Mackey Shea J, Cooke Reinaldo F, de Souza Izadora S, Pickett Autumn T
Department of Animal Science - Texas A&M University, College Station, TX 77845, USA.
Vet Anim Sci. 2025 Apr 26;29:100457. doi: 10.1016/j.vas.2025.100457. eCollection 2025 Sep.
This experiment evaluated physiological and performance responses of feedlot steers administered the maternal bovine appeasing substance () during the finishing period (day 0 to 178). Steers used in this experiment were the same used to evaluate mBAS during the receiving period whose results have been published (Pickett et al., 2024). After the receiving period, steers were fed a growing diet for 65 days before the finishing period (without mBAS administration). On day 0, steers were assigned to topical administration (10 mL) of: 1) mineral oil on day 0 and 88 (), or 2) mBAS on day 0 and 88. Steers that were administered mBAS during the receiving period were also administered mBAS during the finishing period, and the same process applied to CON steers. Cortisol concentrations were measured in tail-switch hair on days 0 and 15. Steers received a growth-promoting reimplant on day 88. Total cattle used since the receiving period was 120 Angus steers, which were assigned in 10 drylot pens (12 steers/pen, 5 pens/treatment). Steers were slaughtered on day 179, and carcass variables were measured. Feed intake did not differ ( = 0.57) between treatments, but average daily gain was increased by 5.6 % ( < 0.04) in mBAS steers, improving their gain:feed by 7.6 % ( < 0.01). No treatment effects were noted ( ≥ 0.24) for carcass weight and variables. Collectively, mBAS administration to feedlot steers at the beginning of the finishing period and at reimplant improved growth rates without altering feed intake, suggesting the use of mBAS to promote productive efficiency of feedlot systems.
本实验评估了育肥期（第0天至178天）接受母体牛安抚物质（ ）的育肥牛的生理和生产性能反应。本实验中使用的育肥牛与在接收期评估母体牛安抚物质时使用的相同，其结果已发表（Pickett等人，2024年）。接收期结束后，育肥牛在育肥期前65天饲喂生长日粮（不施用母体牛安抚物质）。在第0天，将育肥牛分配进行局部施用（10毫升）：1）在第0天和第88天施用矿物油（ ），或2）在第0天和第88天施用母体牛安抚物质。在接收期接受母体牛安抚物质的育肥牛在育肥期也施用母体牛安抚物质，对照组育肥牛也采用相同的处理方式。在第0天和第15天测量尾梢毛发中的皮质醇浓度。在第88天给育肥牛植入促生长剂。自接收期以来使用的牛总数为120头安格斯育肥牛，分配到10个干栏式畜栏（每栏12头牛，每个处理5栏）。在第179天屠宰育肥牛，并测量胴体变量。各处理间的采食量没有差异（ = 0.57），但母体牛安抚物质处理的育肥牛平均日增重提高了5.6%（ < 0.04），其增重：采食量提高了7.6%（ < 0.01）。胴体重和变量未观察到处理效应（ ≥ 0.24）。总体而言，在育肥期开始时和植入促生长剂时给育肥牛施用母体牛安抚物质可提高生长速度，而不改变采食量，这表明使用母体牛安抚物质可提高育肥系统的生产效率。
