The Eighth International Symposium on the Nutrition of Herbivores (ISNH8) was held at Aberystwyth University in September 2011. The conference provided a unique opportunity to address the challenges faced by animal agriculture. Animal agriculture is at a crossroads: competing pressures from competition for land with alternative forms of land use, the need to both mitigate against and adapt to the effects of climate change, combined with the need to meet society's demand for safe nutritious food produced at affordable costs. The symposium presented a unique opportunity for scientists and other stakeholders to work together to shape the future of herbivore production. Some 340 original communications were presented along with 20 invited lectures across seven sessions. The short papers were published in Advances in Animal Biosciences (Vol. 2; http://journals.cambridge.org/abstract_S2040470011002810). This special issue of Animal features 16 of the invited presentations.
Session 1 focused on the role of herbivores in sustainable land-production systems. Herrero et al. (Reference Herrero, Grace, Njuki, Johnson, Enahoro, Silvestri and Rufino2013) emphasised the very important role livestock play in rural livelihoods and the economies of developing countries and noted that in the transition to more intensive production systems it is essential to avoid increases in zoonotic, food-borne and other diseases. Herrero et al. (Reference Herrero, Grace, Njuki, Johnson, Enahoro, Silvestri and Rufino2013) also stressed the requirement for alternative options for producers when intensification of livestock production is not an appropriate option. In contrast, van Vuuren and Chilibroste (Reference van Vuuren and Chilibroste2013) examined the key challenges in the nutrition and management of herbivores in the temperate zones and noted that emphasis on maximising the conversion of solar energy by plants and into animal products is essential to improve the sustainability of livestock-production systems.
Session 2 addressed approaches for reducing greenhouse gas footprint of herbivores with key emphasis on nitrous oxide and methane. Schils et al. (Reference Schils, Eriksen, Ledgard, Vellinga, Kuikman, Luo, Petersen and Velthof2013) examined the efficiency of nitrogen transfer between soil, crop, manure and the animal and approaches for reducing nitrous oxide across these major components of livestock systems. These authors emphasised that, given the strong interaction between nitrogen and carbon cycles in livestock systems, care is required to ensure that measures that reduce nitrogen oxide emissions do not create increases in other greenhouse gases. Clark (Reference Clark2013) noted the range of approaches available to reduce methane emissions from ruminants and acknowledged that this is challenging to achieve in absolute terms particularly for grazing relative to indoor feeding systems. Host differences in methane production are an exciting new observation and potentially open up the opportunity to breed for animals with lower emissions. St-Pierre and Wright (Reference St-Pierre and Wright2013) integrated current knowledge on the population structure of symbiotic methanogens across a broad range of hosts from ruminant livestock species to wild ruminants, and illustrated in particular how such studies are advancing knowledge on gut methanogens and how these are influenced by host and diet.
Session 3 discussed feeding and management in high-forage systems. Peyraud and Delagarde (Reference Peyraud and Delagarde2013) discussed the main factors influencing nutrient supply for grazing dairy cows that deliver on achieving higher levels of production balanced against efficient utilisation of pasture per hectare. These authors identified significant progress in the knowledge on intake and digestion that provide opportunities to increase production from high-producing dairy cows at grass. O'Reagain and Scanlan (Reference O'Reagain and Scanlan2013), using understanding from northern Australia, discussed the difficult challenges of livestock production in rangelands, against a backdrop of increasing variation in climate, in particular rainfall. The use of modelling combined with applied research is helping to provide advice on management options under these production scenarios. Kingston-Smith et al. (Reference Kingston-Smith, Marshall and Moorby2013) highlighted how increased collaboration between plant and animal scientists is helping to drive progress in plant breeding and genetic improvement to help improve ruminant productivity and reduce environmental footprint. These authors suggested that in the future existing forage crops (and/or alternative new crops) must be able to make much improved use of key input resources such as water and nutrients from limited land resources.
Session 4 centred on the progress in two key issues in relation to the quantification of the nutrition of herbivores. Swain and Friend (Reference Swain and Friend2013) discussed how the developments in spatial assessments of available vegetation using on-ground sampling and satellite remote sensing are creating new opportunities to increase the understanding of the nutritional ecology of herbivores. Friggens et al. (Reference Friggens, BrunLafleur, Faverdin, Sauvant and Martin2013) reviewed the major advances in predicting nutrient partitioning in the dairy cow, with emphasis on cow genotype and animal response when nutrient supply is limited or more variable. The paper emphasised that it is important to consider not just nutrient partitioning to productive outputs but also other issues including health and reproduction.
Session 5 addressed two areas in relation to the nutrition and health of herbivores. The first study by Ingvartsen and Moyes (Reference Ingvartsen and Moyes2013) underlined the importance of the interplay between the endocrine system, immune system and nutrition in relation to the management and prevention of diseases in dairy cattle and hence to animal health and welfare. The authors discussed the complex relationships between metabolic status and immune function in relation to the risk of disease during early lactation. De Blas (Reference De Blas2013) reviewed studies defining the nutritional requirements of intensively reared rabbits and noted the importance of high levels of a balanced diet to attain high productivity levels and minimise health disorders.
Session 6 focused on the nutrition and quality of herbivore products. Shingfield et al. (Reference Shingfield, Bonnet and Scollan2013) appraised studies examining the factors influencing the lipid composition of ruminant products, meat and milk. The authors commented that although nutrition is the major aspect influencing the fatty acid composition of ruminant-derived foods, in the future it is expected to progress in genetics, along with the enhanced nutrition that will identify further novel opportunities. Salter (Reference Salter2013) appraised the relationships between dietary lipid classes and the risk of coronary vascular disease (CVD) in man and noted that the literature supports the link between CVD and dietary saturated fatty acids (SFA) and potential trans fatty acids derived from partially hydrogenated vegetable oil. The review suggests that future strategies should focus on replacing dietary SFA with total polyunsaturated fatty acids.
Session 7 concentrated on the developments in the fields of genomics, proteomics, microbial metagenomics and phenomics and the relevance to addressing issues in the nutrition of herbivores. Seo et al. (Reference Seo, Larkin and Loor2013) concluded that the application of cattle genomics has much to offer for future nutritional approaches in feeding dairy cattle. They stressed that among the biggest challenges is the integration of genomic and phenotypic data to deliver not only new biological knowledge but also solutions to practical issues. Morgavi et al. (Reference Morgavi, Kelly, Janssen and Attwood2013) illustrated how advances in high-throughput culture-independent technologies are helping to enhance the understanding of the rumen microbiome and assisting in understanding interactions between the rumen microbiome, the host animal and feed. Such information will help to deliver new approaches in improving efficiency or ruminant livestock production, including reductions in enteric methane.
A special thank you to the scientific and organising committees of ISNH8 and we hope that this special issue of Animal will be of great help to all those working in the nutrition of herbivores. Warm thanks to all members of the local organising committee and to all the staff of the Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, who contributed to the success and efficient running of all aspects of the symposium. The next symposium will be held in association with the XII International Symposium on Ruminant Physiology in Canberra, September 2014 (www.herbivores2014.com).
