Abstract: The experiment was aimed to study the effect on the relevance of hormone level and dairy gain of Xinjiang Brown Bull calves by herding supplementary feeding. Selected 70 10-month-old Xinjiang Brown calves, and divided them into control group (grazing) and experimental group (herding supplementary feeding). Respectively, in the experiment we measured male gives birth weight, and tested blood samples of the content of growth hormone, testosterone, insulin, somatostatin, thyroid group, three iodine a gland acid and glucocorticoids in 0, 30, 60, 90 and 120 d. The results showed that the sire calf serum GHcontents had no significant difference in test the whole period (P>0.05). The serum T content of test group calves was significantly higher than the control group in 90 d (P<0.05). There was no significant difference between the control group and the test group in 30, 60, and 120 d (P>0.05). The serum T4 content of test group calves was significantly higher than the control group in 60, 90 d (P<0.05).The sire calf serum T3 content of the groups was no significant difference in test the 30, 60, and 120 d (P>0.05). The calf serum T3 content of test group was significantly higher than the control group in 90 d (P<0.05). In conlusion, Xinjiang Brown Bull calves were reasonably supplementary the nutrients of protein and energy, could significantly improve the dairy gain of the male calves under the warm season natural pasture grazing conditions (P<0.01).

Key words: grazing; herding supplementary feeding; hormone; dairy gain