Humane Euthanasia and Carcass Disposal.

Euthanasia is ending life in a way that minimizes or eliminates pain and distress. It requires techniques that induce loss of consciousness followed by cardiac and respiratory arrest and loss of brain function. Although euthanasia is the objective for uncontrollable animal suffering, it is not always possible. Euthanasia of animals using barbiturates or barbituric acid derivatives is impractical for situations that require mass euthanasia of multiple animals. Selection of the most appropriate disposal method depends on number of carcasses, potential environmental impact, climatic conditions, and other factors. Preplanning and training are requirements for proper application of euthanasia procedures and disposal of carcasses.

Feedlot Euthanasia and Necropsy.

Timely euthanasia of feeder cattle can minimize suffering of cattle that have little hope of recovery or pain abatement. Euthanasia techniques are described, including primary and secondary steps to ensure humane death. Considerations are discussed to ensure rendered product from euthanized cattle will be safe. A necropsy technique that is time efficient and thorough is outlined. An important aspect is minimizing the number of detached body organs, thereby making it easier to remove the necropsied animal. A necropsy data collection system is discussed that uses check-boxes to record findings. A link to a database that can be downloaded is included.

Management of Cattle Exposed to Adverse Environmental Conditions.

During periods of adverse weather, optimum conditions for animal comfort and performance are compromised. Use of alternative supplementation programs need to be considered for livestock challenged by adverse environmental conditions. Use of additional water for consumption and cooling, shade, and/or alternative management strategies need to be considered to help livestock cope with heat stress. For animals reared outside during winter, strategies that increase animal space and environmental buffers need to be used to minimize effects of mud, wet conditions, and windchill. There are ample opportunities for livestock producers to enhance animal welfare and minimize the impact of environmental stress.

The monster we don't see: subclinical BRD in beef cattle.

Bovine respiratory disease (BRD) is the most expensive disease affecting United States cattle. Recently weaned calves are the focus of prevention and treatment research. Identifying affected cattle early in the course of BRD is difficult. Intervention during the early stages of BRD improves treatment outcomes; however, cattle as prey animals are excellent at hiding signs of disease, especially if the caregiver has not gained their trust. Depression, appetite loss, and changes in respiratory character are the principal signs used to identify BRD. Rectal temperatures from cattle pulled for treatment are a final measure of evaluation. Cattle suffering from subclinical BRD frequently escape identification and treatment. Observations of lungs at packing plants for anterior ventral (AV) lesions frequently document higher BRD incidence rates than observed pre-harvest, suggesting subclinical BRD is common. Data from numerous studies document lower average daily gains (ADG) from cattle with AV lung lesions at packing plants that were not treated for BRD compared with cattle with normal lungs. Scoring lung lesions at the packing plant can be a useful tool for gaining insight into BRD incidence. Data indicate that BRD lowers ADG by 0.2 lbs on average, and lowers the USDA Quality Grade by 50 marbling points.

Development and model testing of antemortem screening methodology to predict required drug withholds in heifers.

A simple, cow-side test for the presence of drug residues in live animal fluids would provide useful information for tissue drug residue avoidance programs. This work describes adaptation and evaluation of rapid screening tests to detect drug residues in serum and urine. Medicated heifers had urine, serum, and tissue biopsy samples taken while on drug treatment. Samples were tested by rapid methods and high-performance liquid chromatography (HPLC). The adapted microbial inhibition method, kidney inhibition swab test, was useful in detecting sulfadimethoxine in serum, and its response correlated with the prescribed withdrawal time for the drug, 5 to 6 days posttreatment. The lateral flow screening method for flunixin and beta-lactams, adapted for urine, was useful in predicting flunixin in liver detected by HPLC, 96 h posttreatment. The same adapted methods were not useful to detect ceftiofur in serum or urine due to a lack of sensitivity at the levels of interest. These antemortem screening test studies demonstrated that the method selected, and the sampling matrix chosen (urine or serum), will depend on the drug used and should be based on animal treatment history if available. The live animal tests demonstrated the potential for verification that an individual animal is free of drug residues before sale for human consumption.

Complete Closed Genome Sequences of Four Mannheimia varigena Isolates from Cattle with Shipping Fever.

Mannheimia varigena is an occasional respiratory pathogen of cattle and pigs. We present the first four complete closed genome sequences of this species.

Bovine dehorning: assessing pain and providing analgesic management.

Dehorning or disbudding in cattle is performed for a variety of reasons using various methods. Pain associated with this procedure has been mostly evaluated through behavioral, physiologic, and neuroendocrine changes following dehorning. Analgesics, including local nerve blockades, anti-inflammatories, and opioids have demonstrated an effective attenuation of the cortisol response. The administration of sedatives with analgesic properties has been indicated in the attenuation of the acute phase of pain associated with dehorning. Following a literature review, this article recommends a multimodal approach to analgesia for dehorning procedures, including the use of a local anesthetic and anti-inflammatory and, when possible, a sedative-analgesic.

Influence of therapeutic ceftiofur treatments of feedlot cattle on fecal and hide prevalences of commensal Escherichia coli resistant to expanded-spectrum cephalosporins, and molecular characterization of resistant isolates.

In the United States, the blaCMY-2 gene contained within incompatibility type A/C (IncA/C) plasmids is frequently identified in extended-spectrum-cephalosporin-resistant (ESC(r)) Escherichia coli strains from both human and cattle sources. Concerns have been raised that therapeutic use of ceftiofur in cattle may increase the prevalence of ESC(r) E. coli. We report that herd ESC(r) E. coli fecal and hide prevalences throughout the residency of cattle at a feedlot, including during the period of greatest ceftiofur use at the feedlot, were either not significantly different (P ≥ 0.05) or significantly less (P < 0.05) than the respective prevalences at arrival. Longitudinal sampling of cattle treated with ceftiofur demonstrated that once the transient increase of ESC(r) E. coli shedding that follows ceftiofur injection abated, ceftiofur-injected cattle were no more likely than untreated members of the same herd to shed ESC(r) E. coli. Pulsed-field gel electrophoresis (PFGE) genotyping, antibiotic resistance phenotyping, screening for presence of the blaCMY-2 gene, and plasmid replicon typing were performed on 312 ESC(r) E. coli isolates obtained during six sampling periods spanning the 10-month residence of cattle at the feedlot. The identification of only 26 unique PFGE genotypes, 12 of which were isolated during multiple sampling periods, suggests that clonal expansion of feedlot-adapted blaCMY-2 E. coli strains contributed more to the persistence of blaCMY-2 than horizontal transfer of IncA/C plasmids between E. coli strains at this feedlot. We conclude that therapeutic use of ceftiofur at this cattle feedlot did not significantly increase the herd prevalence of ESC(r) E. coli.

Field necropsy of cattle and diagnostic sample submission.

Field necropsies can provide a wealth of information that can help guide production management decisions. Techniques outlined can allow a veterinary practitioner to complete a thorough necropsy of a bovine, including examination of the brain when indicated, in less than 20 minutes. An observation and history collection system using form templates and photographs is outlined that improves efficiency of recording necropsy results. One key to necropsy efficiency, speed, and enjoyment is having sharp knives. The first part of the article includes tips for sharpening knives. The article also includes detailed information on appropriate diagnostic specimen handling, packaging, and shipping.

Bacterial pathogens of the bovine respiratory disease complex.

Pneumonia caused by the bacterial pathogens discussed in this article is the most significant cause of morbidity and mortality of the BRDC. Most of these infectious bacteria are not capable of inducing significant disease without the presence of other predisposing environmental factors, physiologic stressors, or concurrent infections. Mannheimia haemolytica is the most common and serious of these bacterial agents and is therefore also the most highly characterized. There are other important bacterial pathogens of BRD, such as Pasteurella multocida, Histophulus somni, and Mycoplasma bovis. Mixed infections with these organisms do occur. These pathogens have unique and common virulence factors but the resulting pneumonic lesions may be similar. Although the amount and quality of research associated with BRD has increased, vaccination and therapeutic practices are not fully successful. A greater understanding of the virulence mechanisms of the infecting bacteria and pathogenesis of pneumonia, as well as the characteristics of the organisms that allow tissue persistence, may lead to improved management, therapeutics, and vaccines.

Bovine pasteurellosis and other bacterial infections of the respiratory tract.

Despite technological, biologic, and pharmacologic advances the bacterial component of the bovine respiratory disease (BRD) complex continues to have a major adverse effect on the health and wellbeing of stocker and feeder cattle. Overlooked in this disappointing assessment is evaluation of the effects that working with younger, lighter-weight cattle have on managing the bacterial component of the BRD complex. Most problems associated with BRD come from cattle taken from and comingled with cattle operations that have inconsistent or nonexistent cattle health management. This article reviews the biologic, clinical, and management aspects of Pasteurella multocida, Mannheimia haemolytica, Histophilus somni, and Mycoplasma bovis, primarily as related to current production management considerations of stocker and feeder cattle.

Cardiac extracorporeal life support: state of the art in 2007.

Mechanical circulatory support is an invaluable tool in the care of children with severe refractory cardiac and or pulmonary failure. Two forms of mechanical circulatory support are currently available to neonates, infants, and smaller children, namely extracorporeal membrane oxygenation and use of a ventricular assist device, with each technique having unique advantages and disadvantages. The intra-aortic balloon pump is a third form of mechanical support that has been successfully used in larger children, adolescents, and adults, but has limited applicability in smaller children. In this review, we discuss the current experiences with extracorporeal membrane oxygenation and ventricular assist devices in children with cardiac disease.A variety of forms of mechanical circulatory support are available for children with cardiopulmonary dysfunction refractory to conventional management. These devices require extensive resources, both human and economic. Extracorporeal membrane oxygenation can be effectively used in a variety of settings to provide support to critically-ill patients with cardiac disease. Careful selection of patients and timing of intervention remains challenging. Special consideration should be given to children with cardiac disease with regard to anatomy, physiology, cannulation, and circuit management. Even though exciting progress is being made in the development of ventricular assist devices for long-term mechanical support in children, extracorporeal membrane oxygenation remains the mainstay of mechanical circulatory support in children with complex anatomy, particularly those needing rapid resuscitation and those with a functionally univentricular circulation.As the familiarity and experience with extracorporeal membrane oxygenation has grown, new indications have evolved, including emergent resuscitation. This utilization has been termed extracorporeal cardiopulmonary resuscitation. The literature supporting emergent cardiopulmonary support is mounting. Reasonable survival rates have been achieved after initiation of support during active compressions of the chest following in-hospital cardiac arrest. Due to the limitations of conventional circuits for extracorporeal membrane oxygenation, some centres have developed novel systems for rapid cardiopulmonary support. Many centres previously considered a functionally univentricular circulation to be a contraindication to extracorporeal membrane oxygenation, but improved results have been achieved recently with this complex subset of patients. The registry of the Extracorporeal Life Support Organization recently reported the outcome of extracorporeal life support used in neonates for cardiac indications from 1996 to 2000. Of the 740 neonates who were placed on extracorporeal life support for cardiac indications, 118 had hypoplastic left heart syndrome. There was no significant difference in survival between these patients and those with other defects. It is now common to use extracorporeal membrane oxygenation to support patients with a functionally univentricular circulation, and reasonable survival rates are to be expected. Although extracorporeal membrane oxygenation has become a standard of care for many paediatric centres, its use is limited to those patients who require only short-term cardiopulmonary support. Mechanical ventricular assist devices have become standard therapy for adults with cardiac failure refractory to maximal medical management. Several devices are readily available in the United States of America for adults, but there are fewer options available to children. Over the last few years, substantial progress has been made in paediatric mechanical support. Ventricular assist devices are being used with increasing frequency in children with cardiac failure refractory to medical therapy for primary treatment as a long-term bridge to recovery or transplantation. The paracorporeal, pneumatic, pulsatile "Berlin Heart" ventricular assist device is being used with increasing frequency in Europe and North America to provide univentricular and biventricular support. With this device, a patient can be maintained on mechanical circulatory support while extubated, being mobilized, and feeding by mouth. Mechanical circulatory support should be anticipated, and every attempt must be made to initiate support "urgently" rather than "emergently", before the presence of dysfunction of end organs or circulatory collapse. In an emergency, these patients can be resuscitated with extracorporeal membrane oxygenation and subsequently transitioned to a long-term ventricular assist device after a period of stability.

Assessing performance of feedlot operations using epidemiology.

The progressive feedlot veterinarian must be well versed not only in individual production animal medicine, but also in population-based medicine. Feedlot health programs must be goal oriented, and evaluation of these goals is accomplished through diligent use of record systems and analytic evaluation of these record systems. Basic feedlot monitoring parameters include health and economic parameters in addition to the use of bench marking parameters between and among feed yards. When these parameters have significant changes, steps should be initiated to begin field investigations. Feedlot epidemiology uses several novel applications such as partial budgeting, risk assessment, and packing plant audits to provide scientifically sound and economically feasible solutions for the feeding industry.

Blood gas strategies and management during pediatric cardiopulmonary bypass.

Blood gas management during hypothermic cardiopulmonary bypass may be corrected by pH stat or alpha stat strategy. The pH stat philosophy is to maintain the blood pH constant at any temperature. Carbon dioxide must be introduced to the oxygenator in order to maintain the pH and pCO2 during hypothermic cardiopulmonary bypass. Conversely, during alpha stat blood gas management pH is maintained according to 37 degrees C despite the patient temperature. Alpha stat management preserves intracellular pH and autoregulation of cerebral vasculature by following the natural shift of the oxyhemoglobin dissociation curve. In-line blood gas analysis is a practical tool in assessing adequate blood gas management, because this technology provides immediate detection for modification of air/oxygen/carbon dioxide parameters. Results from several studies favor the pH stat strategy during neonatal cardiopulmonary bypass. This strategy increases tissue oxygenation and cerebral blood flow while cooling. Data also suggest that pH stat management results in better outcomes with shorter ventilation times and intensive care unit stays after pediatric cardiac surgery.

Extracorporeal membrane oxygenation to cardiopulmonary bypass with a single circuit exposure.

Due to the short supply of donor organs available, many patients decompensate or die while waiting for transplantation. Options for mechanical support for infants and pediatrics with congenital heart disease are limited because of the patient's size and device availability. Extracorporeal membrane oxygenation (ECMO) is the most common means of cardiac and respiratory support for these patients. One of the many indications for ECMO use in cardiac patients is as a bridge to transplantation, with patients being transported to the operating room (OR) on ECMO support. Converting the ECMO circuit to an open cardiopulmonary bypass system in the OR minimizes the patient's exposure to new circuitry, decreases further donor exposures and provides continuous support for patients in cardiac and/or respiratory failure. In addition, the ability to use modified ultrafiltration post-bypass aids in reducing extracellular fluid, increasing the hematocrit and improving hemodynamic stability following an extended duration of ECMO and bypass support. The integrity of the ECMO circuit is maintained and can be converted back to ECMO for support postoperatively if needed.

Modified ultrafiltration postextracorporeal membrane oxygenation.

Modified ultrafiltration (MUF) has been widely used for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. The reported benefits of this technique are improved hematological status and hemodynamic stability post-CPB, as well as a decrease in blood utilization during the operation. MUF has also been associated with improved pulmonary status along with enhanced myocardial performance. With these benefits in mind, we have explored the possible advantages of using MUF following extracorporeal membrane oxygenation (ECMO). The theoretical advantages of using MUF post-ECMO are the reduction of blood use prior to removal from ECMO for optimization of hemoglobin levels, improved pulmonary compliance decreasing the duration of ventilatory support, improved myocardial function, as well as the other reported benefits described with MUF post-CPB. This report communicates the technique used to perform MUF post-ECMO, as well as a simple MUF circuit design for use in the intensive care unit setting.

Alleviating heat loss associated with modified ultrafiltration.

Modified ultrafiltration (MUF) has been described and utilized for the removal of extracellular water in the immediate postcardiopulmonary bypass (CPB) period. This technique has been associated with improved hematological status and hemodynamic stability post cardiopulmonary bypass. Hypothermia during the MUF period has been described as a complication associated with this technique. Decreased patient temperature may be associated with increased bleeding causing an increase in time to sternal re-approximation, OR time, decreases in cardiac function, peripheral vascular perfusion, and an increase in blood product utilization. These complications may reduce some of the benefits described with the use of MUF. The purpose of this study was to evaluate the use of a heated MUF infusion line to reduce the heat loss associated with this technique in a pediatric population. After obtaining Committee for Protection of Human Subjects exemption, a retrospective review to evaluate the efficiency of the hot MUF infusion line was undertaken. Twenty patients under 10 kg who underwent MUF before the change to a heated infusion line were retrospectively identified and matched to patients undergoing MUF with a heated infusion line with regard to weight, lesion, procedure, surgical staff and technique, and disposable equipment. Groups were evaluated for temperature and hematocrit change during the MUF period, blood loss and transfusion postprotamine in the OR and 24 h, and time to sternal re-approximation postprotamine. Statistical significance was seen between the two groups in temperature (-0.24 +/- 0.72 vs. - 1.58 +/- 0.89 degrees C; p < .0001) with the HotLine group having little change post MUF. Significance was also seen in the last OR temperature recorded (37.0 +/- 1.2 vs. 36.0 +/- 1.0 degrees C; p = .01) with the HotLine group having the higher temperature. There were no significant differences in hematocrit levels at 24 hours, last in the OR, or the change after the MUF period. No significant difference was found in blood transfused postprotamine in the OR, 24-h blood transfused, 24-h chest tube loss, or sternal closure. The study suggests that the use of a heated MUF infusion line safely reduces the heat loss associated with MUF in the immediate post-operative period.