Influence of perturbations on the performance of growing pigs: from automatic detection of perturbations to characterisation of the adaptive response of the animals

Improving robustness of farm animals is seen as a new target of breeding strategies. However, robustness is a complex trait, which is not measurable directly. The objective of this study was to quantify and characterise elements of robustness in growing pigs. Robustness can be characterised by examining the animal’s response to environmental perturbations. We developed a generic model and data analysis procedure to detect these perturbations and subsequently characterise the feed intake response of growing pigs in terms of resistance and resilience. A model based on differential equations was developed to characterise the animal’s response to perturbations. In this model, adaptive response to each perturbation can be characterised by four parameters. The start and end times of the perturbation, the immediate reduction in daily feed intake at the start of the perturbation (i.e., a “resistance” trait), and another parameter describing the capacity of the animal to adapt to the perturbation through compensatory feed intake to rejoin the target trajectory of cumulative feed intake (i.e., a “resilience” trait). The model has been employed successfully to identify the target trajectory of cumulative feed intake in growing pigs and to quantify the animal’s response to a perturbation by using feed intake as the response criterion.