Developing a feasible and sensitive judgement bias task in dairy cows

Abstract

Judgement bias tasks (JBTs) are used to assess the influence of farm practices on livestock affective states. The tasks must be adjusted to the species and age group of focus. In cattle, most JBTs were designed for calves instead of adult cows. This study aimed to develop a JBT suitable for adult dairy cows, combining feasibility, validity, sensitivity and repeatability. Three JBTs were developed in which cows were trained to reach or avoid reaching a feeder, the location of which signalled a reward or punisher. The tasks differed in terms of punisher—cows being allocated either to “no-reward”, an air puff or an electric shock. Cows were then exposed twice to three ambiguous positions of the feeder, on two separate occasions. Speed of learning and proportions of correct responses to the conditioned locations were used to assess the feasibility of the task. Adjusted latencies to reach the ambiguous feeder positions were used to examine whether response patterns matched the linear and monotonic graded pattern expected in a valid and sensitive JBT at baseline. Latencies to reach the feeders in the two repeated testing sessions were compared to assess ambiguity loss over tasks’ repetitions. The validity of using spatial JBTs for dairy cows was demonstrated. While the effect on JBT feasibility was nuanced, the punisher did influence JBT sensitivity. None of the JBTs’ repeatability could be supported. We conclude that using an air puff as punisher led to the most sensitive, yet non-repeatable—BT for dairy cows.

Mood swings in cows : Cognitive and physiological assessments

“…Therefore, we encourage researchers to develop alternatives of our JBT set-up (e.g. auditory Go/Go tasks as previously suggested: Kremer et al 2021b) that would be more sensitive to affective shifts when investigating the effects of common farm practices on cow affective states. Once more, this study highlights the necessity for researchers to combine indicators of various nature (cognitive, behavioural and physiological) to assess animal affective states reliably.…”

“…JBT was carried out in the same arena as the one used for the OF test. It was adapted from previous studies conducted in ruminants (Kremer et al 2021b;Destrez et al 2012;Lecorps et al 2018). It consisted of a Go/No-Go task, based on a spatial cue characterised by an automatic feeder always filled with 150 g of concentrates that could be remotely released.…”

“…It consisted of a Go/No-Go task, based on a spatial cue characterised by an automatic feeder always filled with 150 g of concentrates that could be remotely released. For a detailed description of the facilities used for the JBT, the reader is referred to Kremer et al (2021b).…”

“…Heifers were trained to display Go-responses to the feeder to obtain 150 g concentrates when the feeder was located on P. The response was considered correct and deemed a Go when the heifer reached the feeder within 20 s. If she did not reach the feeder within trial duration (90 s), the same procedure as the one used for the positive training session was applied. Alternatively, heifers were trained to display NoGo responses in order to avoid a 6 bar air puff when the feeder was located on N. This combination of reward/punisher was selected to maximise the sensitivity of our JBT to shifts in heifers' affective states (Kremer et al 2021b). The response to N was considered correct and deemed a NoGo if the heifer did not reach the feeder during the whole trial duration, i.e.…”

“…The reward consisted of 150 g concentrates and the punisher consisted of a 7 bar air puff. This combination of reward/punisher was selected to maximise the sensitivity of the JBT to shifts in heifers' affective states (Kremer et al 2021b). A training session was composed of 10 trials, during which the feeder was located on P for 6 trials and on N for 4 trials.…”