The bovine appeasing substance (BAS) is expected to have calming effects in cattle experiencing stressful situations. Therefore, this study investigated the impacts of BAS administration during two of the most stressful events within beef production systems: weaning and feedlot entry. In experiment 1, 186 Bos indicus-influenced calves (73 heifers, 113 bulls) were weaned at 211 ± 1 days of age (day 0). At weaning, calves were ranked by sex and BW, and assigned to receive BAS (Nutricorp, Araras, SP, Brazil; n = 94) or water (CON; n = 92). Treatments (5 ml) were topically applied to the nuchal skin area of each animal. Calf BW was recorded and samples of blood and tail-switch hair were collected on days 0, 15 and 45. Calves that received BAS had greater (P < 0.01) BW gain from day 0 to 15 compared with CON. Overall BW gain (days 0 to 45) and BW on days 15 and 45 were also greater (P ≤ 0.03) in BAS v. CON. Plasma haptoglobin concentration was less (P < 0.01) in BAS v. CON on day 15, whereas cortisol concentrations in plasma and tail-switch hair did not differ between treatments (P ≥ 0.13). In experiment 2, 140 B. indicus-influenced bulls (∼27 months of age) from 2 different pasture-based systems (70 bulls/origin) were transported to a commercial feedlot (≤ 200-km transport; day -1). On day 0, bulls were ranked by source and BW, and assigned to receive BAS (n = 70) or CON (n = 70) and the same sampling procedures as in experiment 1. Bulls receiving BAS had greater (P = 0.04) BW gain from day 0 to 15, but less (P < 0.01) BW gain from day 15 to 45 compared to CON. No other treatment effects were detected (P > 0.14). Therefore, BAS administration to beef calves alleviated the haptoglobin response associated with weaning, and improved calf growth during the subsequent 45 days. Administration of BAS to beef bulls at feedlot entry improved BW gain during the initial 15 days, but these benefits were not sustained throughout the 45-day experiment.

中文翻译：

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简短交流：在断奶和饲养场入口处，给受Bos indicus影响的肉牛施用适量的物质。

预期牛易感物质（BAS）在遇到压力情况的牛中具有镇定作用。因此，本研究调查了牛肉生产系统中两个最紧张的事件：断奶和饲养场进入期间，BAS管理的影响。在实验1中，在211±1天龄（第0天）断奶了186头受到Bos标记影响的牛（73头小母牛，113头公牛）。断奶时，按性别和体重对小牛进行排名，并分配给它们以接受BAS（Nutricorp，Araras，SP，巴西； n = 94）或水（CON； n = 92）。将治疗剂（5 ml）局部施用于每只动物的颈部皮肤区域。记录小腿体重，并在第0、15和45天收集血液和尾巴转换头发的样本。与CON相比，接受BAS的小牛从0天到15天的体重增加更大（P <0.01）。在BAS诉CON中，总体BW增益（第0至45天）以及第15和45天的BW也更大（P≤0.03）。在第15天，BAS v。CON中的血浆触珠蛋白浓度较低（P <0.01），而血浆和尾巴转换毛的皮质醇浓度在两种处理之间没有差异（P≥0.13）。在实验2中，将来自2种不同的以牧场为基础的系统（70头公牛/产地）的140株受到B. indicus感染的公牛（约70头公牛）运到了商业饲养场（≤200公里运输；第-1天）。在第0天，按照来源和体重对公牛进行排名，并分配其接受BAS（n = 70）或CON（n = 70）并采用与实验1相同的采样程序。接受BAS的公牛的BW更大（P = 0.04）从第0天到15天的体重增加，但与CON相比，从第15天到45天的体重增加较少（P <0.01）。未检测到其他治疗效果（P> 0.14）。因此，对牛肉犊进行BAS管理可减轻与断奶有关的触珠蛋白反应，并在随后的45天内改善犊牛的生长。在肥育场入口处向牛肉公牛施用BAS可以改善最初15天的体重增加，但是在整个45天的试验中这些好处并未持续。