Cônsolo N R B, Rodriguez F D, Goulart R S, Frasseto M O, Ferrari V B, Silva L F P
J Anim Sci. 2015 Oct;93(10):4948-55. doi: 10.2527/jas.2015-9291.
This research aimed to evaluate the effects of zilpaterol hydrochloride (ZH; MSD Animal Health, São Paulo, SP, Brazil) on the performance, carcass traits, serum metabolites, body composition, and gain composition of nonimplanted Nellore heifers. Nellore heifers ( = 72; average BW = 267 ± 16 kg; average 18 mo of age) were maintained in a feedlot system for 118 d. Heifers were separated into 2 groups: Control and ZH. The ZH group received ZH (8.3 mg/kg diet DM) for 30 d with 3 d of withdrawal before slaughter. Heifers were allotted to 18 pens, 9 pens per treatment, and assigned to a randomized block design. The animals were weighed, blood samples were collected, and subgroups of heifers were slaughtered at the beginning of supplementation and after 20 and 33 d to evaluate performance, blood metabolites, empty BW (EBW), and EBW composition. Hot carcass and kidney-pelvic fat weights were recorded at slaughter. At 24 h postmortem, carcasses were fabricated and the 9-10-11th rib (HH) section was removed from the primal rib to analyze moisture, protein, ash, and ether extract (EE) content in empty body (EB) and gain composition. Heifers fed ZH had gains in HCW that were 19.7 kg greater than controls, reflecting the 30% increase ( < 0.01) in ADG. There was no change in DMI, resulting in a 20% greater G:F ratio ( < 0.01) for heifers fed ZH. Heifers supplemented with ZH had carcass dressing percentages that were 3% greater than controls ( < 0.01), and there was also a 19% reduction in kidney-pelvic fat ( = 0.05) in ZH-treated heifers. Zilpaterol increased serum creatinine ( < 0.01), tended to increase ( = 0.06) serum triacylglycerol, decreased serum NEFA ( = 0.04), and tended to decrease ( = 0.06) serum glucose. The EBW composition was changed after 20 d of ZH supplementation ( = 0.02), with ZH increasing the moisture, ash, and protein contents, whereas carcass fat was decreased by ZH by 14%. Consequently, the carcass CP:EE ratio after 20 d was increased ( = 0.03) by 24% with ZH supplementation. There was no change on EBW composition after 30 d of ZH supplementation ( = 0.17). Regarding carcass gain composition, ZH increased EBW gain ( = 0.02) by 842 g/d from d 0 to d 30, EB protein gain by 221 g/d ( = 0.05) from d 0 to d 20, and by 180 g/d ( = 0.01) from d 0 to d 33. In conclusion, ZH supplementation in nonimplanted Nellore heifers altered the composition of body weight gain, promoting greater lean tissue deposition and improving feed efficiency.
本研究旨在评估盐酸齐帕特罗（ZH；巴西圣保罗默克动物保健公司生产）对未植入激素的内洛尔小母牛的生产性能、胴体性状、血清代谢物、身体组成及增重组成的影响。内洛尔小母牛（n = 72；平均体重 = 267 ± 16 kg；平均年龄18月龄）在饲养场系统中饲养118天。小母牛被分为两组：对照组和ZH组。ZH组在屠宰前30天饲喂ZH（8.3 mg/kg日粮干物质），停药3天。小母牛被分配到18个栏中，每个处理9个栏，并采用随机区组设计。在补饲开始时、20天和33天后对动物进行称重、采集血样，并宰杀小母牛亚组以评估生产性能、血液代谢物、空体重（EBW）及EBW组成。屠宰时记录热胴体重和肾盆腔脂肪重量。宰后24小时，分割胴体，并从主肋骨上取下第9 - 10 - 11肋（HH）部分，分析空体（EB）中的水分、蛋白质、灰分和乙醚提取物（EE）含量以及增重组成。饲喂ZH的小母牛热胴体重增加量比对照组高19.7 kg，反映出平均日增重（ADG）提高了30%（P < 0.01）。干物质采食量（DMI）没有变化，导致饲喂ZH的小母牛料重比（G:F）提高了20%（P < 0.01）。补充ZH的小母牛胴体屠宰率比对照组高3%（P < 0.01），且ZH处理的小母牛肾盆腔脂肪也减少了19%（P = 0.05）。齐帕特罗使血清肌酐升高（P < 0.01），血清三酰甘油有升高趋势（P = 0.06），血清非酯化脂肪酸（NEFA）降低（P = 0.04），血清葡萄糖有降低趋势（P = 0.06）。补充ZH 20天后EBW组成发生变化（P = 0.02），ZH增加了水分、灰分和蛋白质含量，而胴体脂肪减少了14%。因此，补充ZH 20天后胴体蛋白质:EE比值提高了24%（P = 0.03）。补充ZH 30天后EBW组成没有变化（P = 0.17）。关于胴体增重组成，从第0天到第30天，ZH使EBW增重提高了842 g/d（P = 0.02），从第0天到第20天EB蛋白质增重提高了221 g/d（P = 0.05），从第0天到第33天提高了180 g/d（P = 0.01）。总之，在未植入激素的内洛尔小母牛中补充ZH改变了体重增重组成，促进了更多瘦肉组织沉积并提高了饲料效率。
