rate of ruminal carbohydrate fermentation may be
too slow to allow ruminal bacteria to capture readily
available protein for microbial protein synthesis. Under
these conditions, increasing the rate of carbohydrate
fermentation could increase microbial protein synthesis
and therefore improve the supply of MP to dairy
cows (Broderick et al., 2002). Given that sugars are
more rapidly fermented in the rumen than starch, these
could serve as an effective supplement for high-alfalfa
silage-based diets. Molasses in dry or liquid form is a
practical source of rapidly fermented sugars for feeding
dairy cows. Previous studies showed positive effects of
added dry or liquid molasses on FCM, milk fat concentration,
ruminal NH3-N, MUN, and fiber digestibility
(Broderick and Radloff, 2004). Those authors recommended
an optimum inclusion rate of 2.4% liquid or
dried molasses to diets formulated with alfalfa and
corn silages. However, feeding higher levels of molasses
was found to reduce cow performance (Broderick and
Radloff, 2004). Data regarding the effects of molasses
inclusion in high-alfalfa silage diets on the performance
of dairy cows are limited. The objectives of this study
were to determine the effects of adding dried molasses
to high-alfalfa silage-based diets on performance, ruminal
fermentation, and total-tract nutrient utilization by
lactating dairy cows.