EFFECTS OF DIFFERENT ENERGY-LEVELS, CONCENTRATE FORAGE RATIOS AND LIPID SUPPLEMENTATION TO THE DIET ON THE ADAPTATION OF THE ENERGY-METABOLISM AT CALVING IN DAIRY-COWS/

A low level of energy (110 MJ ME) and a low concentrate/forage ratio ( 10/90) at calving resulted in low basal concentrations of glucose and insulin, but the cows had the capacity to increase the glucose level a fter glucagon injections. No signs of disturbances in the metabolic ad aptation were observed. High intensity feeding (200 MJ ME and 50% conc entrates) resulted in high basal serum insulin levels. The increase in the insulin concentrations after glucagon injections and the changes in insulin levels around calving varied widely between individual cows . The metabolic adaptation period was longer than in cows in the forme r group. An energy level of 170 MJ ME and variations of concentrate/fo rage ratios (5/95, 30/70 and 60/40) resulted in small differences in b asal glucose and insulin concentrations and in response to glucagon in jections. But the cows fed 60% concentrates showed signs of prolonged metabolic adaptation. Increased lipid concentrations in diets containi ng equal levels of energy and protein resulted in a fall in basal gluc ose and insulin levels and the metabolism seemed to be directed toward s catabolism. Because of these metabolic effects, more needs to be kno wn on fat supplementation if it is used in practical feeding. It is al so necessary to take more interest in the effects of protein feeding o n thr periparturient metabolism.