Like Mother Like Child: Do Fearful Sows Have Fearful Piglets?

Abstract

Gestational and early life experiences affect subsequent behavioural and physical development. The objective of the current study was to investigate associations between gilts' fear of humans, gestational stress level, and feeding and maternal behaviour, as well as how these related to aspects of the personality and growth of their offspring. A total of 37 gilts were used. Four human approach tests were performed between d 104 and d 111 of gestation to classify gilts as fearful or friendly. Gilt feeding behaviour and salivary cortisol concentration was measured between d 90 and d 108 of gestation, and gilt nursing behaviour assessed at d 13 of lactation. Piglets were subject to a back test at d 13 of age, to an open field test and a human approach test at d 20 of age, and growth was monitored to weaning (d 26 of age). Gilts classified as having a fearful behavioural profile had higher cortisol levels than friendly gilts (p < 0.05). Human fear level did not affect reproductive performance or the growth of offspring (p > 0.05). The offspring of friendly gilts tended to have a more active response to the back test (p = 0.09), less freezing response in the open field test (p < 0.05), and received human contact more than piglets from fearful gilts (p < 0.05). The present study shows that gilt human fear level is linked to their stress levels, which can affect the personality of their piglets.

Keywords: back test; coping style; cortisol; human approach test; human fear; novel environment test; nursing behaviour; piglets; prenatal stress; sows.

Figure 1

Back-test procedure use on d 13 post-farrowing.

Figure 2

Salivary cortisol levels of gilts categorised to different behavioural profiles which were (A) consistently friendly or fearful in four human approach tests (HAT) and (B) were either friendly or fearful in three out of four tests, or considered unclassified (two friendly and two fearful outcomes). * indicates a difference at p < 0.05 for the contrast between fearful gilts and friendly and unclassifed combined.

Figure 3

The coefficient of variation of the order in which gilts entered the ESF which were (A) consistently friendly or fearful in four human approach tests (PURE gilts) and (B) the same measure for gilts that were either friendly or fearful in at least three out four tests or considered unclassified (two friendly and two fearful outcomes). The number of visits per day to the ESF for (C) PURE gilts and (D) all gilts. ^a,b indicates a difference at p < 0.05, when Tukey’s adjustment was applied post-hoc.

Figure 4

Time taken for sows to lie down and nurse their piglets after piglets had been removed from the pen for 2 h.

Figure 5

Live-weight of piglets from sows that were categorised as friendly or fearful in four human animal approach tests. ^{a, b} indicates a difference at p < 0.1 > 0.05.