Effects of ketamine constant rate infusions on cardiac biomarkers and cardiac function in dogs

Objective

To evaluate the effects of ketamine continuous rate infusions (CRI) at two dose rates on cardiovascular function and serum creatine kinase MB isoenzyme (CK-MB) and troponin I in healthy conscious dogs.

Management of bovine tuberculosis in Michigan wildlife: current status and near term prospects

Surveillance and control activities for bovine tuberculosis (bTB) in free-ranging Michigan white-tailed deer (Odocoileus virginianus) have now been underway for over a decade. Significant progress has been made, lowering apparent prevalence in deer in the core area by >60%, primarily via reduction of deer densities through hunting, and restrictions on public feeding and baiting of deer. These broad strategies of the Michigan Department of Natural Resources (MDNR), implemented with the cooperation of Michigan deer hunters, halved the deer population in the bTB endemic area. However, as hunters see fewer deer, their willingness to sustain aggressive harvests has waned, and public resentment of control measures has grown. During the past four years, apparent prevalence in core area deer has held approximately steady just below 2%. After bottoming out in 2004 at an estimated 10-12 deer/km(2), deer numbers have since rebounded by ～ 30%. Public compliance with baiting and feeding restrictions has been variable. In general, hunters in the core area do not perceive bTB as a problem, in spite of 13 years of MDNR outreach. To date, MDNR has expended more than US$23 million on TB-related activities. Of late, a substantial portion of that funding has been diverted to support other programs which have suffered from budget shortfalls. Livestock herd breakdowns continue to occur sporadically, averaging 3-4 per year 2005 to present. In total, 46 cattle and 4 captive deer herds have been diagnosed bTB positive statewide, the majority yielding only 1 positive animal. Five cattle herds were twice infected, one thrice. Michigan Department of Agriculture (MDA) policy emphasis has shifted towards obtaining producer support for wildlife risk mitigation and farm biosecurity. Funding has proven a limiting factor, with the majority of the US$63 million spent to date devoted to whole herd testing. Nevertheless, some initiatives justify cautious optimism. Promising research to support eventual vaccination of wild deer continues. Some hunters and landowners have begun to recognize the costs of high deer densities and supplemental feeding. A peninsula-wide ban on baiting and feeding was enacted. Some cattle producers, recognizing their precarious circumstances, have begun work to change long-held prevailing opinions among their peers about farm biosecurity. Yet formidable challenges remain, and evidence suggests that eradication of bTB, if it can be achieved, will take decades, and will require greater public and political resolve than has been demonstrated thus far.     

The effect of induced hypocalcaemia on the cardiac output and blood pressure of dairy cattle

A mean reduction of plasma calcium level to 51 per cent of normal infusion of 4.7 per cent Na2EDTA solution into four cows was associated with a mean reduction of 48 per cent in cardiac output. Hypocalcaemia sufficient to produce sternal recumbency in a further four cows resulted in a highly significant fall in the mean arterial blood pressure, which returned to normal immediately after treatment with an intravenous infusion of 350 ml of 32.5 per cent calcium borogluconate.     

Thrombolytic Therapy in Dogs and Cats

Objective: To review the thrombolytic agents most commonly used in humans, their mechanisms of action, potential uses, adverse effects, and reports of their use in dogs and cats.
Human data synthesis: Thrombolytic agents avaliable in human medicine include streptokinase, urokinase, tissueplasminogen activator (t-PA), single-chain urokinase plasma activator (scu-PA) and anisoylated plasminogen-strep-tokinase activator complex (APSAC). These agents were originally used for the management of proximal deep vein thrombosis and severe pulmonary embolism but more recently, use of these drugs has been extended to include the treatment of acute peripheral arterial disease, cerebrovascular disease (stroke) and acute coronary thrombosis. The most predictable side effect associated with the use of thrombolytic therapy is hemorrhage.
Veterinary data synthesis: Clinical experience with thrombolytic agents in small animals is limited to streptokinase and t-PA. It is possible, that as in humans, canine and feline patients with PTE and right ventricular dysfunction may benefit from thrombolytic therapy but there are no veterinary studies to support this theory to date. Successful use of streptokinase has been documented in a small number of canine patients with systemic thromboembolism. ⁶³ Thrombolytic therapy is relatively efficacious in cats with aortic thromboemboli but is associated with a high mortality rate. ^59,60,64 With regard to use of t-PA in veterinary medicine, the small number of animals treated with varying protocols makes it impossible to provide safe and effective dose recommendations at this time.
Conclusions: Future goals for thrombolytic therapy in veterinary medicine include determination of more specific clinical indications, as well as design of effective protocols that minimize mortality and morbidity.     

Effect of administration of a phospholipid emulsion on the initial response of horses administered endotoxin

OBJECTIVE: To evaluate the effect of a phospholipid emulsion (PLE) on the initial response of horses to administration of endotoxin. ANIMALS: 12 healthy adult horses. PROCEDURES: Horses were assigned to 2 treatment groups (6 horses/group). The control group was administered 1 L of saline (0.9% NaCl) solution, and the treated group was administered PLE (200 mg/kg, IV); treatments were administered during a period of 120 minutes. An infusion of endotoxin was initiated in both groups starting 1 hour after initiation of the saline or PLE solutions. Physical examination and hemodynamic variables were recorded, and blood samples were analyzed for concentrations of tumor necrosis factor (TNF)-alpha, interleukin-6, thromboxane B2 (TxB2), 6 keto-prostaglandin F (PGF)1alpha, total leukocyte count, and PLE concentrations. An ANOVA was used to detect significant differences. RESULTS: Administration of PLE resulted in significantly lower rectal temperature, heart rate, cardiac output, right atrial pressure, and pulmonary artery pressure and higher total leukocyte counts in treated horses, compared with values for control horses. The TNF-alpha concentration was significantly less in treated horses than in control horses. The TxB2 and 6 keto-PGFF1alpha concentrations were significantly different between treated and control horses at 30 minutes (TxB2) and at 30 and 60 minutes (6 keto-PGF1alpha). CONCLUSIONS AND CLINICAL RELEVANCE: Prior infusion of PLE in horses administered a low dose of endotoxin decreased rectal temperature, heart rate, pulmonary artery pressure, and TNF-alpha concentrations. Results of this study support further evaluation of PLE for use in the treatment of horses with endotoxemia.     

Effects of administration of antimicrobials in feed on growth rate and feed efficiency of pigs in multisite production systems

OBJECTIVE: To evaluate effect of various regimens for administration of antimicrobials in feed on growth rate and feed efficiency (feed/gain) of pigs in multisite production systems. DESIGN: Controlled trial. ANIMALS: 24,099 growing pigs in 3 multisite production systems. PROCEDURE: 10 trials involving various regimens for administration of antimicrobials in feed were evaluated. Trial 1 compared effects of 2 antimicrobial regimens on finishing pig performance. Trials 2 through 10 compared growth rate and feed efficiency of nursery and finishing pigs given antimicrobials in feed with values for control pigs not given antimicrobials. RESULTS: In trial 1, no significant differences were observed between the 2 antimicrobial regimens. In the remaining trials, growth rate of nursery pigs fed antimicrobials was significantly improved, compared with growth rate of control pigs. However, growth rate of finishing pigs and feed efficiency of nursery and finishing pigs were not significantly improved by adding antimicrobials to the feed. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that use of antimicrobials in the feed to promote growth should be limited to the nursery phase in multisite pig production systems. Use of antimicrobials in the feed of finishing pigs should be limited to therapeutic applications in which a diagnosis of bacterial infection susceptible to the antimicrobial to be used has been confirmed.     

Salinity an Environmental “Filter” Selecting for Plant Invasiveness? Evidence from Indigenous Lepidium alyssoides on Chihuahuan Desert Shrublands

A better understanding of site-specific factors such as soil salinity that regulate plant invasions is needed. We conducted a 3-mo greenhouse study to evaluate the salinity responses of three local maternal sources of Lepidium alyssoides, which is an indigenous species shown to aggressively colonize disturbed shrubland sites in the southwestern United States, including those affected by high salinity and sodicity. Results indicated that there were little or no population effects on plant evapotranspiration (ET), growth, and tissue Na and Cl concentrations. Significant reductions in seedling growth and ET were largely independent of various isosmotic saline irrigation solutions that included NaCl, Na₂SO₄, and CaCl₂, each at ? 0.1 MPa and ? 0.2 MPa, suggesting that ET and growth were controlled by solution osmotic potential. The combined Na and Cl concentrations in leaves were 9–10% of dry weight with no visible sign of injury. However, increasing leaf mortality and abscission as a proportion of total leaf production was observed in the high-salt treatments (? 0.2 MPa), with a combined Na and Cl concentration reaching 16% with high NaCl. Under saline conditions, considerable foliage salt loads of this species could deposit high-salt litter to potentially alter a landscape to its own favor and to the detriment of other salt-sensitive species. Results of this study add to a limited quantitative database on site-specific salinity factors governing plant invasions by showing the potential for these populations to behave invasively under saline conditions and, thus, potential for soil salinity assessment to predict incipient populations. However, due to its halophytic traits and indigenous status, L. alyssoides may alternatively provide ecosystem services to salinized shrublands of the arid and semiarid southwestern United States.     

美国目前和未来的保育猪饲养方案

在过去的20年内美国的猪产业发生了翻天覆地的变化。多址生产系统对畜群的健康和控制断奶仔猪链产生了极大的作用。然而一个成功的断奶仔猪营养方案其基本原则对于任何日龄断奶的仔猪来讲都是相似的。可以归纳成三点：①在断奶时,仔猪尽可能的体重大;②尽可能快的将日粮从复合日粮转化为简单日粮;③重点关注保育仔猪管理。此外,在美国过去的10年通过遗传选育的手段,使窝产仔数大约增加了1.5头,仔猪断奶的日龄也相应地增加到平均为19~23 d。当每头母猪产仔数增加以后,由于初生活仔数的增加,有更多体重轻的仔猪出生,这将是生产者所面临的挑战。因此,对生产者来说,了解影响初生体重轻的仔猪一生的生产性能以及收益的因素是非常必要的。