Caldwell V, DesCôteaux L, Doucet M
Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Québec.
Can Vet J. 1998 Nov;39(11):701-5.
This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily and total weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Quebec. One hundred and twelve heifers from 12 herds were randomly assigned at turnout either to treatment with a commercially-available ivermectin bolus or to remain as untreated controls. Ninety-six heifers, 49 treated animals and 47 controls, completed the trial. Animals were weighed at turnout, midseason, and at the end of the grazing season. Fecal samples were collected at each of these times and nematode eggs counted. Nematode egg excretion was relatively low throughout the pasture season, which was abnormally warm and dry until midsummer. Over the entire pasture season, average daily weight gain was higher in treated than in control animals (difference = 0.08 kg/day, P = 0.010). Total weight gain was also higher in treated animals than in control animals (difference = 12.82 kg, P = 0.013). The results of this study suggest that preventive treatment of breeding age, grazing dairy heifers with a sustained-release ivermectin bolus provides a significant weight gain advantage, in situations with moderate utilization of moderately contaminated pastures.
本田间试验旨在测试在魁北克省南部商业牧场条件下，使用缓释伊维菌素丸剂治疗对繁殖期荷斯坦小母牛平均日增重和总增重的影响。来自12个牛群的112头小母牛在放牧开始时被随机分配，要么用市售伊维菌素丸剂治疗，要么作为未治疗的对照。96头小母牛，49头治疗动物和47头对照，完成了试验。在放牧开始时、季节中期和放牧季节结束时对动物进行称重。在这些时间点分别采集粪便样本并计数线虫卵。在整个牧场季节，线虫卵排泄量相对较低，直到仲夏，牧场季节异常温暖干燥。在整个牧场季节，治疗组动物的平均日增重高于对照组动物（差异 = 0.08千克/天，P = 0.010）。治疗组动物的总增重也高于对照组动物（差异 = 12.82千克，P = 0.013）。本研究结果表明，在中等污染牧场中等利用的情况下，用缓释伊维菌素丸剂对繁殖期放牧的奶牛小母牛进行预防性治疗可提供显著的增重优势。
