Resistance risk assessment within herbicide authorisation – a call for sensitivity data

In most European countries, the risk of herbicide resistance is assessed as part of the authorisation of herbicides in accordance with EPPO Standard PP 1/213(2). Because the susceptibility of weed populations to a certain herbicide may vary greatly, one part of resistance risk assessment is the testing for sensitivity variation among different populations of target weed species with a high resistance risk. This paper emphasises the importance of sensitivity data provision with regard to the recent EU Regulation (EC) 1107/2009 concerning the placing of plant protection products on the market and outlines the main technical requirements for sensitivity data. A useful principle is that sensitivity data should be provided for all herbicides with a high resistance risk regardless of whether resistance has already evolved against the herbicidal substance. Methodical details regarding the generation of sensitivity data are discussed, together with remaining questions that will need to be addressed if a harmonised assessment of herbicide resistance risk is to be achieved. Copyright © 2012 Society of Chemical Industry     

Comparison of isoflurane inhalation anaesthesia, injection anaesthesia and high volume caudal epidural anaesthesia for umbilical surgery in calves; metabolic, endocrine and cardiopulmonary effects

ObjectiveTo compare three anaesthetic protocols for umbilical surgery in calves regarding adequacy of analgesia, and cardiopulmonary and hormonal responses.Study designProspective, randomised experimental study.AnimalsThirty healthy German Holstein calves (7 female, 23 male) aged 45.9 ± 6.4 days.MethodsAll calves underwent umbilical surgery in dorsal recumbency. The anaesthetic protocols were as follows: group INH (n = 10), induction 0.1 mg kg^?1 xylazine IM and 2.0 mg kg^?1 ketamine IV, maintenance isoflurane in oxygen; Group INJ (n = 10), induction 0.2 mg kg^?1 xylazine IM and 5.0 mg kg^?1 ketamine IV, maintenance 2.5 mg kg^?1 ketamine IV every 15 minutes or as required; group EPI (n = 10), high volume caudal epidural anaesthesia with 0.2 mg kg^?1 xylazine diluted to 0.6 mL kg^?1 with procaine 2%. All calves received peri-umbilical infiltration of procaine and pre-operative IV flunixin (2.2 mg kg^?1). Cardiopulmonary variables were measured at preset intervals for up to 2 hours after surgery. The endocrine stress response was determined. Intra-operative nociception was assessed using a VAS scale. Data were compared between groups using appropriate statistical tests. A value of p < 0.05 was considered significant.ResultsAll three protocols provided adequate anaesthesia for surgery although, as judged by the VAS scale, intra-operative response was greatest with INJ. Lowest mean cortisol levels during surgery occurred in EPI. Heart rate and cardiac output did not differ between groups, but mean arterial blood pressure, systemic vascular resistance, and partial pressure of carbon dioxide were higher and arterial pH lower in groups INH and INJ than in Group EPI. Group INJ became hypoxaemic and had a significantly greater vascular shunt than did the other groups.Conclusion and clinical relevanceGroups INH and EPI both proved acceptable protocols for calves undergoing umbilical surgery, whilst INJ resulted in variable anti-nociception and in hypoxaemia. High volume caudal epidural anaesthesia provides a practical inexpensive method of anaesthesia for umbilical surgery.     

Effects of forage and protein source on feedlot performance and carcass traits of Holstein and crossbred beef steers.

Fifty-eight Holstein and 58 crossbred beef steers were individually fed one of four isonitrogenous diets to evaluate the effects of forage source (corn silage and alfalfa haylage) and protein source (soybean meal and fish meal) on feedlot performance. Phase 1 diets (up to 354 kg of BW) were 40% forage and 60% concentrates and were fed for 70 to 136 d (depending on diet and breed group). Phase 2 diets (354 kg of BW until slaughter) were 20% forage and 80% concentrates and were fed for 127 to 150 d (depending on diet and breed group). Slaughter end points were .6 cm of 12th rib fat for Holsteins and 1.0 cm of rib fat for crossbreds using real-time ultrasonic estimates. The steers were fed for a maximum of 330 d each year. Forage source was a significant component of variation for most growth, efficiency, and carcass traits. Holstein and crossbred steers fed alfalfa haylage had significantly lower average daily gain, feed efficiency, dressing percentage, and empty body fat and required more days on feed to reach slaughter end points, but had higher total feed energy intake available for production. Steers fed corn silage diets had significantly greater energetic efficiency (P less than .05) than those fed alfalfa haylage, due to increased use of ME to produce fat in the carcass. Protein type did not influence gain, feed or energetic efficiency, energy intake, or most carcass traits. A significant protein system x forage source interaction among the four diets was detected for crossbred steers fed corn silage and fish meal, for which there was significantly greater feed conversion with lower energy intake above maintenance, possibly due to better fiber digestion and(or) amino acid flow to the lower tract. Alfalfa haylage plus soybean meal diets decreased (P less than .05) the percentage of Holsteins grading USDA Choice or higher. These results indicate that corn silage, because of greater energy concentration, was a more desirable forage in feedlot diets composed of less than or equal to 40% forage and that protein type (soybean meal and fish meal) in growing diets is not an important factor in feedlot performance or carcass traits of Holstein or crossbred steers that are fed these diets.     

Demonstration of Chlamydia from an equine abortion

The isolation and identification of a chlamydial agent from an equine fetus is reported. The fetus was aborted by a mare with respiratory disease and fever in the 9th month of pregnancy. The serum of the mare was investigated by the compliment fixation test. Specific antibodies were detected for chlamydial antigen in a titer of > 1:40 and for equine herpes virus 1 antigen in a titer of 1:32. Pathological lesions were not found in the organs of the fetus. Chlamydiae were detected in the placenta by ELISA and subsequently isolated by cell culture. Using PCR technique the agent was identified as Chlamydophila psittaci.     

The effectiveness of oral and parenteral vitamin A doses in growing cattle with different vitamin A supplies]

The effect of one single oral or parenterally administered dose of 1 million IU vitamin A on the vitamin A depot in the liver and on blood plasma vitamin A concentrations was investigated in 3 individual feeding experiments with involvement of 18 and 24 calves or 24 fattening bulls. 50% of all animals in each of the 3 experiments received feed without any vitamin A through 108 or 112 or 209 days, prior to vitamin A administration, or received 10.000 IU/100 kg live weight and day. Parenteral vitamin A administration in either group yielded rise in blood plasma from 0.06--0.35 to 26.2--30.2 mumol/l, after 1 or 2 days. The maximum value measured after oral administration was 1.9 mumol/l. Most of the plasma values had returned to normal (0.6--12. mumol/l) within 14 days from administration. Oral and parenteral vitamin A doses, after 14 days, caused significant rise in vitamin A concentrations in the liver (from 15.5 to 82.5), with the increase resulting from parenteral administration (from 13.7 to 99.1) being clearly higher than that resulting from oral administration (from 17.3 to 65.9 mumol/kg fresh liver tissue). The same trends were recorded from recovery of vitamin A from the liver (26.8% after parenteral administration versus 15.0% in the wake of oral doses). Storage in and recovery from vitamin-A depleted animals were below values recorded from young cattle with sufficient vitamin A supply. These findings are likely to confirm that one single parenteral vitamin A administration was of clearly higher effectiveness, as compared to oral application.     

Distribution of the Cinnabar moth Tyria jacobaeae L. at landscape scale: use of linear landscape structures in egg laying on larval hostplant exposures

The distribution of the xerothermophilous Cinnabar moth Tyria jacobaeae was studied in a low mountain region in western Germany between 1989 and 2001. T. jacobaeae started its immigration into the study area in 1989 and first established populations in climatically favoured habitats like abandoned quarries and train stations where the larval host plant, ragwort (Senecio jacobaea), occurs. Analysis of landscape features (altitude, morphology) reveals that T. jacobaeae then dispersed along valleys with roads to higher altitudes of the study area. Elevations of occupied sites increased between 1989 and 2001. In order to investigate whether dispersal is affected by linear structures like valleys or roads with gravelled verges, hostplant exposures were placed at a distance of 600 m to the next population of T. jacobaeae. The experiments suggest that egglaying predominantly took place on exposures in valleys with roads and sparsely plant-covered verges but can also occur along valleys lacking roads and suitable habitats. However, larvae were never recorded on Senecio exposures which were placed aside from valleys and roads.This revised version was published online in May 2005 with corrections to the Cover Date.