Prevalence and risk factors for skin lesions on legs of dairy cattle housed in freestalls in Norway

Appropriate indoor housing facilities for dairy cattle promote improved animal welfare. Skin alterations are an indicator of dysfunctional housing. The purpose was to determine the relationship between different housing design and skin lesions, hence providing farmers more insight into how to reduce the occurrence of lesions. A cross-sectional study was conducted on 2,335 animals in 232 Norwegian freestall-housed dairy cattle from September 2006 to June 2007. A model was established to investigate risk factors related to the presence of lesions including hair loss, swelling, and wounds on the legs of dairy cattle. Separate models were developed to investigate risk factors related to the presence of knee and hock lesions. Previously described risk factors were included in the models, together with a questionnaire addressing the attitude of the farmer toward the animals. Mean (± SD) prevalence for hock lesions was 60.5 ± 21.2% with a median value of 64%. The prevalence for knee lesions was 35.3 ± 25.7% with a median of 30%. Cows in herds with a soft freestall base had an odds ratio (OR) for knee and hock lesions of 0.22 (0.06 to 0.73) and 0.62 (0.48 to 0.80), respectively, compared with those in herds with a harder freestall base, such as concrete and compact rubber mats. There was an increased risk of hock lesions when the length in the lying area in a double-row freestall was \u3e250 cm (OR = 2.96; 1.02 to 8.60) compared with ≤250 cm, and when the length of the lying area against a wall was \u3e260 cm (OR = 2.11; 1.53 to 2.90) compared with ≤260 cm. The risk for knee lesions increased if a row against a wall was \u3e270 cm (OR = 1.72; 1.09 to 2.72) compared with ≤270 cm. Hock lesions were associated with lame cows (OR = 5.76; 1.14 to 29.18) versus nonlame cows, and with cows in their second or higher parity (OR = 1.27; 1.06 to 1.52) versus cows in their first parity. Knee lesions were associated with farmers’ negative attitudes toward animals in pain (OR = 3.28; 1.79 to 6.03) versus those with positive attitudes; cows in the beginning of their lactation (OR = 1.84; 1.24 to 2.74) versus those at the end of their lactation; and tall animals (OR = 1.27; 1.00 to 1.61) versus shorter animals. These results show that freestall design is important with respect to skin lesions as are the characteristics of individual animals and the farmer

Increased isobutanol production in Saccharomyces cerevisiae by overexpression of genes in valine metabolism

<p>Abstract</p> <p>Background</p> <p>Isobutanol can be a better biofuel than ethanol due to its higher energy density and lower hygroscopicity. Furthermore, the branched-chain structure of isobutanol gives a higher octane number than the isomeric <it>n</it>-butanol. <it>Saccharomyces cerevisiae </it>was chosen as the production host because of its relative tolerance to alcohols, robustness in industrial fermentations, and the possibility for future combination of isobutanol production with fermentation of lignocellulosic materials.</p> <p>Results</p> <p>The yield of isobutanol was improved from 0.16 to 0.97 mg per g glucose by simultaneous overexpression of biosynthetic genes <it>ILV2, ILV3</it>, and <it>ILV5 </it>in valine metabolism in anaerobic fermentation of glucose in mineral medium in <it>S. cerevisiae</it>. Isobutanol yield was further improved by twofold by the additional overexpression of <it>BAT2</it>, encoding the cytoplasmic branched-chain amino-acid aminotransferase. Overexpression of <it>ILV6</it>, encoding the regulatory subunit of Ilv2, in the <it>ILV2 ILV3 ILV5 </it>overexpression strain decreased isobutanol production yield by threefold. In aerobic cultivations in shake flasks in mineral medium, the isobutanol yield of the <it>ILV2 ILV3 ILV5 </it>overexpression strain and the reference strain were 3.86 and 0.28 mg per g glucose, respectively. They increased to 4.12 and 2.4 mg per g glucose in yeast extract/peptone/dextrose (YPD) complex medium under aerobic conditions, respectively.</p> <p>Conclusions</p> <p>Overexpression of genes <it>ILV2, ILV3, ILV5</it>, and <it>BAT2 </it>in valine metabolism led to an increase in isobutanol production in <it>S. cerevisiae</it>. Additional overexpression of <it>ILV6 </it>in the <it>ILV2 ILV3 ILV5 </it>overexpression strain had a negative effect, presumably by increasing the sensitivity of Ilv2 to valine inhibition, thus weakening the positive impact of overexpression of <it>ILV2, ILV3</it>, and <it>ILV5 </it>on isobutanol production. Aerobic cultivations of the <it>ILV2 ILV3 ILV5 </it>overexpression strain and the reference strain showed that supplying amino acids in cultivation media gave a substantial improvement in isobutanol production for the reference strain, but not for the <it>ILV2 ILV3 ILV5 </it>overexpression strain. This result implies that other constraints besides the enzyme activities for the supply of 2-ketoisovalerate may become bottlenecks for isobutanol production after <it>ILV2, ILV3</it>, and <it>ILV5 </it>have been overexpressed, which most probably includes the valine inhibition to Ilv2.</p

Competitive intra- and extracellular nutrient sensing by the transporter homologue Ssy1p

Recent studies of Saccharomyces cerevisiae revealed sensors that detect extracellular amino acids (Ssy1p) or glucose (Snf3p and Rgt2p) and are evolutionarily related to the transporters of these nutrients. An intriguing question is whether the evolutionary transformation of transporters into nontransporting sensors reflects a homeostatic capability of transporter-like sensors that could not be easily attained by other types of sensors. We previously found SSY1 mutants with an increased basal level of signaling and increased apparent affinity to sensed extracellular amino acids. On this basis, we propose and test a general model for transporter- like sensors in which occupation of a single, central ligand binding site increases the activation energy needed for the conformational shift between an outward-facing, signaling conformation and an inward-facing, nonsignaling conformation. As predicted, intracellular leucine accumulation competitively inhibits sensing of extracellular amino acids. Thus, a single sensor allows the cell to respond to changes in nutrient availability through detection of the relative concentrations of intra- and extracellular ligand

Patterns of Plant Biomass Partitioning Depend on Nitrogen Source

Nitrogen (N) availability is a strong determinant of plant biomass partitioning, but the role of different N sources in this process is unknown. Plants inhabiting low productivity ecosystems typically partition a large share of total biomass to belowground structures. In these systems, organic N may often dominate plant available N. With increasing productivity, plant biomass partitioning shifts to aboveground structures, along with a shift in available N to inorganic forms of N. We tested the hypothesis that the form of N taken up by plants is an important determinant of plant biomass partitioning by cultivating Arabidopsis thaliana on different N source mixtures. Plants grown on different N mixtures were similar in size, but those supplied with organic N displayed a significantly greater root fraction. 15N labelling suggested that, in this case, a larger share of absorbed organic N was retained in roots and split-root experiments suggested this may depend on a direct incorporation of absorbed amino acid N into roots. These results suggest the form of N acquired affects plant biomass partitioning and adds new information on the interaction between N and biomass partitioning in plants

Tetrasubstituted Imidazolium Salts as Potent Antiparasitic Agents against African and American Trypanosomiases.

Imidazolium salts are privileged compounds in organic chemistry, and have valuable biological properties. Recent studies show that symmetric imidazolium salts with bulky moieties can display antiparasitic activity against T. cruzi. After developing a facile methodology for the synthesis of tetrasubstituted imidazolium salts from propargylamines and isocyanides, we screened a small library of these adducts against the causative agents of African and American trypanosomiases. These compounds display nanomolar activity against T. brucei and low (or sub) micromolar activity against T. cruzi, with excellent selectivity indexes and favorable molecular properties, thereby emerging as promising hits for the treatment of Chagas disease and sleeping sickness

BROWSE REMOVAL, PLANT CONDITION, AND TWINNING RATES BEFORE AND AFTER SHORT-TERM CHANGES IN MOOSE DENSITY

We monitored forage-based indices of intraspecific  competition at changing moose (Alces alces) densities to  gauge short-term, density-dependent environmental feedback and to ultimately improve management of moose for elevated sustained yield. In 4 areas of interior Alaska where moose density recently changed, we evaluated the magnitude of change among 4 browse indices: proportional offtake of current annual growth biomass (OFTK), proportion of current twigs that were browsed (PTB), mean twig diameter at point of browsing (DPB), and proportion of plants with broomed architecture. In 1 area where moose density increased 100% in 6 years following effective predation control, browse removal increased 138% for OFTK, 20% for PTB, and 16–42% for DPB of primary browse species, with a 44% increase in brooming. We also studied 3 areas where moose density declined 31–41% following elevated antlerless harvests of 2–4 years duration. In these areas (with intervals of 3–12 years between browse surveys) we found declines of 30–40% in OFTK, 26–68% in PTB, and 11–37% in DPB, but changes in plant architecture were inconsistent. The proportion of parturient cows with neonate twins did not change between browse surveys, presumably because of a substantial lag time influenced by life history of the dominant reproductive cohorts and little change in browse nutrient content and digestibility. Of the 4 browse indices studied, proportional OFTK most consistently reflected the direction and magnitude of short-term changes in moose density. Area-specific measures of habitat and animal conditions at high moose density provided an objective means for gauging the capacity of the respective ecosystems to support moose and maintain forage plants. We used these measures of winter forage and moose condition to justify implementing harvest strategies and to ultimately reduce high moose densities below levels of strong negative feedback

Housing system and herd size interactions in Norwegian dairy herds; associations with performance and disease incidence

<p>Abstract</p> <p>Background</p> <p>According to the Norwegian animal welfare regulations, it has been forbidden to build new tie-stall barns since the end of 2004. Previous studies have shown that cow performance and health differ between housing systems. The interaction between housing system and herd size with respect to performance and disease incidence has not been evaluated.</p> <p>Methods</p> <p>Cow performance and health in 620 herds housed in free-stall barns were compared with in 192 herds housed in tie-stall barns based on a mail survey and data from the Norwegian Dairy Herd Recording and Cattle Health Systems. The housing systems herds were comparable with respect to herd size (15-55 cows). Associations between performance/disease incidence and housing system, herd size and year of building the cow barn were tested in general linear models, and values for fixed herd size of 20 and 50 cows were calculated. On the individual cow level mixed models were run to test the effect of among others housing system and herd size on test-day milk yield, and to evaluate lactation curves in different parities. All cows were of the Norwegian Red Breed.</p> <p>Results</p> <p>Average milk production per cow-year was 134 kg lower in free-stall herd than in tie-stall herds, but in the range 27-45 cows there was no significant difference in yields between the herd categories. In herds with less than 27 cows there were increasingly lower yields in free-stalls, particularly in first parity, whereas the yields were increasingly higher in free-stalls with more than 45 cows.</p> <p>In free-stalls fertility was better, calving interval shorter, and the incidence rate of teat injuries, ketosis, indigestions, anoestrus and cystic ovaries was lower than in tie-stalls. All of these factors were more favourable in estimated 50-cow herds as compared to 20-cow herds. In the larger herd category, bulk milk somatic cell counts were higher, and the incidence rate of mastitis (all cases) and all diseases was lower.</p> <p>Conclusion</p> <p>This study has shown that there is an interaction between housing system and herd size, and that performance and health is not universally better in small free-stalls than in tie-stalls.</p

Pulse‐labeling studies of carbon cycling in arctic tundra ecosystems: Contribution of photosynthates to soil organic matter

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95486/1/gbc827.pd

Pentanol isomer synthesis in engineered microorganisms

Pentanol isomers such as 2-methyl-1-butanol and 3-methyl-1-butanol are a useful class of chemicals with a potential application as biofuels. They are found as natural by-products of microbial fermentations from amino acid substrates. However, the production titer and yield of the natural processes are too low to be considered for practical applications. Through metabolic engineering, microbial strains for the production of these isomers have been developed, as well as that for 1-pentanol and pentenol. Although the current production levels are still too low for immediate industrial applications, the approach holds significant promise for major breakthroughs in production efficiency