What is the presentation of one's opinion on a livestock judging class called?

The presentation of one's opinion on a livestock judging class is referred to as "reasons." This term specifically describes the process by which a judge articulates their evaluation and rationale behind the placements of the livestock after assessing their qualities. In livestock judging, providing reasons is critical as it demonstrates the judge's ability to communicate their thought process clearly, effectively explaining the attributes they observed in the animals and justifying their rankings. This aspect underscores the importance of both knowledge and communication skills in livestock evaluation, as it not only involves making a judgment but also conveying the reasoning behind those judgments to an audience or a panel.

In contrast, the other answers do not accurately capture this specific activity within livestock judging. While public speaking is a broader skill that encompasses delivering talks on various topics, livestock presentation can refer to how animals are shown or displayed at events rather than the judgment of their quality. Speaking exhibition implies a performance aspect, which does not specifically relate to the reasoning component of livestock evaluation. Thus, "reasons" is the most appropriate term for this action in the context of livestock judging.