Grazing Ecology of Sheep and Its Impact on Vegetation and Animal Health on Pastures Dominated by Common Ragwort (Senecio jacobaea L.)—Part 2: Animal Health

Animals

Martin Ganter¹  Peter Wohlsein²  Sabine Aboling³  Bernd Reckels³  Susanne Ohlsen³  Nikola Lenzewski⁴  Aiko Huckauf⁵ 

[1] Clinic for Swine, Small Ruminants, Forensic Medicine and Ambulatory Service, University of Veterinary Medicine Hannover, Foundation, 30173 Hanover, Germany;Department of Pathology, University of Veterinary Medicine Hannover, Foundation, 30559 Hannover, Germany;Institute of Animal Nutrition, University of Veterinary Medicine Hannover, Foundation, 30173 Hannover, Germany;Institute of Plant Science and Microbiology, Universität Hamburg, 22609 Hamburg, Germany;Nature Conservation Foundation Schleswig-Holstein, 24113 Molfsee, Germany;

关键词: Senecio jacobaea L.;    sheep;    ragwort intake;    blood parameter;    copper liver tissue values;    animal health;   

DOI  :  10.3390/ani12101289

来源: DOAJ

【 摘 要 】

Common ragwort (Senecio jacobaea L.) naturally occurs on species-rich grasslands. Containing pyrrolizidine alkaloids (PA), it endangers livestock health through contaminated feed. Although in vitro studies showed a detoxification capacity of PA in sheep, few field data are available on the ability of grazing sheep to cope with ragwort. During two grazing seasons on a ragwort-rich pasture, we studied: (1) To what extent do sheep voluntarily ingest ragwort and (2) What impact their grazing behavior has on animal health. Ragwort intake was monitored by counting missing plant parts and calculating their weight. From 70 sheep, seven were slaughtered at the beginning and in six-week intervals at the end of each grazing period to monitor blood parameters and liver tissue. Sheep continuously preferred ragwort. The daily intake was above the currently assumed lethal dose, varying between 0.2–4.9 kg per sheep. Clinical, hematologic, and blood biochemistry parameters mostly remained within the reference limits. Initially elevated liver copper content declined over time. The liver of all 70 animals displayed slight to moderate hepatitis, fibrosis, and proliferation of the bile ducts, but no morphological signs of liver cirrhosis. Sheep preferred and tolerated ragwort, making their grazing an option to control ragwort from both an animal health and nature conservation perspective.

【 授权许可】

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