Review: Concrete outdoor runs for organic growing-finishing pigs - a legislative, ethological and environmental perspective.

Concrete Outdoor Runs (OUTRUNs) are a characteristic part of organic pig housing. They must allow species-specific behaviours such as rooting and elimination, as explicitly required by organic legislation of the European Union (EU). However, OUTRUN design often fails to fulfil behavioural needs, and excreta can cover large parts of the OUTRUN leading to poor pen hygiene and associated ammonia (NH3) emissions. This review integrates legislative, ethological and environmental requirements for OUTRUNs for organic growing-finishing pigs. While EU regulations specify some welfare-related standards for OUTRUNs (e.g. minimal space allowance), national and private standards interpret some aspects differently, e.g. the proportion of roofed and slatted floor area. Furthermore, reducing NH3 emissions is equally a challenge for organic systems, even though EU legislation does not explicitly refer to OUTRUNs. Depending on the actual use of the OUTRUN for elimination, higher space allowance compared to conventional production norms increases the potential for a large NH3-emitting surface. The design of pen features (e.g. roof, floor, enrichment) can encourage pigs to separate functional areas and consequently reduce the elimination area and associated NH3 emissions. While providing the main lying area indoors, resting outdoors should be possible for sub-groups during the day. A roof protects pigs and resources (e.g. bedding) from adverse weather, but the effect on pig welfare and NH3 emissions is site-specific. A floor design that ensures practicable manure removal and drainage is most important to reduce emissions. Providing opportunities for exploring and rooting in the OUTRUN has particular relevance for pigs' behavioural needs and can improve pen hygiene by reducing the elimination area. Cooling facilities are increasingly important to prevent heat stress and its detrimental effects on welfare and pen hygiene. Finally, practicability for farmers needs to be ensured for all resources provided in OUTRUNs, as good management is crucial. Research gaps emerge regarding the association between soiling and NH3 and the influence of certain pen features (shape, roof, feeder location, pen partitions and wet areas) on pig behaviour and soiling.

Farm and management characteristics associated with boar taint.

Pig farms in the Netherlands producing boars have different levels of boar taint prevalence, as assessed by sensory evaluation with the human nose at the slaughter line. With a questionnaire to 152 Dutch pig producers (response rate 59%), farm and management characteristics were identified that are potentially associated with farm-level boar taint prevalence. Lower farm-level boar taint prevalence was associated with a smaller group size, a smaller pen surface per boar, newer housing equipment, not practicing restricted feeding in the last period before delivery, a longer fasting period before slaughter, a higher stocking weight and a lower fraction of boars from purebred dam line sows or from Pietrain terminal boars. These characteristics can be used to develop farm-level intervention strategies to control boar taint. More research effort is needed to establish causal relationships.

Field research on veterinary problems in group-housed sows--a survey of lameness.

Investigations on two experimental farms with group-housing revealed that lameness occurred mainly at the hind legs of sows, with a higher incidence in first parity sows. The highest incidence of lameness was seen during the first 2 months of gestation and the highest prevalence in the last 2 months of gestation. No relation could be established between lameness of a sow in the last month of gestation and reproduction results. The incidence of claw lesions increased too, during the group-housing during pregnancy and was higher compared to sows kept in crates. This increase was clearest in first parity sows. In addition the observations suggest a pattern in the course of development of lesions. Claw lesions mainly occur on the outer claws of a sow. For two types of lesions left-right symmetry has been established for both the hind and the front legs. On the level of the individual animal there was no relation between the incidence of claw lesions and lameness.

Evaluation of housing systems for sows.

Housing systems of sows have to meet the requirements of the sow and the requirements of the producer. Criteria that have to be taken into account are productivity, labor input and management, welfare and health, and economy. Different housing systems for sows are described with respect to these criteria.

Review of health problems in group-housed sows, with special emphasis on lameness.

In the Netherlands, there is a trend towards housing gestating sows in groups. Vulva biting and lameness have been described as major health problems in group-housed sows. Besides these problems, the effects of group housing on morbidity, reproduction parameters and the occurrence of infectious disease have been investigated. The literature is reviewed, with special emphasis on lameness.