Epitopix LLC, Willmar, Minnesota 56201, USA.
J Food Prot. 2011 Oct;74(10):1599-604. doi: 10.4315/0362-028X.JFP-11-034.
Extensive research, intervention equipment, money, and media coverage have been directed at controlling Escherichia coli O157:H7 in beef cattle. However, much of the focus has been on controlling this pathogen postcolonization. This study was conducted to examine the performance, health, and shedding characteristics of beef calves that were vaccinated with an E. coli O157:H7 SRP bacterial extract. These calves had been born to cows vaccinated prepartum with the same vaccine. Cows and calves were assigned randomly to one of four treatments: (i) neither cows nor calves vaccinated with E. coli O157:H7 SRP (CON), (ii) cows vaccinated with E. coli O157:H7 SRP prepartum but calves not vaccinated (COWVAC), (iii) calves vaccinated with E. coli O157:H7 SRP but born to cows not vaccinated (CALFVAC), (iv) cows vaccinated with E. coli O157:H7 SRP prepartum and calves also vaccinated (BOTH). Calves born to vaccinated cows had significantly higher titers of anti-E. coli O157:H7 SRP antibodies (SRPAb) in circulation at branding time (P < 0.001). Upon entry to the feedlot, overall fecal E. coli O157:H7 prevalence was 23 % among calves, with 25 % in the CON treatment group, 19 % in the CALFVAC group, 32 % in the COWVAC group, and 15 % in the BOTH group (P > 0.05). Fecal shedding of E. coli O157 on arrival to the feedlot was not correlated with fecal shedding at slaughter (Spearman's rho = -0.02; P = 0.91). No significant effects of cow or calf E. coli O157:H7 SRP vaccination treatment were found on feedlot calf health or performance (P > 0.05), prevalence of lung lesions or liver abscess (P > 0.05), or morbidity, retreatment, or mortality numbers (P > 0.05). The findings of this study indicate that the timing of vaccination of calves against E. coli O157:H7 may be an important consideration for maximizing the field efficacy of this vaccine.
大量的研究、干预设备、资金和媒体报道都集中在控制牛肉中的大肠杆菌 O157:H7。然而，大多数研究都集中在控制该病原体定植后的情况。本研究旨在检测用大肠杆菌 O157:H7 SRP 细菌提取物接种的肉牛犊的性能、健康和排毒特征。这些犊牛是通过对产前母牛接种相同疫苗而出生的。将母牛和犊牛随机分配到以下四种处理之一：（i）母牛和犊牛均未接种大肠杆菌 O157:H7 SRP（CON），（ii）母牛产前接种大肠杆菌 O157:H7 SRP 但犊牛未接种（COWVAC），（iii）犊牛接种大肠杆菌 O157:H7 SRP 但出生于未接种母牛（CALFVAC），（iv）母牛产前接种大肠杆菌 O157:H7 SRP 且犊牛也接种（BOTH）。与未接种母牛所生犊牛相比，产前接种母牛所生犊牛在烙印时血液中大肠杆菌 O157:H7 SRP 抗体（SRPAb）滴度明显更高（P < 0.001）。进入饲养场时，犊牛粪便中大肠杆菌 O157:H7 的总体流行率为 23%，其中 CON 处理组为 25%，CALFVAC 组为 19%，COWVAC 组为 32%，BOTH 组为 15%（P > 0.05）。到达饲养场时粪便中大肠杆菌 O157 的脱落与屠宰时粪便中的脱落无关（Spearman's rho = -0.02；P = 0.91）。母牛或犊牛接种大肠杆菌 O157:H7 SRP 疫苗处理对饲养场犊牛的健康或性能（P > 0.05）、肺部病变或肝脓肿的流行率（P > 0.05）或发病率、再治疗或死亡率（P > 0.05）均无显著影响。本研究结果表明，犊牛接种大肠杆菌 O157:H7 的时间可能是影响该疫苗田间效果的重要因素。
