Gastrointestinal nematode infections do not hinder the development of Simmental X Nellore crossbred calves raised with a nutritionally enhanced diet

Abstract An evaluation was made of the effect of anthelmintic treatments on the performance of Simmental X Nellore crossbred calves before and after weaning. To this end, the calves were divided into three groups: (1) treated monthly with a low efficacy anthelmintic drug, ivermectin; (2) treated monthly with a highly effective anthelmintic drug, albendazole; and (3) untreated control group. All the groups in this experiment showed an average fecal egg count of less than 400 eggs per gram (EPG), and no clinical signs of parasitic gastroenteritis. The blood variables were within the normal range and no calf presented anemia. In most of the samplings, mean EPGs were significantly lower (P<0.05) in the group treated with albendazole. The calves received dietary supplementation before and after weaning, which enabled them to gain weight in every month of the experiment and reach a body weight of about 250 kg on the last sampling date, before turning one year old. The anthelmintic treatments did not affect body weight gain, leading to the conclusion that, when fed with suitable dietary supplements, Simmental X Nellore crossbred calves are not affected by gastrointestinal nematode parasites acquired by grazing.

摘要 本研究评估了驱虫治疗对西门塔尔（Simmental）×内洛尔（Nellore）杂交犊牛断奶前后生产性能的影响。为此，将受试犊牛分为三组：（1）每月使用低效驱虫药伊维菌素（ivermectin）进行治疗；（2）每月使用高效驱虫药阿苯达唑（albendazole）进行治疗；（3）未接受任何驱虫处理的对照组。本试验所有组的平均粪便虫卵计数（fecal egg count, EPG）均低于每克400枚，且未观察到寄生性胃肠炎的临床症状。受试犊牛的各项血液指标均处于正常生理范围，无个体出现贫血症状。在多数采样节点中，阿苯达唑治疗组的平均EPG显著低于其余两组（P<0.05）。试验全程（断奶前后）均为犊牛提供日粮补充饲喂，使其在试验各月均实现体重增长，并在末次采样时（满1周岁前）达到约250千克的体重。驱虫治疗对犊牛的体重增重无显著影响，据此可得出结论：在饲喂适宜日粮补充剂的前提下，西门塔尔×内洛尔杂交犊牛不会受到经放牧感染的胃肠道线虫寄生虫的不利影响。