Department of Agricultural Sciences, West Texas A&M University, Canyon, 79016 TX, USA.
College of Veterinary Medicine, Mississippi State University, Starkville, 39759, MS, USA.
J Anim Sci. 2022 Nov 1;100(11). doi: 10.1093/jas/skac249.
Experimental bovine respiratory syncytial virus (BRSV) infection can enhance Histophilus somni (Hs) disease in calves; we thus hypothesized that modified-live virus (MLV) vaccines containing BRSV may alter Hs carriage. Our objective was to determine the effects of an intranasal (IN) trivalent (infectious bovine rhinotracheitis virus [IBRV], parainfluenza-3 virus [PI3V], and BRSV) respiratory vaccine with parenteral (PT) bivalent bovine viral diarrhea virus (BVDV) type I + II vaccine, or a PT pentavalent (BVDV type I and II, IBRV, BRSV, and PI3V) respiratory vaccine, on health, growth, immunity, and nasal pathogen colonization in high-risk beef calves. Calves (n = 525) were received in five truckload blocks and stratified by body weight (213 ± 18.4 kg), sex, and presence of a pre-existing ear-tag. Pens were spatially arranged in sets of three within a block and randomly assigned to treatment with an empty pen between treatment groups consisting of: 1) no MLV respiratory vaccination (CON), 2) IN trivalent MLV respiratory vaccine with PT BVDV type I + II vaccine (INT), or 3) PT pentavalent, MLV respiratory vaccine (INJ). The pen was the experimental unit, with 15 pens/treatment and 11 to 12 calves/pen in this 70-d receiving study. Health, performance, and BRSV, Hs, Mycoplasma bovis (Mb), Mannheimia haemolytica (Mh), and Pasteurella multocida (Pm) level in nasal swabs via rtPCR was determined on days 0, 7, 14, and 28, and BRSV-specific serum neutralizing antibody titer, and serum IFN-γ concentration via ELISA, were evaluated on days 0, 14, 28, 42, 56, and 70. Morbidity (P = 0.83), mortality (P = 0.68) and average daily gain (P ≥ 0.82) did not differ. Serum antibodies against BRSV increased with time (P < 0.01). There was a treatment × time interaction (P < 0.01) for Hs detection; on days 14 and 28, INT (21.1% and 57.1%) were more frequently (P < 0.01) Hs positive than CON (3.6% and 25.3%) or INJ (3.4 % and 8.4%). Also, INT had reduced (P = 0.03) cycle time of Hs positive samples on day 28. No difference (P ≥ 0.17) was found for IFN-γ concentration and Mb, Mh, or Pm detection. The proportion of Mh positive culture from lung specimens differed (P < 0.01); INT had fewer (0.0%; 0 of 9) Mh positive lungs than INJ (45.5%; 6 of 13) or CON (74.0%; 14 of 19). Vaccination of high-risk calves with MLV did not clearly impact health or growth during the receiving period. However, INT was associated with an altered upper respiratory microbial community in cattle resulting in increased detection and level of Hs.
实验性牛呼吸道合胞病毒（BRSV）感染可增强牛嗜血杆菌（Hs）病在犊牛中的发病程度；因此，我们假设含有 BRSV 的活病毒（MLV）疫苗可能会改变 Hs 的携带情况。我们的目的是确定鼻内（IN）三联（传染性牛鼻气管炎病毒[IBRV]、副流感-3 病毒[PI3V]和 BRSV）呼吸道疫苗与皮下（PT）双价牛病毒性腹泻病毒（BVDV）I+II 疫苗，或 PT 五价（BVDV 型 I 和 II、IBRV、BRSV 和 PI3V）呼吸道疫苗对高危肉牛犊牛的健康、生长、免疫力和鼻腔病原体定植的影响。犊牛（n=525）通过五卡车批次接收，并按体重（213±18.4kg）、性别和是否存在先前的耳标进行分层。在每个批次内，将畜栏以三组的方式空间排列，并随机分配到以下治疗组：1）不接种 MLV 呼吸道疫苗（CON），2）IN 三联 MLV 呼吸道疫苗加 PT BVDV I+II 疫苗（INT），或 3）PT 五价 MLV 呼吸道疫苗（INJ）。畜栏是实验单位，每组 15 个畜栏，每个畜栏 11-12 头犊牛。在这个为期 70 天的接收研究中，在第 0、7、14 和 28 天通过 rtPCR 测定鼻拭子中的健康、性能和 BRSV、Hs、牛支原体（Mb）、曼海姆氏菌（Mh）和多杀性巴氏杆菌（Pm）水平，在第 0、14、28、42、56 和 70 天通过 ELISA 评估 BRSV 特异性血清中和抗体滴度和血清 IFN-γ浓度。发病率（P=0.83）、死亡率（P=0.68）和平均日增重（P≥0.82）没有差异。血清中针对 BRSV 的抗体随时间增加（P＜0.01）。在 Hs 检测方面存在治疗与时间的相互作用（P＜0.01）；在第 14 天和第 28 天，INT（21.1%和 57.1%）比 CON（3.6%和 25.3%）或 INJ（3.4%和 8.4%）更频繁地呈 Hs 阳性（P＜0.01）。此外，INT 在第 28 天还降低了 Hs 阳性样本的循环时间（P=0.03）。IFN-γ浓度和 Mb、Mh 或 Pm 的检测没有差异（P≥0.17）。肺标本中 Mh 阳性培养的比例不同（P＜0.01）；INT 中 Mh 阳性肺的比例（0.0%；9 头中无 1 头）低于 INJ（45.5%；13 头中有 6 头）或 CON（74.0%；19 头中有 14 头）。给高危犊牛接种 MLV 疫苗并没有明显影响牛在接收期的健康或生长情况。然而，INT 与牛的上呼吸道微生物群的改变有关，导致 Hs 的检测和水平增加。
