Evaluation of Animal-Based Indicators to Be Used in a Welfare Assessment Protocol for Sheep

Abstract

Sheep are managed under a variety of different environments (continually outdoors, partially outdoors with seasonal or diurnal variation, continuously indoors) and for different purposes, which makes assessing welfare challenging. This diversity means that resource-based indicators are not particularly useful and, thus, a welfare assessment scheme for sheep, focusing on animal-based indicators, was developed. We focus specifically on ewes, as the most numerous group of sheep present on farm, although many of the indicators may also have relevance to adult male sheep. Using the Welfare Quality® framework of four Principles and 12 Criteria, we considered the validity, reliability, and feasibility of 46 putative animal-based indicators derived from the literature for these criteria. Where animal-based indicators were potentially unreliably or were not considered feasible, we also considered the resource-based indicators of access to water, stocking density, and floor slipperiness. With the exception of the criteria “Absence of prolonged thirst,” we suggest at least one animal-based indicator for each welfare criterion. As a minimum, face validity was available for all indicators; however, for many, we found evidence of convergent validity and discriminant validity (e.g., lameness as measured by gait score, body condition score). The reliability of most of the physical and health measures has been tested in the field and found to be appropriate for use in welfare assessment. However, for the majority of the proposed behavioral indicators (lying synchrony, social withdrawal, postures associated with pain, vocalizations, stereotypy, vigilance, response to surprise, and human approach test), this still needs to be tested. In conclusion, the comprehensive assessment of sheep welfare through largely animal-based measures is supported by the literature through the use of indicators focusing on specific aspects of sheep biology. Further work is required for some indicators to ensure that measures are reliable when used in commercial settings.

Developing an Animal Welfare Assessment Protocol for Livestock Transported by Sea

“…As social species, cattle and sheep in extensive systems synchronise their feeding and resting behaviour [49,50], with synchrony being proposed as a welfare measure in other livestock systems [51]. Sheep reduce time spent lying when the resting areas are uncomfortable and space allowance insufficient [27]. Observing cattle in different lying positions, such as sternal vs. lateral recumbency, could indicate thermal comfort or discomfort [25] and provision of suitable deck space allowance.…”

“…It is important that behavioural measures can also capture negative, neutral and positive. Behaviour considered to indicate negative well-being include agitation, aggression and pushing [27]. It is also important to consider how restrictive environments not only change natural behavioural patterns, but also the incidence of aggressive behaviour, as these impact on surrounding animals and interactions with humans.…”

“…Our protocol includes measures that capture positive well-being, including play, exploration and social-and self-grooming; however, these may occur infrequently, reducing their use within a welfare protocol [15]. Play behaviour is considered to be an indicator of a positive emotional state [27], only evident when the animal's needs are met. While play can, therefore, indicate good welfare, the incidence of play is naturally more common in younger animals [25].…”

Prioritization of Farm Animal Welfare Issues Using Expert Consensus

“…These concerns were chiefly those experienced by the breeding stock, which may remain on the farm for several years, rather than the young animals destined for prime meat production. However, this does expose that feeding and nutritional management of pregnant and breeding animals may be sub-optimal, either through deliberate food restriction [e.g., of broiler breeders and pregnant sows; (18)] or through difficulties in managing forage resources at certain times of the year (19,20).…”

Assessing the Validity of Animal-Based Indicators of Sheep Health and Welfare: Do Observers Agree?

“…(2) reliable, in that different observers consistently score the same animal or group of animals in a similar way (inter-observer agreement); (3) feasible to apply under a variety of farm management systems [5].…”