Horns of Plenty

A student stopped into my office recently and asked if I have ever considered the correlation between the use of horns in LOTR and in the Bible. The more I thought about it, the more intriguing it became.
First, where do we see the use of horns in LOTR, what are the circumstances, how are they described, and what impact do they have on the broader story.
Second, placed within the cultural context of Middle Earth how do the characters understand the various roles of horns; what does this tell us about the culture of the people?
Third, as we examine each of the occurrences is it possible to draw scriptural parallels?
And finally, when using LOTR as a personal spiritual reflection what might each presentation be trying to say to the reader?