Document type: scientific article published in Applied Animal Behaviour Science
Authors: Leandro Sabei, Marisol Parada Sarmiento, Cihan Çakmakçı, Sharacely de Souza Farias, Thiago Bernardino, Rosangela Poletto, Erika Alejandra Becerra Mendez, Beatriz Kaori, Adroaldo José Zanella
Abstract in French (translation): Social networks of pregnant gilts during free-range feeding and effects on their offspring
Social relationships are important aspects of pig behavioral biology and can be affected by pig housing type. Studying agonistic interactions and affiliative behaviors can reveal effects on adult pigs and their offspring. This study investigated the social dynamics between gilts throughout gestation during group feeding in an outdoor housing system, and the effects of these dynamics on group stability and the offspring of group members. For this study, 15 gilts were synchronized in estrus and artificially inseminated with three different sperm pools. The pens in which the gilts were housed contained a mud pool, natural shade and two teat drinkers. Two daily meals (∼2.5 kg/day/gilt) were fed to the group on the floor. Feeding behavior was recorded for three continuous days (20 minutes in the morning and again in the afternoon) at each gestation (a total of 42 hours of video recording). Saliva samples were taken at 6 a.m. and 6 p.m. on the same days. A trained observer evaluated all videos using Boris software to determine agonistic and affiliative behaviors. After farrowing, data collected on piglets included sex, mortality and body weight at 10, 25, 29 and 36 days of age. Elo scores were calculated to quantify the relative hierarchy between gilts based on behavioral assessment. Generalized linear mixed models (GLMM) were used for data analysis, and significance of fixed effects was determined at p ≤ 0.05. The tendency of gilts to feed together decreased as gestation progressed. Heavier gilts had lower salivary cortisol concentrations, and high rank correlated with higher morning salivary cortisol concentrations and heavier piglets. Maternal modulation of offspring performance in pigs merits further investigation. Assessment of gilts' social feeding behaviors is useful for considering pig behavior in genetic selection, and for improving commercial facilities and management practices to improve animal welfare.
Preview: Social relationships are important aspects of the behavioural biology of pigs and can be affected by the type of housing pigs are kept in. Exploring agonistic interactions and affiliative behaviours can reveal effects on adult pigs and their descendants. This research investigated the social dynamics among gilts throughout pregnancy during collective feeding in an outdoor housing system and the effects of these dynamics on the stability of the group and the offspring of the group members. For this study, 15 gilts were oestrus synchronised and artificially inseminated with three different semen pools. The paddocks where the gilts were housed contained a mud pool, natural tree shade, and two nipple drinkers. Two daily meals (∼2.5 kg/day/gilt) were provided to the group on the floor. Feeding behaviour was recorded for three continuous days (20 min in the morning and again in the afternoon) every gestational (a total of 42 h of video recording). Saliva samples were collected at 6:00 a.m. and 6:00 p.m. on these same days. A trained observer evaluated all the videos using Boris software to determine agonistic and affiliative behaviours. After farrowing, the piglet data collected included sex, mortality, and body weight (BW) at 10, 25, 29, and 36 d of age. Elo scores were calculated to quantify the relative hierarchy among the gilts based on the behaviour assessment. Generalised linear mixed models (GLMMs) were used for data analyses, and the significance of fixed effects was determined at p ≤ 0.05. The tendency of the gilts to feed together decreased as gestation progressed. Heavier gilts had lower salivary cortisol concentrations, and higher gilt rank was correlated with higher morning salivary cortisol concentrations and heavier piglets. Maternal modulation of offspring performance in pigs warrant further investigation. Assessment of gilts' social feeding behaviours is relevant for considering pigs' behaviour in genetic selection and improving commercial facilities and management practices to improve animal welfare.
