Liquid effluent from baker's yeast production was fed to dairy cows to
determine whether effluent is an acceptable feed and whether it affec
ts milk yield or composition. Effluent averaged 5.4% DM and 6.1% N (DM
basis). In Experiment 1, 20 Holstein cows were offered effluent free
choice or no effluent for 8 wk. Milk yield, composition, and group fee
d intake were measured. In Experiment 2, 20 cows were fed effluent ble
nded into the TMR (11.3 L/d per cow) or no effluent for 4 wk. In Exper
iment 3, six groups of 6 heifers were offered free choice or no efflue
nt. Free choice intake of effluent peaked at 15 L/d per cow at wk 3 bu
t declined to 5.3 L/d per cow by wk 6. Milk and 3.5% FCM yields were n
ot affected by effluent regardless of feeding system. Milk protein and
fat percentages were higher for cows offered effluent free choice. Mi
lk protein percentage and yield were lower with effluent in the TMR. I
ntake of effluent by heifers was 1.05 L/d, and effluent did not affect
DMI or weight gain. Acceptability of yeast effluent fed free choice i
s poor, but when yeast is blended into the TMR, cows consume effluent
without adverse effects on milk yield or DMI.