Time lag between peak concentrations of plasma and salivary cortisol following a stressful procedure in dairy cattle

Background

Measurement of salivary cortisol has been used extensively as a non-invasive alternative to blood sampling to assess adrenal activity in ruminants. However, there is evidence suggesting a considerable delay in the transfer of cortisol from plasma into saliva. Previous studies in cattle have used long sampling intervals making it difficult to characterise the relationship between plasma and salivary cortisol (PLCort and SACort, respectively) concentrations at different time points and determine whether or not such a time lag exist in large ruminants. Therefore, the objective of this study was to characterise the relationship between plasma and salivary cortisol and determine if there is a significant time lag between reaching peak cortisol concentrations in plasma and saliva across a 4.25 h time-period, using short sampling intervals of 10–15 min, following social separation in dairy cattle.Five cows were separated from their calves at 4 days after calving, and six calves were separated from a group of four peers at 8 weeks of age. Following separation, the animals were moved to an unfamiliar surrounding where they could not see their calves or pen mates. The animals were catheterised with indwelling jugular catheters 1 day before sampling. Blood and saliva samples were obtained simultaneously before and after separation.

Results

In response to the stressors, PLCort and SACort increased reaching peak concentrations 10 and 20 min after separation, respectively. This suggested a 10 min time lag between peak cortisol concentrations in plasma and saliva, which was further confirmed with a time-series analysis. Considering the 10 min time lag, SACort was strongly correlated with PLCort (P < 0.0001).

Conclusions

Salivary cortisol correlates well with plasma cortisol and is a good indicator of the time-dependent variations in cortisol concentrations in plasma following acute stress. However, there is a time lag to reach peak cortisol concentrations in saliva compared to those in plasma, which should be considered when saliva samples are used as the only measure of hypothalamic-pituitary-adrenal axis response to stress in cattle.     

Constituents in evening primrose oil with radical scavenging,cyclooxygenase, and neutrophil elastase inhibitory activities

Cold-pressed, non-raffinated evening primrose oil was found to contain lipophilic radical scavengers. A highly enriched fraction of these compounds could be obtained from the oil by extraction with aqueous ethanol and subsequent liquid-liquid partitioning with petroleum. LC-DAD-MS analysis revealed that the fraction contained three aromatic compounds with identical UV and ESI-MS spectra. The compounds were isolated by RP-HPLC and their structures established by chemical and spectroscopic means as 3-O-trans-caffeoyl derivatives of betulinic, morolic, and oleanolic acid. The morolic acid derivative was a new compound. The three esters exhibited pronounced radical scavenging activity against the stable 2,2-diphenyl-1-picrylhydrazyl radical and were potent inhibitors of neutrophil elastase and cyclooxygenase-1 and -2 in vitro. Commercial samples of evening primrose oils contained only traces of these lipophilic antioxidants.     

Feline caries in two cats from a 13th century archeological excavation

Mandibles of two cats containing carious lesions were discovered among the previously published findings of feline dental resorptive lesions from materials examined at an archaeological museum. These lesions were too small to be noted on radiographs, and consisted of two inconspicuous enamel lesions in a mandibular left first molar tooth (309), a clinically visible white spot area containing an enamel lesion in a mandibular left fourth premolar tooth (308), and a root surface caries in the 308 of a different specimen. Histologic examination using special stains and polarized light revealed both initial and early initial stage enamel caries, as well as root surface caries. Knoop hardness measurements confirmed these findings, considered the first documented cases of feline caries.     

Effects of conservation agriculture on soil quality and productivity in contrasting agro‐ecological environments of Zimbabwe

Experimentation by farmers with conservation agriculture (CA) is increasing in southern Africa, but local longer term data on these new production systems are scarce. This study focuses on CA research at two contrasting on‐farm sites and one on‐station long‐term trial in Zimbabwe. The on‐farm trials were conducted at Chikato village on a sandy soil at Zimuto Communal Area with low rainfall and at Hereford farm near Bindura on a clay‐rich soil in a high rainfall area. The on‐station trial was at Henderson Research Station near Mazowe where more in‐depth soil studies were possible. Results of CA systems from the on‐station site show on average 38 and 65% greater water infiltration on ripline‐seeded (RS) and direct‐seeded CA treatments compared with conventionally ploughed control treatments. Results from on‐farm sites show a 123 and 168% greater aggregate stability at Hereford and 11 and 24% lower dispersion ratio at Chikato on the two CA compared with the conventionally ploughed control treatments. Soil carbon increased by 46% in the first 20 cm on the sandy soils at Chikato in RS and by 104% in direct‐seeded CA treatments in four cropping seasons from 2004 to 2008, while it stayed at low levels on the conventionally tilled control treatment. Yields on CA plots were higher on the sandy soils in dry seasons, but lower in very wet seasons because of waterlogging. Yields on clay soils were less affected by the rainfall season. Crop productivity from CA systems increased at all sites over time owing to better management although significant differences between CA and conventional treatments on the three sites were apparent only after several cropping seasons. Conservation agriculture offers practical solutions to small‐scale farmers threatened by future soil degradation and fertility loss, but its successful use will depend on weed control and adequate application of fertilizers. The results indicate that there is no immediate increase in maize (Zea mays L.) yield when changing from a tilled to a CA system, but there is gradual improvement in some soil quality indicators over time.     

Paratuberculosis in a miniature donkey (Equus asinus f. asinus)

Paratuberculosis is mainly an infectious disease of ruminants with worldwide distribution. Infection occurs in early stages of life. Other animal species beyond ruminants are rarely affected, however, experimental and natural infections are possible. A case of paratuberculosis in a miniature donkey (Equus asinus f. asinus) with typical clinical and pathomorphological changes is reported here. Lesions were mainly observed in the intestine. Causative for the profuse diarrhoea with emaciation was massive diffuse granulomatous enteritis involving large quantities of acid-fast organism mainly in macrophages. Granulomatous inflammation with acid-fast bacilli again in macrophages to a lesser degree could be detected in the liver. Mycobacterium avium subsp. paratuberculosis (MAP) was isolated from intestinal contents after an incubation period of four weeks. MAP-specific DNA (IS900 and f57) was detected by polymerase chain reaction in culture material. Additionally MAP-isolates were characterized by multi-target genotyping (MIRU-VNTR- and MLSSR-typing). Isolates belonged to the Type II group and exhibited a unique genotype different from other MAP strains in Germany. The donkey originated from a donkey breeding farm in France with intensive free ranging cattle in the neighbourhood and could have been infected there. Donkeys should be considered as paratuberculosis-susceptible animals in exceptional cases and as possible reservoirs or disseminators of infection.     

Effects of conservation agriculture techniques on infiltration and soil water content in Zambia and Zimbabwe

The adoption of conservation agriculture (CA), based on minimal soil movement, permanent soil cover with crop residues or growing plants and crop rotation has advanced rapidly in the Americas and Australia over the last three decades. One of the immediate benefits of CA in dryland agriculture is improved rainfall-use efficiency through increased water infiltration and decreased evaporation from the soil surface, with associated decreases in runoff and soil erosion. This paper focuses on the effect of CA techniques on soil moisture relations in two researcher-managed trials in Zambia and Zimbabwe. In 2005/2006 and 2006/2007, we found significantly higher water infiltration on both sites on CA fields compared to conventionally ploughed fields. At Henderson Research Station, Zimbabwe, on a sandy soil, a direct seeded CA treatments had a 49% and 45% greater infiltration rate than the conventionally tilled plots after a simulated rainfall in both seasons. At Monze Farmer Training Centre, Zambia, on a finer-textured soil, the same treatment had 57% and 87% greater infiltration rate than the conventionally tilled control treatment in both seasons. Treatments that included reduced tillage and surface residue retention had less water runoff and erosion on runoff plots at Henderson Research Station, Zimbabwe. On average, soil moisture was higher throughout the season in most CA treatments than in the conventionally tilled plots. However, the full potential of CA in mitigating drought was not evident as there was no significant drought period in either season. Results suggest that CA has the potential to increase the productivity of rainfall water and therefore reduce the risk of crop failure, as was apparent at the Monze Farmer Training Centre, Zambia, in 2005/2006 when a period of moisture stress at tassling affected CA treatments less than the conventionally tilled treatment.     

Plant,Microbial and Soil Factors,Determining Nitrogen Fixation in the Rhizosphere

A genotype effect on associative (rhizosphere) N₂-fixation was observed with two cultivars of Sorghum bicolor (nutans) with a maximum rate of 8 μmol C₂H₄ · h^?1 · plant^?1 in one genotype compared to 0.9 μmol in the other. Characteristics of the high fixing genotype were a reduced transpiration rate, a lower number of stomata and increased root exudate production per gram root dry weight with higher concentration of dicarboxylic acids. The bacterial rhizosphere composition revealed a three times higher number of N₂-fixing bacteria, a tenfold reduction of actinomycetes and a threefold reduction of Arthrobacter associated with the high fixing cultivar compared to the low fixing genotype. From these and other plant rhizospheres two new nitrogen fixing bacteria, Pseudomonas stutzeri and Erwinia herbicola, were characterized. With the N₂-fixing bacteria Azospirillum brasilense and Klebsiella pneumoniae an enhancement of specific nitrogenase activity by aromatic compounds, for example phenolics, the herbicide alachlor and the insecticide carbofuran was demonstrated. An oscillating nitrogenase activity in Azospirillum brasilense under microaerobic conditions was found, resulting from an encystation and deencystation under those conditions. Experiments with wheat roots demonstrated that reduced oxygen tensions, essential for a maximum rhizosphere N₂-fixation, reduced root growth significantly and altered the N-metabolism of the roots.     

The <Emphasis Type="Italic">Caenorhabditis elegans</Emphasis> assay: a tool to evaluate the pathogenic potential of bacterial biocontrol agents

Bacterial biocontrol agents (BCAs) open up the possibility of controlling plant pathogens in an environmentally friendly way. Although they are naturally occurring microbes, some of them can cause diseases in humans. For successful registration it is necessary to test potentially adverse effects on the human health of at-risk candidates. Existing pathogenicity assays are cost-intensive, time-consuming and furthermore they are often inappropriate for facultative pathogens. We developed a new, fast and inexpensive bioassay on the basis of the nematode Caenorhabditis elegans, which is a well-accepted model organism to study bacterial pathogenicity. A selection of eight strains from clinical and environmental origin as well as potential and commercial BCAs from the genera Bacillus, Pseudomonas, Serratia and Stenotrophomonas were screened for their potential to kill the nematode in an in vitro agar plate assay. Furthermore, the motility and reproductive behaviour of nematodes exposed to strains were tested in comparison with those fed by the human pathogen Pseudomonas aeruginosa QC14-3-8 (positive control) and the negative control Escherichia coli OP50. Commercial as well as potential biocontrol strains did not display any adverse effects in all tests. In contrast, the C. elegans assay showed slight effects for clinical and environmental Stenotrophomonas strains. Results showed that the nematode C. elegans provides a model system to indicate the pathogenic potential of BCAs in a very early stage of product development.     

Standard Probability Density Functions of Characterizing Water Quality Variables in Dimictic Glacial/Boreal Lakes

With the secure supply of healthy fresh water being a threatened essentiality for the global society, compatibility among scientists working with water quality issues must be considered as highly prioritized. To achieve this, a standard that facilitates compatible comparisons between statistical models that describe and/or predict lake water quality should contribute. A large population of dimictic glacial/boreal lakes – with variable ranges wide enough to represent a majority of such lakes – is therefore analyzed with respect to probability density functions of the seven characterizing water quality variables pH, alkalinity, conductivity, hardness, color, Secchi depth, and total phosphorus concentration. With the lakes being limestone treated, the primary variables are transformed to normal distribution in cases: 1; ‘Before limestone treatment’, 2; ‘After limestone treatment’, and 3; ‘The entire database’ (case 1 + case 2). It is concluded that the transformation functions derived in case 3 are sufficiently valid as optimal transformation functions in all three cases. This suggests that the transformation functions derived approximate the probability density functions of these important water quality variables in the generic class of dimictic glacial/boreal lakes, and that they should be well suited as transformation standards in natural, as well as in limestone treated lakes. It also implies that limestone treatment does not significantly alter the shape of the probability density functions analyzed.