A ‘two-stage’ farrowing and lactation system: piglet survival and growth performance

Loose farrowing systems that meet the biological maternal needs of the sow have been developed (i.e. the PigSAFE system), and minimum pen design criteria for loose farrowing systems have been recommended based on behavioural needs and basic body dimensions of sows and piglets (Baxter et al. 2011). However, any effective pen design requires extra floor space compared to conventional farrowing crates and, consequently, adds capital costs. An additional system is a two-stage system that maximises the throughput of sows by allowing sows to farrow loose in individual pens or farrowing crates then grouping sows and litters into a more cost effective system at approximately 2 weeks after farrowing (i.e. group lactation (GL) systems). This experiment tested the hypothesis that piglet survival and growth performance would be the same in farrowing crates, PigSAFE and a ‘two-stage’ farrowing and group lactation system.

A total of 360 mixed-parity sows (Large White x Landrace, PrimeGro™ Genetics) over six time replicates was studied. Sows were randomly allocated to one of four treatment groups: 1) Farrowing crates (FC): sows housed in farrowing crates until weaning; 2) GL_FC: sows housed in farrowing crates then moved into GL 14 days before weaning; 3) PigSAFE (PS): sows housed in the PigSAFE loose farrowing system until weaning; and 4) GL_PS: sows housed in the PigSAFE system then moved to GL 14 days before weaning. The housing treatments were located in three adjacent buildings, all similar in terms of ventilation and construction material. The buildings were open-sided with shutters and heating which enabled temperature control. All sheds were managed by the same stockpeople. The experiment began in March and finished in November 2014. The total number of piglets born (born alive, still born and mummified piglets), number of piglet deaths and number weaned were recorded for each litter. Piglet live born mortality (%) (from birth to weaning) was calculated for each litter. Individual live weight of piglets was recorded at birth, 14 days before weaning and at weaning (25 ± 2.7 days; mean ± SD). Univariate GLM analysis (IBM SPSS, Version 21.0; USA) was undertaken using each sow/litter at the start as the experimental unit with replicate as a random factor in the design.

There was no difference (P > 0.05) in the number of piglets born alive or number weaned between housing treatments (Table 1). There was however a trend for higher live born mortality in the PS systems compared to FC systems (P = 0.094). Piglets in the GL_FC and GL_PS housing treatments had a lower (P < 0.001) rate of gain in the GL period compared to piglets that remained in the FC and PS housing treatments, which may be attributed to increased socialisation, piglet activity and cross-suckling. The outcomes from this study support the need for further development of loose farrowing systems for Australian conditions and suggest piglet growth performance may be reduced in group lactation systems. Further research is warranted to determine the impact of the GL system on post-weaning and lifetime performance of these piglets.

Table 1.  Piglet survival and average daily gain (ADG) from birth to weaning, and from mixing to weaning, in the different housing treatments