Effects on Growth Performance, Plasma Variables and Gene Expression of Hepatic Gluconeogenic Enzymes in Holstein Calves Fed Limited Amount of Concentrate

This study elucidated the effects of limited concentrate feeding on growth, plasma profile, and gene expression of gluconeogenic enzymes in the liver of dairy calves. The study utilized 12 Holstein male dairy calves (100 days of age) divided into two groups of 6 calves each for 155 days. Control (CON) group received 1.8 kg/calf/day of concentrate, whereas calves in the feed restricted (FR) group only received 1.0 kg/calf/day. Good quality forage (Timothy hay) was available ad libitum to both groups. Body weights (BW) were recorded at start and at fortnightly intervals. Blood samples were collected at start and thereafter at approximately 50 days interval. On days 100 and 155, liver biopsies were collected from all animals in each group. Results showed that the BW was not different between the groups at the end of the study, however, at 6, 7, 8 and 9 fortnights higher (P<0.05) BW were recorded in the CON than the FR group. Total BW gain in CON and FR group was 114 kg and 98.2 kg, with ADG of 736 g and 634 g in respective groups (P=0.051). The plasma variables were within normal range in both groups. The mRNA expressions for the gluconeogenic enzymes, cytosolic phosphoenol pyruvate carboxykinase (EC 4.1.1.32) and pyruvate carboxylase (EC 6.4.1.1) measured by quantitative real-time PCR in liver biopsies showed no differences between groups. Overall, restricting concentrate moderately reduced the growth intensity with-out affecting the normal plasma indices and gene expression indicating that restricting concentrate feeding scheme could be applied in dairy calves.