Animals form an integral part of our planetary ecosystem but balance is critical to effective ecosystem functioning as demand for livestock products has increased, greater numbers of domesticated livestock have created an imbalance and hence had a negative impact on a number of ecosystem services which means that life as we know it will become unsustainable. Policies and technology advances have helped to manage the impact but more needs to be done. The aim of this paper is to highlight ways in which better knowledge of animal science, and other disciplines, can both harness technology and inform policy to work towards a sustainable balance between livestock and the environment. Effective policies require simple, quantifiable indicators against which to set targets and monitor progress. Indicators are clear for water pollution, but more complex for biodiversity. Hence, more progress has been made with the former. It is not yet possible to measure the impacts of changes in livestock management on greenhouse gas emissions per se at a farm level and progress has been slower, although new technologies are emerging. With respect to land use, the simple indicator of area has been used, but total area is oversimplistic. Our analysis of land suitability and use highlights a relatively overlooked role of livestock in acting as a 'buffer' to use by-products and grains which do not meet the standards for processing by industry during years of inclement weather, which in the past has provided an 'insurance policy' for farmers. Since extreme weather events are increasing in frequency with climate change, this role for livestock may be more important in future. The conclusions of the review with respect to strengthening the links between research and policy are i) to encourage animal scientists to identify the relevant environmental indicators, work with the cutting edge experts developing technologies to measure these cost-effectively and across a range of relevant livestock systems and ii) to work with the feed industry to optimize diets not just in terms of least cost financially but also least 'cost' in terms of global carbon flux and engage in dialogue with the food industry and policy makers on regulations for grain quality.

Refers to: Tim Bailey Letter to the Editor on “Strategies to reduce reliance on soya bean meal and palm kernel meal in livestock nutrition” Journal of Applied Animal Nutrition: 8 (2)- Pages: 101 - 102

Greenhouse gas emissions and loss of wildlife habitats have stimulated growing global concern over the continued expansion of soya bean and palm oilseed production on land recently converted from forest and natural grasslands. This paper reviews the roles of soya bean meal and palm kernel meal in livestock nutrition, drawing on research data to explore the potential for their replacement in nutritionally balanced diets. Soya bean meal is a widely used livestock feed due to relatively high levels of total protein and essential amino acids. Palm kernel meal has been used for many years in compound feeds for ruminant livestock and as a supplement to grazed pasture in periods of drought. A range of alternative sources of protein is available to replace soya bean and palm kernel meals, e.g. protected rapeseed meal can replace soya bean meal in diets for productive dairy cows, but constraints to widespread adoption include insufficient supply, anti-nutritional factors which require feeds to be processed or supplemented with enzymes, and imbalances in essential amino acids. Soya ‘milk’ made directly from soya beans is a less efficient process than producing milk from dairy cows, especially when they are grazed on pastures or given diets that do not contain soya bean meal.

Grazing plays an important role in milk production in most regions of the world. In this review, some challenges to the grazing cow are discussed together with opportunities for future improvement. We focus on daily feed intake, efficiency of pasture utilization, output of milk per head, environmental impact of grazing and the nutritional quality to humans of milk produced from dairy cows in contrasting production systems. Challenges are discussed in the context of a trend towards increased size of individual herds and include limited and variable levels of daily herbage consumption, lower levels of milk output per cow, excessive excretion of nitrogenous compounds and requirements for minimal periods of grazing regardless of production system. A major challenge is to engage more farmers in making appropriate adjustments to their grazing management. In relation to product quality, the main challenge is to demonstrate enhanced nutritional/processing benefits of milk from grazed cows. Opportunities include more accurate diet formulations, supplementation of grazed pasture to match macro- and micronutrient supply with animal requirement and plant breeding. The application of robotics and artificial intelligence to pasture management will assist in matching daily supply to animal requirement. Wider consumer recognition of the perceived enhanced nutritional value of milk from grazed cows, together with greater appreciation of the animal health, welfare and behavioural benefits of grazing should contribute to the future sustainability of demand for milk from dairy cows on pasture.

Challenges to ensiling are coming from a wide spectrum. Faster harvest rates are making it more difficult to achieve target silage densities. Larger harvest equipment is increasing soil compaction and rural road issues. Older silos are too small and are overfilled, creating safety issues, or temporary piles are placed on bare ground permitting soil contamination. Mycotoxins and other pathogens in silages are still a problem. Global warming may affect the forage crops grown and crop characteristics as well as rates of silage fermentation and aerobic deterioration. Silage as an input to bio-refineries has an unclear future. Silage analysis is challenged by sampling and knowing what components truly predict nutritional value. The future holds many opportunities for both ensiling and silage research. Robotic harvesting will release more labour for silo packing, and there are opportunities to develop tools to estimate silage density during filling. Total mixed ration silages should allow more by-products in rations. The development of novel silage additives to improve silage hygiene or increase nutrient availability appears promising. Predicting the onset of aerobic deterioration with quick tests for lactate-assimilating yeasts or silage temperatures seems possible. Metabolomics and metabonomics, in addition to the microbiome tools in development, put us at the cusp of being able to see which microorganisms are active in the silo and rumen and what compounds of significance they are producing. This could lead to many advances in silage quality including reduced microbial toxins, better hygiene and improved utilization by livestock.

Highlights of progress in the production of silage over the past 50 years include the introduction of improved hybrids of maize (Zea mays L.), the forage harvester, the big baler, polyethylene covering for horizontal silos, stretch-wrap film for bales and novel additives designed to improve the fermentation and aerobic stability of silage. The key biochemical pathways in the silage fermentation have been described together with the effects of microbial and chemical additives on fermentation and aerobic stability during the feed-out phase. The significance of oxygen and water in silage fermentation has been quantified and efficacy of covering silos has been established, with recent progress in the development of oxygen barrier film. Future perspectives include improving food safety and animal health by increasing the hygienic quality of silage, reducing the environmental impact of silage by decreasing loss of nitrogen to soil and atmosphere, reducing methanogenesis in the rumen and increasing methane yield from silage as biofuel, and the use of silages as feedstocks for multiple end uses in biorefineries.

Silage may contain several agents that are potentially hazardous to animal health, the safety of milk or other animal food products, or both. This paper reviews published literature about microbial hazards, plant toxins, and chemical hazards. Microbial hazards include Clostridium botulinum, Bacillus cereus, Listeria monocytogenes, Shiga toxin-producing Escherichia coli, Mycobacterium bovis, and various mold species. High concentrations of C. botulinum in silage have been associated with cattle botulism. A high initial concentration of C. botulinum spores in forage in combination with poor silage fermentation conditions can promote the growth of C. botulinum in silage. The elevated pH level that is generally associated with aerobic deterioration of silage is a major factor influencing concentrations of L. monocytogenes, Shiga toxin-producing E. coli, and molds in silage and may also encourage survival and growth of M. bovis, the bacterium that causes bovine tuberculosis. Soil is a major source of B. cereus spores in silage; growth of this bacterium in silage appears to be limited. Hazards from plant toxins include pyrrolizidine, tropane and tropolone alkaloids, phytoestrogens, prussic acid, and mimosine, compounds that exist naturally in certain plant species that may contaminate forages at harvesting. Another group of toxins belonging to this category are ergot alkaloids, which are produced by endophytic fungal species in forages such as tall fescue grass, sorghum, and ryegrass. Varying effects of ensiling on the degradation of these plant toxins have been reported. Chemical hazards include nitrate, nitrite, and toxic oxide gases of nitrogen produced from nitrate and high levels of butyric acid, biogenic amines, and ammonia. Chemical and microbiological hazards are associated with poorly fermented silages, which can be avoided by using proper silage-making practices and creating conditions that promote a rapid and sufficient reduction of the silage pH and prevent aerobic deterioration.

SUMMARYA range of options was explored to test the hypothesis that diets for dairy cows could be formulated to reduce the carbon footprint (CFP) of feed, increase efficiency of conversion of potentially human-edible feed into milk, increase nitrogen use efficiency (NUE) and reduce methane (CH4) emissions per kg milk. Diets based on grazed grass, grass silage, maize silage or straw, supplemented with raw material feeds, were formulated to meet requirements for metabolizable energy and metabolizable protein for a range of daily milk yields. At similar levels of milk yield, NUE, predicted CH4emissions and diet CFP were generally higher for diets based on maize silage than for those based on grazed grass, grass silage or straw. Predicted CH4emissions and human-edible proportion decreased, while NUE increased with the increasing level of milk yield. It is concluded that there is potential to reduce the environmental impact of milk production by altering diet formulation, but the extent to which this might occur is likely to depend on availability of raw material feeds with low CFPs.

Nutrition affects the environmental impact of milk production through its direct influence on enteric fermentation and excretion of undigested and excess nutrients, especially nitrogenous compounds, in manure and its indirect influence on daily level of milk output per cow and fertility. The higher the level of milk production and fertility, the lower the emissions intensity, or carbon footprint, of a dairy herd. Increasing feed efficiency reduces greenhouse gas emissions per litre of milk because emissions are spread over higher product output per cow. Nitrogen use efficiency and cow fertility can be increased and diet carbon footprint reduced by altering diet formulation to utilise by-product raw material feeds of low carbon footprint.

Implications of silage hygienic quality for animal production were investigated on forty-five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre-ensiling.

Losses of organic matter in the outer layers of bunker silos covered with conventional polyethylene (PE) plastic can be substantial due to oxygen transmission through the plastic top-covering film during the post-ensiling storage period. The effect of two silo covering materials, oxygen barrier (OB) film (45 mu m thickness) and clear PE film (50 mu m thickness), as underlays to a white-on-black PE plastic top cover (120 mu m thickness), was assessed in the outer layer of whole-plant maize silage stored in three large bunker silos in the People's Republic of China. Samples of the crop at harvest and of silage from the upper 45 cm layer at 5 months post-ensiling, prior to removal of silage for feed-out, were analysed for DM, fermentation profile and chemical composition. Loss of OM was estimated from concentrations of ash in the crop at harvest and in the silage. Differences between underlay films in silage fermentation profile were small. Silage protected with OB underlay film had higher mean concentration of starch (p<.008) and higher mean NDF digestibility (p<.003) than silage under PE underlay film. Concentrations of ash were lower (p<.001) for silage covered with OB film than for PE film in all three trials. Mean estimated losses of OM were 170 g/kg for OB underlay film and 232 g/kg for PE underlay film (p<.001), and whole-silo estimated net economic benefits to OB underlay film ranged from 0.17 to 0.74 US $ per tonne fresh crop ensiled.

The drive to increase the output of animal product in some sectors of ruminant livestock production has led to greater use of feeds such as cereal grains and soyabean meal that are potentially human-edible. This trend has caused concern since, by so doing, ruminants compete not only with monogastric livestock but also with the human population for a limited global area of cultivatable land on which to produce grain crops. Reasons for using potentially human-edible feeds in ruminant diets include increased total daily energy intake, greater supply of essential amino acids and improved ruminal balance between fermentable energy and degradable protein. Soyabean meal, produced on land that has been in arable cultivation for many years can fulfil a useful role as a supplier of undegraded dietary protein in diets for high-yielding dairy cows. However, in the context of sustaining the production of high-quality foods from livestock to meet the demands of a growing human population, the use of potentially human-edible feed resources by livestock should be restricted to livestock with the highest daily nutrient requirements; that is, potentially human-edible feed inputs should be constrained to meeting requirements for energy and protein and to rectifying imbalances in nutrient supply from pastures and forage crops such as high concentrations of nitrogen (N). There is therefore a role for human-edible feeds in milk production because forage-only systems are associated with relatively low output per head and also low N use efficiency compared with systems with greater reliance on human-edible feeds. Profitability on farm is driven by control of input costs as well as product value and examples are given of low-cost bovine milk and meat production with little or no reliance on potentially human-edible feeds. In beef production, the forage-only systems currently under detailed real-time life-cycle analysis at the North Wyke Farm Platform, can sustain high levels of animal growth at low feed cost. The potential of all-forage diets should be demonstrated for a wide range of ruminant milk and meat production systems. The challenge for the future development of ruminant systems is to ensure that potentially human-edible feeds, or preferably human-inedible by-products if available locally, are used to complement pastures and forage crops strategically rather than replace them.

Silage making involves preserving forage crops by fermentation of water-soluble carbohydrates (sugars) to organic acids. The fermentation is relatively uncontrolled and inadequate acidification can allow the growth of undesirable microorganisms such as enterobacteria and clostridia. Ingress of oxygen to the outer layer of the silo or bale during the storage period encourages growth of yeasts and moulds. Mycobacterium bovis may survive in silages with pH above 5.0. Outgrowth of clostridia in aerobically deteriorating silage can lead to high counts of butyric acid spores in silage that can contaminate milk and cheese. Milk may be contaminated with Penicillium toxins and be rejected for containing antibiotics. Specific disease risks to livestock from poorly preserved silage include bacterial endotoxicosis, listeriosis, botulism, mycotoxicosis and nitric acid poisoning in addition to reduced feed value. Rapid acidification is essential once the crop is ensiled to restrict the growth of enterobacteria, listeria and clostridia. Oxygen barrier film, in addition to reducing loss of dry matter during the storage period, prevents clostridial outgrowth in the outer layer of the silo and is also likely to reduce the risk of listeriosis.

Background An extended trochanteric osteotomy (ETO) is a widely used approach for revision hip arthroplasty. Following an ETO it is common practice to use a long stemmed femoral prosthesis at the second stage to bypass the osteotomy. We propose that at the second stage, if the osteotomy has united, it is appropriate to use a standard length prosthesis, which preserves bone stock for any future revisions. Methods We performed a retrospective review of our institution9s prospective arthroplasty database, identifying all patients who had undergone an ETO at the first stage revision. A radiograph review was then performed and any subsequent complications recorded. A selection of patients radiographs were individually reviewed by three reviewers and intra-class correlation (ICC) was performed to assess intra-observer reliability. Results 99 patients underwent 104 second-stage procedures (1 contralateral side, 4 further revisions for subsequent infection) with a mean follow-up of 5.5 years (56 days to 15 years). 72/104 (69%) patients received a standard prosthesis following ETO union and 32/104 (31%) received a long-stem prosthesis at second stage due to concerns regarding ETO union or lateral wall bone loss. Following a radiological review of all cases, 49 (71%) of the short stem group and 17 (52%) of the long stem group had no complications. A significant complication (infection, fracture or dislocation) was observed in 10 (18%) of the short stem group and 5 (16%) of the long stem. 22 patients’ radiographs were reviewed by 3 individual assessors to assess for ETO union and complications and an intra-class correlation (ICC) of 0.84 (p Conclusion We propose that standard length prostheses can be used following an ETO for infection if the osteotomy has united at the second stage with no greater risk of complications. This preserves distal bone stock for any future revision surgery that may be required.

Losses of dry matter and metabolisable energy (ME) occur in silage making due to delayed harvest and also between field and feed trough due to fermentation and aerobic spoilage. Farmers should aim to exert greater control of silage making operations to improve timeliness of harvest and to minimise losses of nutrients. Concentrate input per unit of milk production is often higher than optimal which is more often a reflection of low silage quality than of wasteful overfeeding. A week's delayed harvest of grass is estimated to incur a net cost of 13 pence per cow per day of winter feeding. Mowing a dry crop and spreading it out to maximise rate of water loss during the wilting period can reduce losses in the field. Consolidation of crop in the silo to achieve a minimum fresh weight density of 700 kg/m3 and dry matter (DM) density of 210 kg/m3 will help to minimise losses during the storage period, paying particular attention to the outermost layer which should be covered with an oxygen barrier film. A feed-out progression rate of at least 1 metre per week in winter and 1.5 to 2 metres per week in summer, coupled with harvesting a clean crop with low yeast and mould counts will help to reduce losses during feed-out. Many bunker silos are too old, too small, have no safety rail and are over-filled. Safety issues should be considered at all stages of silage making. Appropriate steps should be taken wherever possible to minimise risk of injury.

Agriculture has a devolved commitment to reduce national emissions of greenhouse gases (GHG). Using a systems model-based life-cycle analysis we explored the potential for reducing GHG in systems used to produce twelve crop and seven livestock commodities. With a functional unit of kg of product, differences in GHG between crops reflect differences in yield. Metabolisable energy (ME) or crude protein (CP) could be used, but deriving an economic value of GB 8.6 pound/GJ ME and GB 0.62 pound/kg CP, leads to a relatively consistent 2.6 kg CO(2)e/ pound nutrient value. Potential GHG reductions ranged from 2% (sugar beet) to 15% (cereals) with agronomic changes, and 4-12% with increased crop yields. The best alternative livestock systems reduced GHG ranging between 7% (beef from the dairy herd) and 21% (extensive sheep meat). Half of the options reduced national production and hence increased imports. Overall, improvements in productivity and use of resources are the best options for reducing GHG. (c) 2014 Elsevier Ltd. All rights reserved.

A total of 8814 samples of pre-grazed herbage samples was analysed by near infrared spectroscopy calibrated against wet chemistry between March 2006 and October 2012. There were decreasing trends over the seven-year period in annual mean crude protein (CP) and nitrates (NO3). Within years, median values for dry matter (DM), water-soluble carbohydrates (WSC) and metabolisable energy (ME) tended to decrease whilst neutral and acid detergent fibre (NDF and ADF) tended to increase from March to October. There was little change in median monthly NO3 during the season. Median CP tended to decrease from March to May and to increase thereafter. Within months, the range in concentration of most components tended to be greatest in mid-season, with the exception of DM and ADF which had relatively large ranges in March. The range in CP was large in all months except October. Mean DM was 183 (+/- 39.4) g/kg fresh weight. Mean ME was 11.7 (+/- 0.75) MJ/kg DM. Mean concentrations (g/kg DM) were, 214 (+/- 52.0) for CP, 442 (+/- 61.3) for NDF, 233 (+/- 45.0) for ADF, 90 (+/- 24.7) for WSC and 36.5 (+/- 8.04) for oil. Mean NO3 was 425 (+/- 781) mg/kg fresh weight. In view of the large range in values within months it is recommended that pre-grazed herbage samples should be taken at weekly intervals to increase accuracy of grazing management and diet formulation for grazing ruminants. (C) 2014 Elsevier B.V. All rights reserved.

A meta-analysis was undertaken of 51 comparisons of standard polyethylene film with oxygen barrier (OB) film in covering systems for bunker silos, unwalled clamp silos and bales. Mean losses of DM or OM during storage from the top 10 to 60 cm of bunker and clamp silos were 195 g kg(-1) for standard film and 114 g kg(-1) for OB film systems (41 sets of data, P < 0.001), while mean total losses of DM from baled silage were 76.8 g kg(-1) for standard film and 45.6 g kg(-1) for OB film systems (10 sets of data, P < 0.001). Top surface silage judged subjectively to be inedible was 107 and 29.6 g kg(-1) for standard film and OB film systems respectively (5 sets of data, P = 0.02). Aerobic stability was 75 h for silage stored under standard film system and 135 h for silage stored under OB film system (11 sets of data, P = 0.001). It is concluded that the OB film system reduces losses from the outer layers of silos and from bales and increases the aerobic stability of silage in the outer layers of silos.

An experiment was conducted to compare a bunker silo sealing system comprising an oxygen barrier film (OB: 45 mu m thickness) with protective woven polypropylene with one comprising standard black polyethylene film (S, 125 mu m thickness) with protective tyres. Analysis of samples taken to 30 cm depth after 365 days of storage showed no differences in pH or lactic acid between the two sealing systems. There were no differences in aerobic bacterial count between silages. Whilst 2.56 log(10) CFU moulds g(-1) fresh weight were found in samples of silage sealed with S, no moulds were found in samples of silage sealed with OB. Aerobic stability, averaged 249 hours and 184 hours for OB and S, respectively. The OB system probably inhibited the development of the micro-organisms responsible for the initiation of aerobic deterioration to a greater extent than the standard silo sealing system.