No abstract

BACKGROUND: There is a need for information on the performance and carcass quality of pigs under different organic management systems. This study compared Duroc-sired progeny from three maternal breed types when kept either at pasture or in housing with an outdoor run and offered ad libitum concentrate either alone or with fodder beet or grass/clover silage as additional forage.

The welfare of early-weaned pigs in different housing systems was examined using a range of indicators. Three replicates of 20 pigs were weaned at 6·4 kg live weight into either: (a) deep-straw; (b) Straw-Flow®; (c) large flatdeck; (d) small flatdeck. A kenneled lying area was provided in (a) and (b). The floor in (c) and (d) was expanded metal. Stocking densities were 0·23 m2 per pig in (a), (b) and (c) and 0·17 m2 per pig in (d). After 4 to 5 weeks (19·6 kg live weight), 16 pigs from each pen were moved into Straw-Flow grower pens (0·68 m2 per pig) and observed until slaughter at 90·6 kg. The remaining pigs were grouped together to examine the effects of mixing. At weaning, 24·1% of pigs had foot injuries. Pigs with foot injuries recovered quickly on deep-straw but the injuries increased in flatdecks immediately after weaning (Straw-Flow was intermediate). Injuries were more persistent in the small flatdeck. Deep-straw prevented adventitious bursitis of the hock. After 1 month in the grower pens, there was no residual treatment effect. Antibody response was examined by immune challenge with keyhole limpet haemocyanin (KLH). Immunoglobulin (Ig) response was greater in straw pens. Pigs mixed at 20 kg showed a decreased immune response to KLH challenge. Growth and food intake showed no treatment effects; food conversion ratio was poorer in (c) than in (b) or (d).

Standards for organic pig production recommend that growing pigs are maintained on pasture. There is currently no information on the nutritional implications of such a system, since grazing intakes have not been recorded in pigs of this production stage. This study used n-alkane methodology previously validated in sows (Wilsonet al., 1999) to measure the herbage intakes of individual pigs under such conditions.

Organic farming is based on the premise that animal welfare is safeguarded primarily through good management; only when this fails are veterinary medicines used to intervene. As this premise is frequently quoted in marketing strategies, there is a need to assess the efficacy of this approach to reassure consumers. To move towards this assessment, a survey was conducted between August 1999 and April 2002 on nine organic pig farms located predominantly in the South West of England. This combined direct measurements of animals and facilities with structured questions to staff. The mean herd size (± standard error of mean) was 212 ± 74 sows, with all progeny being reared outdoors from farrowing to finish. The herds had been in existence for an average of 37 ± 7.0 months. Mange and lice were the highest-ranking current health concerns, and post-mortem report of endoparasitism was the highest-ranking historical health concern chosen by producers from a list pre-written by the experimenters. The main welfare issues reported by the primary stockperson were related to keeping stock clean and dry during periods of high rainfall, managing porcine dermatitis and nephropathy syndrome (PDNS) and postweaning multisystemic wasting syndrome (PMWS) within their herd, and recruiting and retaining good quality personnel. Facility assessment indicated good living conditions, with the exception of some wet paddocks during winter. Sow condition scores were not significantly different from accepted target values during pregnancy, at farrowing, or at weaning. Levels of lameness, skin damage and cleanliness did not cause concern in any class of stock.