Which term describes a young-of-the-year bighorn sheep?

The term that describes a young-of-the-year bighorn sheep is "lamb." This terminology is widely accepted in wildlife management and animal husbandry. In the case of sheep species, a "lamb" specifically refers to a young sheep that is typically less than one year old.

Using the correct term helps in understanding the age and development stage of the animal, which is important for wildlife management practices, conservation efforts, and understanding the species' lifecycle. Different terms are used for young animals of different species, hence "calf" is used for young cattle, "fawn" for deer, and "yearling" generally refers to young animals that are approximately one year old or that have completed their first year. Therefore, referring to a young bighorn sheep as a "lamb" accurately conveys its specific developmental phase.