[email protected] [email protected] Many Thanks To: RESULTS & DISCUSSION 1Animal Sciences Unit, ILVO, Merelbeke-Melle, Belgium 2Department of Veterinary and Biosciences, Faculty of Veterinary Medicine, Ghent University, Merelbeke-Melle, Belgium 3Animals in Science and Society, Department Population Health Sciences, Faculty of Veterinary Medicine, Utrecht University, Utrecht, Netherlands 4Campbell Centre for the Study of Animal Welfare, Department of Animal Biosciences, Ontario Agricultural College, University of Guelph, Guelph, Ontario, Canada Barn climate advice and pig tear staining: preliminary insights into an emerging welfare indicator van Langeveld, Kenny1,2; van Staaveren, Nienke3,4; Van Noten, Noémie1; Rodenburg, Bas3; Tuyttens, Frank1,2 References STUDY DESIGN Fig. 2: tagged Visual Analogue Scale (tVAS) for Tear Staining, adapted from the discrete DeBoer-Marchand-Forde scale [1]. (Images from [1, 5] SlaughterStart +/- 90 days +/- 2 weeks after set-up +/- week before slaughter Fig. 1: Graphical overview of a Finisher round (+/- 25 kg till slaughter weight), highlighting when measurements took place. 5 Dutch farms – Beter Leven 1 ster label 1 finisher unit/farm; each with climate sensor (Slimme Stal, Connecting Agri&Food) Measures: T° (°C), RH (%), CO₂, NH₃ (ppm); + outdoor data (nearest weather station) ‘Crossover design with two rounds (Advice (ADV) vs. Control (CON)): Farms blocked by start month (RND 1) Randomized treatments/block (RND1); Swapped in RND 2 Treatments: ADV: Barn climate advice by an expert CON: no interventions WELFARE MEASUREMENTS (2x/round, Fig. 1) Sampling: up to 5 pens/unit, and max. 15 animals/pen TS (Fig. 2), TB, and lameness were scored using a tVAS (adapted from [1], [2], and [4]). Skin lesions were counted and summed following WQ® [6] Tear Staining Both Eyes (tVAS) Lesions Tail Biting (TB) (tVAS) 1. DeBoer et al. (2015). Isolation and enrichment effects on pig welfare: tear staining and behavior. Anim Welfare, 24, 15-27. 2. DSBS (2017). Deutscher Schweine-Boniturschlüssel (DSBS). [Online] 3. Larsen et al. (2019). Tear staining in finisher pigs and pen-level stressors. animal, 13, 1704-11. 4. Nielsen et al. (2001). Mycoplasma hyosynoviae arthritis in pigs. J Vet Med A, 48, 475-86. 5. Telkänranta et al. (2016). Tear staining as a welfare tool on commercial pig farms. animal, 10, 318-25. 6. Welfare Quality® (2009). Welfare assessment protocol for pigs. Lelystad, NL. Fig. 3: Effect of ADV vs. CON on changes in tear staining (TS) between visits. Colored points and error bars show treatment means ± 95% CI, while grey dots represent individual pen-level observations across all farms and visits. Data: 5 units, 2 rounds; 2–5 pens/unit (21 pens/round). a b c Fig. 4: Effects of ADV vs. CON on air quality and correlations among environmental indicators at the unit level (5 units, two rounds). With: a–b. Mean hours with elevated NH₃ (>20 ppm) and CO₂ (>2000 ppm) concentrations for CON and ADV. Bars show group means ± 95% confidence intervals.; c. Correlation matrix of climate-related variables (Spearman’s ρcorrelation coefficients). EFFECT OF BARN CLIMATE ADVICE ON ΔTS Linear Mixed Modelling (LMM): ΔTS (Left and Right) ~ Treatment (fixed) and Pens|Units (random) RESULTS: No significant effect of Treatment on ΔTS (both eyes, P > 0,05; Fig. 3) Models Output Variation: High between-pens & -farms + large residual (unexplained) variance Other factors play a role in the development of TS. Climate parameters? → See below Welfare Indicators? → See R&D Continued R&D CONTINUED b a Fig. 5: Visual representation of the effect size between change in welfare indicators and TS at pen level (5 units, 21 pens/round in total) (a), and intercorrelations amongst them (Spearman’s ρcorrelation coefficients; excluding TS) (b). Data: 5 units, 2 rounds; 2–5 pens/unit (21 pens/round). EFFECT OF BARN CLIMATE ADVICE ON THE CHANGE IN TS LMM: ΔTS (Left and Right) ~ Welfare Indicator (fixed)+ Treatment (fixed) + Pens|Units (random) RESULTS: Change in Ear Lesions is positively associated with change in Left ΔTS + Change in Lameness is positively associated with Right ΔTS (Fig. 5a) Models Output Variation: High between-pens & -farms + large residual (unexplained) variance Several (environmental) factors may jointly affect ΔTS and explain the above-mentioned levels of variation TS AS A WELFARE INDICATOR Literature: Ear/tail lesions linked to ΔTS + Speculation for lateralization effects (Left side > Welfare relevance) [1,3,5] This study: Ear lesions associated with Left ΔTS → likely reflects total lesion burden (strong intercorrelation; Fig. 5b) No strong evidence for lateralization → Both eye sides associated with Welfare Indicators TS has potential as a Welfare Indicator, but more research is needed towards its robustness, differences between eyesides, the interplay of several factors on ΔTS, etc. HOWEVER: TREATMENT DID AFFECT BARN CLIMATE LMM: Climate parameter ~ Treatment (fixed) + Units (random) RESULTS: CON exhibited, on average, more hours of elevated CO2 (>2000 ppm) and NH3 levels (>20ppm) (Fig. 4a and 4b) Neg. Intercorrelation CO2 (Fig. 4c) → Likely linked to reduced ventilation in colder periods (heat retention) CLIMATE VARIABLES AS PREDICTORS FOR TS LMM: ΔTS (Left and Right) ~ Climate Paramter (fixed)+ Treatment (fixed) + Pens|Units (random) RESULTS: No significant effect of Climate Parameters on ΔTS (both eyes, P > 0,05) CONCLUSIONS Barn Climate Advice improved Barn Climate → did not impact Tear Staining TS seems to have potential as a Welfare Indicator → association with other welfare indicators Preliminary analysis on a limited dataset: Within Larger study (10 farms, 2 rounds) where the relation between Barn Climate (Advice) and Animal welfare is assessed. INTRO TEAR STAINING (TS) IN PIGS Brown-red porphyrin-based stains under the eye corner (produced by Harderian gland) [1] PAST: linked to atrophic rhinitis and bad barn climate [1] LAST DECADE: TS could reflect multiple environmental stressors, beyond just barn climate Such as social isolation, aggression, … [1, 3, 5] RESEARCH QUESTIONS Is a change in TS affected by bad barn climate? Is TS a useful welfare indicator in pigs?
