A study was conducted in grazing dairy heifers to assess anthelmintic efficacy and production responses in dairy heifers treated with a single injection of eprinomectin in an extended-release formulation over a 123 day-period. The study was conducted on a pasture-based dairy in the Southeastern United States (North Carolina) over the summer months. Sixty crossbred dairy heifers were weighed and randomly allocated into 2 groups. One group (n = 30) was given 5% eprinomectin subcutaneously in the cervical region while the other group (n = 30) was given an equivalent volume of saline. Calves were weighed every 30 days throughout the trial for calculation of average daily gain and differences in overall weight gain. In addition, fecal samples were collected at days 0, 30, 60, 90 and 123 for worm egg count and coproculture. Both groups of cattle had similar worm egg concentrations at the start of the study. However, the control group had increasing concentrations of fecal worm eggs throughout the summer months while the heifers that received eprinomectin had minimal fecal worm eggs. The primary parasite species identified in this study were Haemonchus placei, Cooperia species and Ostertagia. The heifers that received eprinomectin gained 105 + 2.8 kg during the 123-day study period, representing an average daily gain of 0.85 kg/day compared to 78.3 + 4.1 kg (0.64 kg/day) for the control group. This represented a 33 % increase in average daily gain associated with deworming. The results of this study indicate that a single dose of extended-release eprinomectin was sufficient to control parasites through a 123-day summer grazing season and that administration of the anthelmintic had a significant impact on weight gain.

在放牧奶牛的过程中进行了一项研究，以评估在123天的时间内以缓释制剂单次注射依普连菌素处理的奶牛的驱虫效果和生产反应。这项研究是在夏季的几个月中，在美国东南部（北卡罗来纳州）基于牧场的乳制品上进行的。称重60头杂交小母牛，并随机分为2组。一组（n = 30）在颈部区域皮下给予5％的抑菌素，而另一组（n = 30）则给予等体积的生理盐水。在整个试验过程中，每30天对小牛称重一次，以计算平均日增重和总增重差异。另外，在第0、30、60、90和123天收集粪便样品以进行蠕虫卵计数和共培养。在研究开始时，两组牛的蠕虫卵浓度相似。然而，在整个夏季，对照组粪便蠕虫卵的浓度增加，而接受埃普诺菌素的小母牛粪便蠕虫卵的含量则最低。在这项研究中确定的主要寄生虫物种是血矛线虫placei，古柏物种和奥斯特线虫。在为期123天的研究期内，接受埃普诺菌素的小母牛的体重增加了105 + 2.8千克，平均每天增加0.85千克/天，而对照组的平均日增重为78.3 + 4.1千克（0.64千克/天）。这表示与驱虫相关的平均每日收益增加了33％。这项研究的结果表明，单剂量的缓释依普诺菌素足以控制整个123天夏季放牧季节的寄生虫，并且驱虫药的使用对体重增加有重大影响。