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Evaluation of sow stall dimensions

Evaluation of sow stall dimensions. John Barnett Animal Welfare Science Centre, Department of Primary Industries, Werribee. Background . Stall housing is a controversial welfare issue for the pork industry Criticisms of individual (stall) housing of sows sows unable to exercise

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Evaluation of sow stall dimensions

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  1. Evaluation of sow stall dimensions John Barnett Animal Welfare Science Centre, Department of Primary Industries, Werribee

  2. Background • Stall housing is a controversial welfare issue for the pork industry • Criticisms of individual (stall) housing of sows • sows unable to exercise • limited social contact between sows • restriction of “naturalistic” behaviours • eg. dunging vs lying vs feeding area • 40-60%(?) of gestating sows in Australia are stall housed • ~26%(?) of Australian sows are stall housed for 15 weeks / parity • concern over long-term individual housing (15 weeks) in stalls then crates • Code of Practice (welfare) defines minimum stall dimensions: • stall width = 0.6 m • stall length = 2.0 m (“clear space”: excludes feeder and water facilities)

  3. Overseas recommendations on stalls • Stalls banned in some countries • Sweden, Norway(?), Finland (2006), Switzerland (2007), Netherlands (2008), Denmark (2014) • Restricted time in stalls • European Union - maximum of 4 weeks post-mating from 2013 • New Zealand - (recommendation only at this stage) maximum of 6 weeks post-mating from 2009 and 4 weeks post-mating from 2013 (to be reviewed in 2009) (new stalls max of 4 weeks post-mating)

  4. Cortisol concentrations in 4 housing treatments (nmol) From Barnett et al., 1991b

  5. Objectives of Project To determine: 1) the effects of stall dimensions on the welfare of sows 2) if there is a minimum time in stalls that results in improved reproduction without compromising sow welfare

  6. Experiments to: Evaluate the effects of: 1) Sow stall dimensions on welfare  2) Time in sow stalls on reproduction and welfare - commercial facility 3) Sow stall length and time in stalls on reproduction and welfare - commercial facility Student project: 4) Effects of housing in stalls and implications for forming social relationships

  7. Experiment 1 - Sow Stall Dimensions • 2 years • 4 replicates in time • 7 treatments (3 x 2 factorial) plus external, negative control • Factors examined: • Stall length (2.0 m vs 2.2 m vs 2.4 m) • Stall width (0.6 m vs 0.75 m) • External, negative control = tether stalls • Positions of treatments (banks of stalls) randomised between reps • 4 sows per bank of stalls • 2 non-experimental and 2 experimental sows • 56 experimental & 56 non-experimental sows • parities 2-6

  8. Stall width Conventional width stall (0.6 m wide) Wide stall (0.75 m wide)

  9. Stall length 2.0, 2.2 and 2.4 m long in banks of 4

  10. Tether stall - control (0.6 m wide)

  11. Measurements • 1) Sow physiology • Surgery to implant catheter in cephalic vein • at ~8 weeks into treatment • day-time profile of plasma cortisol concentrations • cortisol response to ACTH injection • cell-mediated immune response • 2) Sow lameness and live weight • measured at entry and exit from treatments

  12. Measurements • 3) Sow behaviour post-feeding & “at rest” • Video recording at ~7 weeks after entry to stalls • level of activity • social behaviour • aggression • affiliative behaviour (lying together vs apart) • angle of turn in stalls

  13. Results - cortisol concentrations Width of stall Length of stall Tether 0.6 m 0.75 m2.0 m 2.2 m 2.4 m Total cortisol conc.nMol18.4p 25.5q22.5 20.8 22.6 36.6 Free cortisol conc. nMol2.3x 3.0y2.7b 2.3a 2.9b 3.5 a,b: P<0.05; x,y: P<0.01; p,q:P<0.001 Free cortisol concentrations were lower in the 0.6 m wide stall & the 2.2 m long stall

  14. Results - response to ACTH Width of stallLength of stall Tether 0.6 m 0.75 m2.0 m 2.2 m 2.4 m Total cortisol conc. 18.4p 25.5q 22.5 20.8 22.6 26.1 pre-ACTHnMol Total cortisol conc.2.80a 3.02b2.95q 2.76p 3.02q 3.13 post-ACTH % increase(log value) a,b: P<0.05; p,q:P<0.001 In a chronic stress response the response to ACTH is increased There was a lower response to ACTH in the 0.6 m wide stall and the 2.2 m long stall

  15. Results - cell mediated immunity Width of stallLength of stall Tether 0.6 m 0.75 m 2.0 m 2.2 m 2.4 m Cell mediated immunity 108.4b 91.2a 91.1pq 119.1q 89.1p81.7 (% increase in skin thickness) a,b: P<0.05; p,q:P<0.001 The greater the % response the “better” the animal’s immune system (higher response in 0.6 m wide stall and 2.2 m(?) long stall)

  16. Results - Behaviour • Activity Post-feeding observations: • sows in 0.75 m wide stalls were • more active (86% vs 74% of time; P<0.05); and • took longer to lie down (101 min vs 86 min) • No effects of treatment on aggression

  17. Results - Affiliative behaviour (forward index) Index score of the preference of sows to occupy the same spatial alignment as their neighbours during the 2-h observation period ie. heads of neighbours at the front of the stall Width of stallLength of stall Observation period0.6 m 0.75 m 2.0 m 2.2 m 2.4 m Post-feeding-0.04 -0.23-0.16 -0.35 +0.11 Afternoon -0.53 -0.47-0.39 -0.80 -0.31 • A negative index indicates that neighbouring sows were separated. • A positive score indicates that neighbouring sows were together. • A score close to zero implies the spatial alignment between neighbouring sows was random. Sows were generally lying apart (ie. lack of head to head contact)

  18. Results - Angle of turn (post-feeding) Width of stallLength of stall Tether 0.6 m 0.75 m2.0 m 2.2 m 2.4 m Mean turn angle°38p 50q48b 42a 41a36 Mean maximum angle°47x 59y61y 50x 49x 44 a,b: P<0.05; x,y: P<0.01; p,q:P<0.001 Conventional stall width (0.6 m) Wide stall width (0.75 m) Angle of turn greater in 0.75 m wide stall and 2.0 m long stall

  19. Summary - Physiology • Welfare improved in: • 0.6 m wide compared to 0.75 m wide stalls • based on lower total and free cortisol concentrations • reduced responsiveness to ACTH • increased immunoresponsiveness • 2.2 m long stalls compared to 2.0 m long stalls • based on lower free cortisol concentrations • reduced responsiveness to ACTH • increased immunoresponsiveness (vs. 2.4 but not 2.0 m long stalls)

  20. Summary - Behaviour • Behaviour data inconclusive: • No effect on social behaviour? • wider stalls allowed sows to turn more • 2.4 m long stalls allowed more movement • how are these social behaviours perceived? eg threatening • Affiliative behaviour • generally negative scores • indicates sows preferred to be apart at front of stall

  21. Constraints • Experimental study on stall dimensions • stall divisions were horizontal bars • no positive control treatment

  22. Overall conclusions • Stall Width • improved welfare with a stall width of 0.6 m stall Length • improved welfare with a stall length of 2.2 m It is the design of the system rather than the housing system per se that is important to welfare

  23. Thanks A collaborative project between: • Animal Welfare Science Centre / Department of Primary Industries • Australian Pork Limited Thanks to: co-researchers: Greg Cronin, Paul Hemsworth technical staff: Lisa Newman, Samantha Borg, Bruce Schirmer and AWSC students at DPI Werribee

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