Diet composition is shown in
Table 2. The diets were formulated to meet the nutrient
requirements of a 600 kg second lactation cow at 75 DIM
and producing 40 kg of milk daily (National Research Council
(NRC), 2001). Cows were fed the diets as a total mixed
ration (TMR) once daily at 0800 h for ad libitum intake
allowing for 100 g/kg refusals. To determine DMI, the amount
of feed offered and orts were weighed and recorded daily
during the collection period.