Factors associated with high mortality of the piglets in farrowing units

High mortality in the pig industry is a welfare problem as well as it reduces the farmer's income. The Danish Pig farmers have decided to reduce the mortality with 20 % before 2020 compared to the 2011 level. For each percent the mortality is reduced in the farrowing units the gross margin per sow per year is increased by 6 euro. The objective of this study was to provide knowledge of the differences in management, health, feeding, and housing conditions that impact on piglet mortality in the farrowing units.

The hypothesis was that identification of differences in management, health, feeding and housing conditions in herds with high and low mortality can identify risk factors for mortality of piglets in farrowing units.

The study was performed as a case-control study in farrowing herds with high or low total mortality (stillborn and preweaning mortality). Farrowing units with low mortality had a total mortality ≤ 20.3%, and farrowing units with high mortality had a total mortality ≥ 24.6%. Each farm was visited by a veterinarian and a comprehensive questionnaire was filled in during the herd visit.

The initial statistical univariate analysis was performed by logistic regression (Proc Logistic in SAS). Factors significant at P < 5% were considered for further analysis. Factors were selected by two criteria. There should be a plausible biological link to mortality and it should be possible to change the factor.

To check for confounders, factors that were biologically plausible but hard to change were also included in the multivariate analysis. The results are presented as Odds Ratios (OR) for being a farrowing unit with high mortality. An OR > 1 indicates an increased risk and OR < 1 indicates a reduced risk.

A total of 87 farrowing units, where 46 had high mortality and 41 had low mortality, were included in the study. The multivariate analysis showed that for each percent of sows with parity ≥ 7, the OR for being a farrowing unit with high mortality was 1.17. For each percent of sows treated for pain, the OR was 1.02. Herds where piglets were mingled before cross fostering had lower risk of being a farrowing unit with high mortality (OR 0.29). Herds with high pressure washing between farrowing batches and consistently opening of covered creep area by daily supervision also had reduced risk of having high farrowing unit mortality (OR 0.21 and OR 0.19).

This study indicates that the risk of being a farrowing unit with high mortality is associated with number of old sows, treatment for pain, cross-fostering procedure, hygiene level (high-pressure washing), and the level of supervision of the piglets.

Disclosure of Interest: None Declared.