Effects of a non-starch polysaccharidase enzyme preparation from Thermomyces lanuginosus on energy and protein metabolism and milk yield of dairy cattle

Non-starch polysaccharides (NSPs) form an integral part of the cell walls in plants and represent considerable available energy when degraded into absorbable mono-, di-, tri- and oligosaccharides. The ruminal microflora hydrolyses a good part of NSPs, however, recently there have been attempts to enhance the rate of utilisation by using external polysaccharidase enzymes. In the present study the effects of an enzyme preparation (Rumino-Zyme) high in xylanase activity were studied on ruminal volatile fatty acid (VFA) concentration, parameters of energy and protein metabolism, milk yield, feed conversion ratio (FCR) and body condition score of high-yielding dairy cows. A lignolytic enzyme preparation produced by the thermophilic fungus Thermomyces lanuginosus was applied in the present experiment and fed to dairy cows at 34 g/day dosage in the period between calving and the 110th day of lactation. This preparation increased VFA concentration in the rumen from about 32 days after calving and onward. Increased VFA concentration was followed by an about 5 to 10% increase in milk production and an almost 0.1% increase in butterfat production. Increased VFA concentration produced more balanced energy metabolism in the experimental cows as indicated by the lower incidence rate of hyperketonaemia, and lower acetoacetic acid and non-esterified fatty acid (NEFA) concentration in the blood of the experimental cows. Aspartate aminotransferase (AST) activity was tendentiously higher in the control group and the proportion of cows that had AST activity higher than 100 U/l was also higher in the control group. Both control and experimental cows showed balanced protein and acid-base metabolism throughout the experiment. Enhanced VFA concentration contributed to an improvement in energy balance in the experimental cows with a resultant improvement of feed intake and feed utilisation. Due to the more balanced energy metabolism postparturient body condition loss of the treated cows was reduced.     

Objective evaluation of the immunogenic effectiveness of polyvalent vaccines against enteral infections of newborn calves under enzootic conditions

For evaluating the protective effect of polyvalent vaccine against diarrhoea in new born calves caused by rotaviruses, coronaviruses and enterotoxigenic E. coli the method was selected of mathematical and statistical analysis of the set of data characterizing the most important clinical symptoms of the disease during the first three weeks after birth. In two large-scale breeds with a mass occurrence of diarrhoea of the known etiology the state of health of calves before the vaccine application was compared with the state of health of calves born in the period after the vaccination. The following traits were selected for evaluating the severity of the disease: the age of calf at the beginning of the disease, character and intensity of diarrhoea, length of disease and results of treatment. In all the selected indicators, statistically significant differences were determined pointing to the fact that the vaccine used for increasing the immunity against enteropathogenic viruses and bacteria, applied in high pregnant cows and heifers before parturition, protected the sucking calves and calves fed the milk of their mothers against the disease in the first week after birth. The diarrhoea, occurring in the calves of the vaccinated cows and heifers mostly during the second week of age was easy to treat therapeutically and ended in most cases after a short period of a tea diet. After the vaccination, the death loss in both localities decreased more than eight times.     

Comparative osmotic adjustments in barley and tetraploid wheats

Five barley (Hordeum rulgare L.), five durum wheat (Triticum turgidum concar. durum L.) and one wild emmer wheat (Triticum turgidum conrar dicoccoides) genotypes from different origins and differing for drought tolerance and potential yield, were studied for their osmotic adjustment capacity at the same stage and under similar water stress conditions. Differences for water status parameters between barley and tetraploid wheat genotypes were noted and discussed. The lowest osmotic adjustment capacities were noted in drought susceptible varieties, while a high capacity was found in genotypes exhibiting a high yield stability across contrasting environments. Relative water content, leaf osmotic potential and accumulation of soluble sugars were found to be highly related with osmotic adjustment: they could be used as criteria for a rapid evaluation of osmotic adjustment in segregating populations.     

Effects of management intensity and soil chemical properties on <Emphasis Type="Italic">Rumex obtusifolius</Emphasis> in cut grasslands in Lower Austria

Rumex obtusifolius (broad-leaved dock) is a widely distributed weed in managed grasslands and is an indicator for excessive grassland management. Especially in organic farming, its control is highly labour and energy intensive. The effects of management extensification on R. obtusifolius were investigated by on-farm trials with reduced cutting frequencies and manuring amounts from 2004 to 2006 at three sites in Lower Austria. The sites distinctly differed in their nutrient availabilities (LiCl-extract; Ca: ranged from 1,380 to 2,062&amp;nbsp;mg/kg DM, Mg: 211&amp;#8211;611&amp;nbsp;mg/kg, P: 4&amp;#8211;40&amp;nbsp;mg/kg, K: 57&amp;#8211;334&amp;nbsp;mg/kg). At one site reduced management intensity had a significant decreasing effect on R. obtusifolius infestation, whereas at the other sites no effect was observed. Consequently, extensification as a measure for controlling this weed can be effective under certain conditions. Soil analyses indicated that Ca and Mg concentrations were negatively correlated to R. obtusifolius density, and the site where infestation declined under reduced management was characterised by abundant Ca and Mg in the topsoil. K showed a weak positive correlation with plant density development and P was not related to R. obtusifolius. According to the literature, an abundance of Ca and Mg in the soil could reduce the competitiveness of the species. Consequently, high concentrations of these nutrients might enhance the probability for an effective R. obtusifolius control by management extensification. Further research is required to clarify the influence of Ca and Mg on the competitiveness of R. obtusifolius, and may lead to recommendations for the management of this weed.     

Mortality and F1 production of Rhyzopertha dominica (F.) on wheat treated with diatomaceous earth: impact of biological and environmental parameters on efficacy

A series of experiments were conducted in which label rate (0.3 g per kg of wheat) with diatomaceous earth (DE) formulation Protect-It. Exposure studies were carried out at two levels of relative humiditiy (40% and 55%), two levels of insect density (10 or 20 adults per vial), and three levels of exposure periods. Test insects were placed in vials containing 40 g of soft white winter wheat mixed with either 0 or 0.3 g Protect-It per kg of wheat. After relating exposure periods for both insect density and relative humidity levels, highest mortality was only 16%. Mortality, regardless of the dose rate applied (0 and 0.3 g) were not significantly increased as the exposure period increased. Regardless of relative humidity (r.h.) (40% and 55%r.h.), mortality in control were not significantly increased as the exposure period increased for the same insect density. However, significant differences among the three exposure periods in 10 adults&amp;#8217; density in 0.3 g DE application. Mortality was significantly increased in 10 adults&amp;#8217; density. In this case mortality of R. dominica adults increased with the increasing of the exposure intervals. As for 20 adults&amp;#8217; density, mortality in 0.3 g DE application was not significantly changed along with the exposure intervals. After insects were exposed for 1, 2, or 3 week, dead and live insects were removed, and the wheat in the vial were returned to relating humidity box and kept for 8 week until F₁ adults emerged. Then, the number of F₁ adult was counted. The mean numbers of F₁ adults on untreated wheat at all density and r.h. combinations, regardless of exposure periods were significantly higher than that of 0.3 g DE- treated wheat (Fig. 3). At each density and treatment, the mean number of F₁ adults at 55% r.h. were higher that that of 40%r.h. The comparison between adult densities at each r.h. and treatment showed that adult densities influenced the F₁ production of R. dominica and F₁ adults were always higher at 20 adults&amp;#8217; density. The mean number of F₁ adults at each density, regardless of treatment progressively increased as the exposure period increased. Fewer progeny were produced at 10 adults&amp;#8217; density compared to 20 adults&amp;#8217; density for same exposure periods. The highest reproduction occurred in 3 week of exposure period for both insect densities. Regardless of adult densities, the mean number of F₁ adults was significantly increased as the exposure period increased (Fig. 5) for both control and 0.3 g DE treatment. Reduction of F₁ adults at 0.3 g DE application compared to control were found to be 76.88, 74.78 and 67.63% for 1, 2 and 3 week of exposure period, respectively.     

Compatibility relations between the edible carrot Daucus carota and D. pusillus, a related wild species from the Argentinian Pampas

To establish the feasibility of hybridization between the wild carrot species Daucus pusillus Michx. (2n = 2x = 22; 2n = 2x = 22 and 20), collected in the pampas grasslands of Argentina, and the edible carrot, Daucus carota L. (2n = 2x = 18), controlled pollinations were attempted on the plant. Due to the difficulties encountered, flowers of 12 accesions and three commercial cultivars were excised from individual plants and pollinated in Petri dishes following an incomplete diallel design. After processing, the pollinated pistils (four to six per genotypic combination) were observed under a microscope with UV light. Pollen tubes reaching the ovaries and/or the ovules (compatible relation) were observed in six out of nine D. pusillus × D. pusillus and seven out of 18 D. pusillus × D. carota genotypic combinations. In the eight D. carota × D. pusillus genotypic combinations, only ungerminated pollen, pollen not adhered to the stigmas or pollen tubes overlapping the stylar tissue were observed. Additional flowers were pollinated in a sample of compatible genotypic combinations and the pollinated pistils were in vitro culture to study embryo and endosperm development. Eight out of nine pistils from the intraspecific and nine out of 13 from the interspecific crosses enlarged to form apparently normal schizocarps. Histological analyses revealed normal development of embryo and endosperm. The breeding barriers between the two species are incomplete, making feasible the obtainment of interspecific hybrids by conventional techniques.     

Development of PCR-based Detection Methods for the Quarantine Phytopathogen <Emphasis Type="Italic">Synchytrium endobioticum</Emphasis>, Causal Agent of Potato Wart Disease

PCR-based methods were developed for the detection and quantification of the potato pathogen Synchytrium endobioticum in soil extracts and in planta. PCR primers, based on the internal transcribed spacer region of the multi-copy gene rDNA were tested for specificity, sensitivity and reproducibility in conventional and real-time PCR assays. Soil extraction procedures compared included the Hendrickx centrifugation (HC) procedure, nested wet sieving (NWS) and a method used by the Plant Protection Service (PPS). The primers amplified a 472 bp product from S. endobioticum DNA, but did not amplify DNA from other potato pathogens, other plant pathogens, and related species. Standard cell disruption and DNA extraction and purification methods were optimized for amplification of S. endobioticum DNA from resting sporangia. DNA was successfully amplified from a single sporangium and equivalent DNA preparations from soil extracts. Low levels of target DNA in water did not amplify, possibly due to DNA loss during final purification steps. A real-time PCR assay, developed for soil-based extracts using primers and probe based on the rDNA gene sequences, involved co-amplification of target DNA along with an internal DNA fragment. Both conventional and real-time PCR methods performed well with HC- and NWS-extracts having a threshold sensitivity of 10 sporangia per PCR assay. Of the three soil extraction methods, only with the HC method could 100 g soil samples be efficiently processed in one single PCR assay. Such a high capacity assay could be useful for routine soil analysis in respect to disease risk assessments and to secure de-scheduling according to EPPO guidelines.