The Wambiana grazing trial : Key learnings for sustainable and profitable management in a variable environment

Rainfall variability is a major challenge to sustainable and profitable beef production in northern Australia. While grazing management strategies to cope with this variability do exist, they have not been widely adopted. This is partly because there is little data on how these strategies perform relative to existing management. A major problem is the perception that recommended strategies are not profitable and that managers need to stock relatively heavily to be financially viable. The Wambiana trial was established in December 1997 near Charters Towers to objectively test how a range of grazing strategies cope with climate variability. To ensure relevance to the grazing industry, the trial was run in close association with a grazier advisory committee. Trial paddocks contained a range of soil types to reflect conditions in large, commercial paddocks. The different grazing strategies tested were: 1. Heavy stocking (HSR) stocked at twice the long-term carrying capacity (LTCC) of the site. 2. Moderate stocking (MSR) stocked at the LTCC. 3. Variable stocking (VAR) with stocking rates adjusted annually in May based on forage availability. 4. Southern Oscillation Index (SOI)—variable strategy with stocking rates adjusted annually in November according to forage availability and the SOI. 5. Rotational wet season spelling (R/Spell) coupled with moderate-heavy stocking

MiR-142-3p is downregulated in aggressive p53 mutant mouse models of pancreatic ductal adenocarcinoma by hypermethylation of its locus

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive disease with poor prognostic implications. This is partly due to a large proportion of PDACs carrying mutations in TP53, which impart gain-of-function characteristics that promote metastasis. There is evidence that microRNAs (miRNAs) may play a role in both gain-of-function TP53 mutations and metastasis, but this has not been fully explored in PDAC. Here we set out to identify miRNAs which are specifically dysregulated in metastatic PDAC. To achieve this, we utilised established mouse models of PDAC to profile miRNA expression in primary tumours expressing the metastasis-inducing mutant p53R172H and compared these to two control models carrying mutations, which promote tumour progression but do not induce metastasis. We show that a subset of miRNAs are dysregulated in mouse PDAC tumour tissues expressing mutant p53R172H, primary cell lines derived from mice with the same mutations and in TP53 null cells with ectopic expression of the orthologous human mutation, p53R175H. Specifically, miR-142-3p is downregulated in all of these experimental models. We found that DNA methyltransferase 1 (Dnmt1) is upregulated in tumour tissue and cell lines, which express p53R172H. Inhibition or depletion of Dnmt1 restores miR-142-3p expression. Overexpression of miR-142-3p attenuates the invasive capacity of p53R172H-expressing tumour cells. MiR-142-3p dysregulation is known to be associated with cancer progression, metastasis and the miRNA is downregulated in patients with PDAC. Here we link TP53 gain-of-function mutations to Dnmt1 expression and in turn miR-142-3p expression. Additionally, we show a correlation between expression of these genes and patient survival, suggesting that they may have potential to be therapeutic targets

Pasture Yield and Animal Performance from Aeschynomene Americana Cultivars Glenn and Lee

An on farm demonstration site was used to promote and compare the performance of the tropical legumes Glenn American jointvetch and Lee American jointvetch (Aeschynomene americana). Both legumes are widely sown in tropical Australia and are being increasingly sown in South-East Asian pasture projects. Glenn and Lee both grew well and persisted in grass/legume pastures over a 5 year period. Liveweight gain of steers, at a stocking rate of 1.5/ha, slightly favoured the Glenn pasture and gains of 0.49 kg/day for a 595 day period were achieved. Soil seed reserves were much higher under the annual Glenn than for the later flowering perennial Lee. Current recommendations are to sow equal portions of Glenn and Lee in legume/grass pasture mixture

Managing for rainfall variability: effect of grazing strategy on cattle production in a dry tropical savanna

Rainfall variability is a challenge to sustainable and pro. table cattle production in northern Australia. Strategies recommended to manage for rainfall variability, like light or variable stocking, are not widely adopted. This is due partly to the perception that sustainability and profitability are incompatible. A large, long-term grazing trial was initiated in 1997 in north Queensland, Australia, to test the effect of different grazing strategies on cattle production. These strategies are: (i) constant light stocking (LSR) at long-term carrying capacity (LTCC); (ii) constant heavy stocking (HSR) at twice LTCC; (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC; (iv) variable stocking (VAR), with stocking rates adjusted in May based on available pasture; and (v) a Southern Oscillation Index (SOI) variable strategy, with stocking rates adjusted in November, based on available pasture and SOI seasonal forecasts. Animal performance varied markedly over the 10 years for which data is presented, due to pronounced differences in rainfall and pasture availability. Nonetheless, lighter stocking at or about LTCC consistently gave the best individual liveweight gain (LWG), condition score and skeletal growth; mean LWG per annum was thus highest in the LSR (113 kg), intermediate in the R/Spell (104 kg) and lowest in the HSR(86 kg). MeanLWGwas 106 kg in the VAR and 103 kg in the SOI but, in all years, the relative performance of these strategies was dependent upon the stocking rate applied. After 2 years on the trial, steers from lightly stocked strategies were 60-100 kg heavier and received appreciable carcass price premiums at the meatworks compared to those under heavy stocking. In contrast, LWG per unit area was greatest at stocking rates of about twice LTCC; mean LWG/ha was thus greatest in the HSR (21 kg/ha), but this strategy required drought feeding in four of the 10 years and was unsustainable. Although LWG/ha was lower in the LSR (mean 14 kg/ha), or in strategies that reduced stocking rates in dry years like the VAR(mean 18 kg/ha) and SOI (mean 17 kg/ha), these strategies did not require drought feeding and appeared sustainable. The R/Spell strategy (mean 16 kg/ha) was compromised by an ill-timed fire, but also performed satisfactorily. The present results provide important evidence challenging the assumption that sustainable management in a variable environment is unprofitable. Further research is required to fully quantify the long-term effects of these strategies on land condition and profitability and to extrapolate the results to breeder performance at the property level

Proteinase-activated receptor 2 is involved in the behavioural changes associated with sickness behaviour

Proteinase-activated receptor-2 (PAR2) is widely expressed in the CNS but whether it plays a key role in inflammation-related behavioural changes remains unknown. Hence, in the present study we have examined whether PAR2 contributes to behaviour associated with systemic inflammation using PAR2 transgenic mice. The onset of sickness behaviour was delayed and the recovery accelerated in PAR2-/- mice in the LPS-induced model of sickness behaviour. In contrast, PAR2 does not contribute to behaviour under normal conditions. In conclusion, these data suggest that PAR2 does not contribute to behaviour in the normal healthy brain but it plays a role in inflammation-related behavioural changes

‘Our voice started off as a whisper and now it is a great big roar’ : The Salford Dementia Associate Panel as a model of involvement in research activities

This paper presents the work of the ‘Salford Dementia Associate Panel’, based at the Salford Institute for Dementia, Salford University (UK). We discuss the roles of the Dementia Associates, in particular around the areas of engagement and research. The panel is made up of people living with dementia, and current and former care partners. It highlights the development of this group over a four-year period and demonstrates over time how the role of a Dementia Associate member has evolved. The panel is involved in research, education and public engagement activities conducted by staff and students within the Institute. The motivations for becoming involved are clearly articulated and demonstrate how the personal backgrounds of individuals have driven the collective involvement and desire to bring about change. The benefits and challenges associated with working as part of a panel are discussed. We conclude by bringing together our experiences as a set of suggestions for others who may wish to create a similar forum to promote the involvement of people living with dementia and former and current care partners

Using remote sensing to forecast forage quality for cattle in the dry savannas of northeast Australia

In the dry savannas of northeast Australia, forage quality is just as important for cattle production as forage quantity. The seasonal trend of forage quality is broadly predictable by land managers, but it is more difficult to predict the point when quality—which depends on local climate, management, and pasture condition—falls below the requirement for animal maintenance. In this study we use statistical modelling to forecast how forage quality might change at the crucial time of year, i.e., as the summer wet season transitions to the dry winter. We do this with the aid of historical information associated with a long-term cattle-grazing trial in the dry savannas. We combined multiple years of two measures of forage quality (dietary crude protein and in vivo dry-matter digestibility; respectively DCP and DMD) and ground cover information (specifically the ratio of ‘green grass’ cover to ‘dead (i.e., non-photosynthetic) grass’ cover, derived from an archive of Landsat satellite imagery) into a linear mixed model that explicitly considered the correlations with time and between variables. DCP and DMD were estimated by near-infrared spectroscopy of fresh faecal samples; values did not have to be temporally coincident with the satellite imagery. With the end of May considered a nominal decision-point, we forecast monthly averages of forage quality for June to August, over a 12-year period at the study site. Over all months and all years, the median absolute error of the forecasts was DCP = 0.86%, and DMD = 0.95%. The remote sensing information served as a correlated, oft-sampled covariate that helped to guide the forecasts of forage quality. We propose summarising the forecasts (and their uncertainty) as a near-real-time graphical tool for decision-support. Such a product could potentially benefit cattle-grazing enterprises in the northeast of Australia, enabling more timely management of herds through the dry season

More Aeschynomene Pasture Legumes for the Tropics and Sub-Tropics

Two cultivars of Aeschynomene villosa were released in Queensland in 1995. Cultivars ‘Reid’ (previously CPI 91209) and ‘Kretschmer’ (previously CPI 93621) are both native to Mexico and are the first cultivars of A. villosa to be released as pasture legumes. They will complement the three Aeschynomene cultivars already in use in tropical and sub-tropical northern and eastern Australia, namely cultivars ‘Glenn’ and ‘Lee’ (A. americana) and ‘Bargoo’ (A. falcata). Characteristics of Reid and Kretschmer jointvetch include, early seeding perennials within high seed yields, prostrate to semi-erect growth habit, adaptation to a wide range of soil types in medium rainfall areas, tolerance of temporary waterlogging, palatability of high quality forage, responsive to added phosphorus, and tolerance of light frosts. Commercial seed will be available for sale about October, 1997. Reid and Kretschmer villose jointvetch are widely adapted high quality pasture legumes which will complement current legume cultivars and will broaden the scope for sown pasture development in sub-tropical and tropical northern Australia

A 340/380 nm light emitting diode illuminator for Fura-2 AM ratiometric Ca2+ imaging of live cells with better than 5 nM precision

We report the first demonstration of a fast wavelength-switchable 340/380 nm light emitting diode (LED) illuminator for Fura-2 ratiometric Ca2+ imaging of live cells. The LEDs closely match the excitation peaks of bound and free Fura-2 and enables the precise detection of cytosolic Ca2+ concentrations, which is only limited by the Ca2+ response of Fura-2. Using this illuminator, we have shown that Fura-2 acetoxymethyl ester (AM) concentrations as low as 250 nM can be used to detect induced Ca2+ events in tsA-201 cells and while utilizing the 150 µs switching speeds available, it was possible to image spontaneous Ca2+ transients in hippocampal neurons at a rate of 24.39 Hz that were blunted or absent at typical 0.5 Hz acquisition rates. Overall, the sensitivity and acquisition speeds available using this LED illuminator significantly improves the temporal resolution that can be obtained in comparison to current systems and supports optical imaging of fast Ca2+ events using Fura-2