The effect of feeding a glucogenic dietary supplement during early lactation on somatotropic axis of dairy cows

The aim of the present experiment was to evaluate the effect of feeding a glucogenic diet on the somatotropic axis of early lactation Holstein dairy cows. Sixteen fresh cows were used in a completely randomized design with two treatments and eight replicates in each treat. In the treatment of glucogenic diet, cows received 600 g of encasulated glucose daily as top dressed. In the control treatment, the cows received daily the same amount of glucose and coating material (mainly fat). Experimental diets were fed from day 4 to 30 after calving. Milk production and dry matter intake were recorded daily. Blood samples collected on days 4, 15 and 29 after parturition from coccygeal vein. The results show that there is no significant difference between treatments in terms of milk yield, energy corrected milk yield, 3.5% fat corrected milk yield, dry matter intake and blood glucose concentration. The glucogenic diet caused a significant increase in blood insulin (P<0.05) and a numerical increase in blood IGF-1 (P<0.15). Cows that received control diet showed a significant decrease in IGF-1 concentration (P<0.05) but no significant decrease was observed for cows received diet containing glucogenic supplement. The results of this study showed that feeding a glucogenic supplements can affect the somatotropic axis of early cows and cause an increase glucose turnover and blood insulin and relative improvement of blood IGF-1 levels.