The effect of feeding frequency on the hormonal profile, carcass characteristics, and feedlot performance in Iranian Holstein calves

The aim of the present study was to investigate the effect of feeding frequency on body weight, carcass characteristics, and hormonal profile in Iranian Holstein calves. The study included 12 Holstein bull calves that were assigned to 2 groups according to initial live body weight. The animals were fed a TMR ration based on live body weight. The calves were fed a standard diet for 31 weeks; control calves were fed twice a day and treatment calves were fed 7 times a day. Live body weights were recorded every 21 days. Blood samples were collected 1 h after the final feeding and every 4 h during the last during 24 h of the experiment, and were analyzed for plasma leptin and insulin concentrations. Four calves from each group were slaughtered and carcass characteristics were measured. Plasma leptin concentrations were higher (P < 0.01) between midnight and early morning in the treated group than in the control group. Mean plasma insulin concentration was lower (P < 0.01) in the treated calves than in the control calves. Mean internal fat content and depth of subcutaneous fat were (P < 0.05) higher in the control group than in the treated group, while other carcass characteristics did not significantly differ between the 2 groups. It was concluded that increasing the feeding frequency of fattening Holstein calves decreased fat reservoirs, which was probably accompained by plasma leptin and insulin changes.