This study was conducted to investigate the effect of dietary chromium-methionine (Cr-Met) supplementa-tion on growth performance, feeding behavior and physiological responses of Holstein male calves during two different phases of body weight (BW). Twenty six (153.5±9.83 kg of BW) male calves were divided in two groups (n=13) and randomly assigned to treatments: 1) control and 2) Cr-Met (1.1 mg Cr/kg of diet on a dry matter (DM) basis). Each phase consisted of 1 week pen acclimatization, 3 weeks diet adaptation and 1 week sample collection. After the first phase, all calves received the basal diet (without Cr-Met) for 6 weeks. After this period, the second phase started (240.1±12.15 kg BW). During the second phase treat-ments changed between 2 groups. Calves fed with Cr-Met diet had lower DM intake and average daily gain (P<0.05) and rectal temperature (P<0.01) than the control group, whereas blood metabolites and feeding behaviors were similar between 2 groups during the first phase of experiment. During the second phase, calves fed with Cr-Met had greater DM intake, weight gain, average daily gain and standing time behavior (P<0.05) and lower blood glucose concentration, rectal temperature and resting time behavior (P<0.05) compared with calves fed with control diet. In conclusion, effect of feeding 1.1 mg Cr/kg DM as Cr-Met supplement to Holstein male calves on growth performance, blood glucose and resting and standing behav-ior might be related to body weight.
