Derouen S M, Miller J E, Foil L D, Gentry G T
Louisiana State University Agricultural Center, Hill Farm Research Station, Homer, LA 71040, USA.
Vet Parasitol. 2009 Jun 10;162(3-4):320-6. doi: 10.1016/j.vetpar.2009.03.021. Epub 2009 Mar 25.
The objective of this study was to assess the effects of horn fly and gastrointestinal (GI) nematode control on cow-calf performance with a spring-calving system. A total of 508 cow-calf records from two locations in Louisiana were available for study over two trials (2005 and 2006). Cow and calf pairs were stratified by cow age, calf sex, calf age, calf sire breed and calf sire and randomly assigned to three replicate treatment groups across the two locations. The treatments were: (1) no horn fly or GI nematode control; (2) horn fly control administrated to cows with insecticidal ear tags applied in late-May (start of trial); (3) GI nematode control administrated to calves in late-May, mid-July and late-August (each calf received fenbendazole at the rate of 5 mg kg(-1) body weight); and (4) horn fly and GI nematode control as stated above. Length of the trials ranged from 115 to 124 days (late-May to weaning in late-September or early-October). Cows and calves were weighed at the start of the trial, mid-July and weaning. Weekly horn fly counts were conducted. Individual calf fecal samples were collected in late-May, mid-July, late-August, weaning and 10-14 days after late-May and late-August collections. Cows treated for horn flies had lower (P<0.05) fly counts compared with untreated cows for each trial; however, overall fly counts for the treated cows at one location exceeded over 70 flies per side. Calves treated with fenbendazole had lower (P<0.01) GI nematode fecal egg counts (FEC) for the 10-14 day post-treatment collections. Calves treated GI nematodes and whose dams were treated for horn flies had numerically higher or greater (P<0.05) total calf gains (8.6 kg and 11.8 kg) in both trials than untreated calves. Weight gain differences for fenbendazole-treated calves compared with untreated calves were of greater magnitude from mid-July to weaning than weight gain differences from late-May to mid-July in both trials. There were no treatment differences for any of the cow response traits. In conclusion, improvement in calf growth from both horn fly and GI nematode treatments were realized even with marginal levels of fly control and a greater response in calf growth resulted when deworming of spring-born calves occurred when they were 4 months of age or older.
本研究的目的是评估在春季产犊系统中，控制角蝇和胃肠道（GI）线虫对母牛-犊牛生产性能的影响。在两项试验（2005年和2006年）中，共有来自路易斯安那州两个地点的508条母牛-犊牛记录可供研究。母牛和犊牛对按母牛年龄、犊牛性别、犊牛年龄、犊牛父系品种和犊牛父系进行分层，并随机分配到两个地点的三个重复处理组。处理方式为：（1）不控制角蝇或胃肠道线虫；（2）在5月下旬（试验开始时）给母牛佩戴杀虫耳标以控制角蝇；（3）在5月下旬、7月中旬和8月下旬给犊牛进行胃肠道线虫控制（每头犊牛按5 mg kg⁻¹体重的剂量接受芬苯达唑）；（4）如上所述同时控制角蝇和胃肠道线虫。试验时长为115至124天（5月下旬至9月下旬或10月初断奶）。在试验开始时、7月中旬和断奶时对母牛和犊牛进行称重。每周对角蝇数量进行统计。在5月下旬、7月中旬、8月下旬、断奶时以及5月下旬和8月下旬采集后10 - 14天采集个体犊牛粪样。在每次试验中，接受角蝇处理的母牛的蝇数量低于（P<0.05）未处理的母牛；然而，一个地点接受处理的母牛的总体蝇数量超过每侧70只。接受芬苯达唑处理的犊牛在处理后10 - 14天的胃肠道线虫粪便虫卵计数（FEC）较低（P<0.01）。在两项试验中，接受胃肠道线虫处理且其母牛接受角蝇处理的犊牛的总犊牛增重（分别为8.6 kg和11.8 kg）在数值上高于或大于（P<0.05）未处理的犊牛。在两项试验中，与未处理的犊牛相比，芬苯达唑处理的犊牛从7月中旬到断奶时的体重增加差异幅度大于从5月下旬到7月中旬的体重增加差异幅度。对于任何母牛反应性状，均无处理差异。总之，即使角蝇控制水平较低，对角蝇和胃肠道线虫的处理仍实现了犊牛生长的改善，并且当春季出生的犊牛4月龄及以上时进行驱虫，犊牛生长的反应更大。
