Fetal infection with bovine viral diarrhea virus (BVDV) after 150 d results in transient fetal infections (TI). Twenty-five unvaccinated, yearling Hereford heifers, seronegative for antibodies to BVDV1 and BVDV2, were bred by artificial insemination with X chromosome-bearing sperm from one Angus sire to examine the impact of TI on postnatal growth, estimated dry matter digestibility, blood parameters, and carcass characteristics. On d 175 of pregnancy, dams were intranasally inoculated with either sham control or 4.0 log median tissue culture infectious dose noncytopathic type2 BVDV to generate control or TI offspring, respectively. All control dams remained seronegative and all BVDV-inoculated dams seroconverted by d 14 post-inoculation. All control offspring were seronegative and all TI offspring were seropositive for antibodies to type 2 BVDV at birth. All offspring were raised on pasture until weaning. At weaning, all calves were transported to our research feedlot facility, housed in three pens, and transitioned to a high-energy concentrate-based diet. Heifer body weights (BW) and jugular blood samples were collected every 28 d. On d 84 of the feeding period, titanium dioxide was added to the diet of 12, age-paired, individually fed, heifers (6 control and 6 TI heifers; approximately 1 yr. of age) for 28 d and used to estimate dry matter digestibility. On d 105 and 240 ruminal fluid (approximately 900 ml) was collected from every animal using a stomach pump and analyzed for short chain fatty acids (SCFA). After approximately 287 d on feed, heifers were transported to a USDA-inspected abattoir and harvested. TI heifers had lighter final BW (P < 0.04) when compared to control heifers. Average daily gain was greater (P < 0.01) in control compared to TI heifers. TI heifers had a 2.2% lesser (P < 0.05) apparent dry matter digestibility, lighter (P < 0.01) hot carcass weights, but similar ruminal SCFA compared to controls. Blood glucose concentrations were similar (P > 0.8) between control and TI heifers. Ceruloplasmin activity (P < 0.03) and the oxidized form of glutathione (GSSG; P < 0.01), indicators of chronic inflammation, were increased in plasma from TI heifers compared to controls. Other indicators of oxidative stress were not impacted (P > 0.10) by TI status. These data suggest that fetal BVDV transient infection negatively impacts growth throughout the feeding period, possibly by impacting gastrointestinal tract function and increasing systemic inflammation.

中文翻译：

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妊娠晚期母体感染牛病毒性腹泻病毒会影响后代饲养场的性能、消化、血液参数和热胴体重量


150 天后胎儿感染牛病毒性腹泻病毒 （BVDV） 会导致短暂性胎儿感染 （TI）。25 头未接种疫苗的一岁赫里福德小母牛，BVDV1 和 BVDV2 抗体血清反应阴性，通过人工授精与来自一头安格斯公牛的 X 染色体精子进行繁殖，以检查 TI 对出生后生长、估计干物质消化率、血液参数和胴体特征的影响。在妊娠第 175 天，鼻内接种假对照或 4.0 对数中位组织培养感染剂量非细胞病性 2 型 BVDV，分别产生对照或 TI 后代。所有对照母细胞保持血清阴性，所有接种 BVDV 的母细胞在接种后第 14 天发生血清转化。所有对照后代在出生时均呈血清阴性，所有 TI 后代的 2 型 BVDV 抗体血清反应呈阳性。所有后代都在牧场上饲养，直到断奶。断奶时，所有犊牛都被运送到我们的研究饲养场设施，饲养在三个围栏中，并过渡到以高能量精料为基础的日粮。每 28 d 收集一次小母牛体重 （BW） 和颈静脉血样。在饲喂期的第 84 天，将二氧化钛添加到 12 头年龄配对、单独饲喂的小母牛（6 头对照小母牛和 6 头 TI 小母牛;大约 1 岁）的饮食中，持续 28 天，用于估计干物质消化率。在第 105 天和第 240 天，使用胃泵从每只动物身上收集瘤胃液 （约 900 ml） 并分析短链脂肪酸 （SCFA）。在饲料大约 287 天后，小母牛被运送到美国农业部检查的屠宰场并收获。与对照小母牛相比，TI 小母牛的最终体重较轻 （P < 0.04）。与 TI 小母牛相比，对照组的平均日增重更高 （P < 0.01）。 与对照组相比，TI 小母牛的表观干物质消化率降低了 2.2% （P < 0.05），热胴体重量较轻 （P < 0.01），但瘤胃 SCFA 相似。对照小母牛和 TI 小母牛的血糖浓度相似 （P > 0.8）。铜蓝蛋白活性 （P < 0.03） 和谷胱甘肽的氧化形式 （GSSG;P < 0.01），与对照组相比，TI 小母牛血浆中慢性炎症指标增加。氧化应激的其他指标不受 TI 状态的影响 （P > 0.10）。这些数据表明，胎儿 BVDV 短暂感染会对整个喂养期的生长产生负面影响，可能是通过影响胃肠道功能和增加全身炎症。