The selenium status of dairy herds in Prince Edward Island

Bulk tank milk selenium (Se) concentration was compared with mean serum Se concentration in 15 herds and was found to be an accurate reflection of the herd Se status. The Se status of 109 Prince Edward Island (PEI) dairy herds was monitored for 1 year using bulk tank milk Se concentration. Fifty-nine percent of the herds surveyed were, at some point, found to be marginal or deficient in Se, putting them at risk of disease and suboptimal production. The periods of greatest risk of deficiency were fall and winter, at which time 5% and 4%, respectively, of herds sampled fell in the range considered truly deficient in Se. Herds in which Se supplementation was provided in the form of a commercial dairy concentrate were over 4 times more likely to be Se-adequate than herds not using this method, and adjusted average daily milk yield was 7.6% greater in herds determined to be Se-adequate when compared with Se-marginal herds. We conclude that many dairy producers in PEI are providing insufficient supplementary Se in the ration to meet the recommended Se intake for lactating cows.     

A mechanical comparison of 4.5 mm narrow and 3.5 mm broad plating systems for stabilization of gapped fracture models

OBJECTIVE: To evaluate and compare the mechanical properties of 4.5 narrow and 3.5 broad plating systems using their respective cortical and cancellous screws in unstable, central, and eccentric gap fracture models. STUDY DESIGN: Mechanical evaluation and comparison of 2 dynamic compression plate (DCP) systems. SAMPLE POPULATION: Eighteen cortical and 30 cancellous gapped fracture models. METHODS: DCP (4.5 mm narrow, 3.5 mm broad) with their respective cortical screws were applied to cortical bone density polyurethane foam blocks to construct center gap cortical fracture models that were tested in gap closing monotonic 4-point bending. DCP (4.5 mm narrow, 3.5 mm broad) with their respective cancellous screws were applied to cancellous bone density polyurethane foam blocks to construct eccentric gap cancellous fracture models. The cancellous constructs were tested in monotonic gap opening and gap closing cantilever bending and in cyclic axial loading. Univariate and multivariate repeated measures ANOVA were used to compare the maximum loads at failure of the 4.5 mm constructs and 3.5 mm constructs. RESULTS: The 4.5 mm narrow plating system withstood significantly higher loads at failure than the 3.5 mm broad plating system in 4-point bending (P<.0001) and gap opening cantilever bending (P<.0001). The 4.5 mm system failed in gap closing cantilever bending by plastic deformation of the plate, whereas the 3.5 mm system failed by screw pullout. There was no difference between the 2 systems in cyclic axial loading. CONCLUSION: Results indicate that the 4.5 mm narrow plating system has a mechanical advantage over the 3.5 mm broad plating system for stabilization of gapped fracture models. CLINICAL RELEVANCE: The 4.5 mm narrow plating system may be mechanically advantageous compared with the 3.5 mm broad plating system for stabilizing unreconstructed comminuted long bone fractures in large dogs.     

Intraosseous gentamicin perfusion of the distal metacarpus in standing horses

OBJECTIVE: To report tissue gentamicin concentrations after intraosseous (IO) perfusion in standing horses. STUDY DESIGN: In vivo study. ANIMALS OR SAMPLE POPULATION: Twelve horses. METHODS: Sedated horses had a cannulated cortical bone screw inserted into the dorsolateral aspect of the treated metacarpus and a tourniquet applied proximally. Gentamicin (2.2 mg/kg) diluted in sterile saline solution (0.1 mL/kg) was infused through the screw. Two horses were euthanatized at each time interval: 0, 2, 6, 12, 24, and 36 hours. Synovial fluid and bone samples were collected distal to the screw from both forelimbs. Gentamicin concentrations were measured using fluorescence polarization immunoassay. RESULTS: The highest synovial fluid gentamicin concentrations were 385+/-273 microg/mL (mean+/-SD) in the metacarpophalangeal joint, 225+/-205 microg/mL in the proximal interphalangeal joint, 215+/-205 microg/mL in the distal interphalangeal joint, 382+/-195 microg/mL in the digital flexor tendon sheath, and 206+/-161 microg/mL in the navicular bursa. The highest bone concentrations of gentamicin were 55+/-30 microg/g in the distal metacarpus, 34+/-27 microg/g in the proximal, 16+/-15 microg/g in the middle, and 16+/-2.2 microg/g in the distal phalanges, and 27+/-17 microg/g in the proximal and 24+/-11 microg/g in the distal sesamoid bones. CONCLUSION: Standing IO perfusion of gentamicin resulted in local antibiotic concentrations in the synovial structures and bones of the distal aspect of the limb that exceed the reported minimum inhibitory concentration of pathogens commonly implicated in equine orthopedic infections. CLINICAL RELEVANCE: Standing IO perfusion of gentamicin in the distal aspect of the limb should be considered for treatment of orthopedic infections of this region in horses.     

The biological effects of five feline IFN-alpha subtypes

IFN-alpha has been shown to induce both antiviral and antiproliferative activities in animals. This report describes the biological activity of five recently identified feline IFN-alpha subtypes expressed in the Chinese hamster ovary (CHO) cell line (rfeIFN-alpha1[CHO], rfeIFN-alpha2[CHO], rfeIFN-alpha3[CHO], rfeIFN-alpha5[CHO] and rfeIFN-alpha6[CHO]) and the feIFN-alpha6 subtype expressed in and purified from Pichia pastoris (rfeIFN-alpha6[P. pastoris]). The rfeIFN-alpha[CHO] subtypes were tested for antiviral activity against either Vesicular stomatitis virus (VSV) or feline calicivirus (FCV) infected feline embryonic fibroblast cell line (AH927) or Crandell feline kidney cell line (CRFK). Antiviral activity was induced against both VSV and FCV infected AH927 cells and VSV infected CRFK cells by all five of the rfeIFN-alpha[CHO] subtypes and rfeIFN-alpha6[P. pastoris]. In addition, the IFN-alpha inducible Mx gene (associated with antiviral activity) was upregulated in vivo 24 h following treatment with rfeIFN-alpha6[P. pastoris], compared to baseline levels seen prior to treatment. All of the rfeIFN-alpha[CHO] subtypes and rfeIFN-alpha6[P. pastoris] exhibited antiproliferative activity in the FeT-J cell line (an IL-2 independent feline T-cell line). Both necrosis and apoptosis were observed in rfeIFN-alpha6[P. pastoris]-treated FeT-J cells. The rfeIFN-alpha3[CHO] subtype consistently exhibited lower antiviral and antiproliferative activity compared to that observed with the other four rfeIFN-alpha[CHO] subtypes. In summary, this paper demonstrates that five previously described feIFN-alpha subtypes induce both antiviral and antiproliferative activities in vitro and are capable of upregulating the feMx gene in vivo.     

Routes of transmission and consequences of small ruminant lentiviruses (SRLVs) infection and eradication schemes

Small ruminant lentiviruses (SRLV = maedi-visna in sheep and caprine arthritis encephalitis in goats) are distributed throughout most countries of the world, particularly Europe. Laboratories from 16 European countries established collaborations within the framework of a COST (CO-operation in the field of Scientific and Technical Research) action sponsored by the European Union in order to (i) better organize their research programmes on SRLVs and (ii) to coordinate efforts to combat these two diseases. After five years, a consensus conference--the first one in the veterinary medicine field--concluded the work of this network of laboratories by reviewing the present position and discussing three important questions in the field of SRLVs: routes of transmission, consequences of infection and potential role of eradication programmes at either a European or local level, according to the situation in each country or region. This paper brings together existing information regarding these questions and identifies areas for future research.     

Seroprevalence of Bartonella infection in American free-ranging and captive pumas (Felis concolor) and bobcats (Lynx rufus)

Bartonella henselae is the main agent of cat scratch disease in humans and domestic cats are the main reservoir of this bacterium. We conducted a serosurvey to investigate the role of American wild felids as a potential reservoir of Bartonella species. A total of 479 samples (439 serum samples and 40 Nobuto strips) collected between 1984 and 1999 from pumas (Felis concolor) and 91 samples (58 serum samples and 33 Nobuto strips) collected from bobcats (Lynx rufus) in North America, Central America and South America were screened for B. henselae antibodies. The overall prevalence of B. henselae antibodies was respectively 19.4% in pumas and 23.1% in bobcats, with regional variations. In the USA, pumas from the southwestern states were more likely to be seropositive for B. henselae (prevalence ratio (PR) = 2.82, 95% confidence interval (CI) = 1.55, 5.11) than pumas from the Northwest and Mountain states. Similarly, adults were more likely to be B. henselae seropositive than juveniles and kittens (PR = 1.77, 95% CI = 1.07, 2.93). Adult pumas were more likely to have higher B. henselae antibody titers than juveniles and kittens (p = 0.026). B. henselae antibody prevalence was 22.4% (19/85) in bobcats from the USA and 33.3% (2/6) in the Mexican bobcats. In the USA, antibody prevalence varied depending on the geographical origin of the bobcats. In California, the highest prevalence was in bobcats from the coastal range (37.5%). These results suggest a potential role of wild felids in the epidemiological cycle of Bartonella henselae or closely related Bartonella species.