EFFECTS OF LOW AND HIGH FILL DIETS ON INTAKE AND MILK-PRODUCTION IN DAIRY-COWS

Thirty-four lactating dairy cows were allotted to two groups based on previous lactation mature equivalent 305-d milk production (average 30 and 23 kg/d) and assigned randomly to four dietary treatments. Diets with slow (high fill) or fast (low fill) estimated rates of NDF disappearance, with or without the addition of 1.5% sodium bicarbonate, were limit-fed 2 wk prior to calving, then fed for ad libitum consumption until 10 wk postpartum. In a summary of pooled data from high and low production groups, average milk and milk protein production (kilograms per day), and NDF and ADF in-takes on a percentage of BW basis were higher for cows given the low fill diet (35.22 vs. 32.07, 1.13 vs. .97, 1.16 vs. 1.05, and .58 vs. .51, respectively). Production of 4% FCM, milk fat, and percentages of milk protein and fat were not affected by diet. Dry matter intake and mean BW did not differ significantly among diets. The addition of sodium bicarbonate had no effect on production responses. © 1990, American Dairy Science Association. All rights reserved.