Ben Abdelkrim Ahmed, Puillet Laurence, Gomes Pierre, Martin OlivierPlease use the format "First name initials family name" as in "Marie S. Curie, Niels H. D. Bohr, Albert Einstein, John R. R. Tolkien, Donna T. Strickland"
<p>Background Understanding the effects of environment on livestock provides valuable information on how farm animals express their production potential, and on their welfare. Ruminants are often confronted with perturbations that affect their performance. Evaluating the effect of these perturbations on animal performance could provide metrics to quantify how animals cope with their environment and therefore better manage them. In dairy systems, milk production records can be used to evaluate this effect because (1) they are easily accessible, (2) the overall dynamics throughout the lactation process have been widely described, and (3) perturbations often occur and cause milk loss. In this study, a lactation curve model with explicit representation of perturbations was developed. Methods The perturbed lactation model is composed of two components. The first one describes a theoretical unperturbed lactation curve (unperturbed lactation model), and the second describes deviations from the unperturbed lactation model. The model was fitted on 319 complete lactation data from 181 individual dairy goats allowing the characterization of individual perturbations in terms of their starting date, intensity, and shape. Results The fitting procedure detected a total of 2354 perturbations with an average of 7.40 perturbations per lactation. Loss of production due to perturbations varied between 2% and 19%. Results show that it is not the number of perturbations is not the major factor explaining the loss in milk yield over the lactation, suggesting that there are different types of animal response to disturbing factors. Conclusions By incorporating explicit representation of perturbations, the model allowed the characterization of potential milk production, deviations induced by perturbations, and thereby comparison between animals. These indicators are likely to be useful to move from raw data to decision solutions in dairy production. </p>
Dairy Goats, Milk Yield, Individual Variability, Resilience
