Fertility and fertility problems in some beef herds in Sweden (author's transl)]

The purpose of the study was to investigate the fertility level, some factors affecting fertility and problems of infertility in selected Swedish beef herds. The investigation included 31 herds, 19 of which had Herefords, 13 Charolais, 2 Aberdeen Angus and 1 Limousins. The total number of mature females was 703, including 147 feifers of breeding age. Most data were collected at personal visits to the herds. The results are presented in Tables I--XV and Figures 1--2. The service period coincided roughly with the grazing period and lasted usually 4--5 months. Seventyfive per cent of the females calved during the period February-May. The fertility levels were comparatively good. The percentage of pregnancy at rectal examination performed at the end of the service period was 89.5; however the average calving percentage was only 87.5. The highest calving percentages were recorded for Aberdeen Angus and crossbreds. Also the calf crop, it is the number of calves born alive and surviving 24 hours per mature female was the highest for these two groups; 0.91 and 0.90 respectively. The mean interval from calving to conception was 80.3 days in Herefords, 83.4 days in Aberdeen Angus, 85.6 days in crossbreds and 92.3 days in Charolais. The percentage of animals pregnant within 90 days after calving was on an average slightly more than 50 per cent. The interval from calving to conception rose gradually when the interval from calving to expoure to bull exceeded 40 days. Mean percentages of still born calves were 5.9 in cows and 13.7 in heifers. As far as the fertility level is concerned there does not seem to be any disadvantage in keeping the bull together with the females during the calving period. However, in this case the next calvings will occur over an extended period of time. If the intention is to concentrate 50 per cent of the calvings within the period of one month then the females should be exposed to the bull from 41--60 days after calving at the earliest. In case the females were exposed to the bull from 41--60 days after calving and onwards, 95 per cent of the females finally pregnant had conceived at the end of a 3 months service period. Under such conditions a bull may be able to serve two groups of females within the same grazing period. Cows calving during July-September had the lowest pregnancy rate and those calving during October-December the highest at the following service period. The incidence of ovarian cysts was very low. About 1/3 of those buls serving at least 10 females each obtained calving percentages less than or equal to 80. Herds recording low calving percentages had to a great extent used young bulls, 12--15 months of age at the beginning of the service period. Only for two groups of females out of eleven which had been served by young bulls calving percentages greater than 80 were noted. A more efficient control of the fertility of the bulls could markedly improve the fertility of some herds.     

Cortisol in synovial fluid from normal and diseased canine joints—a preliminary report

Cortisol was determined in synovial fluid from normal and diseased canine joints. It was found that the amount of cortisol was considerably increased in diseased joints.     

Outbreak of Mycobacterium tuberculosis infection among captive Asian elephants in a Swedish zoo

Between 2001 and 2003, there was an outbreak of tuberculosis in a Swedish zoo which involved elephants, giraffes, rhinoceroses and buffaloes. Cultures of trunk lavages were used to detect infected elephants, tuberculin testing was used in the giraffes and buffaloes, and tracheal lavage and tuberculin testing were used in the rhinoceroses. The bacteria isolated were investigated by spoligotyping and restriction fragment length polymorphism. Five elephants and one giraffe were found to have been infected by four different strains of Mycobacterium tuberculosis.     

Imaging bond formation between a gold atom and pentacene on an insulating surface

A covalent bond between an individual pentacene molecule and a gold atom was formed by means of single-molecule chemistry inside a scanning tunneling microscope junction. The bond formation is reversible, and different structural isomers can be produced. The single-molecule synthesis was done on ultrathin insulating films that electronically isolated the reactants and products from their environment. Direct imaging of the orbital hybridization upon bond formation provides insight into the energetic shifts and occupation of the molecular resonances.     

Estimation of stem attributes using a combination of terrestrial and airborne laser scanning

Properties of individual trees can be estimated from airborne laser scanning (ALS) data provided that the scanning is dense enough and the positions of field-measured trees are available as training data. However, such detailed manual field measurements are laborious. This paper presents new methods to use terrestrial laser scanning (TLS) for automatic measurements of tree stems and to further link these ground measurements to ALS data analyzed at the single tree level. The methods have been validated in six 80 × 80 m field plots in spruce-dominated forest (lat. 58°N, long. 13°E). In a first step, individual tree stems were automatically detected from TLS data. The root mean square error (RMSE) for DBH was 38.0 mm (13.1 %), and the bias was 1.6 mm (0.5 %). In a second step, trees detected from the TLS data were automatically co-registered and linked with the corresponding trees detected from the ALS data. In a third step, tree level regression models were created for stem attributes derived from the TLS data using independent variables derived from trees detected from the ALS data. Leave-one-out cross-validation for one field plot at a time provided an RMSE for tree level ALS estimates trained with TLS data of 46.0 mm (15.4 %) for DBH, 9.4 dm (3.7 %) for tree height, and 197.4 dm³ (34.0 %) for stem volume, which was nearly as accurate as when data from manual field inventory were used for training.     

Impact of harvest year on amino acids and sugars in potatoes and effect on acrylamide formation during frying

Acrylamide is formed via the Maillard reaction between reducing sugars and asparagine in a number of carbohydrate-rich foods during heat treatment. High acrylamide levels have been found in potato products processed at high temperatures. To examine the impact of harvest year, information on weather conditions during growth, that is, temperature, precipitation, and light, was collected, together with analytical data on the concentrations of free amino acids and sugars in five potato clones and acrylamide contents in potato chips (commonly known as crisps in Europe). The study was conducted for 3 years (2004-2006). The contents of acrylamide precursors differed between the clones and the three harvest years; the levels of glucose were up to 4.2 times higher in 2006 than in 2004 and 2005, and the levels of fructose were 5.6 times higher, whereas the levels of asparagine varied to different extents. The high levels of sugars in 2006 were probably due to the extreme weather conditions during the growing season, and this was also reflected in acrylamide content that was approximately twice as high as in preceding years. The results indicate that acrylamide formation is dependent not only on the content and relative amounts of sugars and amino acids but also on other factors, for example, the food matrix, which may influence the availability of the reactants to participate in the Maillard reaction.     

Foraging strategies of the external mycelium of the arbuscular mycorrhizal fungi Glomus intraradices and Scutellospora calospora

The responsiveness of the external mycelium of Glomus intraradices and Scutellospora calospora was tested in a multiple-choice experimental system in which mycelium encountered patches amended with nitrogen (N) or phosphorus (P), either alone or in combination with a host plant. We hypothesised that only AMF mycelium with sufficient supply of photosynthate from an actively growing host would respond to the amendments provided. Mycelium was allowed to grow either 11 or 21 weeks before we analysed hyphal proliferation in amended patches introduced in mesh bags that were not reached by roots but by foraging mycelium only. Hyphal length, the AMF signature fatty acid 16:1w5, and root colonisation in new host plant seedlings were used to measure AMF growth and resource allocation in the patches. Mycelium from both fungal strains was able to colonise new host roots and sand in all patches but S. calospora was overall more responsive to the amendments than G. intraradices. G. intraradices grew equally into all patches, including the unamended control, whereas S. calospora produced significantly more hyphal length in the patch containing a host plant than in the rest of the patches. Both strains showed lower hyphal growth at the second harvest and mycelium of G. intraradices lost almost entirely its capacity to develop new mycelium in all choices presented. Lipid measurements showed this fungus did not use storage lipids to exploit the patches. S. calospora mycelium had reduced growth and colonisation ability but still showed some growth in the patches at the second harvest. A reduction in the content of NLFA 16:1w5 from the first to the second harvest suggested that S. calospora mycelium likely used storage lipids to sustain proliferation in the patches. The results indicated that S. calospora was more active and used more resources for foraging than G. intraradices and that external mycelium foraging was maintained mainly with recently acquired plant carbon (C). This supported in general our hypothesis but showed as well that the two AMF strains had different strategies and resource allocation to forage. The overall low response of both AMF to the choices presented suggested that the responsiveness of mycelium searching freely in the substrate is lower than that observed in experimental systems in which the amendments have been placed in close contact with actively growing mycelium fronts in close vicinity with host roots.