Höhe der Erhaltungsdüngung und Ausnutzung von Düngerphosphat vor dem Hintergrund der P-Alterung im Boden

Phosphorus fertilizer rate to maintain the soil P status and the utilization of fertilizer P Once a soil has a P status adequate for optimum plant growth the aim of the farmer is to maintain it. Fertilizer phosphate, even water soluble, is utilized by crop plants generally by less than 20% only in the year of application. Furthermore, the solubility of residual P in soil decreases with time, a process known as “aging” of P. These observations have led to the widespread assumption, that fertilizer P is partly converted into a status unavailable to plants. This would mean that the amount of P necessary to maintain the soil P status has to be permanently higher than P removal of plants. The objective of this work was to test the validity of this conclusion. For this purpose long-term P fertilizer field and pot experiments were carried out on different soils. The results show that the soil test values, lactate (DL or CAL) and water extractable P, remained almost at the same level if fertilizer P was applied in amounts equal to those removed by the crop harvest products. A tendency of decreasing the soluble soil P level was only observed if the soluble soil P content was much higher than necessary for plants. However, the easily extractable P decreased or increased if P applications were less or higher than the amount of P removed by crops, respectively. Desorption studies have revealed that the amount of P desorbed within one week also remained constant if P application was equal to P removal. However, if P was applied in excess of plant removal this proportion was not fully desorbed within one week, whereas the plants were able to utilize it on the long run. We conclude that the “aging” of fertilizer P in soil does not result in a loss of P for crop plants. On the contrary, fertilizer P applied to the soil in a soluble form is fully utilized by the plants in extended periods of time. The rate of P application to maintain the P status of the soil is therefore equal to the quantity of P removed by the plant material.     

Transient hyperglycaemia in a prediabetic dog treated with prednisone and cyclosporin A

A dog with immune-mediated haemolytic anaemia developed transient hyperglycaemia and glucosuria requiring insulin therapy in association with prednisone and cyclosporin A therapy. Following short-term therapy with insulin and cyclosporin A, the dog remained on prednisone therapy but required no further insulin therapy for 12 weeks, at which time the dog became permanently diabetic. We hypothesise that prednisone and cyclosporin A contributed to insulin resistance in a prediabetic dog with suboptimal endogenous insulin concentration and that the degree of insulin resistance decreased when cyclosporin A therapy was discontinued.     

Prevalence of proliferative enteritis on pig farms in Australia

SUMMARY Three surveys, undertaken to assess the prevalence of proliferative enteritis (PE) on pig farms in Australia and to investigate risk factors associated with clinical disease, indicated that PE was a common disease in pig farms. Forty of the 71 (56%) randomly-selected producers had either observed PE or had a veterinarian diagnose the disease in their herd during 1988 to 1990. A relatively low prevalence of the disease was recorded at veterinary diagnostic laboratories, and this suggested that diagnoses of PE were often not confirmed by histopathological examination of the intestines of affected pigs. Non-haemorrhagic PE occurred most often in six- to 24-week-old pigs, but was also reported in 52-week-old pigs. Proliferative haemorrhagic enteropathy usually affected pigs over 16 weeks of age, but was also reported in pigs as young as six weeks and as old as four years of age. A survey of pig-specialist veterinarians indicated that most veterinarians diagnosed PE based on clinical and gross pathological examination of affected pigs, without laboratory confirmation. There were difficulties associated with measuring the prevalence of PE among herds, including the effectiveness of antibacterials for its prevention and control, its subclinical nature and probable mis-diagnoses. This study highlighted the need for an ante-mortem diagnostic test to measure the prevalence of PE more accurately.     

Comparison of two methods of seminal plasma removal on buffalo (Bubalus bubalis) sperm cryopreservation

Cryopreservation causes damage to spermatozoa, and methods minimizing this damage are therefore needed. Although much discussed, seminal plasma removal has become an alternative to improve sperm quality and viability after freezing and has been applied to different species in attempt to obtain good results. The objective of this study was to evaluate semen quality in buffaloes submitted to two methods for seminal plasma removal (filtration and centrifugation). Semen samples were collected from seven Murrah buffalo bulls (Bubalus bubalis) once a week for 8 weeks. Each ejaculate was divided into three groups: control (presence of seminal plasma), centrifugation and filtration. Sperm kinetics was evaluated with the computer‐assisted sperm analysis (CASA) system. Plasmalemma and acrosomal membrane integrity, mitochondrial membrane potential and reactive oxygen species (ROS) were measured by flow cytometry, and lipid peroxidation was evaluated by the thiobarbituric acid reactive substances (TBARS) assay. Seminal plasma removal did not improve sperm kinetics compared to the control group. Centrifugation increased the number of cells with damaged acrosomal membranes (0.77 ± 0.05) and filtration caused greater plasmalemma and acrosomal membrane damage (22.18 ± 1.07). No difference in the mitochondrial membrane potential was observed between groups. In contrast, ROS production was higher in the centrifugation group compared to the control and filtration groups, although no differences in TBARS formation were detected. In conclusion, seminal plasma removal did not improve the quality of thawed buffalo semen compared to control in terms of sperm kinetics, membrane integrity, mitochondrial membrane potential or lipid peroxidation.     

Barriers to innovation in human rabies prophylaxis and treatment: A causal analysis of insights from key opinion leaders and literature

Rabies is an essentially 100% fatal, zoonotic disease, caused by Lyssaviruses. Currently, the disease is vaccine‐preventable with pre‐ and post‐exposure prophylaxis (PrEP and PEP). Still, rabies virus is estimated to cause up to 60,000 human deaths annually, of which the vast majority occurs in rural Asia and Africa, due to the inaccessibility of prophylaxis and non‐existence of treatment. Despite these unmet clinical needs, rabies control mainly focuses on the sylvatic reservoir and drug innovation receives relatively little attention compared to other neglected tropical diseases (NTDs). As such, the lag of innovation in human rabies prophylaxis and treatment cannot be explained by limited return on investment alone. Strategies countering rabies‐specific innovation barriers are important for the acceleration of innovation in human rabies prophylaxis and treatment. Barriers throughout society, science, business development and market domains were identified through literature review and 23 semi‐structured interviews with key opinion leaders worldwide. A subsequent root cause analysis revealed causal relations between innovation barriers and a limited set of root causes. Finally, prioritization by experts indicated their relative importance. Root causes, which are fundamental to barriers, were aggregated into four types: market and commercial, stakeholder collaboration, public health and awareness, and disease trajectory. These were found in all domains of the innovation process and thus are relevant for all stakeholders. This study identifies barriers that were not previously described in this specific context, for example the competition for funding between medical and veterinary approaches. The results stress the existence of barriers beyond the limited return on investment and thereby explain why innovation in human rabies medication is lagging behind NTDs with a lower burden of disease. A re‐orientation on the full spectrum of barriers that hinder innovation in rabies prophylaxis and treatment is necessary to meet unmet societal and medical needs.