The objective of this study was to assess the effects of the season, travel duration and trailer compartment location on blood creatine-kinase (CK), lactate and cortisol concentrations in 384 pigs and assess their relationships with trailer temperature, heart rate and gastrointestinal tract temperature (GTT), behavior, carcass damage scores and meat quality. Blood CK was greater in pigs transported in summer (p = 0.02), after 18 h transportation (p < 0.001) and in pigs located in C4, C5 and C10 (p = 0.002). In winter, the concentration of blood lactate was higher (p = 0.04) in pigs transported for 6 h in C5. Pigs located in C10 showed higher (p = 0.01) concentration of cortisol than those transported for 18h in C4 in summer. The highest correlations were between blood cortisol and GTT (r = 0.53; p < 0.001), and between blood CK and GTT (r = 0.41; p < 0.001), truck temperature (r = 0.42; p < 0.001), and pH_u in the longissimus muscle (r = 0.41; p < 0.001). In conclusion, although increased blood cortisol and CK levels appear to indicate a physical stress condition in transported pigs, the weak to moderate correlations with environmental and other animal welfare indicators suggest that blood stress parameters can only be used as a complementary measurement in the assessment of the pigs’ response to transport stress.

The goal of this study was to identify practical enrichments for sows in partially or fully slatted pen systems. Four treatments were applied: (1) Constant: constant provision of wood on chain; (2) Rotate: rotation of rope, straw and wood enrichments; (3) Stimulus: rotation of enrichments (as in Rotate) with an associative stimulus (bell or whistle); and (4) Control: no enrichment, with each treatment lasting 12 days. Six groups of 20 ± 2 sows were studied from weeks 6 to 14 of gestation in pens with one electronic sow feeder. Each group received all treatments in random order. Six focal animals (3 dominant and 3 subordinate) were selected per pen using a feed competition test. Digital photos were collected at 10 min intervals for 8 h (between 8 a.m. and 4 p.m.) on 4 days/treatment (d 1, 8, 10 and 12) to record interactions with enrichment. Skin lesions were assessed on days 1 and 12, and saliva cortisol samples collected in weeks 6, 10 and 14 of gestation on focal pigs. Sows spent more time in contact with enrichments in Rotate and Stimulus treatments than Constant. Enrichment treatments did not influence lesion scores. Subordinate sows spent more time standing and near enrichments than dominants. Subordinate sows also received more skin lesions and had higher salivary cortisol concentrations than dominants. These results indicate that access to enrichment is valued by sows but can result in greater aggression directed towards subordinates.

Positive emotions can reduce disease susceptibility during infectious challenges in humans, and emerging evidence suggests similar effects in farm animals. Because play behaviour may support a positive emotional state in pigs, this study investigates whether rearing pigs with regular intermittent play opportunities enhances disease resilience when challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Litters were assigned to either play (PLY; n = 5 L) or control (CON; n = 4 L) treatments at birth. In PLY, play was promoted with extra space and enrichment items for three hours daily from five days of age (doa). At weaning (25 ± 2 doa; mean ± SD), 28 pigs (14/treatment) were selected for a disease challenge, based on weight, sex, and sow. The pigs were transported to a disease containment facility and at 43 ± 2 doa (day 0 post-inoculation, DPI) inoculated with PRRSV. Skin lesions, blood, rectal temperature, clinical signs, body weight, and behaviour were collected pre- and post-inoculation. Play opportunities for PLY continued every other day until euthanasia of all pigs at 65 ± 2 doa (22 DPI). PLY pigs exhibited fewer skin lesions following transport and throughout the infection compared to CON. Although the viral load did not differ between treatments, PLY pigs had a lower probability of experiencing moderate and severe respiratory distress, with a shorter duration. PLY also performed better throughout the infection, showing higher ADG and greater feed efficiency. The immune response differed as well. PLY pigs had fewer monocytes on 8 DPI than CON, with levels returning to baseline by 21 DPI, whereas CON levels exceeded baseline. Regardless of day of infection, lymphocyte counts tended to be lower in PLY than in CON, and white blood cells and neutrophils were also lower, but only in slow-growing pigs. PLY pigs continued to play during the infection, demonstrating less sickness behaviour and emphasizing the rewarding properties of play. Results suggest that PLY pigs were less affected by PRRSV and developed increased resilience to PRRSV compared to CON. This study demonstrates that rearing pigs in an environment supporting positive experiences through provision of play opportunities can enhance resilience against common modern production challenges, underscoring the value of positive welfare in intensive pig farming.

A novel behavioural test using a handling chute was evaluated over two trials as an objective method to assess pain in piglets following castration. Piglet (n = 98) navigation time (NT) through a handling chute was measured at specific time points up to 24 h post treatment. In trial 1, comparing the NT of castrates (C) and sham castrates (SC), C piglets had a longer NT than SC at 0 and 15 min post treatment (P < 0.05), with no differences thereafter. In trial 2, the effect of an analgesic to control postoperative pain on NT was examined, with castrated piglets given a half (CH) or full (CF) dose of meloxicam 1 h prior to treatment, compared with piglets castrated and given saline (CS) or sham castrated and given saline (SS). Post treatment, CS piglets had a longer NT than SS at 0 min (P < 0.005), and at 15 min, piglets CS had a longer NT than all groups (P < 0.001). No significant associations were found between piglet behaviour in the home pen and NT during the 60 min following treatment. These data demonstrate potential for the use of a handling chute to measure NT as a quick, standardized, method to assess piglet pain in response to castration.

The effect of washing procedure and contamination level on the concentrations of cortisol and dehydroepiandrosterone (DHEA) in swine hair was explored over two studies. Hair shaved from finisher pigs (n = 8) and sows (n = 8, cortisol study 1 only) was split into two treatments (two hair samples/pig) to receive either three isopropanol or methanol washes, and two paired subsamples of hair were contaminated with feces and urine, mildly or severely. Samples were further subdivided and received one, three, or five methanol washes. Hormone concentrations were quantified from the hair and wash solvent, and the ratio of hormones in the solvent to that in the hair calculated. When grouping sow and grower hair together for analysis, hair cortisol concentrations were 13% greater after three isopropanol washes compared to methanol (22.84 ± 3.12 vs. 19.77 ± 2.64 pg/mg, respectively). When analyzing sow and grower hair separately, sow hair cortisol concentrations were 20% higher following three isopropanol washes compared to methanol washes (22.06 ± 5.21 vs. 27.72 ± 5.65 pg/mg), with no differences in grower pig hair concentrations. The solvent cortisol concentrations did not differ with wash solvent. No differences were seen for DHEA. Contamination level did not influence hormone concentrations. Hair cortisol concentrations were 24% higher after one wash compared to five washes (11.98 ± 1.47 vs. 9.05 ± 0.92 pg/mg), whereas the solvent cortisol concentrations were 80% and 84% higher after one wash compared to three and five washes, respectively (21.09 ± 4.04 vs. 4.21 ± 1.62 vs. 3.36 ± 1.32 pg/mg). The solvent–hair cortisol ratio was 65% and 73% higher following one wash compared to three and five washes (1.36 ± 0.80 vs. 0.47 ± 0.12 vs. 0.37 ± 0.14). Hair DHEA concentrations were 39% higher after one wash compared to five washes (42.39 ± 6.87 vs. 26.02 ± 5.69 pg/mg). The solvent DHEA concentrations, and the solvent–hair ratio for DHEA were 94% and 98% and 92% and 98% higher going from one wash to three and five washes, respectively (solvent: 5.07 ± 0.26 vs. 0.28 ± 0.12 vs. 0.12 ± 0.09 pg/mg and solvent–hair ratio: 0.13 ± 0.006 vs. 0.010 ± 0.004 vs. 0.003 ± 0.002). Following three methanol washes, the non-contaminated hair had 46% and 48% higher hair (17.47 ± 1.12 vs. 9.35 ± 0.80 vs. 9.05 ± 1.06 pg/mg) and a 76% and 72% higher solvent (16.31 ± 8.07 vs. 3.92 ± 0.50 vs. 4.50 ± 2.31 pg/mg) cortisol concentration compared to mild and severely contaminated hair, respectively. Wash solvent influences cortisol concentrations in swine hair, but not DHEA. Contaminated swine hair should be avoided in analyses when possible.