With the objective of evaluating different levels of IGF-I on the hepatical and intestinal indicators of cellular activity in newborn calves, 42 pregnant Holstein cows were randomly assigned to two groups: a) control: injection of vitamin E or b) rbST: injection of growth hormone (rbST). Injections started 35 days pre-partum and were repeated every 14 days until parturition. Newborn calves were randomly assigned to a 2 x 3 factorial arrangement of treatments (two mother groups and three different ages). After slaughter, samples from liver, jejunum and ileum were collected. Calves from rbST group showed lower levels of DNA and protein in jejunum at seven days of age, while protein concentration increased at two days of age. Similar response was observed for the ratio of protein/RNA in jejunum. In the control group, the increase in protein concentration was observed in the seventh day of age. The indicators of cellular activity measured in this trial suggested that greater IGF-I concentration in colostrum of rbST treated cows promoted intestinal cellular maturation by affecting behavior of first generation enterocytes.
calf; cellular activity; IGF-I; intestinal tract; somatotropin
