A meta-analysis was performed to determine the possible effects of dietary sugar on feed intake
and milk production in lactating dairy cattle. The database used in this analysis included 18
treatment comparisons frozm 10 studies reported from 1985 through 2011. Treatment comparisons
were used only if: (1) either sucrose (9 comparisons) or molasses (9 comparisons) replaced
corn grain without adding fat; and (2) sugar added by treatment ranged from 2 to 5% of
dry matter. First, responses to sucrose and molasses were compared to assess whether these sugar
sources could be considered together. Statistical analysis provided no evidence for different
responses across sugar sources for dry matter intake (DMI), milk yield, energy-corrected milk
(ECM) yield, milk fat content, or milk protein content. Different sugar sources were pooled for
the remaining analyses; the combined data showed that adding sugar tended to increase DMI
by 0.84 lb/day and milk fat content by 0.085%. No effects were detected for milk yield, ECM
yield, or milk protein content. This analysis indicates that adding 2 to 5% dietary sugar may
promote small increases in DMI and milk fat content but does not consistently increase ECM
yield in lactating dairy cattle.
