Myotonic goats are often referred to as wooden leg, stiff leg or Tennessee fainting goats. These goats have a recessive gene that makes their skeletal muscles lock up when the animal is startled, causing them to fall over briefly. It is one of the few breeds indigenous to the United States and although the true origins are not definitively known, the history can be traced back to the 1880s where a herd in Tennessee sported the spontaneous mutation resulting in myotonia congenita, or "fainting". In the 1950s some Myotonic Goats were taken to Texas. These goats tend to be larger were selectively bred for the meat market. Subsequently there are now 2 main types. The smaller type mostly found in Tennessee was bred more for the pet market due to the novelty of their condition and have a higher degree of myotonia. The larger type, the Tennessee Meat Goat, was renamed by ranchers in Texas and display qualities sought after by producers including growth rate, reproductive efficiency, and conformation. Not having a dairy influence has caused some producers to utilize them more since the breed has a higher meat producing ratio.
The name Myotonic goat refers to the animal’s myotonia congenita, a condition in which the muscle cells experience prolonged contraction when the goat is startled. The transitory stiffness associated with these contractions can cause the goat to fall down. This is not a true faint, but a muscular phenomenon unrelated to the nervous system. This renders the animal immobile for a few seconds after it becomes startled or excited. Another explanation is an over-simplification, but the chemicals which are rushed to humans' muscles and joints to prepare them for "fight or flight" are withheld in the Myotonic. It is a curious condition that is becoming better understood through focused research. The degree of stiffness varies from goat to goat, with some showing a consistently stiff response and others exhibiting stiffness only rarely. Myotonia is associated with their high degree of muscularity. This gene is also recessive, so it often does not appear in crossbred animals.
The Myotonic goat that is selected for meat production is heavily muscled in the rump and deep in the chest but smaller than the other major meat breeds. They are variable is size and can range from 60 to 175 pounds, although heavy muscling remains consistent. Does are prolific and can breed any time of the year (some have been known to kid twice a year), are easy kidders and have good milk production as well as being good mothers. Since Myotonic goats are not good climbers and jumpers due to their myotonia, they are somewhat easier to keep than other goats, however, can make them more susceptible to predators. The ears of Myotonic goats are larger and more horizontal than Swiss breeds, but smaller and less drooping than Nubian or Spanish goats. The facial profile is usually concave. Most goats are horned, and horns vary from large and twisted, to small and simple. While most of the goats have short hair, long-haired goats are not unusual and some animals produce cashmere. The Myotonic goats are found in almost all colors known in goats.
The Myotonic breed is used primarily to introduce more muscularity into commercial stock. Prairie View A&M found that any meat goat that was at least 50% Myotonic yielded 6% to 10% more useable meat. Goats are being used both as purebreds and for crossing with other breeds. While crossbreeding can demonstrate the genetic value of the Myotonic goat, overuse of purebred does for crossing would threaten the survival of this unique and important American goat breed. It is a high conservation priority. The American Livestock Breed Conservancy has placed this breed of goat on their "rare" list, with an estimated world population of under 10,000.
References:
American Breeds of Livestock Notebook.The Livestock Conservancy PO Box 477, 33 Hillsboro St, Pittsboro, NC 27312. 1989.
Myotonic goats come in varying sizes. The medium to large animals of this breed are generally used for meat production while the smaller animals are generally sought after as pets. Myotonic goats of all sizes are stocky and wide. The body is wide, full, and deep, with heavier than average muscling evident throughout. Muscle development increases with age, so that older goats are more heavily muscled than younger ones. Tennessee bloodlines tend to be lower and broader than Texas bloodlines, which tend to be taller and a little less blocky. They are alert, good-natured animals with a conformation that is smooth, functional, and rugged.
Extreme blockiness can result in difficult kidding and poor mobility in range conditions. Thinly fleshed goats or those with a very delicate and refined conformation are atypical for the breed. Even the mini strain of the Myotonic breed generally holds true to carrying a more blocky and stocky appearance than breeds of similar size.
Size varies within the breed, and the ranges of weights is considerable between the two types. The weight of Tennessee line does usually ranges from 80 to 110 pounds. The weight of Texas line does is generally somewhat higher at 90 to 120 pounds. Mature bucks of lines selected for large size can be close to 200 pounds or above for both Texas and Tennessee lines.
Size is important, but size alone should not direct the maintenance and direction of the breed. Goats smaller than the minimums above rarely grow sufficiently to be productive, healthy goats. Goats larger than the maximums above are rarely well adapted and functional in low-input forage-based systems, even though they look impressive and meat breeders may be tempted to think that bigger is always better. Overall balance is more important than overall size. No specific minimum or maximum size is indicated. Very small, dwarf-like goats are poor examples of the type of the breed and tend to have health problems. Overly large goats tend to lack breed character and are generally poorly adapted to the original low-input history of the breed.
The head is medium length with a broad muzzle. Well formed jaws with an even bite (neither overshot nor undershot) is important. The head is broad, and the eye orbits are prominent, especially from above. The eye orbits protrude outward further than in other breeds, giving the head a distinctive appearance with the eyes prominent and obvious. The profile is usually straight, or occasionally slightly convex. The ears are moderately sized, and most are held horizontally or somewhat forward toward the face. Myotonics can be horned or polled. Horns are usually well developed and large and should have at least an inch or two of separation between them.
All of these head and ear characteristics help define the breed type and are also where crossbreeding first shows itself. Although most don’t impact function, the bite is critical, as it relates to function of the animal. The horn set on horned animals is important and horns should not grow in a way to touch the head or neck. Atypical ears show up from crossbreeding.
Coat length varies from short and smooth to very long and shaggy. Many goats grow abundant cashmere in the winter. Presence of beards is variable, with many females lacking them but nearly all males having them. No coat type is to be preferred over another.
All colors are acceptable, all combinations, and all patterns or markings.
The stiffness of these goats relates to their myotonia congenita, which is an essential portion of the breed type. The various levels of stiffness are arbitrary, but an acceptable guide is useful for breeders.
The stiffness is integral to the breed and its character, but this breed is much more than stiffness. Genetic consistency and type traits other than the stiffness are equally important to the stiffness when evaluating goats for breed type. Extreme level 6 stiffness is more than usual and can impede a goat from using the environment well, and extreme stiffness is not necessarily desirable. Levels 4 and 5 are most typical of the breed. Levels 2 and 3 are useful in purebred herds, and when these levels are combined with heavy muscling they are entirely typical. Level 1 goats are referred to as "limber" or limber leg" and should be scrutinized. Breeders should avoid both overly stiff and non-stiff goats. However, each of these classes will be of occasional use to some breeding programs, and therefore, if they are used at all it needs to be done with much thought and care.
Neck should be well- muscled and moderate in length. Female necks are more slender and feminine, with males being more massive and masculine. The neck skin on many males is thick and wrinkled.
The neck is important as a revealer of femininity and masculinity and should be consistent with the overall blocky conformation of the breed.
Forelimbs should be reasonably muscular, well-angulated from the side, and tightly attached to the body with no tendency toward a loose top attachment (mutton withered). Point of shoulder should be somewhat behind the most anterior portion of the sternum. Legs, from the front view, should be straight from the shoulder down. From the side view the shoulder and elbow should be well-angulated (not too straight), and the forelimb from elbow to fetlock should be straight (neither back nor over at the knees). The pasterns should be short, strong, and have a moderate angle. Joints should be broad without coarseness. Legs should be sound and serviceable, showing good bone density, being neither coarse nor delicate. Relatively heavy bone is typical. The chest should be moderately broad.
Tight shoulder conformation relates to overall soundness. Loose shoulders usually correlate with an overall looseness throughout the animal, and such animals tend to break down at young ages. Angulation is important as it relates to overall mobility and soundness and contributes to longevity. Broadness relates to muscling, and bone must be adequate to support this. Extreme broadness and coarse bone could lead to difficult births, so moderation is in order even though the breed should be broad and robust. Extreme coarseness and poor angulation should be avoided. Too little angle in the shoulder, elbow, and fetlock leads to early degenerative disease and arthritis. Too sloping a pastern leads to weak joints, breakdown and locomotion problems. Enlarged and poorly mobile knees are typical of chronic arthritis and should be avoided.
Back should be strong and level, broad and well-muscled. Many goats rise slightly toward the pelvis. Ribs should be well sprung, providing for large capacity in chest and abdomen. The body should be deep and full.
Overall broadness is reflected in the back and barrel, with extreme broadness potentially contributing to unsoundness. Weediness likewise is a fault, especially in a stout breed such as Myotonic goats. Depth is important for both chest and abdominal capacity, and these are important for respiratory, digestive, and reproductive function. Swaybacks or weak backs, flat barrels, bodies with inadequate depth ("weedy") are all faults and poorly functional.
Rump should be moderately angled from the side view, from back to tail, moderately broad and long. Tail is symmetrical, and narrows to tip. The tail is usually carried up over back.
Moderately sloping rumps contribute to good mobility, which results in goats that can use the environment well. Correct rump conformation also contributes to good fertility and ease of kidding. Rumps that are too steep, or too flat, can both contribute to locomotion problems in addition to contributing to difficult births.
The rear limbs should have good angles from the side, with no tendency toward excessive straightness (postiness). They are moderately short, in keeping with the overall stockiness of the breed. A perpendicular line from the pin bones should fall right behind the cannon, which should be straight. From the rear the legs should be set moderately wide apart and should be reasonably straight with little tendency to be cow hocked. Muscling should be heavy, and bone should be proportional.
Rear limbs are important for overall soundness, especially when mobility is considered. Excessively cow hocked individuals usually need foot trimming more than those with sounder, truer conformation. Some slight tendency towards cow hocks may be functional, but extreme cases should be avoided. Avoid poor angles (too straight at the stifle, too angled or too straight at the hock), which relate to poor mobility. Thinly fleshed animals should also be avoided, as they are not typical of the breed. The overall impression should be one of thick, rugged, serviceable conformation. Too much selection for square, true, broad animals will result in soundness problems, so selection should keep the breed broad but moderate.
Feet should be proportional to the goat, and large enough to carry the goat effectively. Feet should be symmetrical and sound. The pasterns should be short and with moderate angle from the cannon.
Feet are essential for mobility, and therefore to successful foraging. Functional feet are important and any foot conformation that suggests weakness should be avoided.
Skin should appear clean, resilient, with a clean, shiny coat.
Skin and hair coat reveal the general health and robustness of the animal. Avoid thin, weak, skin and hair coats that are dull and lifeless.
Does should be feminine, and bucks masculine. In general does should be finer without being delicate, and bucks should be more robust without being coarse. Head and neck are useful for evaluating sex character. Does have less massive heads, and thinner, more delicate horns. They also have thinner necks than males, although ewe-necks are a fault. Bucks have more thickly made heads. This is especially true of the horns on horned animals, which are generally thick, long, and in most cases also have an outward flare. The bone structure is heavier on bucks than does. Hair coat is also generally longer, coarser, and thicker on bucks than on does.
Sex characteristics are an indication of overall reproductive soundness. Does should look like does, bucks should look like bucks. Reproductive function on masculine does or feminine bucks is frequently below par.
High and tightly attached, with no tendency to be pendulous. Halves evenly balanced, with no lumps or scar tissue. Teats should be uniform and not bulbous nor pendulous, and generally moderate to small in size. Teats should only be two, although variations not leading to functional problems are not disqualifications.
The best proof of udder capacity is the kids and their weaning weights. Teat conformation is important, and two are best. Fused teats or double teats, or supernumerary teats can interfere with function and should be penalized. This is especially true in males. Any udder conformation that suggests problems should be penalized. These include evidence of past mastitis (asymmetry, lumps, scars) or poor attachment (pendulous udders) or poor, dilated teat conformation. These defects make successful rearing of kids more difficult and should be avoided.
There should be two testes that are symmetrical, fully descended, and with good tone. There should be no lumps in testis or epididymis. Teats should be symmetrical, nonfuctional, and there should only be two.
Avoid asymmetrical testes as these imply cryptorchidism or testicular hypoplasia.
The vulva should be normal, and a normal distance from the anus.
Vulvas that are smaller or larger than normal can indicate intersexuality and such goats generally fail to reproduce normally. Avoid any abnormality in female external genitalia.