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American Mammoth Jackstock is an American creation.  A fact I found fascinating is that our first President, George Washington, was among the first well known breeders in the United States to formally begin refining and breeding up these giant donkeys in the United States. A farmer at heart, he saw the need for bigger quality jack sires for better mule production and over all improved agricultural returns.  Thus mammoth jackstock have been a quiet humble partner in our history, helping to build and improve our country almost from the very beginning.

Looking at the origins of the American Mammoth Jackstock, we can see how the needs of the times determined looks and function.  Jackstock in the beginning was optimally bred for draft mule creation.  Jackstock needed to complement the draft mares they were bred to.  These jack sires were working animals that had strength and proportion  as well as disposition and size.  Jackstock breeding was taken seriously, and highly competitive in some circles.  Big money was spent on importing and supporting quality jackstock herds.  Only the best Jackstock sires were allowed to reproduce by reputable, knowledgeable breeders.   

After the creation of the tractor, jackstock almost died out in obscurity.  But once again people are beginning to realize the worth of these fine animals, and mammoths are slowly making a come back from an endangered breed of equine. However,  we find that the direction of Jack sires has changed with time. The most popular demand for jackstock is still as a mule sire - but the demand is for saddle mules rather than draft mules.  Only the best jacks being used as jennet jacks.

There are different opinions, but foremost the breeding jack should be an animal of beauty, refinement, yet with size, bone, depth and proportion to be able to successfully do hard work. (See breed conformation) Once the public began to rediscover that  jackstock were not only for mule breeding but could be ridden, driven and perform in their own right - jackstock have become a unique, ultimate alternative type of equine.  Quality animals are now sought and the value of jennets and geldings increased, as they are no longer viewed as just a lesser by-product of breeding for jack sires. Well bred jennets and geldings are themselves considered as an optimum performance animal and enjoyed across the country.

So what is mammoth jackstock?  Jackstock is more than being just a big donkey.  The public tends to call any large donkey a mammoth jackstock - the buyer must beware because that is not always truth.  There are unethical breeders that are marketing and pricing crossbred stock as pure jackstock.  Not only are people not getting the animals they think they are purchasing, but it is diluting the jackstock gene pool.  True American Mammoth Jackstock has pedigree and breeding behind it that will consistently duplicate itself for type, size, bone, proportion and depth.  Of course, quality of disposition and conformation is dependant upon the individual breeder and the bloodlines he incorporates into his overall breeding program. 

American Mammoth Jackstock Registry, established in 1888,  requires the following measurements:

• 56 inches and up in wither height for jennets and geldings, at least 7 1/2" mid cannon bone circumference (measured at the narrowest point between knee and fetlock on the front leg) and at least a 61" heart girth.

• 58 inches and up in wither height for jacks, at least 8" mid cannon bone circumference (measured at the narrowest point between knee and fetlock on the on the front leg) and at least a 64" heart girth.

Cross bred stock (i.e.:  mammoth jackstock crossed with standard donkeys)  is simply that - not pure mammoth jackstock no matter what the size of the offspring.  This crossbred donkey is unable to genetically, consistently duplicate itself.  Out crossing for different traits such as color (spotted or dun stock comes from standard bloodlines) takes many generations to fix back into the bloodlines for true jackstock type.  Throwbacks of small size and mis-proportion are not uncommon in these instances.  Black was the original jackstock color of choice at the beginning.  Red is a diluted derivative of black.  Currently most registries accept all colors now.

Registries need more support than ever (see Why Jackstock?) for the vital roll they play in tracking and helping to maintain the purity of  this living history.  American Mammoth Jackstock is a distinct breed.  You don't call just any tall horse a thoroughbred just because of it's size - it must have it's Jockey Club Registration to be the real McCoy.  Most of the jackstock bloodlines that were imported from Europe, that took centuries to develop, are gone - extinct.  If we destroy the integrity of our own jackstock - we cannot recreate this breed, there will be nothing left to draw from.  We need to breed appropriately to conserve rather than deliberately diluting and losing jackstock bloodlines.   We all need to realize that we are handling something delicate and precious.  What we choose to breed today will impact and define future generations to come.  

For further information please see:
American Mammoth Jackstock Registry
http://www.amjr.us/