Coon, R. E., Tucker, C. B. 2024. Measuring motivation for alfalfa hay in feedlot cattle using voluntary interaction with an aversive stimulus. Applied Animal Behaviour Science 271, 106165.

Typical diets for finishing cattle are concentrate-rich and low in roughage, which may limit species-specific feeding behaviours and increase the risk of digestive disorder. Our objective was to measure how motivated finishing steers are to access alfalfa hay compared with nothing or more of the finishing ration through their willingness to interact voluntarily with an electrified barrier. Twenty-four 13-mo-old steers, fed a high-concentrate finishing ration ad-libitum, had access to one of three treatments (n=8 steers/treatment) behind the barrier: 1) 1.5 L (200 g) of alfalfa hay (AF), 2) 1.5 L (∼600 g) of the finishing ration (TMR), or 3) an empty bin (E). The primary diet (finishing ration) was fed 2x/d while the treatments (AF and TMR) were delivered only in the morning. The steer voluntarily pushed his muzzle against a barrier which rose out of his way, allowing free access to the treatment. The electrical current on the barrier increased exponentially every 48 h (0, 156, 312, 625, 1250, 2500, 5000 µA) until the animal ceased accessing the bin. Visits to the bin were video recorded 24 h/d. The final sample size was five AF, eight TMR, and four E, largely because animals did not continue to participate in the study, particularly in the AF and E treatments. Of those that remained in the study, animals with access to an empty bin were less likely to advance to the next current than AF and TMR animals (P<0.01). They also stopped accessing the treatment rapidly while AF and TMR animals continued to interact with the electrified barrier, up to likely aversive maximum currents (195±39, 1000±153 and 977±138 μA, respectively; P=0.01). Animals with access to alfalfa ate more of it as a percentage of the amount offered (P=0.03) and visited more (P<0.02) than TMR animals as they approached the highest current they were willing to touch. We found no evidence of differences in latency to approach either the TMR or AF, except 48 h before their highest current pushed, when AF animals tended to be quicker (P=0.07). The electrified barrier distinguished differences in motivation for food resources versus access to an empty feeder, indicating that finishing cattle are motivated to access alfalfa and additional offerings of TMR. Despite the limitations of a small sample size, this is the strongest evidence to date that these cattle are motivated to contrafreeload. The rationale behind these results, be it exploration or other benefits associated with each feed type, remain unclear, as forage was not clearly preferred over TMR as predicted.

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