This study aimed to determine semen quality and seminal biochemicals at 1^st ejaculate, puberty, and maturity of Holstein bulls administrated with GnRH, hCG and testosterone. Holstein male calves (n=16, 8 mo old) were divided into four groups, 4 in each. During 10-weeks interval, each animal was bi-weekly i.m injected with saline (2 ml), 2 ml GnRH, 1500 IU hCG, and 2 ml testosterone. Results indicated the earliest ages to 1^st ejaculation, puberty, and maturity by hCG. Ejaculate volume was higher (P<0.05) by GnRH. Sperm motility and livability increased (P<0.05) by GnRH. Seminal total proteins (TP) and albumin (AL) decreased (P<0.05) by GnRH and hCG. Globulin (GL) and fructose decreased (P<0.05) by treatments in the 1^st ejaculate. At puberty and maturity, TP, AL, and fructose increased (P<0.05) by treatments. GL increased (P<0.05) by GnRH and hCG. AL:GL increased by GnRH and testosterone at puberty, and by testosterone at maturity. Triglycerides in 1^st ejaculation increased (P<0.05) by GnRH. At puberty, HDL, LDL, cholesterol, and triglycerides in GnRH; LDL, cholesterol, and triglycerides in hCG; and triglycerides in testosterone increased (P<0.05). while HDL in hCG and testosterone decreased (P<0.05). At maturity, LDL and cholesterol in hCG, and triglycerides in GnRH and hCG increased (P<0.05), while HDL decreased (P<0.05) by treatments.This study concluded that the treatment of Holstein male calves with GnRH or hCG (once/two weeks) for 10 weeks prior to puberty (8 months of age) leads to early sexual puberty-maturity ages and semen with good quality and chemical composition.