Herein, we investigate the effects of a long-term release trenbolone acetate and estradiol implant (200 mg and 40 mg respectively, Revalor-XS; Merck Animal Health; Summit, NJ) on implanted [IMP; n = 9, body weight (BW) = 473.13 kg ± 25.22] and non-implanted (NIMP; n = 9, BW = 481.13 kg ± 21.78) finished Angus Hereford steers fed a single diet three times daily (0600, 1100, 1600 h). The objectives were to identify water and feed efficiency parameters and mechanisms of IMP and NIMP steers. Parameters evaluated included daily dry matter intake (DMI), freshwater intake (FWI), average daily gain (ADG), animal water units (AWU), drinking behavior, feed conversion (FC), feed conversion ratio (FCR), water conversion (WC), water conversion ratio (WCR), residual growth rate (RGR), and Kleiber index (KI). Linear mixed models were fitted to analyze the data under assumption of a completely randomized design, and variable relationships examined through partial correlation networks and principal component analysis. Implanted animals were more feed efficient than NIMP for FC (P < 0.001; SEM = 0.00), FCR (P < 0.001; SEM = 0.29), RGR (P < 0.001; SEM = 0.0.02), and KI (P < 0.001; SEM = 0.00). When evaluating water efficiency, IMP animals had less WCR (P < 0.001; SEM = 1.54) and greater WC (P < 0.001; SEM = 0.001). No differences were observed on marbling and carcass grades, but carcass weight, final BW, and rib eye area were greater for IMP groups (P < 0.001, P < 0.001, P = 0.004, respectively). For IMP, multivariate variable contribution (values > 10) appeared to associate FWI on the first and second eigenvectors with DMI, FC, and FCR. For NIMP, FWI was associated with WC, WCR, and AWU. The FWI of Implanted animals was associated with AWU, WCR, while NIMP was associated with AWU. Feed conversion ratio and DMI had the greatest node strength for the IMP animals, whereas for NIMP, KI was the only node with strength greater than 2. Our results indicate that feed and water efficiencies may share mechanistic pathways. We present a simple metric that accurately remains relevant in evaluating water requirements for both IMP and NIMP steers as AWU. We show how relationship strength is related to gain and efficiency for IMP animals, whereas metabolic activity, potentially in relation to body composition changes, drives the variation and relationships for NIMP animals.

中文翻译：

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PSX-18 成品安格斯赫里福德犊牛的长期植入：研究饲料与水效率之间的关系


在此，我们研究了长期释放醋酸群勃龙和雌二醇植入物（分别为 200 毫克和 40 毫克，Revalor-XS;默克动物保健公司;新泽西州萨米特）对植入的 [IMP;n = 9，体重 （BW） = 473.13 公斤± 25.22] 和非植入的 （NIMP;n = 9，BW = 481.13 公斤 ± 21.78） 完成的安格斯赫里福德阉牛每天喂食 3 次（0600、1100、1600 小时）。目标是确定 IMP 和 NIMP 犊牛的水和饲料效率参数和机制。评估的参数包括每日干物质摄入量 （DMI）、淡水摄入量 （FWI）、平均日增重 （ADG）、动物水单位 （AWU）、饮用行为、饲料转化率 （FC）、饲料转化率 （FCR）、水转化率 （WC）、水分转化率 （WCR）、残余生长率 （RGR） 和克莱伯指数 （KI）。在完全随机设计的假设下拟合线性混合模型来分析数据，并通过部分相关网络和主成分分析检查变量关系。植入的动物比 NIMP 的 FC 饲料效率更高 （P < 0.001;SEM = 0.00）、FCR （P < 0.001;SEM = 0.29）、RGR （P < 0.001;SEM = 0.0.02）和 KI （P < 0.001;SEM = 0.00）。在评估水效率时，IMP 动物的 WCR 较低 （P < 0.001;SEM = 1.54）和更大的WC（P < 0.001;SEM = 0.001）。在大理石花纹和胴体等级上未观察到差异，但 IMP 组的胴体重量、最终 BW 和肋眼面积更大 （分别为 P < 0.001、P < 0.001、P = 0.004）。对于 IMP，多变量变量贡献 （值 > 10） 似乎将第一和第二特征向量上的 FWI 与 DMI 、 FC 和 FCR 相关联。对于 NIMP，FWI 与 WC、WCR 和 AWU 相关。 植入动物的 FWI 与 AWU 、 WCR 相关，而 NIMP 与 AWU 相关。饲料转化率和 DMI 在 IMP 动物中具有最大的节点强度，而对于 NIMP，KI 是唯一强度大于 2 的节点。我们的结果表明，饲料效率和水效率可能共享机械途径。我们提出了一个简单的指标，该指标在评估 IMP 和 NIMP 公牛作为 AWU 的水分需求时准确保持相关性。我们展示了关系强度与 IMP 动物的增重和效率的关系，而可能与身体成分变化相关的代谢活动推动了 NIMP 动物的变化和关系。