The effectiveness of a single dose of doramectin pour-on in the control of gastrointestinal nematodes in yearling stocker cattle

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• 作者：Skogerboe ; T.L. ; Thompson ; L. ; Cunningham ; J.M. ; Brake ; A.C. ; Karle ; V.K.
• 关键词：Doramectin ; Pour-On ; Beef cattle ; Nematoda ; Parasite control ; Weight gain
• 刊名：Veterinary Parasitology
• 出版年：2000
• 出版时间：January, 2000
• 年：2000
• 卷：87
• 期：2-3
• 页码：173-181
• 全文大小：88.0 K

文摘

Three field studies were conducted to determine the efficacy of a single dose of doramectin pour-on in the control of gastrointestinal nematode infections in yearling stocker calves on pasture. These 140-day studies were carried out between October 1995 and March 1996 in Tennessee (TN), between January and June 1997 in Louisiana (LA), and between May and September 1997 in Wisconsin (WI). Calves with patent nematode infections were equally allocated to treatments (doramectin pour-on, at 500 μg/kg body weight or untreated control) and pastures as randomized complete-block designs (LA and TN studies) or completely at random (WI study). There were six pasture replicates per treatment at each site, with each pasture replicate accommodating six calves at the TN site (36 calves per treatment), five calves at the LA site (30 calves per treatment), and seven calves at the WI site (42 calves per treatment). Fecal samples for nematode egg counts were collected on Day 0, and at 28-day intervals thereafter. Body weights were recorded on Day 0 and at 28-day intervals until study termination. Nematode egg output of the doramectin-treated groups was reduced over the entire grazing period compared to those in the untreated control groups, resulting in average daily weight-gain advantages of 0.055 kg (p ≤ 0.05) for the TN study, 0.208 kg (p ≤ 0.05) for the LA study, and 0.116 kg (p ≤ 0.05) for the WI study.