cows were used in a replicated Lati

cows were used in a replicated Latin
square experiment to determine the effect of adding
dried molasses to high-alfalfa silage diets on dairy cow
performance. Three isonitrogenous diets were formulated
with a 68:32 forage:concentrate ratio, with alfalfa
silage as the only forage source. Dietary treatments
were a control diet with no added molasses and 3 and
6% dried molasses diets. Three lactating Holstein cows
fitted with ruminal cannulas were used to determine
the effects of dietary treatments on ruminal fermentation.
Dietary treatments had no effect on dry matter
(average 23.3 kg/d), crude protein (average 4.4 kg/d),
or neutral detergent fiber (average 7.4 kg/d) intake.
Milk yield, energy-corrected milk (average 35.4 kg/d),
and 4% fat-corrected milk (average 33.8 kg/d) were not
influenced by dietary treatments. Cows fed the control
diet produced milk with less milk urea nitrogen
concentration than those fed molasses-supplemented
diets. Ruminal pH, NH3-N concentration, and total
volatile fatty acids were not different among dietary
treatments. The molar proportion of acetate linearly
increased, whereas the molar proportion of propionate
linearly decreased as the level of dried molasses increased.
It was concluded that addition of dried molasses
to high-alfalfa silage diets at 6% of the diet (dry
matter basis) increased milk urea nitrogen but had no
effect on animal performance.