Early behavioral indicators for the onset of post-weaning diarrhea in piglets

Abstract

Introduction: Post-weaning diarrhea (PWD) is common in pig production and has a substantial economic impact. Moreover, PWD has a great impact on piglet health and welfare. Diarrhea presents itself in the first week post weaning as yellowish or grey fluid and usually lasts three to five days but can last up to two weeks. PWD is most frequently caused by enterotoxigenic Escherichia coli (ETEC) and rotavirus. Multifactorial stressors and sudden diet changes around weaning are risk factors for developing PWD. These factors, and PWD itself, may result in changes in piglet behavior. Detection of behavior in piglets that are early indicators for PWD, preceding detection of diarrhea, may contribute to predicting and diagnosing PWD at an early stage and provides more opportunities for early interventions to improve welfare and reduce risks for mortality. The aim of this research is to determine if there are early behavioral indicators of PWD that can be used as a non-invasive tool to predict which individual piglet and/or pens will develop PWD. Material and methods: A total of 24 piglets (Sus Scrofa, TN70 x Tempo) from four different non-mixed litters were weaned at 28 days of age and housed in four pens at a semi-commercial pig farm. Data was collected during the first two weeks of weaning between 28 days until 41 days of age. To evaluate presence of PWD, rectal swabs were taken on days 1, 3, 5, 8, 10 and 12 post weaning from each piglet and scored for color and consistency. Piglet activity was monitored by video recordings of the first week post weaning. Lying, huddling, standing, walking, eating and drinking behavior was scored by instantaneous sampling of individual piglets with an interval of 5 minutes. Piglets were considered to have diarrhea at fecal consistency scores from 2 or 3 onwards for statistical analyses. Logistic regression analyses were done with diarrhea as outcome variable and day (3, 5 and 8) and proportions of the different behaviors, either 1 or 2 days prior to fecal scoring, as predictive variables with piglet included as random effect. Results: Low fecal consistency scores were reported on all days, whereas high scores were mainly observed on day 5. The highest proportion of diarrhea was observed on day 5 compared to day 3 and 8. Lying behavior was expressed predominantly compared to other behaviors, with ‘standing’ being second. In the best fitted regression models only day remained as explanatory variable with a significantly higher odds (OR 5.0; 95% CI 1.2-28.5) for observing diarrhea on day 5 compared to day 3 at a cut off value for diarrhea of 2, based on fecal consistency scores. No significant correlation between behavior and the occurrence of diarrhea was observed during this experiment. Discussion and conclusion: Fecal swab scoring was considered to be a useful tool for identifying diarrhea on the individual level. For future research into non-invasive early indicators for diarrhea, it is recommended to use a larger number of piglets, pens, farms and timepoints around weaning to increase the power of the study. Also, including other methods and technologies to measure behavior, feeding and drinking and activity level, could contribute to identifying relevant indicators as well. In conclusion: No early behavioral indicators for PWD could be identified in this study. Further research is required to identify relevant early behavioral indicators for diarrhea and to establish how it can be used as a predictive tool