Welfare Assessment on Pasture: A Review on Animal-Based Measures for Ruminants

SIMPLE SUMMARY: Welfare assessment in outdoor and extensive systems has rarely been investigated, and little is known about the most appropriate indicators. This study aimed at compiling a list of animal-based measures of welfare for domestic ruminants raised on outdoor/extensive systems by means of a systematic review. Out of 810 papers retrieved, 52 matched the inclusion criteria and went through an in-depth analysis. According to available literature, 45 indicators have been used to assess welfare on pasture, often following different methodologies. Most indicators were measured by observers even if the use of sensor technologies increased in recent years. Considering the growing interest in pasture-based or grass-fed products, it is suggested that welfare assessment in outdoor/extensive farming systems is carried out by following shared methodologies in order to provide evidence of the higher animal welfare claims that these products often imply compared to indoor systems. ABSTRACT: Outdoor and extensive farming systems allow animals to behave in a natural way and are often perceived as welfare friendly. Nonetheless, the natural environment poses multiple challenges to the welfare of animals, sometimes hampering their capacity to cope. Welfare assessment in outdoor and extensive systems has been rarely investigated, and little is known about the most appropriate indicators. The aim of this review was to identify animal-based measures of welfare to apply in extensive and pasture-based systems in domestic ruminants. Through the use of a dedicated software for systematic reviews, 810 papers were screened and a total of 52 papers were retained for in-depth analysis. ABM resulting from these papers were initially divided according to the species (cattle and small ruminants, including sheep and goats) and then to four principles: comfort, behavior, feeding and health. The results showed that welfare data were collected applying different methodologies, with an increasing use of sensors in recent years. The need to herd and restrain animals for individual data collection is one of the major constraints to data collection in extensive farming systems. It is suggested that welfare assessment in outdoor/extensive farming systems is carried out by following shared procedures in order to provide evidence of the higher animal welfare claims that these products often imply compared to indoor systems.