The argument of intelligent design doesn't imply that every aspect of creation is sublime and there have not occurred any evolutionary negatives. Since life evolves somewhat randomly, and there are evolutionary dead ends, there are going to be diseases, features that are destructive, features that bear no benefit (that will be naturally selected out, "voted off the island," so to speak), and sometimes growth (as per your goat example) that is counter-productive and even painful. Such is the process of evolution.

Intelligent design says that some natural phenomena are best explained by an intelligent cause because, in our experience, intelligence is the [most reasonable] cause of their informational properties. It means that there are so many examples of things in nature that are best explained (via Occam's Razor) as having an intelligent and purposeful cause that we are remiss to ignore theism as a possibility.

''Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.''

Here is an example of runaway selection in a goat, it literally causes the goats horns to grow so large that the grow into the goats head and pierce it. https://www.youtube.com/watch?v=GL0SPA-5K-M