The purpose of this experiment was to determine the effects of Zilmax (Merck Animal
Health, Summit, NJ) on changes in blood metabolites. Zilmax is a feed additive
designed to improve production efficiency in cattle when fed during the last phase at
the feedlot. Zilmax works by redirecting the energy use in the body to form more lean
muscle at the expense of fat deposition. The blood metabolites measured in our experiment
were glucose and lactate, which are the energy sources for various body functions
including muscle growth. Plasma urea nitrogen was measured as an indicator of protein
catabolism. Non-esterified fatty acids also were measured as they were released into the
bloodstream with the breakdown of adipose tissue.