Increased Foraging in Outdoor Organic Pig Production—Modeling Environmental Consequences

Abstract

Consumers’ motivations for buying organic products include a wish of acquiring healthy, environmentally friendly products from production systems that also ensure a high level of animal welfare. However, the current Danish organic pig production faces important challenges regarding environmental impact of the system. High ammonia emissions arise from outdoor concrete areas with growing-finishing pigs and sows on pasture possess an increased risk of nitrogen (N) leaching. Direct foraging in the range area is suggested as a way to improve the nutrient efficiency at farm level and to support a more natural behavior of the pig. Thus, by modeling, we investigated the environmental consequences of two alternative scenarios with growing-finishing pigs foraging in the range area and different levels of crops available for foraging; grass-clover (lowest integration of forage) or a combination of lucerne, grass-clover and Jerusalem artichokes (highest integration of forage). It was possible to have growing-finishing pigs on free-range without increasing N leaching compared to the current practice. The alternative system with lucerne, grass-clover and Jerusalem artichokes showed the lowest carbon footprint with 3.12 CO2 eq kg−1 live weight pig compared to the current Danish pasture based system with 3.69 kg CO2 eq kg−1 live weight pig. Due to positive impact on soil carbon sequestration, the second alternative system based on grass-clover showed a similar carbon foot print compared to current practice with 3.68 kg CO2 eq kg−1 live weight pig. It is concluded that in practice there is room for development of organic pig production systems where direct foraging plays a central role.

Effect of poplar trees on nitrogen and water balance in outdoor pig production – A case study in Denmark

“…where feed is the measured mean feed (Table 2) with assumed 14.3% crude protein with 16% N, straw is N from straw provided to the huts with 5 kg N ha −1 (Nielsen and Kristensen, 2005), fix is biological N fixation by the grass-clover of 30 kg N ha −1 (Jakobsen et al, 2015) and atm is atmospheric deposition of 16 kg N ha −1 (Halberg et al, 2010). The output pig is N in weaned piglets with assumed 25 g N kg −1 (Poulsen and Kristensen, 1997) and calculated according to the measured number of piglets (Table 2).…”

Forage Consumption and Its Effects on the Performance of Growing Swine—Discussed in Relation to European Wild Boar (Sus scrofa L.) in Semi-Extensive Systems: A Review

“…Moreover, the proportion and composition of the ingested forage affects the antioxidant and fatty acids composition of muscles, which, in turn, affects the contents of α-tocopherol, total phenols, hydrophilic and lipophilic antioxidant activity, and fatty acid profile [11]. Outdoor pig production systems based on high nutrient intake from pasture are considered more sustainable compared to indoor systems that are typically dependent on high inputs of cereals and soya [12,13]. Such crops are fit for human consumption and the feeding of them to animals represents an inefficient use of the resources used to produce them.…”

Effect of Three Husbandry Systems on Environmental Impact of Organic Pigs

“…Since pig production is dominated by non-organic production systems, most studies cover conventional systems [4]. As for most LCA studies dealing with pigs, for organic pig production, which is still comparatively small-scale, but nevertheless rapidly developing, only a few modelling studies are available [12][13][14]. Only a few studies have conducted an LCA using individual farm data [15], and even fewer have been based on a considerable number of organic farrow-to-finish pig farms.…”

“…Keeping pigs on pasture has a potentially higher risk regarding nutrient losses [14,21] compared to pigs kept indoors, where manure is collected, stored, and spread in a controlled way on fields. Furthermore, due to a more controlled (thermal) environment, pigs kept indoors might have better feed conversion ratios and a higher number of piglets weaned, both reducing the environmental impact [22,23].…”