Risk factors associated with dystocia in swine

Abstract

Background and Aim: Dystocia in swine can increase the stillbirth rate; however, its importance in pig-breeding systems has been underestimated. Until now, few studies have investigated dystocia and associated risk factors. Therefore, in this study, we aimed to evaluate the effects of various risk factors on dystocia in swine. Materials and Methods: Out of 5,557 piglets, we included 4,997 piglets in risk analysis study. The dependent variable was dystocia, which was recorded when a birth interval exceeded 45 min or when obstetric assistance was applied. The independent variables were parity, gestation length, litter size, birth order, gender, presence of a dead piglet, birthweight, crown rump length, body mass index, ponderal index, and oxytocin use. We used generalized linear mixed models to examine the associations between potential risk factors and dystocia at the piglet level. Results: A total of 6% of the piglets were born with a dystocia event, and 47.2% of the farrowing experienced at least one event. Dead piglets and piglets with a crown rump length of >31 cm were associated with an increased dystocia rate. This rate decreased from birth order 2 to 7, stabilized to 11, and then increased till the end of the fetal expulsion process. Conclusion: Dystocia is common in swine. Therefore, this condition should be carefully addressed by veterinarians and farrowing house personnel so that its adverse effect on welfare and productivity of sows and survivability of piglets can be reduced. Further studies investigating dystocia status and risk factors in different swine farrowing systems should be undertaken to provide more knowledge about this neglected condition.

Incidence of dystocia at piglet level in cloprostenol-induced farrowings and associated risk factors

“…Therefore, the incidence of dystocia at piglet level (11.0 %) and at litter level (75.3 %) in this study is expected to be similar to that in the previous study (Ward et al, 2019). Surprisingly, this study is one of few reporting the incidence of dystocia at piglet level and its associated risk factors (Nam and Sukon, 2021b). The effect of RBO on dystocia in cloprostenol-induced farrowings in the present study is similar to that in spontaneous farrowings in a previous report (Nam and Sukon, 2021b) where incidence of dystocia decreased to RBO of 50 %-60 % and increased thereafter.…”

“…However, for the purpose of investigation of risk factors for dystocia, classification results were not presented in this study, and stillbirth as a whole was used as a risk factor for dystocia. A dystocia event was recorded when a birth interval exceeded 45 min or when manual extraction of piglets was applied (Ward et al, 2019;Nam and Sukon, 2021b).…”

“…However, recent studies defining dystocia as an birth interval of more than 30-60 min have provided evidence that dystocia rate at farrowing level varies between 11.0 % and 73.6 % (Boonraungrod et al, 2018;Oliveira et al, 2020). We recently found that in spontaneous farrowings the incidence of dystocia at piglet and farrowing levels was 6.0 % and 47.2 %, respectively (Nam and Sukon, 2021b). Prolonged farrowing duration and birth interval increase stillbirth rate (Baxter et al, 2008(Baxter et al, , 2009Nam and Sukon, 2020b) and decrease viability and preweaning survivability (Edwards and Baxter, 2015).…”

“…During the farrowing process sows are in pain and in distress (Mainau et al, 2016;Navarro and Mainau, 2020). Selection of large litter size in recent decades has resulted in increased farrowing duration (van Dijk et al, 2005;Nam and Sukon, 2020a), which compromises the welfare of both sows and piglets by increasing dystocia rate (Nam and Sukon, 2021b) and stillbirth rate (Mota-Rojas et al, 2012;Nam andSukon, 2020b, 2021a). In comparison to perinatal stillbirth, dystocia is an unattractive topic because it does not directly relate to the number of piglets born alive as does the stillbirth, resulting in underestimation of this farrowing abnormality.…”

“…Several previous studies have assessed effects of various factors including litter size, gestation length, stillbirth, and birth weight on farrowing duration and birth interval (van Rens and van der Lende, 2004;van Dijk et al, 2005;Motsi et al, 2006;Nam and Sukon, 2020a). In a recent report, factors associated with dystocia in spontaneous farrowings were also documented (Nam and Sukon, 2021b). Nevertheless, studies on risk factors for dystocia, particularly in induced farrowings, are still inadequate.…”