[Effect of high-carbohydrate diet in the form of sugar beet on glucose and ketone body levels in the blood serum of highly pregnant and freshly lactating cows].

In an experiment using 24 high-yielding cows (3rd and 6th lactations), group II was fed sugar beet as carbohydrate source (2 kg DM per animal and day) for 4 weeks before and for 4 weeks after parturition, whilst group I was given the equivalent amount of dried spent beet pulp. Sugar beet feeding during the dry period caused the glucose level in the blood to rise significantly from 48 to 55 mg/100 ml. On the 21st day of lactation the glucose concentration in group II (27 mg) had declined more strongly than in group I (37 mg). Feeding large amounts of easily soluble carbohydrates during the dry period obviously inhibits gluconeogenesis during early lactation. The ketone body level of group II was found to rise to 14 mg/100 ml by the 21st day of lactation (group I--4 mg), a level indicative of ketosis. The ketogenous action (strong formation of butyric acid in the rumen) of sugar beet enhances this effect, too. The daily milk yield did not vary much coming to 26.8 and 27.8 kg in the control and in the experimental group, respectively. The results allow to conclude that feeding fresh sugar beet to high-yielding cows just before and shortly after parturition is not advisable.