Management of reproduction: piglet survival and fertility of the sow

Introduction

During pig breed domestication, breeding has focused on lean tissue deposition, feed conversion efficiency, and above all, on prolificacy [1,2]. The larger the litter, the better the profitability for the farmer. Average litter sizes may have increased by 0.2–0.3 piglets/year [3]. However, increased litter size is associated with negative aspects such as high energy demand for milk production [4], prolonged farrowing duration [3], and pre-weaning mortality [5]. Thus, increased litter size negatively affects metabolic and reproductive health of the sow, and survival and health of the neonates.

Based on 20 different studies carried out between 1990 and 2019, litter size has increased from ca. 10 to 20 piglets and farrowing duration has increased from 1.5-2 to 7-8 h (Figure 1; [3, 6]). While the described tendency is subject to differences in breeds and farrowing housing environments, the overall tendency is therefore rather worrying. The extended duration of farrowing appears as an outcome of intensive breeding for prolificacy in the pig [3]. [...]