Herbal Remedies

Through the centuries, herbalists in almost every society have collected plants to be used as treatments for human or animal ailments. The medicinal lore of these sages was passed from generation to generation by oral tradition and eventually was compiled into books.

That many plants contain pharmacologically active com­pounds is disputed by none. That all of the plants espoused in the popular press, including what is written for goats (Levy 1976), have the beneficial actions ascribed to them is, however, frequently questioned. This is partly because many of the conditions for which herbal treatments are recommended are poorly characterized or are themselves self-limiting. For example, without sophisticated double­blind trials, it would be difficult to prove that raw cucum­ber juice squeezed into the eyes is excellent for keratoconjunctivitis or that celandine (Chelidonium majus) juice cures warts on the udder. The ethnobotanical uses of plant-derived products for treating internal and external parasites of goats around the world have been reviewed recently (Mazhangara et al. 2020).

Herbs as Supplemental Therapy

Practitioners treating vague or chronic diseases of goats that belong to people who are intrigued by herbal medicine may be in a position to monitor the effects of various “natu­ral” remedies on their patients, while at the same time supplying essential modern drugs. For instance, there are testimonials that yucca relieves the swelling of caprine arthritis encephalitis (Padilla 1986), and an owner who had been told that nothing more could be done for an affected goat might choose to try the herbal remedy in addition to or in place of non-steroidal anti-inflammatory drugs.

Possible Problems with Herbs

Many opponents of old herbal cures stress the uncertainty in the dosage of drug administered. Would it not be better to give just the right amount rather than deal with nature’s variability? Experienced herbalists not only agree that the efficacy of a remedy varies, but specify a stage in the life cycle or time of day at which each plant should be collected in order to maximize potency. It has also been pointed out that modern allopathic drugs, because they have been developed to be very potent, often cause multiple, serious side effects that might be avoided by using a natural mixture of compounds (Thomson 1976).

Currently, the US Food and Drug Administration (FDA) classifies herbal products as food supplements and they can only be marketed as such (de Guzman 1998). Because there is no proof of efficacy required for these products, there also is no information provided on safety, potency, or quality. When a product is purchased, it should at the very least be labeled with the genus and species, harvest date, and expiration date. Herbal remedies of toxicologic concern have been summarized (Poppenga 2007).

Foxglove

Foxglove (Digitalis spp.) may well be the first plant that comes to mind when discussing the dangers of self­treatment with herbs. Foxglove contains a variety of cardi­oactive glycosides known collectively as digitalis. The plant has been used for several centuries for treating heart dis­ease in people. Although most physicians and veterinari­ans now prescribe synthetic forms (digoxin), toxicity is very common during the process of establishing an appro­priate dosage for the patient. It has been claimed that the plant preparation has fewer undesirable side effects. However, overdosage or giving foxglove when another plant, such as comfrey, was intended may be fatal.

Comfrey

Comfrey (Symphytum officinale) has been cultivated as both a fodder plant and a medicinal plant. Reported uses include controlling hemorrhage, healing fractures, treating pulmonary diseases and arthritis, and as a poultice (Levy 1976). It is now known that comfrey contains toxic pyrrolizidine alkaloids (Duke et al. 1998). Goats are consid­ered to be relatively resistant to these toxins (Hooper 1978), but it is conceivable that chronic consumption of comfrey might lead to toxic changes in liver, kidney, or other organs. Herbal remedies containing comfrey have caused serious liver damage in people (Weston et al. 1987). The milk from goats consuming comfrey or other pyrrolizidine alkaloid- containing species may be toxic (Panter and James 1990).

Anthelmintics

Anthelmintic treatments constitute another area where herbal treatment may be disadvantageous because a more effective remedy is withheld. Both garlic and tobacco have been used to treat worms. Controlled studies in small rumi­nants have failed to show a beneficial effect of garlic juice or a commercial herbal dewormer mixture containing garlic on intestinal worms (Allen et al. 1998; Burke et al. 2009a, b). The nicotine from tobacco does paralyze worms, but has a narrow margin of safety. Diatomaceous earth, a non-herbal substitute for modern anthelmintics, is not effective for worm control in concentrations at which it is included in feed for this purpose (Allen et al. 1998; Stromberg and Gasbarre 2006). In instances in which an owner sincerely believes that modern drugs would be harmful to their animals or organic farming techniques (see Chapter 20) are used to access a niche market, veteri­narians should stress the use of nutrition, sanitation, and pasture rotation to control parasites.

Some plants may appear to have an anthelmintic effect because they act as purgatives and goats may pass visible tapeworm segments, suggesting to the owner that the plant is an effective dewormer. However, at least in the case of kamala (Mallotus philippinensis), it was demonstrated in a controlled study that while tapeworms were passed after treatment, the plant had no effect on clearing the more dangerous nematode parasites present in the goat's diges­tive system (Jost et al. 1996).

Fecal examinations should be performed several times a year to verify that the goats and their parasites are in bal­ance. In large herds on small wet pastures or when nutri­tion and management are suboptimal, herbs alone do not control parasites. Only if the owner envisions generations of natural selection for resistance would this be a rational approach. Even then, it would be more humane to treat the susceptible goat but remove it from the breeding population.

Several plant-derived chemicals have been scientifically evaluated as anthelmintics for goats (Akhtar et al. 2000; Ketzis 2006). Goals have included finding plants that poor farmers could grow to aid in parasite control and isolating active plant compounds that might be synthesized and marketed commercially. When a potential plant has been identified though ethnoveterinary or traditional medicine information or by seeing a parasitized animal self-medicate with it, a crude extract is prepared and analyzed for com­pounds of potential interest. in vitro screens for bioactivity, such as Haemonchus contortus egg hatch tests, are then followed by in vivo studies to evaluate the plant-derived compound for efficacy, safety, and food residues. When this process was followed to test Chenopodium ambrosioides in goats, chenopodium oil caused death of some kids and milk contamination (Ketzis 2006).