127 research outputs found
Prevalence and risk factors of claw lesions and lameness in pregnant sows in two types of group housing
Claw lesions and lameness in sows are an important welfare concern as well as a cause of considerable economic loss. These problems are more common in group housing than in individual housing systems. Given that group housing for gestating sows will become mandatory in the EU from 2013 onwards, the aim of the present study was: (1) to determine the prevalence of lameness and claw lesions in sows housed in groups during gestation, and (2) to analyze whether the type of group housing system and sow-related factors were associated with lameness and claw lesions. Eight Belgian pig herds with group housing of gestating sows were selected. Four herds used pens with electronic sow feeders (dynamic groups), the other four herds kept their sows in free access stalls (static groups). All sows were visually examined for lameness at the end of gestation. Claw lesions were scored after parturition. Information about feed, housing conditions and culling (strategy) was collected, as well as information about parity and breed. Of all 421 assessed sows, on average 9.7% (min. 2.4%, max. 23.1%) were lame. Almost 99% of the sows had one or more claw lesion with overgrowth of heel horn (93%) and cracks in the wall (52%) as the most prevalent lesions. Neither for lameness nor claw lesions was significant differences found between the two types of group housing. Lameness decreased while the mean claw lesion score increased with ageing. These results suggest that lameness can be caused by reasons other than claw lesions, especially in older sows. Although no difference was found between the two types of group housing, a huge variation between herds was observed. Moreover, as the prevalence of lameness and claw lesions in group housing is quite high and group housing will become mandatory in 2013, further investigation on risk factors of locomotor disorders in sows is necessary
Antimicrobial resistance of Escherichia coli and Enterococcus faecalis in housed laying-hen flocks in Europe
The aim of this study was to determine the potential association between housing type and multiple drug resistance (MDR) in Escherichia coli and Enterococcus faecalis isolates recovered from 283 laying-hen flocks. In each flock, a cloacal swab from four hens was collected and produced 1102 E. coli and 792 E. faecalis isolates. Broth microdilution was used to test susceptibility to antimicrobials. Country and housing type interacted differently with the MDR levels of both species. In the E. coli model, housing in a raised-floor system was associated with an increased risk of MDR compared to the conventional battery system [odds ratio (OR) 2·12, 95% confidence interval (CI) 1·13-3·97)]. In the E. faecalis model the MDR levels were lower in free-range systems than in conventional battery cages (OR 0·51, 95% CI 0·27-0·94). In Belgium, ceftiofur-resistant E. coli isolates were more numerous than in the other countrie
Photofission and Quasi-Deuteron-Nuclear State as Mixing of Bosons and Fermions
The empirical-phenomenological quasi-deuteron photofission description is
theoretically justified within the semiclassical, intermediate statistics
model. The transmutational fermion (nucleon) - boson (quasi-deuteron) potential
plays an essential role in the present context and is expressed in terms of
thermodynamical and of microscopical quantities, analogous to those commonly
used in the superfluid nuclear model.Comment: 7 pages, RevTex, to appear in Zeit. f. Phys.
Measurement of the Beam-Recoil Polarization in Low-Energy Virtual Compton Scattering from the Proton
Double-polarization observables in the reaction have been measured at . The experiment
was performed at the spectrometer setup of the A1 Collaboration using the 855
MeV polarized electron beam provided by the Mainz Microtron (MAMI) and a recoil
proton polarimeter. From the double-polarization observables the structure
function is extracted for the first time, with the value , using the low-energy theorem
for Virtual Compton Sattering. This structure function provides a hitherto
unmeasured linear combination of the generalized polarizabilities of the
proton
The first determination of Generalized Polarizabilities of the proton by a Virtual Compton Scattering experiment
Absolute differential cross sections for the reaction (e+p -> e+p+gamma) have
been measured at a four-momentum transfer with virtuality Q^2=0.33 GeV^2 and
polarization \epsilon = 0.62 in the range 33.6 to 111.5 MeV/c for the momentum
of the outgoing photon in the photon-proton center of mass frame. The
experiment has been performed with the high resolution spectrometers at the
Mainz Microtron MAMI. From the photon angular distributions, two structure
functions which are a linear combination of the generalized polarizabilities
have been determined for the first time.Comment: 4 pages, 3 figure
The helicity amplitudes A and A for the D resonance obtained from the reaction}
The helicity dependence of the reaction
has been measured for the first time in the photon energy range from 550 to 790
MeV. The experiment, performed at the Mainz microtron MAMI, used a
4-detector system, a circularly polarized, tagged photon beam, and a
longitudinally polarized frozen-spin target. These data are predominantly
sensitive to the resonance and are used to determine its
parameters.Comment: 5 pages, 4 figure
A new measurement of the structure functions and in virtual Compton scattering at 0.33 (GeV/c)
The cross section of the reaction has been measured at
(GeV/c). The experiment was performed using the electron beam
of the MAMI accelerator and the standard detector setup of the A1
Collaboration. The cross section is analyzed using the low-energy theorem for
virtual Compton scattering, yielding a new determination of the two structure
functions P_LL}-P_{TT}/epsilon and which are linear combinations of
the generalized polarizabilities of the proton. We find somewhat larger values
than in the previous investigation at the same . This difference, however,
is purely due to our more refined analysis of the data. The results tend to
confirm the non-trivial -evolution of the generalized polarizabilities and
call for more measurements in the low- region ( 1 (GeV/c)).Comment: 9 pages, 10 figures. EPJA version. slight revisions in the text and
figure
First measurement of the Gerasimov-Drell-Hearn integral for Hydrogen from 200 to 800 MeV
A direct measurement of the helicity dependence of the total photoabsorption
cross section on the proton was carried out at MAMI (Mainz) in the energy range
200 < E_gamma < 800 MeV. The experiment used a 4 detection system, a
circularly polarized tagged photon beam and a frozen spin target.
The contributions to the Gerasimov-Drell-Hearn sum rule and to the forward
spin polarizability determined from the data are 226 \pm 5 (stat)\pm
12(sys) \mu b and -187 \pm 8 (stat)\pm 10(sys)10^{-6} fm^4, respectively, for
200 < E_\gamma < 800 MeV.Comment: 6 pages, 3 figures, 3 table
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