Fazzio L E, Sánchez R O, Streitenberger N, Galvan W R, Giudici C J, Gimeno E J
Vet Parasitol. 2014 Dec 15;206(3-4):240-5. doi: 10.1016/j.vetpar.2014.10.010.
The aim of this study was to evaluate, in a commercial feedlot, the effect of different anthelmintic drugs on the productivity of naturally infected calves from a cow-calf operation, where resistance to ivermectin (IVM) has been previously detected. The study began with the random selection of 80 calves whose weight was 132 ± 12 kg. Four groups were made: IVM, ricobendazole (RBZ), ricobendazole plus levamisol (RBZ + LEV) and a control group (CG) without treatment. On days 0, 21, 42, 70, 98 and 126, manual collection of fecal matter and individual weight were registered. Mixed SAS procedure was used for statistical analysis. The percentages of fecal egg count reduction test (FECRT) calculated 21 days post treatment (PT) were 18%, 96% and 100% for the IVM, RBZ and RBZ + LEV groups, respectively. Body weight (± SEM) at the end of the trial was 266 kg (± 0.9), 269 kg (± 1.1), 276 kg (± 1.3), 280 kg (± 1.9) for CG, IVM, RBZ and RBZ + LEV groups, respectively. The effect on live weight was highly significant (p < 0001). After 126 days of fattening, the deleterious effect of the combination of Cooperia and Haemonchus in the IVM group on body weight was evident. Undetected animals carrying anthelmintic resistant (AR) worms entering the feedlot, could cause major productivity losses.
本研究的目的是在一个商业饲养场中，评估不同驱虫药物对来自一个已检测到对伊维菌素（IVM）耐药的肉牛繁育场中自然感染犊牛生产力的影响。该研究始于随机选择80头体重为132±12千克的犊牛。将其分为四组：伊维菌素组（IVM）、瑞考苯达唑组（RBZ）、瑞考苯达唑加左旋咪唑组（RBZ + LEV）和一个未治疗的对照组（CG）。在第0、21、42、70、98和126天，记录人工采集的粪便样本和个体体重。使用混合SAS程序进行统计分析。治疗后21天计算的粪便虫卵计数减少试验（FECRT）百分比，IVM组、RBZ组和RBZ + LEV组分别为18%、96%和100%。试验结束时，CG组、IVM组、RBZ组和RBZ + LEV组的体重（±标准误）分别为266千克（±0.9）、269千克（±1.1）、276千克（±1.3）、280千克（±1.9）。对活体重的影响非常显著（p < 0.001）。育肥126天后，IVM组中库珀属线虫和血矛线虫组合对体重的有害影响明显。携带抗驱虫药（AR）蠕虫的未检测到的动物进入饲养场，可能会导致重大的生产力损失。
