Evolution of fructosaminaemia and glucaemia during the growth of unweaned and early weaned half-bred zebu calves.

The purposes of the study were to obtain the confidence intervals for serum fructosamine concentrations in unweaned and early weaned calves, to verify the changes in this glycated protein during growth, when glucaemia declines, and to assess the changes in both parameters attributable to stress or alarm. Sixty out of 120 suckling half-bred zebu calves (60-75 days old) were weaned at day 0 and then received a commercial balanced diet, while the remainder continued to suck. Blood samples were taken at 0, 7, 14, 21, 28, 60, 90 and 120 days and the serum fructosamine and glucose concentrations were measured by conventional methods. Both biochemical parameters declined with time, but there were no statistical differences between the unweaned and weaned calves. The fall in fructosamine concentration correlated significantly with the decline in glucose concentrations in both groups. The confidence interval for fructosamine concentration decreased with age, from 294-303 micromol/L at 2 months old to 215-232 micromol/L at 6 months old. At the same time, glucaemia declined from 7.5-8.6 mmol/L to 4.8-5.3 mmol/L. Acute elevations in glucaemia, especially in the younger calves, were attributed to alarms, such as those caused by handling and blood extraction. The absence of resultant increases in fructosamine concentration discounts the existence of prolonged hyperglucaemias (stress) in early weaned calves.