Case–control study evaluating the sow’s risk factors associated with stillbirth piglets in Midwestern in Brazil

Abstract

Reproductive failure in swine herds is often difficult to diagnose and is important to swine production. The present study aims to identify the potential risk factors (infectious/noninfectious) for stillborn piglets in two commercial swine farms situated in midwestern region of Brazil. The potential risk factors were included in a multivariable logistic model, and the dependent variable was defined as the presence of at least one stillborn piglet in a given litter (yes or no). In the best fit model, two variables from the multivariable analysis, total litter size (p = 0.01), and average birth weight (p = 0.03) were significantly associated with the presence of stillborn piglets at the farms examined in this study. Porcine circovirus type 2 (PCV2) was detected in 29.1 % of the litters. Neither parvovirus (PPV) nor leptospirosis infections were identified in this study, suggesting that they have a minor impact on reproductive disease.

Viral DNA genomes in sera of farrowing sows with or without stillbirths

“…In swine reproduction, the term "stillbirth" refers to piglets with healthy appearance born dead at term. The average incidence of stillbirths in commercial farms may range between 3% to 8%, causing significant losses to swine producers [1][2][3]. Such condition is considered a multifactorial problem [4]; on occasions, stillbirths have been associated to a number of known pathogens, including bacteria, protozoa, and viruses.…”

“…Among viruses, those which have been most often associated with stillbirths are porcine parvovirus (ungulate protoparvovirus 1, UPV1) [5], porcine circovirus type 2 (PCV2) [6], Aujeszky's disease virus (ADV), Influenza virus [7], porcine reproductive and respiratory syndrome virus (PRRSV) [8], encephalomyocarditis virus (EMCV) [9] and classical swine fever virus (CSFV) [10]. Nevertheless, frequently, no viruses or other known pathogens seem to play a role in such condition [1,2,11,12].…”

“…More recently, the polymerase chain reaction (PCR) has been employed in this kind of studies [1,11]; however, this method is still unable to detect agents to which no previously published genome sequences are available. Currently, high throughput sequencing (HTS) has been applied to investigate the full content of nucleic acids in a sample with no need for previous knowledge of specific nucleic acid sequences.…”

An examination of epidemiological study designs in veterinary science

“…As an example, a case-control study was undertaken to examine risk factors for stillbirths in pigs. Farms in Brazil were recruited between a specific calendar time and all farrowing pigs were monitored for stillbirths (as the outcome) (Silva et al, 2015). This is a fairly common type of fixed cohort in veterinary and human research, namely a birth cohort.…”