Use of zilpaterol hydrochloride on feedlot diets of nellore cattle

Author(s)

André Luis Coneglian Brichi

• Document type: Master's Dissertation
• Press: Botucatu. 2015-03-03.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu
• Defense date: 2014-11-14
• Advisor: Mario de Beni Arrigoni; Danilo Domingues Millen

Abstract

This objective was to evaluate the inclusion of Zilpaterol hydrochloride (CZ) ration on performance, carcass characteristics, feeding behavior and meat quality of feedlot Nellore. 72 male animals were used, 36 steers and bulls 36, with average weight of 347.5 kg ± 21.61 kg, and from rearing in continuous grazing. The experimental design was a randomized block in a 2 x 2 factorial arrangement of treatments (sex and ZH), as follows: steers without CZ (CC) or with CZ (CCZ), bulls without CZ (NCC) or with CZ (NCCZ). Each treatment consisted of 6 pens (3 animals/pen), which were considered the experimental units for this study. The CZ was administrated during the last 20 days of feeding (7,5 mg/kg of dry matter), allowing 3 days of withdrawl priot to slaughter. There was CZ main effect (P < 0,01) for average daily gain and feed efficiency during CZ treatment period. Morevoer, it was an interaction (Sex x CZ) (P < 0,04) where both dry matter intake in kilos (DMI) and as percentage of body weight (IMSPV) were reduced for CCZ. The administration of CZ considering the entire trial resulted (P < 0,04) in reduction of IMSPV and improved feed and biological efficiencies. Also, it was observed a CZ main effect (P < 0,04), where animals fed CZ presented heavier hot and cold carcass weight, and larger LM area. The feeding of CZ led to heavier weights for most of the meat cuts analyzed, especially the cuts from the hindquarter. No significant CZ main effect was observed for final 12th back fat thickness, shear force and meat color. For sensory analysis of meat, steers were not harmed when supplemented with CZ. Thus, the addition of CZ in diets for finishing Nellore bulls and steers improves performance and carcass yield without substantially affecting the quality of the final product. (AU)

• FAPESP's process: 13/04593-6 - Use of dietary zilpaterol hydrochloride Nelore cattle feedlot
• Grantee: André Luis Coneglian Brichi
• Support Opportunities: Scholarships in Brazil - Master