Steers are often implanted with androgenic and/or estrogenic hormones to repartition nutrients to increase protein synthesis while increasing feed efficiency and profitability. Long-acting implants with 200 d of activity are available that may simplify multi-implant regimens and reduce labor costs and cattle handling. The purpose of this study was to determine if steers grazing wheat pasture for 180 d and implanted with a long-acting implant containing 150 mg trenbolone acetate and 21 mg estradiol benzoate in a novel, coated formulation (Synovex ONE Grass [SYN]) would increase growth performance compared to steers implanted with either Ralgro (RAL) or Revalor G (REV-G). Crossbred beef steers (n = 345; BW = 252 ± 1.9 kg) were stratified by BW and allocated randomly to 1 of 3 implant treatments (SYN, RAL, or REV-G) based on d -1 BW in a completely randomized design. On d 0, calves were administered the treatment implant according to label. Steers were grazed as a single group and rotated according to forage availability for 180 d on wheat pastures. Body weights were recorded on d -1, 0, 90, 180, and 181. Data were analyzed using the MIXED procedures of SAS with calf serving as the experimental unit with significance declared at P ≤ 0.05. Final BW were not different (P = 0.26; SE = 2.7 kg) between treatments; however, BW were numerically greater in SYN (406 kg) steers compared to RAL (400 kg) and REV-G (401 kg) steers. Average daily gain from d 0 to 90 tended to be greater (P = 0.08) in RAL and REV-G steers compared to SYN. Synovex ONE Grass (1.14 kg/d) ADG from d 90 to 180 was greater (P < 0.0001; SE = 0.02) compared to RAL (1.02 kg/d) or REV-G (1.04 kg/d) steers. Overall, ADG tended to be greater (P = 0.06) in SYN implanted steers compared to RAL and REV-G. The use of SYN improved steer growth performance from d 90 to 180 while BW were not affected by implant for the duration of the 180-d study in steers grazing wheat pasture.

牛通常植入雄激素和/或雌激素，以重新分配营养，以增加蛋白质合成，同时提高饲料效率和利润。有200 d活动的长效植入物可供使用，可以简化多植入物的治疗方案并减少人工成本和牲畜处理。这项研究的目的是确定放牧小麦草场180 d并植入长效植入物（包含150 mg醋酸群勃龙和21 mg雌二醇苯甲酸酯）的新型包衣配方（Synovex ONE Grass [ SYN ]）是否会增加与植入Ralgro（RAL）或Revalor G（REV-G）的ste牛相比，其生长性能更高。牛杂交肉牛（ñ = 345; BW = 252±1.9 kg）通过BW进行分层，并根据完全随机设计将其随机分配至基于d -1 BW的3种植入治疗（SYN，RAL或REV-G）中的1种。在第0天，根据标记向小牛施用治疗植入物。将ers牛放牧作为一个单独的组，并根据草场上的牧草可获得量旋转180天。体重记录于d -1，0，90，180，以及使用SAS的MIXED程序与小牛作为实验单位的显着性在声明181对数据进行分析P  ≤0.05。两次 治疗之间的最终体重无差异（P = 0.26； SE = 2.7 kg）；然而，相比RAL（400 kg）和REV-G（401 kg）牛，SYN（406 kg）牛的体重更高。从d 0到90的平均每日收益趋于更大（ 与SYN相比，RAL和REV-G操纵杆的P = 0.08）。 与RAL（1.02 kg / d）或REV-G（1.04 kg / d）的公牛相比，Synovex ONE Grass（1.14 kg / d）的ADG从d 90到180更高（P <0.0001; SE = 0.02）。总体而言， 与RAL和REV-G相比，SYN植入ste牛的ADG倾向于更大（P = 0.06）。在180天的研究中，SYN的使用将er牛的生长性能从90 d提高到180 d，而在放牧小麦牧场的ers牛中，BW不受植入物的影响。