Impact of farrowing crate enrichment strategies on the welfare and performance of sows, suckling piglets, and post-weaned piglets

Abstract

In conventional pig production, lactating sows are typically housed in farrowing crates that restrict movement and environmental engagement, raising welfare concerns. Farrowing pens also lack behavioral stimulation for suckling piglets, hindering species-specific behaviors. Environmental enrichment may improve welfare by redirecting behaviors-such as chewing-away from conspecifics in piglets and pen fixtures in sows. However, few studies have explored its effects in farrowing crates, particularly regarding optimal placement within these spatial constraints. This study evaluated the impacts of enrichment strategies on the welfare and performance of 37 lactating sows and their litters from birth through early post-weaning. Sows and litters were divided into three groups: both had access to enrichments (SPE), only piglets had access (PE), and a control group with no enrichments (CON). Point-source objects (PorkyPlays and wooden blocks on rope) were placed 2 d after sows moved into farrowing crates until 2 wk post-weaning. Sow salivary cortisol was collected at four timepoints, and pressure sores were assessed at 8 timepoints from 24 h after crate entry to weaning. Piglet tear stains and skin lesions were recorded throughout the lactation phase. Suckling piglet average daily gain (ADG) was analyzed at days 1 to 7, 7 to 14, and 14 to weaning. In the nursery, salivary cortisol, tear stains, and skin lesions were measured on days 1, 7, and 14 post-weaning, with an additional cortisol sample at day 0 post-weaning. Nursery piglet ADG was analyzed from weaning to day 14 post-weaning. CON sows were more likely to have a pressure sore compared to SPE sows (P = 0.02); PE sows tended to have a higher likelihood of developing a pressure sore than SPE sows (P = 0.097). No treatment effect was found for salivary cortisol of sows or nursery piglets. However, CON piglets had the largest tear stains during lactation (P < 0.001) and nursery (P = 0.001). Treatment affected piglet skin lesions during lactation, with CON piglets having more ear (P < 0.001) and front (P = 0.002) lesions and a higher overall lesion score (P < 0.0001). No treatment effect was found for ADG, piglet crushing, or nursery skin lesions. In conclusion, enrichment strategies in farrowing crates improved piglet skin health and tear stains without affecting performance. Enrichment access for sows tended to reduce pressure sores, suggesting enrichments can enhance welfare in farrowing crate systems.

Keywords: environmental enrichment; farrowing crates; pig welfare; skin lesions; tear stains.

Figure 1.

Depiction of each treatment group in the lactation phase. (A) SPE = both sow and piglets enriched; both enrichments shown were placed on either side of the farrowing crate, (B) PE = Only piglets enriched, and (C) CON = no enrichments, control.

Figure 2.

The two types of enrichments used in the study. (Left) PorkyPlay and (Right) wooden blocks hung by sisal rope.

Figure 3.

Depiction of each treatment group in the nursery phase. (A) SPE = both sow and piglets enriched or PE = Only piglets enriched and (B) CON = control, no enrichments.

Figure 4.

Schematic representation of the study timeline. ¹Sow; ²Suckling piglets; ³Nursery piglets.

Figure 5.

Photograph of a piglet with tear stain.

Figure 6.

Tear stain area (cm²; LS means ± SE) of (A) suckling piglets in CON (no enrichment), PE (only piglets enriched), and SPE (both sow and piglets enriched) treatment groups averaged across days 1, 4, 7, 10, 14, and 17 after birth (P = 0.0002); (B) suckling piglets on days 1, 4, 7, 10, 14, and 17 after birth (P < 0.0001); (C) nursery piglets in CON (n = 13 pens, 51 piglets), PE (n = 12 pens, 48 piglets), and SPE (n = 12 pens, 48 piglets) groups averaged across day 1, 7, and 14 post-weaning (P < 0.01); and (D) nursery piglets on days 1, 7, and 14 post-weaning (P < 0.001). ^a,bWithin each graph, LS means without a common superscript differed due to treatment or age.