I started thinking more about the oil thing today though. I can't come up with any reason she needs the oil; she's definitely not trying to gain weight and she's not a hard keeper. In fact, the vet thinks she really still needs improvement in her overall conditioning (i.e., decreasing her belly). He wanted her to stay on the grain since we were having some problems with hay quality (those have since been addressed), but now that I think about it, I never discussed the oil with him.
It's such a small amount, I can't imagine it's really affecting her overall condition one way or the other, but I'm inclined to just cut it out. Thoughts on that?