Final answer:
The characteristics such as lop ears and spots relate to swine production, with feed efficiency and rate of gain being critical for economic viability in pig farming.
Step-by-step explanation:
The characteristics mentioned - spots, lop ears, feed efficiency, rate of gain, carcass quality, and early maturing - are all relevant to animal breeding and are specifically associated with swine production. In the context of agriculture, these characteristics are selected to improve efficiency and profitability in pig farming operations. Feed efficiency and rate of gain are particularly valued in swine production as they directly impact the economic viability of the operation, while good carcass quality ensures that the meat meets the standards required for sale and consumption.