Plunkett Amanda H, Graham Thomas W, Famula Thomas R, Oberbauer Anita M
Department of Animal Science, College of Agricultural and Environmental Sciences, University of California-Davis, Davis, CA 95616, USA.
J Am Vet Med Assoc. 2013 Jun 1;242(11):1564-72. doi: 10.2460/javma.242.11.1564.
To determine whether vaccination with a monovalent vaccine against Leptospira borgpetersenii serovar Hardjo strain hardjobovis would improve reproductive efficiency in Holstein cattle in a commercial dairy setting.
Randomized controlled trial.
1,894 Holstein cows and heifers from a Central California dairy.
Cattle were assigned to undergo SC administration of a monovalent vaccine against Leptospira borgpetersenii serovar Hardjo strain hardjobovis (n = 986) or a placebo (lactated Ringer's solution; 908). At the end of their lactation period, cows received 2 doses of the vaccine or placebo, 28 to 35 days apart, with the initial dose administered in conjunction with oxytetracycline. Heifers received the same treatments, with the second dose administered at least 2 weeks before their entrance into the heifer breeding pen. Urine and blood samples were collected from randomly selected cattle immediately before and 1 year after the trial began and submitted for fluorescent antibody and microscopic agglutination testing to identify any infecting Leptospira serovar.
The initial herd prevalence of active infection with strain hardjobovis was 13% (6/46 tested cattle), followed by 15% (6/40) 1 year after the trial began. The odds of heifers conceiving over the period at risk for conception, regardless of vaccination, was approximately 2.8 times as high as for primiparous and pluriparous cows. Survival analysis of days from parturition to conception revealed that the vaccine protocol had no effect on the probability of conception between the vaccinated and control groups. The vaccine protocol had no impact on pregnancy loss.
The evaluated vaccination protocol against Leptospira strain hardjobovis was not effective in improving reproductive efficiency in commercial Holstein dairy cows or in decreasing urine shedding of leptospires.
确定接种针对波氏疏螺旋体哈氏变种hardjobovis血清型的单价疫苗是否会提高商业化奶牛场荷斯坦奶牛的繁殖效率。
随机对照试验。
来自加利福尼亚州中部一家奶牛场的1894头荷斯坦奶牛和小母牛。
牛被分配接受皮下注射针对波氏疏螺旋体哈氏变种hardjobovis血清型的单价疫苗（n = 986）或安慰剂（乳酸林格氏液；908）。在泌乳期末，奶牛接受2剂疫苗或安慰剂，间隔28至35天，初始剂量与土霉素联合给药。小母牛接受相同的处理，第二剂在进入小母牛繁殖栏前至少2周给药。在试验开始前和开始后1年，从随机选择的牛身上采集尿液和血液样本，提交进行荧光抗体和显微镜凝集试验，以鉴定任何感染的疏螺旋体血清型。
试验开始时，hardjobovis菌株的初始群体感染率为13%（46头检测牛中有6头），试验开始1年后为15%（40头中有6头）。无论是否接种疫苗，小母牛在受孕风险期受孕的几率约为初产和经产奶牛的2.8倍。从分娩到受孕天数的生存分析表明，疫苗方案对接种组和对照组之间的受孕概率没有影响。疫苗方案对妊娠丢失没有影响。
评估的针对hardjobovis菌株的疫苗接种方案在提高商业化荷斯坦奶牛的繁殖效率或减少钩端螺旋体尿排泄方面无效。
