When the market hog travels, muscling should be evident in which of the following locations?

The correct answer highlights that muscling should be evident in all places mentioned: the shoulder, ham, and loin. In evaluating market hogs, strong muscling is crucial as it directly correlates with meat quality and yield.

The shoulder area should exhibit prominent muscle development, which is essential for the overall muscling and weight of the animal, contributing to the desirable market characteristics. The ham is another critical area, as it contains some of the most valuable cuts of meat. Adequate muscling here is indicative of a higher meat yield. Lastly, the loin is particularly important, as it is a prime cut for pork products. Well-developed muscle in the loin area signifies a healthy and robust hog capable of producing meat that meets market demands.

Considering all these factors, the presence of muscling in all specified regions underlines the overall conformation and market appeal of the hog.