Effects of Space Allocation and Parity on Group-housed Gestating Sows25 May 2015
At the stocking densities used in this Australian study, stocking density, parity and space allocation had minimal effects on commonly-used welfare measures although the older sows had larger litters when the had more space.
The effects of parity and space allocation on reproduction and selected measures of welfare in female pigs have been investigated by Alexandra Whittaker of the University of Adelaide in Australia and co-authors there and at the South Australian Research and Development Institute.
In their paper in Livestock Production Science, they explain that the space allocations they used were within normal production ranges and include 1.4 and 2.8 square metres per animal, yet they found that improved reproduction was seen in older parity sows with increased space allowance.
The researchers had selected animals that were at first parity or parity three or greater.
Welfare outcome measures included: injury and lameness scores, plasma cortisol levels, neutrophil:lymphocyte ratios and reproductive performance. These values were recorded at a range of timepoints in the first 24 hours after mixing, and at 28 days after mixing.
In general, there were few significant effects of space allowance and parity level on the measured outcomes. However, improved reproduction, as evidenced by increased litter size and born alive figures, was seen as a result of increased space allowance in older animals.
A contrary response was observed in gilts.
Cortisol responses also indicated that there was a rapid habituation to the stress of mixing with levels returning to baseline within 24 hours. Cortisol levels remained low in older animals but unexpectedly showed a peak at 28 days in gilts. The researchers postulated that this may have arisen as a result of handling events associated with pregnancy testing.
At the chosen stocking densities, parity and space allocation have minimal effect on a number of commonly-used welfare measures, Whittaker and co-authors concluded.
Whittaker A.L., K.J. Plush, R. Terry, P.E. Hughes, D.J. Kennaway and W.H.E.J. van Wettere. 2015. Effects of space allocation and parity on selected physiological and behavioural measures of well-being and reproductive performance in group-housed gestating sows. Livestock Science. 176:161-165.
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