Consistency over time of animal-based welfare indicators as a further step for developing a welfare assessment monitoring scheme : the case of the animal welfare indicators protocol for dairy goats

Consistency over time (COT) of animal-based indicators is key to a reliable and feasible welfare protocol, indicating that results are representative over long-term situations. High levels of consistency ensure fairness for the farmer and credibility of the system. In addition, indicator COT reduces recording costs, as having indicators that do not change over a long period of time will require less farm visits to achieve reliable estimates. To date, COT of animal-based indicators included in the welfare assessment of dairy goats has never been tested. Therefore, our aim was to investigate COT of animal-based indicators included in the Animal Welfare Indicators (AWIN) welfare assessment prototype protocol for dairy goats. To meet this goal, a study was designed where an average of 3 mo elapsed between 2 sets of visits to the same 20 dairy goat farms (10 in Portugal and 10 in Italy), with no major changes in management routines or housing conditions occurring during this period. Initially, we performed a Wilcoxon signed rank test to investigate whether the results obtained during the 2 visits were significantly different. After this preliminary screening, the indicators presenting nonsignificant differences between visits were submitted to a second step analysis, where discriminative and evaluative analyses were conducted to reach a final indicator lineup. The discriminative approach helped distinguishing among farms, whereas the agreement analysis showed us the range of differences between repeated assessments. Some particular conclusions could be drawn from this combined analysis, helping to the development of the final AWIN welfare assessment protocol for dairy goats and as a further step to develop a welfare assessment monitoring scheme for this and other species. In this sense, the AWIN welfare assessment protocol allows for the quick differentiation between farms based on the identification of persistent welfare problems, by recording highly consistent and feasible indicators. In a second step, a more comprehensive protocol, consisting of indicators more likely to be subject to variations along time, was applied. Repeated assessments and long-term studies of indicator consistency are needed to help determine the frequency of visits required to obtain a consistent and feasible welfare assessment scheme. This paper adds to the literature by providing guidance on the variability of animal-based indicators over time.