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

SIMPLE SUMMARY: Outdoor-reared European wild boar (Sus Scrofa L.) is regarded as a delicacy by consumers due to its favourable meat properties and an association with high welfare standards. The rearing of wild boar on pasture has the potential to minimise input costs relative to conventional production systems. However, some pasture production systems have been found to perform poorly due to low growth rates. This review collates the available scientific evidence on pasture-based production of wild boar and domestic pigs, to identify factors that influence feed intake, performance, and behaviour. Factors explored include season/weather, dietary supplementation, grazing management, forage availability, herbage quality, and sward type. For example, the additional feed availability associated with pasture grazing has been shown to be a significant factor that positively correlates with dry matter intake of wild boar. This has been demonstrated to result in better feed conversion efficiency and reduced feed costs without reductions in growth rates compared to animals without access to pasture. Furthermore, the increased availability of favoured species in pasture may also promote dry matter intake. The long-term sustainability of wild boar production is dependent on the economic, social, and environmental viability of the systems. Pasture-based production systems may be one way by which this can be achieved, but only if implemented correctly. ABSTRACT: Due to its distinct properties, wild boar meat is considered a highly desirable consumer product, in a market that is expanding. Outdoor production is also favoured by consumers who value animal welfare and environmental sustainability when choosing meat products. There is evidence that farms that include pasture for grazing typically have reduced feeding costs. Such production systems can also be more environmentally sustainable as the input (pasture) is inedible to humans, compared to conventional indoor systems, which use human-edible feeds (e.g., soya). However, some wild boar farms have performed poorly compared to those rearing other swine such as hybrid wild boar and domestic pigs. Diet is central to all livestock production and is likely a significant influencing factor of wild boar performance, both in terms of forage consumption and nutritional composition. Other factors may also influence performance, such as weather, behaviour and grazing management. Wild boar production systems hold their own intrinsic value in a growing marketplace. However, information gathered through the study of wild boar has external applications in informing outdoor domestic pig production systems to encourage the use of pasture as part of the habitat of domestic pigs.