پردیس کشاورزی و منابع طبیعی دانشگاه تهران Iranian Journal of animal Science 2008-4773 41 1 2010 05 22 Effect of Zinc, Copper and Chlortetracycline Supplementation on Fat Thickness and Longissimus muscle in Young Holstein Bulls Effect of Zinc, Copper and Chlortetracycline Supplementation on Fat Thickness and Longissimus muscle in Young Holstein Bulls 21019 FA Hadi Fagari Nobijari Hamid Amanlou Mehdi Dehghan Banadaki Seyed Hosein Hoseini Sabeghi Khosro Ghazvinian Journal Article 1970 01 01 Three hundred eighteen young Holstein bulls (initial BW = 375 ± 17.5 kg) were randomly allotted to one of six treatments in a completely randomized design for 56 d the treatments of which consisted of 1) the basal diet (control); 2) basal diet plus 30 mg of Cu/kg of DM as CuSO4; 3) basal diet plus 150 mg of Zn/kg of DM as ZnSO4; 4) basal diet plus chlortetracycline (200 mg/animal/d; CTC); 5) basal diet + Cu + CTC; and 6) basal diet + Zn + CTC within the same dose. Effects of treatments on blood metabolites and Back fat thickness, Rump fat thickness, Longissimus muscle area and Hip height were evaluated. Serum urea nitrogen (P < 0.001) and plasma total protein (P < 0.001) were different among treatments. Copper supplementation improved ultrasound index, however, zinc supplementation negatively affected (P < 0.001). As a result, the control of Cu and Zn levels, as replacers for CTC, in the diet of young bulls can increase Longissimus muscle area and can decrease fat thickness. Three hundred eighteen young Holstein bulls (initial BW = 375 ± 17.5 kg) were randomly allotted to one of six treatments in a completely randomized design for 56 d the treatments of which consisted of 1) the basal diet (control); 2) basal diet plus 30 mg of Cu/kg of DM as CuSO4; 3) basal diet plus 150 mg of Zn/kg of DM as ZnSO4; 4) basal diet plus chlortetracycline (200 mg/animal/d; CTC); 5) basal diet + Cu + CTC; and 6) basal diet + Zn + CTC within the same dose. Effects of treatments on blood metabolites and Back fat thickness, Rump fat thickness, Longissimus muscle area and Hip height were evaluated. Serum urea nitrogen (P < 0.001) and plasma total protein (P < 0.001) were different among treatments. Copper supplementation improved ultrasound index, however, zinc supplementation negatively affected (P < 0.001). As a result, the control of Cu and Zn levels, as replacers for CTC, in the diet of young bulls can increase Longissimus muscle area and can decrease fat thickness. https://ijas.ut.ac.ir/article_21019_178c143bf6b4e12f1a4a52ed0223e585.pdf