Grazing Ecology of Sheep and Its Impact on Vegetation and Animal Health in Pastures Dominated by Common Ragwort (Senecio jacobaea L.)—Part 1: Vegetation

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 Hannover, 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;    grazing behavior;    animal health;    free-choice conditions;    ecological impact;   

DOI  :  10.3390/ani12081000

来源: DOAJ

【 摘 要 】

Species-rich pastures naturally contain potentially toxic plants such as common ragwort (Senecio jacobaea L.), whose pyrrolizidine alkaloids (PA) impose a risk, mainly for cattle and horses. Although in vitro studies showed detoxification capacity of PA in sheep, few field data are available to ascertain whether grazing sheep can both tolerate and reduce ragwort. In a two-year study in a ragwort-rich pasture with a stocking density of 12 sheep/hectare, we documented (1) the extent of voluntarily ingested ragwort, (2) the correlation of nutritional parameters and feeding behavior, and (3) the impact of grazing on the yield proportion and number of flowers of dominant plants. Every six weeks the vegetation underwent a botanical survey and a chemical analysis. Sheep continuously ingested ragwort between 1.2 and 4.9 kg (2020) and 1.0 and 2.2 kg (2021) per individual per day without any impact on animal health. The more biomass ragwort produced, the more it contained sugar (r = 0.59–0.74), and the more sheep ingested it (r = 0.94–0.95). Other herbs increased their yield proportion from 23.3 to 36.5%, while that of ragwort decreased from 26.3 to 18.8% (2020/2021), doubling its flowers. Sheep preferred and tolerated ragwort, making their grazing an option to control ragwort from both an animal health and a nature conservation perspective.

【 授权许可】

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