Forages That Help, Forages That Harm
Reading Time: 5 minutes
Browsers rather than true grazers, goats are unique among domestic livestock. This characteristic — eating a bit here and a bit there — has positives and negatives.
It makes them master brush clearers who are capable of finding lots of nutrient-dense and healthful forages. On the flip side, this also leaves them open to finding a lot of nasty stuff.
But the vigilant goat owner need not fear. A bit of awareness and familiarity with your region allows you to eliminate negative plants in your pastures while promoting the positive.
Pasture management is an ongoing process; what you get will vary according to grazing intensity, season, or other climate factors. Taking an active role, you can make the most of nutrients accessible to your herd.
Goat breeders have long spoken about the effect certain plants seem to have by decreasing wormloads in their animals. Science attributes this to the level of tannins in certain forage species.
Tannins are essentially biological molecules that bind certain proteins and other molecules together very tightly inside the rumen. Research has shown they affect many types of parasites in the larval stage by preventing hatching or development. Even adult worm populations are known to decrease or even disappear entirely.
Various traditional plants and herbs used for deworming purposes, such as wormwood or black walnut, contain tannins.
Hopefully, future research will allow grazers to strategically grow a complete pasture that promotes “self-deworming” in their animals by greatly reducing or eliminating the need for chemical dewormers while maintaining optimal health and nutrition.
One plant that may help is sericea lespedeza (Lespedeza cuneata). This is a hardy legume variety that goats seem to love, and in some places, it is listed as an invasive species making the controlled grazing a bonus.
Lespedeza is not only nutrient-rich but also full of tannins. A 2005 research study examined lespedeza hay fed to 20 growing Boer bucklings. Researchers found that the kids fed the lespedeza hay had significantly lower fecal egg counts than those fed bermudagrass hay.
At the time of harvest, the kids fed lespedeza also had fewer adult worms in their digestive tracts than the bermudagrass ones.
Forage chicory is another variety that, similar to lespedeza, is shown to have high nutritional value and tannins that reduce wormload.
While, like many herbivores, goats seem to have a predisposition to select certain beneficial forages, there are lots of unknowns as to how well they know it. In an interesting 2019 study, researchers observed goats who foraged in the Mediterranean to see if they had a preference for certain Pistacia lentiscus shrubs that had better tannings for binding proteins.
Overall, their findings didn’t conclusively show goats had a preference — in fact, it showed they were more negative toward those with high capacities.
Researchers noted this is likely context-dependent on many other factors in the plant and herd behavior that influence browsing selection. Hopefully, researchers will do more work to get a deeper understanding of what influences feeding behaviors.
Similarly, feeding willow fodder to dairy goats may promote immunity and resistance against mastitis, according to another 2019 study from Israel. Willow has long been a remedy for different pains and ailments in people; researchers attributed the results to the plant’s anti-inflammatory and anti-stress effects.
Many forages can be toxic goats — but it all depends on the dosage. Unfortunately, goats can be exceptionally prone to this as they can eat bitter and abrasive forages that other animals would avoid.
Even tannins, while certainly beneficial, can be poisonous when consumed in high concentrations and/or grazed extensively. Oak leaves, for example, are notoriously very high in tannins which is why grazing animals near them is not recommended.
This is where it’s critically important to have familiarity with your particular region and the types of toxic plants known to grow there.
As a rule of thumb, woodland and wet or swampy areas tend to have a higher likelihood of harboring poisonous plants.
The list of all plants with a degree of toxicity to goats is extensive — and some specifications require further research.
Fellow goat breeders in your region and university extension offices can be invaluable in narrowing down what you should look for. You may even be able to find someone to walk your pasture with you and advise what hay not to buy.
Here are some of the broad categories of toxic plants.
Cyanogenetic plants: These types carry prussic or hydrocyanic acid that can interfere with blood oxygen. This includes stone fruits like peaches, plums, and wild cherries, which are especially toxic when leaves are wilted, and death can be sudden.
Alkaloid-containing plants: Alkaloids are powerful organic substances known for their physiological impacts — nicotine and morphine are a couple of famous examples. Plants in the hemlock family, nightshade, and poppies are a few examples that livestock might encounter.
Photosensitizing plants: These negatively impact animal skin particularly vulnerable to sun exposure — such as those without pigmentation. Buckwheat, St. John’s Wort, and goat weed fall into this category.
Saponin-containing plants: Saponin is a chemical that is similar to hormones. They can cause a variety of different issues, including bloat and irritation of internal membranes. Bagpod, coffee weed, and soapwort are examples.
And of course, there are many various plants and toxicities as well.
Developing a healthy pasture or forage-based diet is a bit of an art, one that requires patience, observation, and experience. It all begins with awareness then learning from the resources available to you. Buddy up with a good goat friend and educate yourself on the flora in your region. With a bit of practice, you can build a superior goat-friendly pasture.
- Muklada, H., et al. “The Effect of Willow Fodder Feeding on Immune Cell Populations in the Blood and Milk of Late-Lactating Dairy Goats.” Animal, vol. 14, no. 12, 2020, pp. 2511–2522., doi:10.1017/s1751731120001494.
- Navon, Shilo, et al. “Volatiles and Tannins in Pistacia Lentiscus and Their Role in Browsing Behavior of Goats (Capra Hircus).” Journal of Chemical Ecology, vol. 46, no. 1, 2019, pp. 99–113., doi:10.1007/s10886-019-01124-x.
- Contributed by National Agricultural Library. Poisonous Plants Extension Goat Handbook. Nov. 2014, tuscarawas.osu.edu/sites/tuscarawas/files/imce/Program_Pages/4H/Livestock/SmallAnimals/Poisonous%20Plants%20approved%20branding.pdf.
- “Department of Animal Science – Plants Poisonous to Livestock.” Plants Poisonous to Livestock – Cornell University Department of Animal Science, poisonousplants.ansci.cornell.edu/goatlist.html.
- “Goat Pastures and Forages.” Goats, 14 Aug. 2019, goats.extension.org/goat-pastures-and-forages/.
- “Goat Pastures Chicory.” Goats, 14 Aug. 2019, goats.extension.org/goat-pastures-chicory/.
- “Goat Pastures Poisonous Plants.” Goats, 14 Aug. 2019, goats.extension.org/goat-pastures-poisonous-plants/.
- “Grazing Plants for Deworming Livestock.” Grazing Plants for Deworming Livestock (Critter Care Forum at Permies), permies.com/t/9650/Grazing-plants-deworming-livestock.
- Pfeifer, Mallory. “Livestock Owners Encouraged to Be Aware of Toxic Plants.” AgriLife Today, 3 Feb. 2021, agrilifetoday.tamu.edu/2021/02/02/livestock-owners-encouraged-to-be-aware-of-potentially-toxic-plants/.
- “Sericea Lespedeza.” Forages, georgiaforages.caes.uga.edu/species-and-varieties/warm-season/serecia-lespedeza.html.
Originally published in the May/June 2021 issue of Goat Journal and regularly vetted for accuracy.