A behavioural scale to measure ease of farrowing in sows

Farrowing is one of the most critical phases in pig production, as it has an impact on neonatal pig survival. Assessing the ease of farrowing can improve the management of sows and thus increase litter survival. The aims of this study were: 1) to develop an ease of farrowing score (EFS) in sows based on the behaviour of the sows and their piglets, and 2) to determine the relationship between the EFS and productive, physiological, and subjective parameters. Eighty hybrid (Large White × Landrace) sows from first to seventh parity housed in individual crates were used. An EFS was constructed using the total duration of farrowing, the birth interval, the total time standing or sitting, the number of position changes during the day before and the day of farrowing, the sow posture at birth, the viability and the position of the piglets at birth (head or back born). Moreover, rectal temperature at 90 min after farrowing, a four categorical subjective visual assessment (VA) of farrowing and litter size (piglets born alive, stillborn and mummified foetus) were recorded. A common factor analysis model yielded five factors with an eigenvalue higher than 0.95 that accounted for 75.05% of the total variation between individuals. The three main factors were "farrowing duration", "sow posture", and "sow activity" of sows and explained 23.44%, 15.67%, and 14.23% of the variance, respectively. Primiparous sows had higher values for factor 3 (sow activity) than multiparous sows (P = 0.02). Sows without stillborn or mummification foetus showed higher values of EFS than sows with at least one stillborn or mummification foetus (P = 0.06 and 0.01, respectively). Sows that received a visual assessment of 3 and 4 showed higher values of EFS than sows that received a VA of 1 and 2 (P = 0.0017). The EFS appears to be a good behavioural scale to measure ease of farrowing in sows kept in individual farrowing crates. Duration of farrowing, sow position, and presence of stillborn piglets and mummified foetuses appear to be important ease of farrowing indicators.