by R.A. Frost, J.C. Mosley, and B.L. Roeder
Targeted grazing by sheep or goats is a potentially useful tool for suppressing the noxious weed sulfur cinquefoil (Potentilla recta). However, possible transmission of weed seeds by grazing livestock is a serious concern that needs to be addressed in any targeted grazing prescription. Researchers investigated the effect of sheep and goat digestion on the viability of sulfur cinquefoil seeds. Eight sheep and 8 goats were each orally gavaged with 5,000 sulfur cinquefoil seeds. Four animals of each species received immature seeds and 4 animals of each species received mature seeds. Total fecal collection began immediately after oral gavage and continued for 7 consecutive days. Once each day, all identifiable sulfur cinquefoil seeds were recovered and counted from fecal subsamples. Passage through the digestive tract of sheep or goats dramatically reduced the viability of both immature and mature sulfur cinquefoil seeds, but some viable seed was excreted. Almost all (98%) of the viable seeds recovered from sheep and goats were excreted during Day 1 and Day 2 after oral gavage. No viable seeds were recovered from either sheep or goats after Day 3. Grazing livestock that consume sulfur cinquefoil seeds should be kept in a corral for at least 3 days to prevent transferring viable seeds to uninfested areas.