The role of rendering in relation to the BSE epidemic, the development of EU animal by‐product legislation and the reintroduction of rendered products into animal feeds

The bovine spongiform encephalopathy (BSE) epidemic in 1986 highlighted the importance of the rendering industry as a key component of the food supply chain. Prior to 1986 the rendering industry was poorly understood. However, following the emergence of BSE research was commissioned to characterise rendering systems and investigate their ability to inactivate transmissible spongiform encephalopathy (TSE) agents. Six rendering systems were found to be operational in Europe but their key process parameters, such as particle size, process temperature and transit time, were poorly characterised. This review describes how these key process parameters were determined and used to inform protocols for the subsequent TSE inactivation trials which subsequently shaped both EU legislation and the development of techniques used to validate rendering systems. It also describes how EU legislation banning the use of animal‐derived proteins in animal feeds ('feed ban') effectively eliminated the market for meat and bone meal (MBM) and how the rendering industry sought to 'add value' to rendered products by conducting research to support the development of new markets for rendered products. The nutritional, environmental and economic characteristics of modern processed animal proteins (PAPs) mean that they represent valuable ingredients for use in animal feeds. Recent research has paved the way for legislative changes allowing the safe reintroduction of nonruminant PAP into aqua‐feeds and may soon facilitate their reintroduction into pig and poultry feeds. However, resistance from key stakeholders in the food chain remains a significant challenge that must be overcome before their full potential can be realised. Further research is required to characterise modern PAPS and to ensure their appropriate, safe and acceptable inclusion in animal feeds

An Observational Overview of Solar Flares

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections. We also discuss flare soft X-ray spectroscopy and the energetics of the process. The emphasis is to describe the observations from multiple points of view, while bearing in mind the models that link them to each other and to theory. The present theoretical and observational understanding of solar flares is far from complete, so we conclude with a brief discussion of models, and a list of missing but important observations.Comment: This is an article for a monograph on the physics of solar flares, inspired by RHESSI observations. The individual articles are to appear in Space Science Reviews (2011

Geometric means provide a biased efficacy result when conducting a faecal egg count reduction test (FECRT)

The process of conducting a faecal egg count reduction test was simulated to examine whether arithmetic or geometric means offer the best estimate of efficacy in a situation where the true efficacy is known. Two components of sample variation were simulated: selecting hosts from the general population which was modelled by the negative binomial distribution (NBD), and taking an aliquot of faeces from the selected host to estimate the worm egg count by assuming a Poisson distribution of sample counts. Geometric mean counts were determined by adding a constant (C) to each count prior to log transformation, C was set at 25, 12 or 1. Ten thousand Monte Carlo simulations were run to estimate mean efficacy, the 2.5% (lower) and the 97.5% (upper) percentile based on arithmetic or geometric means. Arithmetic means best estimated efficacy for all different levels of worm aggregation. For moderate levels of aggregation and with C = 1 the geometric mean substantially overestimated efficacy. The bias was reduced if C was increased to 25 but the results were no better than those based on arithmetic means. For very high levels of aggregation (over-dispersed populations) the geometric mean underestimated efficacy regardless of the size of C. It is recommended that the guidelines on anthelmintic resistance be revised to advocate the use of arithmetic means to estimate efficacy

Comparison of molecular and McMaster microscopy techniques to confirm the presence of naturally acquired strongylid nematode infections in sheep

Patent strongylid nematode infections were identified using McMaster worm egg counts (WEC) and PCR assays (ITS-2 nuclear ribosomal DNA) to screen genomic DNA extracted directly from lamb faecal samples. Lambs from four different farms in southern Western Australia were sampled rectally on two separate occasions, with McMaster WECs and PCRs conducted on a total of 858 samples. Negative controls (n = 96) (WEC < 50 eggs per gram [epg]) and positive controls (n = 96) (faecal samples spiked with a 100 μL suspension of third-stage larvae (L3) containing approximately equal proportions of Teladorsagia circumcincta, Trichostrongylus colubriformis, Haemonchus contortus, Oesophagostomum spp. and Chabertia ovina) were generated. All control samples amplified in accordance with positive controls. High levels of agreement (Kappa values ≥ 0.93) were identified between the two diagnostic tests. PCRs detected an additional 2.0% of samples as strongylid-positive but there was no significant difference in the number of strongylid-positive samples identified using PCR or McMaster WEC

Impacts of naturally acquired protozoa and strongylid nematode infections on growth and faecal attributes in lambs

On two separate sampling occasions, faecal samples were collected from lambs (2-5 months of age) grazing pasture on two separate sheep farms in southern Western Australia. Live weight, body condition score (BCS), faecal consistency score (FCS) and faecal dry matter percentage (DM%) were measured. Faecal samples were screened by PCR for Cryptosporidium (18S rRNA, actin and 60kDa glycoprotein [gp60] loci), Giardia duodenalis (glutamate dehydrogenase [gdh] and β-giardin) and patent strongylid nematode infections (ITS-2 nuclear ribosomal DNA for Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus spp. Chabertia ovina and Oesophagostomum spp.). Faecal worm egg counts (WECs) were performed using a modified McMaster WEC technique. The WECs were adjusted for FCS and transformed using log 10(adjusted WEC+25) prior to statistical analyses.Cryptosporidium, Giardia and Trichostrongylus spp. detected by PCR were associated with an increased risk of non-pelleted faeces (FCS ≥ 3.0) for both flocks. Cryptosporidium-positive lambs were 2.8-11.6 times more likely to have non-pelleted faeces and Giardia-positive lambs were 2.4-14.0 times more likely to have non-pelleted faeces compared to lambs negative for each respective parasite. Lambs positive for both Cryptosporidium and Giardia were 2.9-11.8 times more likely to have non-pelleted faeces than lambs positive for only one or neither of these parasites. Mixed internal parasite infections were found to have greater impacts on FCS and BCS than single infections. A higher number of internal parasites detected per lamb was associated with lower BCS and more loose faeces. The relationship between parasite detection and live weight or growth rate were inconsistent for both flocks. Adjusted WEC was correlated with FCS and faecal DM% for one flock only, although little or no correlation was found with live weight and growth rate for both flocks. Cryptosporidium ubiquitum and Cryptosporidium parvum were the most prevalent Cryptosporidium species isolated in the two flocks. Giardia assemblage E was the most commonly isolated genotype assemblage from both flocks, while assemblage A was isolated almost as frequently as assemblage E in the one flock. One flock was a potential source of zoonotic Cryptosporidium and the other flock was a potential source of zoonotic Giardia

Summer-autumn rainfall effects on wool staple strength and position of break. I. Small-scale field simulations of rainfall onto sheep grazing dry pasture in February and April

Despite a great deal of anecdotal evidence linking summer–autumn rainfall events to the position of break (POB) of wool from sheep grazed in a Mediterranean environment, there are no published experiments directly investigating this relationship. This trial examined the effects on staple strength (SS) and POB of simulated rainfall onto sheep grazing dry pasture residues during February and April. The simulated rainfall events had few significant effects on the wool quality parameters of the sheep in this trial. The natural rainfall associated with the ‘break’ of the season had a much greater influence on SS and POB. A significant effect on POB was noted in the wool from sheep that had been exposed to simulated rainfall and then grazed germinating green pasture for approximately 15–20 days. The effect on POB could be an effect of the green feed alone or a combination of the green feed and simulated rainfall. When grazing wetted dry pasture, sheep appeared to alter their grazing behaviour and showed more apparent ‘selectivity’. Overall grazing times did not appear to be affected and sheep in several treatment groups were observed to graze whilst their rainfall simulations were in progress. Wetting of dry pasture also appeared to increase the ‘toughness’ of the plant material available

Summer-autumn rainfall effects on wool staple strength and position of break. II. Rainfall simulations, with or without wind, on sheep on days of different ambient temperatures

Previous small-scale field work failed to show any influence on staple strength from various different rainfall simulations, other than those where sheep grazed germinating green pasture following rainfall. The present study was designed to incorporate variables such as ambient temperature and the influence of wind into rainfall simulations onto Merino sheep. Different treatments did not show any effect on staple strength despite sheep being subjected to simulated rainfall events on warm and cool days, with or without additional wind. This lack of effect on wool quality was despite significant treatment effects on sheep rectal and skin temperatures

The potential for energy self-sufficiency in the United Kingdom rendering industry

Animal by-products (ABPs) are co-products of meat production system that include on-farm fallen stock and slaughterhouse co-products that are not fit for human consumption (different types of fat, offal and bone). Slaughterhouse co-products represent between 30 to 50% of the life weight of farm animals. In the UK, fat, offal and bone are normally handled by rendering. Rendering is a process where ABP are sized and then dried to produce rendered products: tallow and a protein meal. Depending on the category of the ABP, rendered products can be used in pet foods manufacturing, the oleochemical industry and as biofuels (with and without further processing). The UK rendering industry uses both tallow and natural gas as fuel for heat production during the drying process. A study of UK rendering plants was undertaken to determine the total tallow production and the relative proportions of tallow and natural gas used as fuels. Data on fuel and energy use was collected from five rendering plants, representing 50% of the ABP processed in the UK. The results indicate that tallow use by the UK rendering industry ranged from 15 – 100% of total heat production with the remainder being derived from natural gas. When scaled up, it can be calculated that between 2006 and 2008 the UK rendering industry required around 5.7 PJ of heat per annum. During the same period the energy potentially available from rendered tallow (usable as biofuel) was 6.7 PJ. It can be concluded that potentially the UK rendering industry could be self-sufficient in energy use. However, use of tallow as a biofuel depends on the relative cost of natural gas compared to alternative markets for tallow