Department of Animal Science, University of Arkansas, Fayetteville 72701, USA.
J Anim Sci. 2013 Mar;91(3):1400-8. doi: 10.2527/jas.2011-4875. Epub 2013 Jan 23.
Exposure to animals persistently infected (PI) with bovine viral diarrhea virus (BVDV) results in immunomodulation in cohorts. It is hypothesized that the extent of modulation differs for low-risk, preconditioned (PC) vs. high-risk, auction market (AM) beef cattle. Our objective was to compare immune responses of PC or AM calves in the presence (PI) or absence (CON) of a PI-BVDV pen mate. Crossbred PC steers (n = 27) from a single ranch origin were weaned, dewormed, vaccinated against respiratory and clostridial pathogens, tested for PI-BVDV, and kept on the ranch for 61 d. Subsequently, PC steers were transported to a receiving unit (RU), weighed, stratified by d -1 BW, and assigned randomly to treatment (PCPI or PCCON) with no additional processing. Simultaneously, crossbred AM calves (n = 27) were assembled from regional auction markets and transported to the RU. The AM calves were weighed, stratified by gender and d -1 BW, processed under the same regimen used for PC steers at their origin ranch, except bull calves were castrated, then assigned randomly to treatment (AMPI or AMCON). Treatment pens were arranged spatially so that PI did not have fence line contact with CON. Blood samples were collected on d 0, 1, 3, 7, and 14 to determine serum concentrations of haptoglobin (Hp), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), IL-4, and IL-6. Rectal temperature (RT) was recorded concurrent with blood sampling. In AM calves, RT and Hp increased (management effect; P < 0.001) sharply on d 1; however, exposure to a PI-BVDV pen mate did not affect either variable (P ≥ 0.79) during the 14-d evaluation period. Serum concentrations of TNF-α tended to increase (P = 0.09) for the PI cohort. A treatment × day interaction (P ≤ 0.05) was observed for IFN-γ on d 7 and 14 and IL-6 on d 14; these indices were greatest for AMPI. Results indicate weaning management and PI-BVDV exposure alter the immune status of newly received beef cattle. These main effects may be additive because proinflammatory cytokine concentrations were greatest for AMPI. Therefore, results further indicate that potential health or growth consequences in cohorts exposed to a PI-BVDV pen mate are impacted by previous management and health history.
动物持续感染牛病毒性腹泻病毒（BVDV）会导致队列中的免疫调节。据推测，低风险、预处理（PC）与高风险、拍卖市场（AM）肉牛之间的调节程度存在差异。我们的目的是比较存在（PI）或不存在（CON）PI-BVDV 圈舍伴侣时 PC 或 AM 小牛的免疫反应。来自单一牧场的杂交 PC 阉牛（n = 27）断奶、驱虫、接种呼吸道和梭菌病原体疫苗、检测 PI-BVDV，并在牧场饲养 61 天。随后，PC 阉牛被运往接收单位（RU），称重，按 d-1 BW 分层，并随机分配到处理（PCPI 或 PCCON），无额外处理。同时，从区域拍卖市场汇集了杂交 AM 小牛（n = 27），并运往 RU。AM 小牛称重，按性别和 d-1 BW 分层，按照他们在起源牧场使用的相同方案进行处理，除了公牛小牛被去势，然后随机分配到处理（AMPI 或 AMCON）。处理栏空间排列，使 PI 与 CON 没有围栏线接触。在 d 0、1、3、7 和 14 时采集血样，以确定血清中结合珠蛋白（Hp）、肿瘤坏死因子-α（TNF-α）、干扰素-γ（IFN-γ）、IL-4 和 IL-6 的浓度。同时记录直肠温度（RT）。在 AM 小牛中，RT 和 Hp 在 d 1 急剧升高（管理效应；P < 0.001）；然而，在 14 天的评估期内，接触 PI-BVDV 圈舍伴侣并未影响这两个变量（P ≥ 0.79）。PI 队列中 TNF-α的血清浓度有升高趋势（P = 0.09）。在 d 7 和 14 时观察到 IFN-γ和 d 14 时的 IL-6 存在处理×天交互作用（P ≤ 0.05）；这些指数在 AMPI 中最大。结果表明，断奶管理和 PI-BVDV 暴露改变了新接收肉牛的免疫状态。这些主要效应可能是相加的，因为促炎细胞因子浓度在 AMPI 中最大。因此，结果进一步表明，暴露于 PI-BVDV 圈舍伴侣的队列中的潜在健康或生长后果受到先前管理和健康史的影响。
