This research was undertaken with the understanding that the use of safe and effective medicinal plants can reduce farmers' input costs, preserve the resource base, enhance biodiversity and protect animal health. If plants are grown on-farm this will enhance the biological interactions on which productive agriculture depends. Successful medicinal plant use can contribute to farm incomes, maintain the resilience of farm communities, promote self-reliance and contribute to an internationally recognized safe and good quality food supply, in addition to providing improved and affordable livestock health care. It can also strengthen rural community capacity building, leadership and skills development and help preserve the ethnomedicinal heritage of British Columbia.
Ethnoveterinary alternatives (based on medicinal plants) are an option for small-scale livestock farmers who cannot use allopathic drugs or for those larger conventional farmers whose economic circumstances prevent the use of veterinary services for minor health problems of livestock. Participatory workshops in combination with non-experimental validation are an effective means of producing information to be disseminated to farmers in a user-friendly format. Scientists may be motivated to conduct formal validation on plants that they know are being used for specific purposes.
The majority of the plants were used for goats. This reflects the browsing nature of the goat and the corresponding need for their owners to monitor what they were browsing and its constituents. Goats and sheep were the main species medicated or self-medicated on the Pinaceae, Cupressaceae and Ericaceae.
The majority of the plants achieved the mid to high levels of validity. This may be due to the fact that the majority of the respondents were referring to published material [5, 6, 7 and 120 among others] in their decision making. Some of the plants showing high levels of validity were Hedera helix for retained placenta and Euphrasia officinalis for eye problems. Plants with high validity for wounds and injuries included Hypericum perforatum, Symphytum officinale, Usnea spp., Malva parviflora and Prunella vulgaris. Treatments with high validity against endoparasites included those with Juniperus communis and Pinus ponderosa. Anxiety and pain are well treated with Valeriana officinalis, Melissa officinalis and Nepeta caesarea. Verbascum thapsus has high level validity as a respiratory tonic.Zingiber officinale is a good, but possibly expensive, treatment for diarrhea as are the other spices used. This high level of correspondence with the published literature is a reflection of the many ancient folk traditional practices that have been translated into ethnoveterinary practices and also reflects the recent scientific interest in subjecting medicinal plants to clinical trials.
In the participatory manual that we produced from this research and gave to participants, we cautioned against giving goats large amounts of red cedar (Thuja plicata) in early pregnancy (first six weeks) because of a neurotoxin in the plant. Red cedar (Thuja plicata) gives the milk of dairy animals a pitchy flavour. Respondents were initially concerned about the safety of Western hemlock (Tsuga heterophylla) branches fed to goats during pregnancy for its vitamin C content. Western yew foliage is poisonous to cattle and horses, the berries are poisonous.
Many plants designated as weeds by professionals (who have devoted considerable resources to understanding and eradicating them) are included in the diets of ruminants and the non-experimental validation of them suggests that they are nutritious and valuable feed supplements. The preliminary evaluation of the plants used for ruminants in British Columbia indicates that they are practical and possibly efficacious remedies that merit more formal evaluation.