Goats are highly adaptable foragers, but they are naturally selective browsers, preferring the leaves, twigs, and bark of shrubs and trees over simple pasture grass. They possess an impressive ability to select the most nutritious parts of a plant, often consuming a diet that is over 80% browse when given the choice. Their feeding strategy, characterized by picking and choosing, means that the term “will not eat” often relates to a strong preference for other forage or a natural defense mechanism against toxins.
Factors Influencing Plant Rejection
A goat’s decision to reject a plant is driven by chemical, physical, and behavioral factors. The sensory evaluation begins with taste, where chemical compounds play a significant role in deterrence. Many plants contain secondary compounds like alkaloids, glycosides, or high concentrations of tannins that impart a bitter or astringent flavor. While goats tolerate bitterness better than some other livestock, extreme levels or specific compounds still trigger rejection.
Physical characteristics also serve as natural barriers. Extremely tough or fibrous textures, such as those found in mature grasses, are often avoided in favor of tender growth. Thorny or spiny defenses on branches, while not always an absolute deterrent, can significantly reduce the intake of a plant species, especially when other forage is available.
Goats also exhibit learned aversion, a sophisticated survival mechanism. If a goat samples a plant that causes digestive discomfort or illness, the animal associates the taste and smell with the negative consequence. This memory-based rejection helps them avoid toxic plants in the future. However, this learned behavior can be overridden by extreme hunger, leading the goat to consume plants it would normally bypass if desirable forage is scarce.
Plants Goats Find Unpalatable
Many common plants are rejected by goats due to unappealing taste, smell, or texture, rather than toxicity. These unpalatable species are typically left behind by a satiated goat. Tough, mature grasses, for example, are generally avoided because their high fiber content and low digestibility make them less appealing than young shoots or woody browse. Goats select the most palatable parts of a pasture, often leaving behind the coarse, dry remnants.
A variety of ornamental and herbaceous plants are frequently ignored due to their strong aromatic properties. Herbs like common sage, lavender, and rosemary contain potent volatile oils that make them highly undesirable. Although a curious goat may sample these plants, the intense flavor or scent often causes them to be spat out. The Great Mullein (Verbascum thapsus), a common weed, is typically bypassed because its dense, woolly leaves create an unpleasant texture in the mouth.
Certain shrubs and perennials are also often left untouched in landscaping. Hydrangea and Mahonia are examples of plants frequently ignored by goats in favor of other foliage. Rejection is based on preference; a starving goat may consume an unpalatable plant if no other food source is accessible.
Highly Toxic Plants Goats Must Avoid
Beyond unpalatability, certain plants contain compounds that are highly toxic, posing a serious threat to a goat’s health even in small quantities. The presence of these plants in a pasture or near a fence line requires immediate attention and removal. Oleander (Nerium oleander) is one of the most dangerous, as all parts contain cardiac glycosides that can cause severe gastrointestinal distress, heart failure, and rapid death. Even dried leaves remain toxic, posing a risk when incorporated into hay or yard waste.
Ornamental shrubs in the Rhododendron and Azalea genera also contain these highly dangerous cardiac glycosides. Consumption of only a few leaves can lead to symptoms like excessive drooling, abdominal pain, and an irregular heart rate, often progressing to coma and death. Similarly, the common landscaping shrub Yew (Taxus spp.) is extremely toxic; its needles and seeds contain taxine alkaloids that can cause sudden cardiac arrest, frequently without prior noticeable symptoms.
Other toxic offenders include plants containing potent alkaloids or cyanogenic glycosides. The Solanum family, which includes Nightshade and Jimsonweed, contains alkaloids that disrupt the nervous system, leading to neurological symptoms, labored breathing, and tremors. Plants like Wild Cherry (Prunus serotina) and other stone fruits become toxic when their leaves wilt, as the damaged tissue releases cyanogenic glycosides that interfere with oxygen transport in the blood. Ingestion of these wilted leaves can lead to rapid death from cyanide poisoning.
Management Strategies for Pasture Safety
The most effective way to ensure a goat’s safety is to actively manage their environment based on plant toxicity and preference. A primary strategy involves routine inspection of all accessible areas, including pastures and fence lines. Any highly toxic plants, such as Yew or Oleander, should be physically removed or fenced off with a double barrier to prevent accidental browsing. This proactive clearance is the most reliable defense against lethal poisoning.
Providing adequate amounts of high-quality forage and browse is another practical safety measure. Goats with access to a balanced diet of preferred food sources are far less likely to sample toxic species out of desperation. Supplemental hay and browse materials should be offered consistently, especially during periods of drought or limited pasture growth.
Pasture management should also include strategies that prevent overgrazing, which can force goats to eat less desirable plants. Implementing a rotational grazing system ensures that goats always have access to a variety of taller, healthy forage.