Higher preweaning mortality in free farrowing pens compared with farrowing crates in three commercial pig farms

Abstract

If loose-housed farrowing systems are to be an alternative to traditional farrowing crates, it is important that they can deliver the same production results as can be achieved in farrowing crates under commercial conditions. The aim of this study was to compare preweaning mortality in farrowing crates and free farrowing pens (FF-pens) within herds that had both systems. The study was conducted over 2 years in three commercial Danish herds that had FF-pens as well as traditional farrowing crates in their farrowing unit. Piglet mortality was analysed in two periods: before litter equalisation and after litter equalisation. Linear models were used to analyse effects of housing (crate or pen), herd (Herd A, B or C), parity (parities 1, 2, 3 to 4 or 5 to 8) as well as the effect of number of total born piglets on mortality before litter equalisation, and the effect of equalised litter size on piglet mortality after litter equalisation. All corresponding interactions were included in the models. Before litter equalisation piglet mortality was higher ( P < 0.001) in pens (13.7%) than in crates (11.8%). Similarly, piglet mortality after litter equalisation was higher in pens than in crates in all three herds, but the difference between pens and crates were dissimilar ( P < 0.05) in the different herds. In addition, piglet mortality, both before ( P < 0.001) and after litter equalisation ( P < 0.001), grew with increasing parity of the sows. Mortality before litter equalisation moreover increased with increasing number of total born piglets per litter ( P < 0.001), and mortality after equalisation increased when equalised litter size increased ( P < 0.001). No significant interactions were detected between housing and parity or housing and litter size for any of the analysed variables. In conclusion, there is knowledge how to design pens for free farrowing; but this study showed a higher preweaning mortality in the FF-pen. Nonetheless a noteworthy proportion of the sows in the FF-pens delivered results comparable to those farrowing in crates. This indicates that FF-pens are not yet a robust type of housing for farrowing sows.

Confinement of sows for different periods during lactation: effects on behaviour and lesions of sows and performance of piglets

“…Using similar farrowing pens with integrated crates as used in this study, Moustsen et al (2013) observed a higher piglet mortality rate in pens where sows were loose-housed throughout the whole lactation period than in those that were crated during the first 4 or 7 days pp; suggesting that crating for just 4 days pp is sufficient to avoid unnecessary crushings. Comparing farrowing crates with free farrowing pens, Hales et al (2014) found greater mortality rates in pens than in crates, even though pen sizes were, at 5.3 to 6.3 m 2 , considerably larger than in this as well as the aforementioned study. Contrarily, Weber et al (2007) found similar mortality rates in crates and loose-farrowing systems;…”

“…In fact, this farrowing system was developed for intensive production systems, in which the abrupt change from continuous confinement as practiced at the moment to free farrowing is not an option; mainly due to increased management requirements. Even under optimized management regimen excessive piglet mortality might arise (Hales et al, 2014) and this limits the implementation of free farrowing pens in the field. Given the compromise between the ability of the sow to express its natural behaviour and the consequences this might have on the piglets in terms of crushings, the pen under study is able to provide the sow with a certain additional area to move and turn around, but not to the same extent as several of the recently developed free farrowing pens exceeding sizes of 5 m 2 (Weber et al, 2007;Hales et al, 2014).…”

“…Even under optimized management regimen excessive piglet mortality might arise (Hales et al, 2014) and this limits the implementation of free farrowing pens in the field. Given the compromise between the ability of the sow to express its natural behaviour and the consequences this might have on the piglets in terms of crushings, the pen under study is able to provide the sow with a certain additional area to move and turn around, but not to the same extent as several of the recently developed free farrowing pens exceeding sizes of 5 m 2 (Weber et al, 2007;Hales et al, 2014). Nevertheless, the sow had twice the space allowance (2.8 m 2 ) when the crate was opened compared to the closed crate in our study.…”

“…However, the Lambertz, Petig, Elkmann and Gauly optimal space allowance for sows in loose housing pens is still unknown and effects on piglet mortality in relation to the pen size and dimensions are warranted to be evaluated. In order to avoid excessive piglet crushings the crates were opened in the present study at 7 or 14 days pp as other previous studies identified the first week pp as the most important period in terms of piglet crushings Hales et al, 2014). …”

“…Nevertheless, crating for at least the first 4 days postpartum (pp) seems to be necessary ; otherwise piglet crushing might be detrimental (Hales et al, 2014). In the study of Baumgartner et al (2007), loosehoused sows tended to be more active than crated ones, whereas weaning weights were not affected.…”