Comparison of worm control strategies in grazing sheep in Denmark.

Control of nematode parasites with reduced reliance on the use of anthelmintics was studied in 16 ewes with suckling twin lambs on contaminated pasture in Denmark. Ewes and lambs were treated with albendazole at turn-out 3 May. Ewes were removed from the groups on 26 July, and lambs were slaughtered on 11 October. The animals were allocated to 4 groups of 8 lambs and their 4 ewes. Group TS was treated with albendazole at weeks 3, 6 and 8 after turnout and set-stocked; group TM was similarly treated but moved to clean pasture in conjunction with the last drenching; group US was untreated and set-stocked, and group UM was left untreated but moved to clean pasture week 8 after turn-out. Supplementary feed was offered in June and August due to scarcity of pasture. Strategic treatments of ewes and lambs weeks 3, 6 and 8 after turn-out, with or without a move to clean pasture, were highly effective in controlling nematode infections for most of the season. This was reflected in better weight gains and carcass characteristics in the treated compared to untreated lambs, resulting in an average increase in the value of the product by 36%. The effect of moving without treatment (UM) on faecal egg counts was limited but peak pasture infectivity was reduced to less than 10% compared to the set-stocked group and weight gains of lambs were significantly better despite poor feed availability in late season. The study showed that under set-stocked conditions repeated anthelmintic treatments of both ewes and lambs in early season may ensure sufficient nematode control whereas moving animals to clean pasture without dosing was less efficient. The latter may, however, still be a viable option in organic and other production systems where routine use of anthelmintics is banned, particularly if weaning and moving are combined or a second move is performed.     

Injection technique and arthrography of the shoulder, elbow and carpal joints of the cat]

Nine cats were available for the present trial. Six thoracic limbs were dissected without any previous treatment. In the remaining twelve thoracic limbs, each articular space was injected with silicone and then fixed with a 5% formalin solution before being submitted to dissection. For the radiological examination ten adult cats were available and arthrographs were taken in two axial planes of each joint. The elbow-joints of six additional cats were injected with six differently formulated contrast media. Radiographs were taken at different time intervals: instantly, five and ten minutes after intraarticular injection. The quality of the contrast and clarity of the structures are discussed. A lateral and a cranial location for injection are described for shoulder-joint, as well as a caudolateral and a craniolateral location for the elbow. A dorsal injection location is recommended for the antebrachiocarpal articulation and the middle carpal articulation. The injection sides described are discussed comparing them with those taken from the literature on dogs and cats. The results obtained from arthrograms are compared with data from literature on dogs. The radiographs of the elbow show clear differences in quality depending on the contrast medium used and on time between injection and exposure. As a result, recommendations can be made for suitable contrast media for arthrograms of the shoulder-, elbow- and carpal-joint in cats. Further, it is recommended that radiographs should be taken not later than five minutes after injection of the contrast media.     

The effects of medetomidine on radial nerve blockade with mepivacaine in dogs

OBJECTIVE: To compare the sensory and motor effects of adding medetomidine to mepivicaine, administered either perineurally or systemically, for radial nerve block in dogs. STUDY DESIGN: Prospective randomized cross-over study. ANIMALS: Six healthy Beagles, aged 18.7 +/- 6.3 months and weighing 10.4 +/- 1.3 kg. METHODS: Dogs were anesthetized briefly with sevoflurane on three separate occasions and received each treatment administered in random order: mepivacaine 5 mg kg(-1) perineurally around the radial nerve with saline 0.01 mL kg(-1) intramuscularly (CONTROL); mepivacaine 5 mg kg(-1) and medetomidine 0.01 mg kg(-1) combined, perineurally with saline 0.01 mL kg(-1) intramuscularly (MEDPN); mepivacaine 5 mg kg(-1) perineurally around the radial nerve with medetomidine 0.01 mg kg(-1) intramuscularly (MEDIM). All nerve blocks were performed with the aid of a nerve locator. Motor effects were evaluated based on the ability to bear weight. Sensory effects were evaluated by the response to a graded-electrical stimulus. These were evaluated at 5-minute intervals for the first hour, and at 10-minute intervals thereafter. Mean intervals were calculated as follows: time to motor block onset, duration of motor block, time to peak sensory block, duration of peak sensory block (i.e. period of no response to maximal stimulus intensity), and duration of residual sensory block (i.e. time to return to baseline sensory function). Treatment means were compared using a one-way analysis of variance for repeated measures and, where significant differences were noted, a Student-Newman-Keuls test was applied; p < 0.05 was considered significant. RESULTS: Medetomidine, administered either systemically or perineurally, significantly prolonged duration of peak motor block, peak sensory block, and residual sensory block compared with CONTROL. CONCLUSION: Medetomidine prolonged sensory and motor blockade after radial nerve block with mepivacaine in dogs. CLINICAL RELEVANCE: Medetomidine may prove to be a useful adjunct to peripheral nerve blockade with local anesthetics.     

Short-term effects of an exceptionally hot and dry summer on decomposition of surface peat in a restored temperate bog

The restoration of drained peat bogs in Northwest (NW) Europe is an important task of soil protection, but needs to cope with warmer and drier summers. Our examination took place in the Pietzmoor bog (Schneverdingen, NW Germany) that had been drained for fuel peat extraction until the 1970s and rewetted since then. We determined carbon dioxide (CO₂) efflux in situ and in laboratory incubations. Also, we analyzed pore water for dissolved organic carbon (DOC), total and dissolved organic N (DON), nitrate (NO₃^–) and ammonium (NH₄⁺) concentration. In Schneverdingen, the summer 2003 was record-breaking hot (mean temperature June to August elevated > 3 K compared to long-term average) and dry (precipitation during the same period < 59% of long-term average). In July 2003, the water table in the Pietzmoor subsided to > 42 cm below the surface in July 2003, when in situ soil CO₂ efflux was up to 23.4 g m^–2 d^–1 compared to 15.7 g m^–2 d^–1 in September. Prior to March 2003, DOC concentrations in pore water were < 180 mg l^–1 and NH₄⁺ was the dominant fraction of mineral N. In July 2003, DOC concentration rose to 249 g l^–1, DON concentrations more than doubled, and NO₃^– became the dominant fraction of mineral N. Due to the increased future likelihood of hot and dry summers in NW Germany, peat bog restoration efforts need take care that a water table close to the surface is maintained.     

The effects of levamisole on oxidative stress induced by copper intoxication in broilers

Abstract

AIM: To determine the effects of Cu and levamisole on concentrations of Cu and Fe in plasma and liver, and the effects of levamisole on lipid peroxidation induced by Cu intoxication in broiler chickens.

METHODS: In a 2×4 factorial study, 80 one-day-old Ross PM3 broiler chicks were fed diets for 21 days containing either 8 mg/kg Cu (Low Cu) or 250 mg/kg Cu (High Cu) and were treated with 0 (L0), 4 (L4), 8 (L8) or 16 (L16) mg/kg bodyweight levamisole per day from Day 7 of the study, on three consecutive days in their drinking water. This treatment was repeated three times, at 3-day intervals. On Day 21, blood samples were collected from each bird for analysis of concentrations of Cu, Fe and malondialdehyde, and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase, catalase and glutathione peroxidase (GSH-Px). The birds were killed and liver samples collected for analysis of Cu and Fe.

RESULTS: Mean concentrations of Cu and Fe in plasma, and Cu in liver, were increased overall in the High Cu groups compared with the Low Cu groups (p<0.001). Compared with the L0 treatment group on the High Cu diet, treatments L4, L8 and L16 decreased concentrations of Cu in plasma, and L8 and L16 increased concentration of Cu in liver (p<0.05). Mean activities of AST and ALT were increased in untreated birds (L0) fed the High compared with Low Cu diets (p<0.01). In birds receiving the High Cu diet, treatments L4 and L8 decreased activities of AST, and L4 and L16 decreased activity of ALT, compared with L0 (p<0.05). The High Cu diet induced an oxidative stress characterised by increased mean concentrations of malondialdehyde and decreased activities of superoxide dismutase, catalase and GSH-Px (p<0.001). Concentration of malondialdehyde, and activities of superoxide dismutase and catalase were not changed following levamisole treatment in birds on the High Cu diet, and activity of GSH-Px was decreased by the L4 and L8 treatments compared with the L0 group.

CONCLUSIONS AND CLINICAL RELEVANCE: The results of the study suggest that treatment with levamisole might alleviate the harmful effects of Cu on the liver, as demonstrated by decreased activities of AST and ALT induced by a diet containing 250 mg/kg Cu.     

Distribution modelling of Japanese honeysuckle (Lonicera japonica) invasion in the Cumberland Plateau and Mountain Region, USA

Predicting the potential distribution of invasive plants within a specific region is pivotal to planning effective management but is challenged by attempting to model expanding populations that are rarely at equilibrium with their environment. We adopt an ensemble modelling approach to assess the potential distribution of Japanese honeysuckle (Lonicera japonica), a vine invasive to forests of the Cumberland Plateau and Mountain Region in the southeast of USA. The influence of disturbance, spatial and temporal heterogeneity and other landscape characteristics were assessed by creating regional level models based on occurrence records from the United States Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) database. Logistic regression and maximum entropy (MaxEnt) models were assessed independently and evaluated as predictive tools to test the value of presence/absence and presence only data in predicting species distributions. Ensemble models were also developed that combined the predictions of the two modelling approaches to obtain a more robust prediction. While logistic and MaxEnt models were similar in their predictive ability and dominant input variables, the ensemble approach derived the best fitting model overall. The regional distribution of Japanese honeysuckle was influenced greatly by environmental conditions such as elevation, slope, and temperature with anthropogenic activity having significant, though lesser, influence. The ensemble models predict that Japanese honeysuckle has nearly reached its potential distribution. However, given the critical role of minimum temperature on Japanese honeysuckle distribution, future occupancy at higher elevations is likely to increase since January temperatures for this region are predicted to rise by 1-4 °C over the next 100 years. The models also give some indication of the likely effect of land cover change on its distribution. Japanese honeysuckle tended to be associated with a high component of farming or low component of forest within the local neighbourhood. This suggests disturbed forest and/or high fragmentation has a higher invasion potential and given past trends and expected continued population growth this disturbance and fragmentation will only increase. The models can be integrated into forest management decision support systems and assist in the development of long term management plans, integrating the impact of potential climate and land cover change scenarios.     

The radio-frequency single-electron transistor (RF-SET): A fast and ultrasensitive electrometer

A new type of electrometer is described that uses a single-electron transistor (SET) and that allows large operating speeds and extremely high charge sensitivity. The SET readout was accomplished by measuring the damping of a 1.7-gigahertz resonant circuit in which the device is embedded, and in some ways is the electrostatic "dual" of the well-known radio-frequency superconducting quantum interference device. The device is more than two orders of magnitude faster than previous single-electron devices, with a constant gain from dc to greater than 100 megahertz. For a still-unoptimized device, a charge sensitivity of 1.2 x 10(-5) e/hertz was obtained at a frequency of 1.1 megahertz, which is about an order of magnitude better than a typical, 1/f-noise-limited SET, and corresponds to an energy sensitivity (in joules per hertz) of about 41 Planck's over 2pi.