Ball Jase J, Taube Patrick C, Hallberg John W, Wood-Follis Stacey L, Dykstra Carleen R, Nadrasik Angela N, Eberhart Nicole L, Jones Shelby L, Borchers Karmella D, Scramlin Jordan A, Bechtol David T, Waite Audie R, Edmonds Matthew D, Herrick Ryan T, Lechtenberg Kelly F, Lawrence Ty E
Zoetis, Inc., Kalamazoo, MI 49007, USA.
Agri Research Center, Inc., Canyon, TX 79015 , USA.
Transl Anim Sci. 2022 Aug 18;6(4):txac109. doi: 10.1093/tas/txac109. eCollection 2022 Oct.
Growth-promoting implants are broadly used in the feedlot industry to improve growth performance and to increase production efficiencies. With cattle being fed longer and to heavier weights, there is demand for extended-release implants that payout for at least 200 d. Our objective was to evaluate feedlot growth of Synovex ONE Grower, a moderate potency (150 mg trenbolone acetate [TBA] and 21 mg estradiol benzoate [EB]), extended-release, growth-promoting implant for 200 d. At four locations (Texas, Idaho, California, and Nebraska), 200 steers ( = 800; d 0 body weight [BW] = 320.2 ± 9.5 kg) and 200 heifers ( = 800; d 0 BW = 311.5 ± 9.5 kg) were blocked by BW and randomized to 1 of 2 treatments: 1) , empty subcutaneous needle inserted and extracted from the middle third of one ear; 2) , 150 mg TBA and 21 mg EB extended-release implant administered in middle third of one ear. Treatments were commingled within pen of the same sex ( = 4/site; 2/sex/site) in a split plot design replicated across four sites. Cattle were fed finishing ration ad libitum common to each geographical region at least once daily and were observed for any abnormal health events twice daily. Treatments were administered on d 0. Mid-study implant site evaluations were performed on d 35 or 41. Initial BW was recorded on d 0 and final BW was recorded on d 200 to 204. Cattle were harvested from d 201 to 231; however, carcass data were not collected due to slaughter facility complications brought on by the COVID-19 pandemic. Data were analyzed using the PROC MIXED and PROC GLIMMIX procedures of SAS (Version 9.4, SAS Institute, Cary, NC; < 0.05), and animal was the experimental unit. There were no treatment × sex interactions ( ≥ 0.052) for any variable. Final BW on d 200 was greater ( < 0.01) for steers and heifers implanted with ONE Grower compared to Control; ONE Grower improved final BW by 5.7% for steers and 3.9% for heifers. Overall average daily gain (ADG) from d 0 to 200 was greater ( < 0.01) for ONE Grower steers and heifers compared to Control with an increase in ADG of 13.1% for steers and 8.9% for heifers. For cattle implanted with ONE Grower, implant retention rates at d 35 or 41 were 95.7% and 96.3% for steers and heifers, respectively. There was no difference ( ≥ 0.32) in percentage deads, removals, or bullers (steers) between treatments. Synovex ONE Grower improved final BW and ADG in feedlot steers and heifers fed for at least 200 d.
促生长植入剂在育肥牛产业中被广泛使用，以提高生长性能并提升生产效率。随着牛的饲养期延长且体重增加，人们对释放期至少为200天的长效植入剂有了需求。我们的目标是评估Synovex ONE Grower（一种中等效力[150毫克醋酸群勃龙（TBA）和21毫克苯甲酸雌二醇（EB）]、长效、促生长植入剂）对育肥牛200天生长情况的影响。在四个地点（得克萨斯州、爱达荷州、加利福尼亚州和内布拉斯加州），200头公牛（共800头；第0天体重[BW]=320.2±9.5千克）和200头小母牛（共800头；第0天BW=311.5±9.5千克）按体重进行分组，并随机分为两种处理中的一种：1）对照组，在一只耳朵的中三分之一处插入并拔出空的皮下注射针；2）处理组，在一只耳朵的中三分之一处植入150毫克TBA和21毫克EB长效植入剂。在四个地点重复进行的裂区设计中，相同性别的牛群（每个地点4组；每个性别每个地点2组）被混合在一个围栏内。牛每天至少自由采食一次每个地理区域常见的育肥牛日粮，并每天观察两次是否有任何异常健康事件。处理在第0天进行。在第35天或第41天对植入部位进行中期评估。在第0天记录初始体重，在第200天至204天记录最终体重。牛在第201天至231天进行屠宰；然而，由于新冠疫情导致屠宰设施出现并发症，未收集胴体数据。使用SAS（版本9.4，SAS研究所，北卡罗来纳州卡里）的PROC MIXED和PROC GLIMMIX程序对数据进行分析（P<0.05），动物为实验单位。对于任何变量，均不存在处理×性别交互作用（P≥0.052）。与对照组相比，植入ONE Grower的公牛和小母牛在第200天的最终体重更高（P<0.01）；ONE Grower使公牛的最终体重提高了5.7%，小母牛提高了3.9%。与对照组相比，ONE Grower公牛和小母牛从第0天到200天的总体平均日增重（ADG）更高（P<0.01），公牛的ADG增加了13.1%，小母牛增加了8.9%。对于植入ONE Grower的牛，在第35天或第41天，公牛和小母牛的植入保留率分别为95.7%和96.3%。两种处理之间在死亡、淘汰或公牛（公牛）百分比方面没有差异（P≥0.32）。Synovex ONE Grower提高了育肥牛和育肥小母牛至少200天饲养期后的最终体重和ADG。
