Improving robustness for farm animals has been seen as a new target of breeding strategies. However, robustness is a complex trait and is difficult to measure. The objective of this study is to quantify and characterize robustness in growing pigs. Although the origin of environmental perturbations may not be known, the effect of a perturbation on the animal can be observed quickly, for example through a change in voluntary feed intake. Perturbations such as heat stress and sanitary challenges typically have a negative and transitory effect on the voluntary feed intake. We aim to develop a generic model and data analysis procedure to detect and characterize the feed intake response of growing pigs in terms of resistance and resilience (as elements of robustness) when faced with perturbations. We hypothesize that there is an ideal trajectory curve of cumulative feed intake, which is the amount of feed that the pig desires to eat when it is not facing any perturbations. Deviations from this ideal trajectory curve are considered as potential periods of perturbations, which can be characterized by their duration and magnitude. It is also hypothesized that, following a perturbation, animals strive to regain the ideal trajectory curve of cumulative feed intake. A model based on differential equations was developed to characterize the animal’s response to perturbations. In the model, a single perturbation can be characterized by four parameters. The start and end times of the perturbation are “imposed” by the perturbing factor (e.g., a period of heat stress) while two other parameters describe the resistance and resilience potential of the animal to the perturbing factor. One parameter describes the immediate reduction in daily feed intake at the start of the perturbation (i.e., a “resistance” trait) while another parameter describes the capacity of the animal to adapt to the perturbation through (compensatory) feed intake to rejoin the ideal trajectory of cumulative feed intake (i.e., a “resilience” trait). The model has been employed successfully to identify the ideal trajectory of cumulative feed intake in growing pigs and to quantify resistance and resilience using feed intake as the response criterion. Further developments include the analysis of individual feed intake curves of group-housed pigs that can be exposed to the same environmental perturbing factors to quantify and to compare resistance and resilience of different pigs.