Höglund J, Svensson C, Hessle A
Department of Parasitology (SWEPAR), National Veterinary Institute and Swedish University of Agricultural Sciences, P.O. Box 7073, SE-75189 Uppsala, Sweden.
Vet Parasitol. 2001 Aug 1;99(2):113-28. doi: 10.1016/s0304-4017(01)00452-6.
Infections with internal parasites are one of the most important causes of reduced productivity in first-grazing season cattle (FGSC). In conventional herds, nematode infections can be controlled by prophylactic anthelmintic treatments, but this is prohibited in organic production. The purpose of this investigation was to monitor the status of internal parasitism on 15 organic cattle enterprises in southwestern Sweden during the 1997 and 1998 grazing seasons, and to estimate the benefits of some management practices in parasite control. On each farm, the numbers of Eimeria alabamensis oocysts per gram of (opg) faeces were counted in seven fresh dung pats collected from the paddock 8-10 days after the turnout of FGSC. Faecal samples from 5 to 15 FGSC were also analysed for nematode eggs per gram (epg) faeces at four occasions during each grazing season. In addition, the FGSC and one group of second-grazing season cattle (SGSC) were weighed at turnout and housing and at the same time blood samples were collected, and analysed for serum pepsinogen concentration and antibodies against the lungworm, Dictyocaulus viviparus. On seven farms, 1-6 samples with more than 100000 opg were found, indicating considerable pasture contamination by E. alabamensis. However, clinical signs of coccidiosis were not observed. The highest outputs of nematode eggs were observed 45-55 days after turnout. More than 500 epg were only observed in 12 (2.2%) of the calves in 1997 and in three (0.6%) animals in 1998. Only 1% of the serum samples had pepsinogen values exceeding 3.6 U tyrosine, indicative of subclinical Ostertagia ostertagi infection. Lungworm infection was detected in five and nine herds in 1997 and 1998, respectively. The number of seropositive animals on these farms ranged between one (10%) and seven (70%). Clinical signs of dictyocaulosis were observed on two farms. The results indicate that dictyocaulosis is a problem in organic dairy herds in Sweden. On the other hand, the study shows that good management such as usage of parasite safe pastures and supplementary feeding may help control gastrointestinal parasites.
体内寄生虫感染是初牧季牛（FGSC）生产力下降的最重要原因之一。在传统牛群中，线虫感染可以通过预防性驱虫治疗来控制，但在有机生产中这是被禁止的。本研究的目的是监测1997年和1998年放牧季节瑞典西南部15个有机养牛企业的体内寄生虫感染状况，并评估一些管理措施在寄生虫控制方面的益处。在每个农场，在FGSC转入牧场8 - 10天后，从围场收集7份新鲜牛粪堆，计算每克粪便中阿拉巴马艾美耳球虫卵囊（opg）的数量。在每个放牧季节的四个时间点，还对5至15头FGSC的粪便样本进行了每克粪便线虫卵（epg）分析。此外，在FGSC转入和圈养时对其以及一组二牧季牛（SGSC）进行称重，同时采集血样，分析血清胃蛋白酶原浓度以及针对肺线虫（胎生网尾线虫）的抗体。在7个农场中，发现1 - 6份样本的opg超过100000，表明阿拉巴马艾美耳球虫对牧场污染严重。然而，未观察到球虫病的临床症状。线虫卵产量最高出现在转入后45 - 55天。仅在1997年12头（2.2%）犊牛和1998年3头（0.6%）动物中观察到epg超过500。仅1%的血清样本胃蛋白酶原值超过3.6 U酪氨酸，表明存在亚临床奥斯特他线虫感染。1997年和1998年分别在5个和9个牛群中检测到肺线虫感染。这些农场中血清阳性动物数量在1头（10%）至7头（70%）之间。在两个农场观察到网尾线虫病的临床症状。结果表明网尾线虫病在瑞典有机奶牛群中是个问题。另一方面，研究表明良好的管理措施，如使用无寄生虫牧场和补充饲喂，可能有助于控制胃肠道寄生虫。
