摘要
With increased regulations regarding the use of feed-grade antimicrobials in livestock systems, alternative strategies to enhance growth and immunity of feedlot cattle are warranted. Hence, this experiment compared performance, health and physiological responses of cattle supplemented with feed-grade antibiotics or alternative feed ingredients during the initial 60 days in the feedlot. Angus×Hereford calves (63 steers+42 heifers) originating from two cow–calf ranches were weaned on day −3, obtained from an auction yard on day −2 and road-transported (800 km; 12 h) to the feedlot. Upon arrival on day −1, shrunk BW was recorded. On day 0, calves were ranked by sex, source and shrunk BW, and allocated to one of 21 pens. Pens were assigned to receive (7 pens/treatment) a free-choice total mixed ration containing: (1) lasalocid (360 mg/calf daily of Bovatec; Zoetis, Florham Park, NJ, USA)+chlortetracycline (350 mg/calf of Aureomycin at cycles of 5-day inclusion and 2-day removal from diet; Zoetis) from days 0 to 32, and monensin only (360 mg/calf daily of Rumensin; Elanco Animal Health, Greenfield, IN, USA) from days 33 to 60 (PC), (2) sodium saccharin-based sweetener (Sucram at 0.04 g/kg of diet dry matter; Pancosma SA; Geneva, Switzerland)+plant extracts containing eugenol, cinnamaldehyde and capsicum (800 mg/calf daily of XTRACT Ruminants 7065; Pancosma SA) from days 0 to 32 and XTRACT only (800 mg/calf daily) from days 33 to 60 (EG) or (3) no supplemental ingredients (CON; days 0 to 60). Calves were assessed for bovine respiratory disease (BRD) signs and dry matter intake was recorded from each pen daily. Calves were vaccinated against BRD pathogens on days 0 and 22. Shrunk BW was recorded on day 61, and blood samples collected on days 0, 6, 11, 22, 33, 43 and 60. Calf ADG was greater (P=0.04) in PC v. EG and tended (P=0.09) to be greater in PC v. CON. Feed efficiency also tended (P=0.09) to be greater in PC v. CON, although main treatment effect for this response was not significant (P=0.23). Mean serum titers against bovine respiratory syncytial virus were greater in EG v. PC (P=0.04) and CON (tendency; P=0.08). Collectively, the inclusion of alternative feed ingredients prevented the decrease in feed efficiency when chlortetracycline and ionophores were not added to the initial feedlot diet, and improved antibody response to vaccination against the bovine respiratory syncytial virus in newly weaned cattle.
摘要译文
随着关于在牲畜系统中使用饲料级抗微生物剂的更多规定，有必要采取替代策略来提高饲养场牛的生长和免疫力。因此，该实验比较了在饲养场中最初60天期间补充有饲料级抗生素或替代饲料成分的牛的性能，健康和生理反应。安格斯×赫里福德牛犊（63头阉牛+42头小母牛）来自两头牛犊牧场，在第-3天断奶，第二天从拍卖场获得，并在公路上运输（800公里; 12 h）到饲养场。在第-1天到达时，记录了缩小的BW。在第0天，小牛按性别，来源和缩小的BW进行排名，并分配给21支笔中的一支。钢笔被指定接受（7笔/处理）自由选择的全混合日粮，其中含有：（1）拉沙里菌素（每天360毫克/小牛的Bovatec; Zoetis，Florham Park，NJ，USA）+金霉素（350mg /小时的金霉素，包括5天的周期和从饮食中取出2天; Zoetis）从第0天到第32天，仅使用莫能菌素（每天360毫克/小时的瘤胃素; Elanco Animal Health，Greenfield，IN，USA，第33至60天（PC），（2）基于糖精的甜味剂（Sucram，0.04 g / kg饮食干物质; Pancosma SA;瑞士日内瓦）+含有丁子香酚，肉桂醛和辣椒的植物提取物（每天800毫克/小牛的XTRACT反刍动物7065; Pancosma SA）从第0天到第32天和仅XTRACT（每天800毫克/小牛）从第33天到第60天（EG）或（3）没有补充成分（CON;第0天到第60天）。评估小牛的牛呼吸道疾病（BRD）征兆，每天记录每支笔的干物质摄入量。在第0天和第22天对小牛进行BRD病原体疫苗接种。第61天记录收缩的BW，第0,6,11,22,33,43和60天收集血样。小牛ADG更高（P = 0.04） PC v.EG并且在PC v.CON中倾向于（P = 0.09）更大。尽管对该反应的主要治疗效果不显着（P = 0.23），但在PC v.CAN中饲料效率也倾向于（P = 0.09）更大。 EG v.PC（P = 0.04）和CON（趋势;平均值）对牛呼吸道合胞病毒的平均血清滴度更高。 P = 0.08）。总的来说，当新的断奶牛中没有添加金霉素和离子载体时，包含替代饲料成分可以防止饲料效率降低，并改善对牛呼吸道合胞病毒疫苗接种的抗体反应。
K. A. de Souza (a1) (a2); R. F. Cooke (a1); K. M. Schubach (a1); A. P. Brandão (a1); T. F. Schumaher (a1) (a3); I. N. Prado (a2); R. S. Marques (a1);D. W. Bohnert (a1).... Performance, health and physiological responses of newly weaned feedlot cattle supplemented with feed-grade antibiotics or alternative feed ingredients[J]. animal, 2018,12(12): 2521-2528