Measuring Animal Welfare Over Time: A Case Study With Goats
If we can effectively assess the welfare of farmed animals, we can use the information to identify areas that need improving, to ensure compliance with animal welfare laws, and to differentiate between farms with different welfare standards. Welfare indicators can be visual or behavioral attributes of farmed animals that signify the presence or absence of good welfare.
Of course, to get reliable results, it’s important for the indicators that we use in welfare assessments to be consistent over time. Indicators that are consistent over time are more reliable than those that are not, and could provide better data more quickly. This study, published in the Journal of Dairy Science, measured the consistency over time of indicators that farmers were using to assess the welfare of dairy goats. The researchers made two visits to 20 dairy goat farms, 10 of which were in Portugal and 10 of which were in Italy. None of the farms had any major changes in management or housing conditions between the visits.
Of all the welfare indicators that the researchers observed during the two visits, only body abscesses and cleanliness of the lower legs provided fully consistent results between visits. For example, the number of body abscesses the researchers found on the goats in the 20 farms only showed a 0.2% difference between visits. Based on this, the authors support the inclusion of body abscess counts as a welfare indicator in dairy goat welfare assessments. Cleanliness of the lower legs, on the other hand, may not be a great indicator because the coat color of the goat influences how an observer may perceive the level of cleanliness. This could make the indicator less valid and less reliable.
Another indicator that may not be reliable includes head lesions because they are influenced by differences between breeds and molting stages. The avoidance distance from humans when approached is another potentially unreliable indicator because of variations between breeds and the lack of practical ways to measure this indicator.
When using an evaluative approach to analyze the data, the authors found that many farms with a high prevalence of certain welfare issues (e.g., asymmetric udders, overgrown hooves, severe lameness, and knee calluses) on the first visit also had a high prevalence of those same welfare issues on the second visit. For example, the researchers found that on average 44.7% of goats had overgrown hooves on the first visit, and this number remained high at 36.5% on the second visit. The authors suggest that such indicators—those measuring chronic conditions rather than outbreaks—may be useful for detecting persistent welfare issues and thus identifying areas that we could greatly improve upon.
The authors suggest that we need more welfare assessments and long-term studies to provide a full picture of the welfare indicators that are best suited to use for dairy goats. Animal advocates can use this information to promote the development of welfare assessments that provide reliable data by focusing on the use of indicators that have a proven high level of consistency over time. This applies not only to goats, but to all animals.