hown positive trends in performance variables. Using
a meta-analysis approach to combine results from several
studies in which formic acid-formates were used
showed that addition of formates improved ADG and
feed conversion efficiency in weaned pigs with inclusion
rates from 46 to 444 mEq of formate per kilogram of
diet and in fattening pigs with inclusion rates from 77
to 231 mEq of formate per kilogram of diet (Partanen
and Mroz, 1999; Partanen, 2001). Feed intake was also
greater on the acidified diets in weaned pigs (Partanen,
2001). Inclusion rates in the current experiment were
from 154 to 232 mEq of formate per kilogram of diet in
the nursery phase and from 116 to 193 mEq/kg of diet
in the grower-finisher phases. These levels are within
the range evaluated by Partanen and Mroz (1999).