Realistically, how do you think you'd do in this course? How did you do in biochem I? What is your GPA currently, and how could it be impacted by this extra class (in both positive and negative ways)? You don't have to answer these questions publicly, but at minimum answer them for yourself.
If you think you can do well in it, and it won't be too impossible of a burden for you, then I think it would be a good idea, especially if you need to apply to more schools in a future cycle. However, if your GPA is already really high, if you have lots of other upper-division science coursework that you did well in, and/or if you think you might not get an "A" (or at least a "B+") in this class, then you might be better off saving your time and money for now, and only taking it if you get rejected from school(s) this cycle (hopefully not!).
I'm sure there will be others on here that say you should take as many upper-division classes as possible to prepare yourself for vet school. While my undergrad was one of the most rigorous in the country regarding the sciences, I definitely took the easy way out with biochem (only one semester, through the night school at my university, a.k.a. much easier than my other classes), and I'm getting an "A" in Davis' physiological chemistry course (fancy name for biochemistry).
