by 40 min. Of interest, CT concentrations returned to baseline despite hypercalcemia, suggesting thyroid gland C-cell CT depletion. Resting CT values higher than 40 pg/mL were considered abnormally elevated. No significant changes in serum Ca²⁺ or CT concentrations were found in control horses. The coefficients of variation for the CT radioimmunoassay were lower than 11.9%. We conclude that the equine thyroid gland C-cell responds quickly to changes in extracellular Ca²⁺ concentrations by secreting large quantities of CT into the systemic circulation, indicating that CT is important in equine calcium homeostasis. The human CT radioimmunoassay can be used to measure changes in equine CT.     

Polyneuropathy associated with forage sources in Norwegian horses

BACKGROUND: Cases of hindlimb digital extensor weakness of unknown etiology have been observed in Norway since 1995. HYPOTHESIS: We hypothesized that the observed bilateral extensor weakness was attributable to neuropathy of the distal nerves and that this was related to environmental factors, possibly dietary. ANIMALS: Seventy-five horses with digital extensor weakness occurring from 1995 to 2004 are described. METHODS: Eleven horses were examined at The Norwegian School of Veterinary Science, and the medical records of 64 horses seen in ambulatory practice were reviewed. RESULTS: There was no apparent sex, age, or breed predilection, but the majority were horses kept for pleasure or breeding purposes. Clinical signs varied from intermittent knuckling of the hindlimbs to paraplegia. Some horses showed no or only slow progression of signs, whereas others developed severe signs within hours. No other neurologic deficits were detected in any of the horses. Epidemiologic data and laboratory results were not supportive of an infectious etiology. The only common factor for all affected horses seemed to be feeding big bale silage or, occasionally, hay of poor microbiologic quality. Forty of the 75 horses were euthanized. Histopathologic examination of peripheral nervous tissue was performed in 22 horses, all of which had neuronal fiber degeneration. The majority of horses with mild signs recovered after 5-6 months of rest. CONCLUSIONS AND CLINICAL IMPORTANCE: Clinical signs correlated with polyneuropathy involving sciatic nerves.     

Lawsonia intracellularis infection in horses: 2005-2007

Background: Lawsonia intracellularis is an emerging equine pathogen that is a cause of equine proliferative enteropathy (EPE).
Objective: To describe the signalment, month of presentation, common clinical signs, clinicopathologic values, diagnostic tests used, antimicrobial use, and survival status in horses affected with EPE; to evaluate how affected horses sold at public auction as yearlings; and to determine results of fecal polymerase chain reaction (PCR) and serum immunoperoxidase monolayer assay (IPMA) results in age matched, clinically normal herdmates.
Animals: The study group was 57 horses treated for disease associated with L. intracellularis infection between August 2005 and January 2007.
Methods: Retrospective study examined horses exhibiting evidence of infection with L. intracellularis and testing positive for fecal PCR or serum IPMA.
Results: Horses ranged in age from 2 to 8 months with a median age of 6 months, and all were examined between August and January. Ventral edema was present in 81% of horses and hypoalbuminemia occurred in all horses. Only 50% of horses tested positive on both PCR and IPMA. Ninety-three percent of horses survived, and survival was unrelated to antimicrobial administered. Affected horses sold as yearlings an average of 68% less than other yearlings by the same sire. Age matched, clinically normal herdmates also tested positive for L. intracellularis on fecal PCR (6%) and IPMA (33%).
Conclusion: L. intracellularis infection should be considered in young horses with ventral edema and hypoalbuminemia that are examined between August and January. Both fecal PCR and serum IPMA are needed to help determine disease status. Treated animals usually survive, although they do not sell for as high a price at public auction as other yearlings by the same sire. Age matched, clinically normal herdmates also test positive for L. intracellularis on fecal PCR and serum IPMA.     

Pulmonary dysfunction and skeletal muscle changes in horses with RAO

BACKGROUND: Chronic pulmonary diseases (recurrent airway obstruction [RAO]) have been reported to alter skeletal muscle cells in humans. The purpose of this study was to evaluate a potential relationship between pulmonary and muscle variables in horses with a clinical diagnosis of RAO. Muscle biopsies from healthy horses and from horses with RAO were investigated and the relationship between the severity of lung disease and the degree of muscular changes was determined. HYPOTHESIS: We hypothesized that chronic pulmonary disease can lead to changes of the skeletal muscle in horses. ANIMALS: Fifteen healthy horses (control) and 50 horses with RAO were examined. METHODS: In a prospective clinical trial, a complete lung examination was performed in all horses. In all horses, muscle enzyme activity at rest and after exercise and muscle biopsies from the M. gluteus medius were examined. RESULTS: None of the horses had clinical or histologic signs of primary or neurogenic myopathies. According to the clinical, endoscopic, and radiographic findings and with a scoring system, the horses with RAO were grouped according to the severity of pulmonary findings (15 horses mild, 24 horses moderate, 11 horses severe RAO). Pathologic changes of the skeletal muscle (fiber atrophy or fiber hypertrophy, myofibrillar degeneration, hyperplasia of mitochondria, and ragged-red-like fibers) were identified in most horses with RAO but in only a few individual control horses. In addition, a marked depletion of muscle glycogen storage was evident in the RAO horses but not in the control group. Other pathologic changes of skeletal muscle such as centralized nuclei and regenerating fibers were rare, but were more frequent in horses with lung diseases than in the control group. The degree of muscle cell changes was also graded with a scoring system and correlated with the severity of pulmonary disease (r= 0.55). CONCLUSION: Chronic pulmonary disease in horses is associated with structural changes in skeletal muscle. CLINICAL IMPORTANCE: Because chronic pulmonary disease may affect muscles, early and effective therapy may prevent these changes. This finding could be of clinical importance but requires further studies.