In this experiment, MP-deficient diets depressed fiber
digestibility and decreased milk production compared
with an MP-adequate diet. The NRC (2001) model
severely underpredicted (7 to 8 kg/d) milk yield on
the MP-deficient diets. Lowering the MP supply and
dietary CP considerably decreased urinary N and total excreta N losses and increased milk N efficiency.
Supplementing the MP-deficient diet with coconut oil
decreased ruminal protozoal counts, but depressed DMI
and cow productivity. In addition, coconut oil caused
milk fat depression. Coconut oil supplementation had
no effect on the methanogen population in the rumen.
As expected, coconut oil supplementation increased
milk C12:0 and C14:0 content.