Buckhaus Elizabeth M, Smith Zachary K
Department of Animal Science, South Dakota State University, Brookings, SD 57007, USA.
Animals (Basel). 2021 Feb 23;11(2):579. doi: 10.3390/ani11020579.
Maine-Anjou × Angus cross-bred steers ( = 156 steers; initial body weight (BW) 366 ± 37.2 kg) were used in a 132 d finishing study conducted at the Ruminant Nutrition Center (RNC) in Brookings, SD. Steers were blocked by weight ( = 5 BW blocks) and randomly assigned to an implant and dietary treatment of a randomized complete block design with each pen containing seven to eight steers ( = 20 pens). Dietary treatments consisted of (1) 15% (CS15) or (2) 30% corn silage (CS30) where corn silage displaced corn grain in the diet. Steers received one of two implants (both from Zoetis, Parsippany, NJ) containing equal doses of trenbolone acetate (TBA) and estradiol benzoate (EB): (1) Synovex PLUS (non-coated implant; 200 mg TBA and 28 mg EB; PLUS) or (2) Synovex ONE Feedlot (coated implant; 200 mg TBA and 28 mg EB; ONE-F). Bunks were managed using a slick bunk approach, and all diets contained dry matter (DM) basis 33 mg/kg monensin sodium. All steers were offered access to feed, and feeding occurred twice daily in equal portions. There was no interaction between the implant and dietary treatment for any variables measured ( ≥ 0.08). Carcass-adjusted basis final BW, average daily gain (ADG), and grain to feed (G:F) were increased ( ≤ 0.02) by 2.2%, 6.5%, and 7.2%, respectively, for CS15. Observed net energy (NE) and the ratio of observed-to-expected NE for maintenance and gain was not influenced ( ≥ 0.15) by silage inclusion treatment. Beef production per hectare was not impacted ( ≥ 0.13) by corn silage inclusion level. Fecal output was increased, and digestibility coefficients for dry matter, organic matter, and crude protein were decreased in CS30 ( ≤ 0.03). Dressing percent and hot carcass weight (HCW) were greater ( ≤ 0.02) in CS15. Implant type did not influence any traits measured ( ≥ 0.14) except for marbling. Marbling was decreased for PLUS (433 vs. 466 ± 17.5; 0.02) compared to ONE-F steers. Similar beef produced per hectare of crop land-based upon silage feeding level means producers can feed greater inclusions of corn silage to finishing cattle without impacting carcass quality or beef production; implanting with a coated implant had no detrimental effects to growth performance but increases marbling scores.
在南达科他州布鲁金斯的反刍动物营养中心（RNC）进行了一项为期132天的育肥研究，使用了缅因-安茹×安格斯杂交阉牛（共156头阉牛；初始体重（BW）366±37.2千克）。阉牛按体重进行分组（共5个体重组），并随机分配到植入物和日粮处理组，采用随机完全区组设计，每个围栏中有7至8头阉牛（共20个围栏）。日粮处理包括：（1）15%玉米青贮（CS15）或（2）30%玉米青贮（CS30），其中玉米青贮替代了日粮中的玉米籽粒。阉牛接受两种植入物之一（均来自新泽西州帕西帕尼市的硕腾公司），其含有等量的醋酸去甲雄三烯醇酮（TBA）和苯甲酸雌二醇（EB）：（1）赛诺威克PLUS（非包被植入物；200毫克TBA和28毫克EB；PLUS）或（2）赛诺威克ONE育肥场（包被植入物；200毫克TBA和28毫克EB；ONE-F）。采用光滑饲槽法管理饲槽，所有日粮以干物质（DM）计含有33毫克/千克莫能菌素钠。所有阉牛均可自由采食，每天分两次等量投喂。对于所测量的任何变量，植入物和日粮处理之间均无交互作用（P≥0.08）。以胴体调整后的最终体重、平均日增重（ADG）和谷物与饲料比（G:F）计算，CS15组分别提高了（P≤0.02）2.2%、6.5%和7.2%。青贮料添加处理对观察到的净能（NE）以及维持和增重的观察净能与预期净能之比没有影响（P≥0.15）。每公顷牛肉产量不受玉米青贮添加水平的影响（P≥0.13）。CS30组的粪便产量增加，干物质、有机物和粗蛋白的消化率系数降低（P≤0.03）。CS15组的屠宰率和热胴体重（HCW）更高（P≤0.02）。除大理石花纹外，植入物类型对所测量的任何性状均无影响（P≥0.14）。与ONE-F阉牛相比，PLUS阉牛的大理石花纹减少（433对466±17.5；P=0.02）。基于青贮料饲喂水平，每公顷耕地生产的牛肉相似，这意味着生产者可以在不影响胴体品质或牛肉产量的情况下，给育肥牛饲喂更多的玉米青贮；使用包被植入物对生长性能没有不利影响，但会提高大理石花纹评分。
