Nematode parasites of reindeer in Fennoscandia
Nematode infections of semi-domesticated reindeer of northern Finland were monitored by faecal egg counts. The tracer calf technique was also used to estimate the acquisition of nematode infection from pasture. The most abundant parasite in the worm counts of tracer animals and in faecal egg counts...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
2006
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| Online Access: | https://pub.epsilon.slu.se/1207/ https://pub.epsilon.slu.se/1207/2/PhD_Thesis_complete_Jackie_T_Hrabok.pdf https://pub.epsilon.slu.se/1207/3/FRONTCOVER_illust_size_3_jth1.JPG |
| Summary: | Nematode infections of semi-domesticated reindeer of northern Finland were monitored by faecal egg counts. The tracer calf technique was also used to estimate the acquisition of nematode infection from pasture. The most abundant parasite in the worm counts of tracer animals and in faecal egg counts of adult female reindeer was Ostertagia gruehneri. Capillaria sp. eggs were detected in calves and adults, but Nematodirinae eggs were only recovered from calves. Egg output of O. gruehneri was most abundant from late summer to autumn whereas Capillaria sp. and the Nematodirinae dominated the winter months. The proportion of inhibited larvae of O. gruehneri and Nematodirinae steadily increased from summer to early winter, followed by a decline and a commensurate increase in the number of adult parasites in the second summer. High prevalence and low intensity also characterized the nematode infections of winter-slaughtered reindeer from other northern herds examined. Our investigations showed that parasite transmission occurs throughout the year in this part of the sub-Arctic. We demonstrated that reindeer are suitable hosts for important nematode parasites of sheep and goats (Haemonchus contortus and Teladorsagia circumcincta) and cattle (Ostertagia ostertagi), as well as for Trichostrongylus axei. However, it is not known if all of these parasite species reach maturity in reindeer. With the trend towards increasing numbers of livestock in the southern grazing regions of reindeer, these findings highlight the increased risks with parasites not normally associated with reindeer. Approximately 80% of reindeer in Finland are de-wormed with ivermectin once annually in the winter. We analysed soil samples containing faeces from reindeer treated with ivermectin. Ivermectin degraded rapidly during the first spring, but residual levels were detected for more than two summer seasons following treatment. Residues were similar from ungrazed and grazed reindeer pastures, but the levels in faeces from reindeer treated with oral ivermectin were higher than for the subcutaneous formulation. Our results show that ivermectin persists on pasture longer than previously shown. However, the levels found had no detectable negative effects on the soil nematode communities beneath the faeces. |
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