Risk factors for stillbirths in two swine farms in the south of Brazil

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Abstract

We evaluated stillbirth risk factors in two commercial swine farms of the Rio Grande do Sul State (south of Brazil). The study was conducted during 1 month in Farm A and during 2 months in Farm B, both during 1999. Data for all farrowings that occurred during the study period were recorded (101 for Farm A and 373 for Farm B), without interference in the farm management. In Farm A, 39% of all litters born during the period of interest had stillborn piglets and the stillborn risk for piglets was 12%. In Farm B, 25% of all litters had stillborn piglets whereas the stillborn risk was 2%. Variables considered as potential risk factors for stillbirths were: parity (1, 2–3, 4+); breed (purebred or crossbred); sow body-condition (normal or fat); use of oxytocin during parturition (yes or no); obstetric intervention through vaginal palpation (yes or no); farrowing duration (<4 or ≥4 h); mummified fetuses (yes or no); total litter size (<12 or ≥12 piglets); and litter birth weight (<11 or ≥11 kg). All stillborn piglets had their classification validated by necropsy. In multivariable logistic-regressions, the cases were the litters having at least one stillborn piglet. In Farm A, litters having at least 12 pigs and in which oxytocin was used during the parturition had 20.8-times-higher odds of stillborn occurrence. In Farm B, litters from sows having parity ≥4 had 2.2-times-higher odds of stillborn occurrence than litters from parity 2 to 3 females, litters having ≥12 pigs had 2.0-times-higher odds of a stillborn piglet than smaller litters and farrowings in which vaginal palpation was performed had 8.0-times-higher odds. Farrowing room management to minimize stillborn risk should target higher-parity females, large litters and optimization of practices of obstetric interventions.

Introduction

Stillborn piglets are those that are apparently normal but die shortly before or during the parturition (Christianson, 1992, Dial et al., 1992). The main cause of stillbirths is anoxia (English and Wilkinson, 1982, Christianson, 1992, Herpin et al., 2001), which is common in cases of dystocia. Additionally, stillbirths can be related to environment, nutrition and to sire and dam factors (Christianson, 1992).

Stillborn risks are highly variable in different countries (English and Wilkinson, 1982, Marsh et al., 1992, King and Xue, 1996), which commonly reflects differences in the sow:personnel ratio attributed to differences in labor costs (Holyoake et al., 1995). High stillborn risks are related negatively to breeding-herd efficiency, because they are associated with reduction in both the number of pigs weaned per litter and the number of pigs weaned per female per year (Wilson et al., 1986, Dial et al., 1992). Thus, identification of risk factors associated with stillbirths could help to optimize reproductive efficiency. However, risk factors for stillbirths have not been characterized clearly. Our objectives were to describe the distribution of litters having stillborn piglets and to characterize stillbirth risk factors in two commercial swine farms in Brazil.

Section snippets

Material and methods

This study was conducted in two different commercial swine farms located in the Rio Grande do Sul State, in the southern region of Brazil. In the first farm (Farm A, which had an average breeding-herd inventory of 400 females), the study was conducted during March 1999. In the second farm (Farm B, with an average breeding-herd inventory of 1050 females), the study period was September and October 1999. The difference between the study periods was because the same technicians were used in both

Results

Farm-specific parity and stillborn distributions are in Table 1 and descriptive statistics are shown in Table 2. In Farm A, 39% of the litters farrowed during the period of interest had stillborn piglets and 12% of a total of 1565 piglets born were stillborns. In Farm B, 25% of all litters farrowed had stillborn piglets and 2% of the 3997 piglets born during that period were stillborns.

Table 3 shows farm-specific frequency distributions of individual risk factors. Factors offered to the

Discussion

The stratification by farm was justified by the difference of almost 10% points between the stillborn risks observed in the two analyzed farms. According to industry benchmarks (King and Xue, 1996), the risk observed for Farm A (12%) would be considered extremely high. Stillborn risks commonly observed in Brazil are lower than those observed in other countries such as USA, Canada and Japan (King and Xue, 1996) probably as a function of the lower labor cost in Brazil.

Total litter size was the

Conclusions

High-parity females and litters having ≥12 piglets require special attention in the farrowing room due to higher stillborn risk. Practices aimed to reduce stillborn risk, such as use of oxytocin and obstetric intervention through vaginal palpation, should be conducted carefully because they can be associated with higher stillbirth risk, if used incorrectly.

Acknowledgements

This research was funded by CNPq (Conselho Nacional de Desenvolvimento Cientı́fico e Tecnológico), Grant No. 300702/97-3.

References (15)

  • J.-P. Vaillancourt et al.

    Validation of producer-recorded causes of preweaning mortality in swine

    Prev. Vet. Med.

    (1990)
  • Christianson, W.T., 1992. Stillbirths, mummies, abortions and early embryonic death. In: Tubbs, R.C., Leman, A.D....
  • Dial, G.D., Marsh, W.E., Polson, D.D., Vaillancourt, J.-P., 1992. Reproductive failure: differential diagnosis. In:...
  • English, P.R., Wilkinson, V., 1982. Management of the sow and litter in late pregnancy and lactation in relation to...
  • Herpin, P., Hulin, J.C., Le Dividich, J., Fillaut, 2001. Effect of oxygen inhalation at birth on the reduction of early...
  • P.K. Holyoake et al.

    Reducing pig mortality through supervision during the perinatal period

    J. Anim. Sci.

    (1995)
  • Kelsey, J.L., Thompson, W.D., Evans, A.S., 1986. Methods in observational epidemiology. Monographs in Epidemiology and...
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