Fainting Goats: Why Do They Faint?
Do Fainting Goats Faint?
Wondering what is the deal with goats that faint and fall over when frightened or sometimes even when you bake them cookies? Despite the name "fainting goats", they do not faint at all.
The condition with which these goats and several other animals, including mice, dogs, cats, horses, water buffalo, and pigs are affected is called myotonia, which is a medical term for muscle stiffness.
Tennessee goats suffer from a hereditary type of disorder called myotonia congenita. If these goats are suddenly surprised or frightened, they often become perfectly rigid. According to Jay L. Lush, the animal geneticist who first described fainting goats, they can be pushed or turned over "as if they were carved out of a single piece of wood" while affected by this condition.
The goats usually stay passed out for about 10–30 seconds. Once recovered, they cannot be frightened into myotonia again for 20 to 30 minutes, no matter how great the excitement might be.
The inherited muscle disorder in fainting goats is Thomsen's disease, an autosomal dominant type of genetic disorder. It is caused by a mutation in the gene expressing chloride channels called ClC-1 on the membranes of skeletal muscles.
Did You Know?
Myotonia congenita is also seen in humans. Within our species, it can be inherited in a dominant or recessive form. Fainting goats and mice were the first animals to be studied to understand this disorder. Even today, some drug studies use myotonic goats as experimental animals.
What Causes Muscle Stiffness?
To understand how muscles can stiffen, you need to have a little bit of background physiological knowledge. A muscle contracts when it is stimulated. With the contraction of a muscle, several changes take place on physical, electrical, chemical, and molecular levels.
Electrical changes that occur when a muscle is stimulated are called action potentials. These are carried out by ions that move in and out of the muscle cells. The movement of ions is facilitated by small channels or pumps that are present in the cell membrane. Ions may either be positive (potassium, sodium) or negative (chloride). These ions are unequally distributed across the cell membrane. Normally, there is negativity inside the cell and positivity outside (entirely because of ions).
A high concentration of K+ inside the muscle fibres is essential to check this negativity. When the needed concentration of K+ is decreased or not present, the negativity increases—this is called hyperpolarization. At this point, the development of action potential is either delayed or does not occur. Conversely, increased K+ concentration can lead to depolarization and spontaneous action potentials which will not allow the muscle to relax.
An action potential generated in the muscle fibre is spread throughout the membrane via the T-tubules. Chloride moves in and out of the membrane of skeletal muscle fibre via the ClC-channels. In the resting state, the chloride conductance stabilizes the resting membrane potential and lessens abnormal depolarization resulting from increased extracellular K+ at T-tubules during repetitive muscle stimulation.
In myotonic goats, the ClC-channels are dysfunctional, which causes a 50% decrease in chloride concentration. Less chloride means more K+ moves out of the cells to try to maintain the ion balance. This causes K+ accumulation in the T-tubules, and as a result, depolarization occurs.
The depolarization spreads to the surface membrane triggering spontaneous action potentials and continuous muscle contraction even after the cessation of a voluntary act. This leads to muscle stiffness, or the inability of a muscle to relax after it has been contracted.
Other Names for Fainting Goats
- Myotonic goats
- Scared goats
- Tennessee fainting goats
- Tennessee meat goats
- Stiff goats
- Texas wooden-leg goats
- Narcoleptic goats
- Falling goats
- Passing out goats
Is It Ethical to Make These Goats Fall?
The breed is listed as "endangered" in North America in the database of the Food and Agriculture Organization of the United Nations. Since the breed first appeared in the 1880s, breeders wanted to keep them the way they were because they are quite unable to jump over regular fences or climb as well as other goats. This, in addition to their excellent meat production capability, attracts breeders and meat manufacturers from around the world.
Older goats try to avoid falls by spreading their legs or leaning against walls. This implies that they do not want to fall. Therefore, even if it is painless, deliberately trying to make them fall just for a laugh is wrong.
Other Animals Affected With Myotonia CongenitaClick thumbnail to view full-size
Interesting Videos of Fainting Goats
- What the heck is a fainting goat?
This video comes right from the owners of a small herd of fainting goats. They talk about the breed's history and its advantages and disadvantages.
- Buying a Fainting Goat
Missing their traditional grub, two Kenyan guys visit a Texas farm to buy a goat. But these goats aren't like the goats back home!
- Funny Fainting Goats
This video is a compilation of the best fainting goat videos of 2020.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2020 Sherry Haynes