Results from the present experiment suggest that the
increases in milk and milk protein yields due to folic
acid supplements were not dependent of the vitamin B12
supply and were probably closely related to the role of
folic acid in the DNA cycle. Lactational performance was
not modified by supplementary vitamin B12. Nevertheless,
it appears that, when folic acid was given in combination
with vitamin B12, utilization of the 2 vitamins
seems to be increased, especially in extrahepatic tissues.
Moreover, it appears that when folic acid was given in
combination with vitamin B12, metabolic efficiency was
improved, as suggested by similar lactational performance and DMI than cows fed folic acid supplements
alone, but increased plasma glucose and decreased hepatic
concentrations of lipids