Mayer Lauren M, Martens Kevin, Word Alyssa B, Holland Ben P, Lucherk Loni L, Lawrence Ty E, Tennant Travis C
Beef Carcass Research Center, West Texas A&M University, Canyon, TX 79016, USA.
Life Products, Inc., Norfolk, NE 68701, USA.
Transl Anim Sci. 2022 May 26;6(3):txac073. doi: 10.1093/tas/txac073. eCollection 2022 Jul.
Crossbred beef heifers (= 1,394; initial shrunk body weight [BW] 291 ± 9.9 kg) were used to investigate the efficacy of 10-G Armor (Life Products, Inc., Norfolk, NE; 10-G) upon feedlot performance, carcass characteristics, and fecal and subiliac lymph nodes prevalence. Heifers were blocked by day of arrival and allocated to 1 of 20 pens ( = 70 heifers/pen) and assigned one of two treatments (10 pens/treatment): no direct-fed microbial (CON) or 2 g/heifer/d of and , respectively (Life Products, Inc., Norfolk, NE; 10-G). Twenty-four animals were randomly selected from each pen for sampling. Recto-anal mucosal swab samples (RAMS) were obtained at initial processing and harvest; subiliac lymph nodes were collected at harvest. In addition, pen surface fecal pats were collected and composited by pen (10 pats per composite, 5 composites per pen) on days 0, 52, 120, and 192. Data were analyzed as a generalized complete block design, and pen served as the experimental unit. No differences were observed in live growth performance metrics ( ≥ 0.55). Yield grade distributions did not differ between treatments ( ≥ 0.62); however, cattle fed 10-G tended ( = 0.06; 14.6% vs. 18.9%) to have fewer USDA Select carcasses and more ( = 0.09; 73.6% vs. 78.0%) USDA Choice carcasses. Cattle fed 10-G tended ( = 0.10; 9.2% vs. 12.3%) to have fewer liver abscesses and had fewer ( = 0.04; 5.3% vs. 8.5%) severe liver abscesses. prevalence of RAMS did not differ between treatments at initial processing ( = 0.97; CON = 11.6%, 10-G = 11.5%) or at harvest ( = 0.91; CON = 99.0%, 10-G = 98.6%); however, RAMS differed ( < 0.01) in prevalence between the two collection times. Cattle fed 10-G had a lower frequency of positive lymph nodes ( = 0.01; CON = 15.8%, 10-G = 7.4%) than CON. However, log (mpn/g) of lymph nodes did not differ between treatments at harvest ( = 0.34; CON = 0.73, 10-G = 0.34). These data indicate that cattle fed 10-G have decreased rates of severe liver abscesses without altering live animal performance or carcass characteristics. Supplementation of 10-G significantly reduced the prevalence rate of recovered from the subiliac lymph nodes. The factors responsible for the observed difference in the effects of 10-G on warrant further investigation.
选用杂交肉牛小母牛（共1394头；初始缩体体重[BW]为291±9.9千克）来研究10-G Armor（生命产品公司，内布拉斯加州诺福克；10-G）对饲养场性能、胴体特征以及粪便和髂下淋巴结患病率的影响。小母牛按到达日期进行分栏，分配到20个栏舍中的1个（每个栏舍70头小母牛），并给予两种处理之一（每种处理10个栏舍）：不添加直接投喂微生物（CON）或每头小母牛每天分别投喂2克10-G（生命产品公司，内布拉斯加州诺福克）。从每个栏舍中随机选取24头动物进行样本采集。在初始处理和出栏时获取直肠-肛门黏膜拭子样本（RAMS）；在出栏时收集髂下淋巴结。此外，在第0、52、120和192天收集栏舍表面的粪便块，并按栏舍进行混合（每个混合物10块粪便，每个栏舍5个混合物）。数据作为广义完全区组设计进行分析，栏舍作为实验单位。在活体生长性能指标方面未观察到差异（P≥0.55）。处理之间的产量等级分布没有差异（P≥0.62）；然而，饲喂10-G的牛倾向于（P = 0.06；14.6%对18.9%）拥有更少的美国农业部精选级胴体和更多（P = 0.09；73.6%对78.0%）的美国农业部特选级胴体。饲喂10-G的牛倾向于（P = 0.10；9.2%对12.3%）有更少的肝脓肿，并且严重肝脓肿更少（P = 0.04；5.3%对8.5%）。在初始处理时（P = 0.97；CON = 11.6%，10-G = 11.5%）或出栏时（P = 0.91；CON = 99.0%，10-G = 98.6%），处理之间RAMS的患病率没有差异；然而，在两个采集时间点之间，RAMS的患病率存在差异（P<0.01）。饲喂10-G的牛的阳性淋巴结频率低于CON（P = 0.01；CON = 15.8%，10-G = 7.4%）。然而，出栏时淋巴结的log（mpn/g）在处理之间没有差异（P = 0.34；CON = 0.73，10-G = 0.34）。这些数据表明，饲喂10-G的牛严重肝脓肿的发生率降低，而不会改变活体动物性能或胴体特征。添加10-G显著降低了从髂下淋巴结中检出的患病率。导致观察到的10-G对影响差异的因素值得进一步研究。
