Organic dairy farming: towards sustainability

Livestock is a key element of organic agriculture. The concept of closed nutrient cycles requires the close integration of crop and livestock systems whenever possible within a farm, or at least within regions (e.g. IFOAM, 2014; Bioland, 2016; Bio Suisse, 2016). Ruminants play a particularly important role in integrated organic systems, since they can efficiently utilize grassland resources, legume forages from crop rotations and crop residues, and they provide valuable manure for the soil. However, large amounts of concentrates are still fed to organic cattle, requiring the transport of soya bean on a large scale across the globe (Früh et al., 2014) with severe ecological and social consequences (Pellentier and Tyedmers 2010; Semino et al., 2009). Furthermore, the demand for arable land areas to produce cereals for organic ruminant production is still very high. This is a status quo that should be overcome against the background of the environmental and social claims of organic agriculture (IFOAM, 2014). On the other hand, it is particularly the ruminal digestion of fibre which produces methane, thus directly impacting climate change dynamics in a most problematic way (Beauchemin et al., 2008). In this context, a dilemma of contemporary ruminant production becomes obvious, which is of particular relevance for the targets of organic systems as there seem to be serious contradictions between some of the key aspects of sustainable livestock production. These can be summarized as follows: a) Globally, it appears unavoidable to make efficient and ecologically sustainable use of the large permanent grassland resources for animal source food production, thereby lowering the demand for livestock feed from arable land (Wilkinson, 2011; O’Mara, 2012; Schader et al., 2015). b) Ruminants, as important providers of dairy and meat products, are the most efficient livestock species to utilize fibrous grassland swards (Clauss et al., 2010), and are, compared to poultry and pigs, less efficient in utilizing human-edible feedstuffs, when these are fed in high proportions (Wilkinson, 2011). c) The digestion of fibre is the most prominent source of enteric methane production in ruminants (Johnson and Johnson, 1995). This results in the apparent dilemma that the more a ruminant production system is based on roughages and avoids concentrates, the higher the methane emission is per unit of product (Beauchemin et al., 2008; Grandl et al., 2016), a challenge which is even more relevant for organic dairy production, due to lower yields. Possible options to deal with this dilemma are more holistic and systemic views on agricultural production systems, the integration of milk and meat production in dual-output production systems (Zehetmeier et al., 2012), the integration of feeding systems with breeding schemes (Spengler Neff et al., 2007) and critically assessing what level of demand for animal products is reasonable and responsible (Schader et al., 2015). Furthermore, organic principles aim at high animal welfare, based on choice of suitable breeds, species-appropriate management, housing and feeding conditions. This implies space requirements, animal-friendly barn systems, explicit framing of the human–animal relationship and, again, the principle that ruminant grazers such as cattle and sheep should be predominantly fed on roughages, while high proportions of concentrates are considered inappropriate for these species. This is another reason why organic principles include restrictions on supplying ruminants with concentrates. Animal health is a further key target of organic dairy systems. Currently, the average productive lifetime of dairy cows in conventional systems is clearly lower than three lactations in many industrialized countries (Knaus, 2009; Stiglbauer et al., 2013). The most common reasons for culling are fertility problems, diseases of the mammary gland or lameness (Pritchard et al., 2013), which may all be considered to be potentially related to metabolic problems due to high yields and inappropriate feeding (Knaus, 2009). There is no general evidence that the figures are better for organic cows, but the high significance of animal welfare in organic standards requires farmers to pay particular attention to this problem. This is further reinforced by the fact that realizing a long productive lifespan integrates higher animal welfare with environmental and production efficiency (Zehetmeier et al., 2012; Grandl et al., 2016). In conclusion, the main issue requiring a solution for sustainable organic dairy production is the proper fit of regionally available feed resources, feeding systems and breeding strategies with the target of optimal roughage utilization, low emissions and healthy long-living cows. The implied contradictions represent big tasks for research and system development and are a core challenge for achieving sustainable food systems