Can Associations Between Qualitative Descriptors and Quantitative Behavioral Measures in Nursery Age Pigs Improve Interpretation of Behavioral studies?

Abstract Qualitative Behavior Assessments (QBA) are a useful way to assess animal welfare by capturing behavioral signals of emotionality not captured by quantitative measures. The objective of this study was to determine if QBA descriptors assigned to nursery age gilts during a social dyad test in a novel arena were associated with differences in quantitative behavioral measures recorded from the test such as latency to make social contact and amount of time spent in proximity. To investigate this, 30 weight-matched purebred Yorkshire gilt pairs underwent a social dyad test at 6 wk-of-age. Dyads were unfamiliar with each other, and one was assigned as the focal gilt. The test began as soon as both gilts were in the novel arena and lasted for 5 minutes. Four independent, untrained observers were asked to perform a QBA by circling all terms that they felt described the focal gilt throughout the test duration from a set list of 20 terms. Overhead video was recorded and used to collect quantitative measures including number of quadrant crosses, percentage of crosses entering an already occupied quadrant, percentage of crosses exiting an already occupied quadrant, latency of the focal pig to touch the other pig, and time spent in an occupied quadrant. For each focal gilt, only terms that were used by at least two observers were kept. To be included in the analysis a given term had to be assigned to at least 6 of the 30 focal gilts such that each group had sufficient sample size to make comparisons. This filtering resulted in 10 terms being kept for analysis including Active (22), Agitated (7), Aimless (10), Calm (15), Indifferent (8), Lively (13), Playful (9), Positively Occupied (16), Sociable (14), and Tense (8). Quantitative measures were analyzed using a t-test to determine if pigs described by each term differed from those that were not. Pigs described as Aimless, Calm, Positively Occupied, Sociable, or Tense did not significantly differ in any of the quantitative measures of behavior. Pigs described as Active, Indifferent, or Lively had significantly more quadrant crosses (P = 0.0003, 0.003, 0.022 respectively). Pigs described as Agitated had a greater proportion of crosses that were entering an occupied quadrant (P = 0.022), while those described as Playful had a significantly lower proportion of crosses that were exiting an occupied quadrant (P = 0.031). Understanding how qualitative descriptors associate with quantitative measures of behavior may assist in better interpretation of QBA results as well as confirming that a chosen metric is capturing the intended behavior.