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What Weeds Cause Bloat in Goats?

Goats have an image in popular culture as the ultimate omnivores, able to choke down anything from a tin can to laundry on the line. The reality is much different. Like other ruminants such as sheep and cattle, their health can easily be affected by the foods they eat. Bloat is a common hazard, a condition that prevents the animals from venting gas by belching or flatulence. It can be caused by many dietary factors, including some common weeds.

Milkweed
- There are several varieties of milkweed found across the U.S., and they are uniformly hazardous to ruminants, including goats. Most ruminants find the taste of milkweed to be unpleasant and will avoid it when forage is plentiful, but if they have been kept on the same patch of grass for too long they will be less choosy. Change of forage is an important part of prevention. Dried milkweed in hay cut for winter feeding is just as dangerous as fresh milkweed, so fields growing hay should be closely checked for milkweed and other noxious species.
Larkspur
- Larkspur is another common weed that causes bloat in goats. Unfortunately, unlike milkweed, goats and other ruminants consider it palatable and will eat it happily. Larkspur contains powerful alkaloids, similar in their effect to the curare used on poisoned blowpipe darts. In addition to bloat, larkspur causes animals to act intoxicated. This accounts for one of its alternate names, "staggerweed." The toxins are most powerful in the spring, when the plant gets its early growth, and in late summer when it goes to seed. Other symptoms include drooling, irregular heartbeat and paralysis.
Hemlock
- Poisonous hemlock is a bloat-causing weed that grows wild along ditches, irrigation waterways and similar habitats. It is most dangerous to grazing animals such as goats in early spring, when other forage is sparse and hemlock is at its most palatable. It becomes more bitter in summer, and is less likely to be a problem. Aside from bloat, goats poisoned from hemlock are noticeably cold at the extremities, and remain torpid for a period of days before recovering. Animals that survive the first 10 hours generally recover.
Clovers and Other High-Protein Forage
- Alfalfa and some varieties of clover are grown deliberately by farmers as forage, while other varieties are weeds or "volunteers" that grow freely in pasture. All of these high-protein forage plants present a potential source of bloat, especially early in the spring when the goats have been accustomed to hay and other dry fodder. The high levels of protein in the plants are thought to interfere with the animals' ability to pass gas naturally. Making sodium bicarbonate available to the goats, or giving them balanced quantities of dry fodder and pasture, can minimize the risk of bloat.

Animals & Science