Pig farming conditions

In North West Europe, organic and low-input pig production in countries such as Germany, Sweden, Denmark and The Netherlands is characterized by the use of mainly conventional breeds in indoor housing systems with outdoor runs (Wallenbeck, Rydhmer and Thodberg, Reference Wallenbeck, Rydhmer and Thodberg2008; Edwards, Reference Edwards2011; Früh, Reference Früh, Forster and Weidmann2011). In Great Britain, sows live in paddocks and just before farrowing the sow is moved to a farrowing paddock with individual huts (Edwards, Reference Edwards2011). Finishing pigs are also kept in paddocks for most of the time and some farms have deep straw yards for the last 2–4 weeks before slaughter. Small farms (less than 20 sows) with direct sales usually have a wide range of traditional breeds, including Large Black, Middle White and Gloucester Old Spots (Martins et al., Reference Martins, Kelly, Day, Stopes, Browning, Edwards and Day2002). Larger herds of over 50 sows have sales through key wholesale outlets, mainly supplying multiple retailers (Martins et al., Reference Martins, Kelly, Day, Stopes, Browning, Edwards and Day2002). On these farms, mainly conventional breeds such as Large White, Duroc and Landrace crosses or commercial hybrids from breeding companies are used. Feeding on North West European organic farms is according to EU organic regulations.

In Eastern European countries such as Hungary, Croatia and Poland, pigs in organic and low-input systems are kept under extensive conditions in large pens or on pasture. They feed on natural resources of pasture and oak woodland supplemented with mixtures of cereals and green fodder (Egerszegi et al., Reference Egerszegi, Rátky, Solti and Brüssow2003; Karolyi, Luković and Salajpal, Reference Karolyi, Luković and Salajpal2007). Breeds used are mainly traditional, local breeds.

In Southern Europe, there are different rearing systems according to geographical location. In Italy, most of the organic pig herds are outdoors and situated in hills and mountains (Edwards, Reference Edwards2011). Farrowing and weaning are about 95 percent outdoors in huts. Fattening is about 60 percent outdoors, with the rest indoors with an outdoor run (Edwards, Reference Edwards2011). Animals are fed on locally available nutrients such as grass, crops, acorns, herbs, sometimes supplemented with cereals or concentrates. Organic feeds are allowed to contain a maximum of 5 percent of conventional components. Around 50 percent conventional breeds (Large White, Landrace and Duroc) and 50 percent traditional breeds (Nero Siciliano and Cinta Senese) are used (Früh, Reference Früh, Forster and Weidmann2011). In Spain, performance data were available of the Iberian pig and the Majorcan Black pig. Data on Iberian pigs included reproductive and finishing performance under free-range conditions. In the fattening period (i.e. ‘montanera’), pigs are fed on acorns and grass in Mediterranean forest (Daza et al., Reference Daza, Olivares, Rey, Ruiz and López-Bote2008). Majorcan Black pigs are reared similarly in extensive conditions (Gonzalez et al., Reference Gonzalez, Gispert, Rodríguez, Gil, Jaume, Tibau and Oliver2007).

Reproductive performance

The majority of data on reproductive performance of conventional breeds comes from North West Europe. In Eastern and Southern Europe, reproductive performance data of conventional breeds in organic and low-input production systems were scarcely available, because of the predominant use of traditional breeds in these regions.

In North West Europe, conventional breeds have relatively high reproductive performance compared with traditional breeds. The relatively large litter sizes at birth and high numbers of weaned piglets of conventional breeds are due to years of selection pressure on this trait in the breeding goal of conventional breeding programmes (Wallenbeck, Gustafson and Rydhmer, Reference Wallenbeck, Gustafson and Rydhmer2009). Preweaning mortality is relatively high (>16 percent) for conventional breeds compared with traditional breeds. Various factors explain these high mortality rates.

First, the high litter sizes at birth in conventional breeds are considered as a risk factor for stillbirth and mortality of liveborn piglets (Bille et al., Reference Bille, Nielsen, Larsen and Svendsen1974; Zaleski and Hacker, Reference Zaleski and Hacker1993). Problems with mortality related to high litter sizes are even exacerbated in low-input and organic production systems compared with conventional systems, owing to the structurally higher litter sizes in these environments (Leenhouwers et al., Reference Leenhouwers, Ten Napel, Hanenberg and Merks2011). In large litters, the farrowing process may be prolonged, which may lead to a larger proportion of piglets suffering from oxygen stress during birth. This may lead to stillbirth and reduced vitality of liveborn piglets (Zaleski and Hacker, Reference Zaleski and Hacker1993). Additionally, both absolute birth weight and within-litter uniformity in birth weight decrease with increasing litter size. Light piglets at birth have a higher risk of mortality owing to starvation or crushing, especially in litters with low birth weight uniformity (English and Smith, Reference English and Smith1975; Canario et al., Reference Canario, Lundgren, Haandlykken and Rydhmer2010).

Secondly, both piglet vitality and maternal behavioral characteristics have often been neglected in conventional breeds, because of the confined, controlled farrowing and lactation environments which are aimed at prevention of mortality, e.g. the use of heating areas for piglets and the use of farrowing crates that prevent mortality owing to crushing (DEFRA, 2002). Indeed, preweaning mortality rates are substantially lower in indoor systems compared with outdoor systems (Sabbioni et al., Reference Sabbioni, Beretti, Zanon, Superchi, Manini and Cervi2007; Wallenbeck, Gustafson and Rydhmer, Reference Wallenbeck, Gustafson and Rydhmer2009; Leenhouwers et al., Reference Leenhouwers, Ten Napel, Hanenberg and Merks2011). In organic and low-input systems, good maternal abilities and high piglet vitality are obviously crucial for piglet survival, because sows are housed loose in the farrowing pen, which makes piglets more at risk to be crushed by the sow (Honeyman and Roush, Reference Honeyman and Roush2002; Wallenbeck, Gustafson and Rydhmer, Reference Wallenbeck, Gustafson and Rydhmer2009) and less possibilities of herdsmen to supervise and care for piglets in a group-housed and outdoor lactation environment (Wallenbeck, Gustafson and Rydhmer, Reference Wallenbeck, Gustafson and Rydhmer2009).

Thirdly, in organic and low-input systems, lactation feeds of lower protein quality and higher roughage content are used. Conventional sows may be less adapted to these diets (Kelly et al., Reference Kelly, Browning, Day, Martins, Pearce, Stopes and Edwards2007), which may lead to problems with milk production and consequently mortality of liveborn piglets owing to starvation.

For traditional breeds, there was high between-breed variation in reproductive performance. In Great Britain and Germany, some prolific traditional breeds, such as German and British Saddlebacks, wean similar numbers of piglets (9–10) as conventional breeds, e.g. Landrace × Large White × Duroc crosses and German Edelschwein × Landrace crosses. British Saddlebacks originally are a hybrid cross of Essex and Wessex Saddleback breeds. Especially the Wessex was noted for its high prolificacy (Alderson, Reference Alderson2007). Saddlebacks often are mated with white conventional breeds to produce blue crossbred sows for outdoor systems and were selected by major breeding companies as one of the parents of commercial hybrid breeding sows (e.g. Camborough) because of their grazing ability, temperament, maternal qualities and the level of fatness which serves as a buffer against outdoor conditions (Alderson, Reference Alderson2007).

In Eastern Europe, the Polish Pulawska breed actually weans more piglets per litter than the Landrace and Landrace × Large White crosses used in this region. Pulawska is an indigenous breed from Eastern Poland and originally was a cross between primitive local pigs and Berkshire boars. Later on, English Large White has been used to upgrade the Pulawska breed. Pulawska has a spotted coat pattern and its utilization is between a meat and fat-meat pig (Elbarn, 2010). Traditional breeds used for special meat production, for example French breeds such as Nustrale, Basque and Gascon, the Hungarian Mangalitza, the Spanish Iberian pig and the local Italian breeds Mora Romagnola and Cinta Senese, typically have low reproductive performance because these breeds are generally unimproved in fertility traits (Egerszegi et al., Reference Egerszegi, Rátky, Solti and Brüssow2003).

Finishing performance

In general, conventional breeds such as German Edelschwein and German Landrace grew faster and more efficiently than traditional breeds. However, some traditional breeds such as German and British Saddleback and Swabian-Hall achieved similar growth rates than commercial hybrids developed by breeding companies. Additionally, carcasses of the majority of conventional breeds were leaner than carcasses of traditional breeds. These results confirm the effects of genetic selection in conventional breeds on daily gain, feed conversion ratio and lean meat percentage (Blair, Reference Blair and Blair2007; Brandt et al., Reference Brandt, Werner, Baulain, Brade and Weissmann2010). In contrast, in traditional breeds such as Ibérica, focus has been more on meat quality characteristics (e.g. drip loss, marbling, colour and structure). Extra added value is obtained through specific nutritional and taste characteristics of special meat products such as hams, salamis and other cured products. In this way, the low reproductive and finishing performance of these breeds is offset by price premiums of the pigs produced.

General suitability of breeds

Taken together, the suitability of traditional versus conventional breeds for low-input and organic production systems depends on finding a balance between productivity, suitability to outdoor conditions and market suitability (Compendium of Animal Health & Welfare in Organic Farming, 2000). The traits important for a good outdoor sow are: prolificacy, good maternal instincts, good fat reserves to provide both protection against weather and energy reserves for an active outdoor life, and independence combined with ease of handling (Blair, Reference Blair and Blair2007).

Results from this review show that conventional breeds wean many piglets, have efficient and fast growth and lean carcasses. These conventional breeds may thrive well in North West European climatic conditions where summers are warm, but not hot, and winters are cool instead of cold. Optimal housing may be indoors with outdoor runs, as currently predominantly used in countries such as Denmark, Germany, Sweden and The Netherlands. This provides a more controlled environment in which large litters are more easily managed and in combination with balanced formulated feeds, high lean growth rates can be sustained. The relatively lean meat of conventional breeds is suitable for sales through key wholesale outlets serving the commodity organic pork market. Together with the use of conventional breeds in organic and low-input systems, a suitable breeding strategy should be chosen to provide farmers with adequate replacement gilts. For the Dutch organic pig sector, Leenhouwers et al. (Reference Leenhouwers, Ten Napel, Hanenberg and Merks2011) proposed a two-breed rotation system where animals from conventional Yorkshire and Landrace sow lines with the highest genetic merit for desirable traits (e.g. mothering ability, piglet vitality, sow longevity) for organic pig production are selected. Conventional breeds may be less suitable in more free-range extensive environments as found in Eastern and Southern Europe, where large litter sizes pose a risk for piglet mortality. Also the climatic conditions in these regions may be unfavourable. In cold winters, their lack of carcass fat gives them poor protection against cold and in hot summers their white skin pigment makes them sensitive for sunburn.

Traditional breeds roughly fall into two categories: (1) a group of prolific breeds with good finishing performance such as Saddlebacks and Pulawska and (2) breeds kept for special meat production (e.g. Ibérico, Cinta Senese). The prolific and leaner traditional breeds belonging to the first group are suitable for commodity organic pork production, especially when crossed with conventional white boar breeds (e.g. Large White, Landrace or Duroc) to give some extra leanness to the carcass. Special meat breeds are unsuitable for commodity organic pork production because of their low fertility and high carcass fatness, but extra added value is obtained by their specific meat and fat quality. Moreover, their black skin pigment makes them well adapted to be reared outdoors in hot climates as found in Southern European regions.