This study was conducted to evaluate effects of mixture essences of thyme, oregano and rosemary and mixture of the essence extracted residues on growth performance, weaning age and blood metabolite in Holstein calves. A total of 60 male and female Holstein calves were assigned to treatments using a completely randomized design with 3 × 2 factorial methods. The treatments were: 1- basic starter without additives (control), 2- basic starter with equal portion of the three herbal essences (thyme, oregano and rosemary, 300mg/kg dry matter), and 3- basic starter with equal portion of the three essence extracted residues (thyme, oregano and rosemary, 50g/kg dry matter). The starters were fed from day 7 until weaning time and then all calves were fed with routine weaned calves’ diets without any additive up to 4 months age. Weaning age was determined according to reach 1000 g dry matter intake in three consecutive days. Two methods were used for weaning: 1- suddenly weaning, and 2- gradually weaning. So, befor weaning 3 treatments and after weaning 6 treatments were tested. The intake of starter wasmeasured daily. Body weight and fecal score were recorded weekly. Blood sampleswere collectedduringthe weaning days. The results showed that consumption herbal essence and the residual improved average daily gain, feed intake and feed conversion ratio compared to the control group (p 0.05). Weaning age in residue and essence group was lower than the control group (p 0.05). The weight at one month after weaning was higher (p 0.05) for residue and the essence group than the control group. The weight at two months after weaning was not affected by the treatments. Gradually weaning and using the essences increased calves' blood glucose levels and reduced the blood cholesterol numerically, however the differences was not significant (p 0.05). On day 1 of weaning the essence group with suddenly weaning had lower AST (p 0.05) compared to the control group with gradually weaning. Suddenly weaning decreased (p 0.05) triglyceride levels compared to the gradually weaning. It was concluded that essence and essence extracted residues of thyme, oregano and rosemary had positive effects on performance of Holstain calves and reduced their weaning age. Keywords : Essential oil, Essence extracted residue, Weaning age, Holstein calves
