Pancreatic beta-cell function is positively correlated with the size of newborn Holstein calves

Newborn calves (40 males and 38 females) of Holstein heifers (n = 28) and cows (n = 50) were used to evaluate the association between their body size and pancreatic b-cell function. The calves were weighed and specific body sizes were measured in the morning of their 3rd day of life following an overnight fast. At the same time an intravenous glucosestimulated insulin secretion (GSIS) test was performed. For this, blood samples were taken before and exactly 10 min after the calves had been given an intravenous glucose bolus of 150 mg/kg. The body weight, heart girth and diagonal length of the calves were 41.2 ± 5.03 kg, 80.1 ± 3.62 cm and 70.5 ± 3.56 cm, respectively. Although the basal glucose (G0, 5.9 ± 0.68 mM/l vs. 6.0 ± 0.83 mM/l) did not differ between calves of primiparous vs. multiparous dams (p = 0.73); the basal insulin (I0) of calves of primiparous dams tended (p = 0.14) to be lower (8.5 ± 6.47 mU/l vs. 10.5 ± 8.83 mU/l). The I0 was
positively correlated with the weight (r = 0.22, p = 0.05), heart girth (r = 0.21, p = 0.06), and diagonal length (r = 0.24, p = 0.03) of the calves. The insulin sensitivity index (ISI, I0/G0) was also positively correlated with the weight (r = 0.24, p = 0.05), heart girth (r = 0.21, p = 0.08), and diagonal length (r = 0.29, p = 0.01) of the calf. The insulin secretion following a standard glucose bolus as quantified by
the insulinogenic index [IGI, (I10-I0)/(G10-G0)] tended to be positively correlated with the weight (r = 0.17, p = 0.16), heart girth (r = 0.22, 0.07), and diagonal length (r = 0.15, p = 0.23) of the calf. These preliminary data suggesting a significant correlation between the b-cell function and the size of a newborn Holstein calf warrant further investigation with a higher number of calves.