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It has come to the attention of the IMZA Board of Directors, that some of the short stocky Miniature Zebu animals that many of us love, may carry a dwarfism gene. This gene may have been a part of Miniature Zebu cattle since they were first imported.  Previous DNA dwarfism tests did not allow this gene to be identified.


The IMZA's Science and Technology Committee has been working diligently with the University of California Davis, Veterinary Genetics Laboratory (VGL) to assist in the development of a test to identify this newly discovered gene, now called BDz. We are now able to announce that after a significant testing period, a test for the dwarfism gene found specifically in Miniature Zebu, is available.


Although the existence of this newly discovered dwarfism gene (BDz) is not good news, it also is not a catastrophic event which should panic Miniature Zebu owners. Animals that carry this gene are typically normal, although they may be shorter and more compact.  With knowledge and careful management practices, these cattle can continue to be a valuable part of the Miniature Zebu Cattle industry.  With the availability of this new testing, you are now able to make better breeding decisions.


This newly identified form of dwarfism, (BDz) is similar to the BD1 dwarfism which has existed in Dexter Cattle for hundreds of years. According to VGL, BD1 has also been found in a few Miniature Zebu Cattle. BD1 testing is a different process and will not detect the BDz gene. Because the 2 forms of dwarfism may possibly occur in Miniature Zebu Cattle, it is recommended that breeding animals be tested for both, BD1 and BDz. Carriers of either form, or a combination thereof, are subject to the same risk. As a result of our efforts, a simple combination panel test for BD1 and BDz, using tail hair pulled from your animals, is now available through UC Davis VGL. 


Most of the possible negative repercussions of this gene occur only when two animals carrying this gene are mated together.  Please refer to the Probability Statistics for Breeding Miniature Zebu Cattle below to further explain the risk factors involved.


----- Probability Statistics for Breeding Miniature Zebu Cattle-----

Non-carrier bred to a non-carrier = 100% chance of a non-carrier offspring
Non-carrier bred to a carrier = 50% chance of a carrier offspring and a 50% chance of a non-carrier offspring

Carrier animal bred to a carrier animal = 25% chance of a non-carrier offspring, 50% chance of an offspring which will carry the BDz gene, & a 25% of a dead bulldog dwarf calf.


With the availability of this new testing, you will now be able to make better breeding decisions. Through our continuing efforts, our herd book and record keeping, the IMZA will be able to educate, help you manage and allow you to make responsible breeding choices. The IMZA's foremost concern is to preserve the breed and to serve our members. Through new technology and research, we will continue to do so.



IMZA Board of Directors


If you would like to test your Miniature Zebu and need assistance please contact:

You can read more about BDz here:

How to submit an IMZA registered Miniature Zebu for testing:   see below

  • How do I register a calf?
    The Owner of the dam at the time of calving is required to register the calf. If you are the owner of the dam and would like to register the calf fill out the Report of Birth Form that can be found here. To use this form both the Sire and Dam must be already IMZA registered. And if the Dam and/or Sire are over the age of 3 years they must first have a permanent registration completed. Please complete that step first before submitting a Report of Birth for any offspring. That form can be found here. REGISTRATION FORMS If you did not own the Bull at time of servicing you will need to have the Bulls owner complete a Breeders Certificate to verify they bred the Sire to the Dam. That Form can be found here. REGISTRATION FORMS If you are not a Member yet and would like to have discounted registration fees you can join the IMZA. Learn more about that here. MEMBER BENEFITS
  • Do I need an Adult Permanent Registration?
    Yes! Once your IMZA Miniature Zebu turns 3 years of age you will need to measure the animal directly behind the hump. You will not be able to register any progeny from the animal if over 3 years of age and the Permanent adult registration and measurement is not submitted to the registrar. You will find that form here. REGISTRATION FORMS
  • Who Transfers the animal to the new owner?
    The Seller is responsible to transfer the animal to the new owner and pay the appropriate fees within 60 days of the sale. The Ownership Transfer Form can be found here. REGISTRATION FORMS The only exception to this are for animals reported as sold at auction to the IMZA. That form and instructions can be found here. REGISTRATION FORMS
  • I bought a miniature zebu at auction.... what do I do next?
    The Seller should have promptly reported any cattle sold at auction to the IMZA registrar using the Auction Cattle Form. Once the Seller has reported the cattle sold at auction to the IMZA the buyer can register the cattle. The New Owner/ Auction Buyer has 60 days to transfer the cattle to their name or it is considered an open transfer and may not be allowed.
  • The sire and dam are not registered can I still register a calf?
    At this time you have two options to register this calf that is an offspring of unregistered parents. Option A. You could hardship both the sire and the dam. Option B. You can hardship just the calf once it is 24 months of age. You can go to this link to learn more about the Hardship Program. HARDSHIP GUIDELINES
  • I purchased a bred cow.  How do I register the calf?
    You simply fill out a Report of Birth Application following the instructions and paying the appropriate fee. As long as the following criteria applies: The Sire and Dam are both IMZA Registered. The Sire and/or Dam if over 3 years of age have a permanent adult registration. The owner of the sire at the time the cow was serviced must fill out and submit a breeders certificate. The Breeders Certificate can be found here REGISTRATION FORMS
  • How much does it cost to register a Miniature Zebu?
    Each form has a separate fee. Remember there is a discount for IMZA Members. If you would like to join or renew your membership you may do so here. MEMBERSHIP FORM
  • How long should it take to get my certificate of registration?
    Your registration should be to you within 4 weeks. First check the Online Herd Book to see if your Registration has been processed. ONLINE HERD BOOK You will see the date on your animals profile when it was entered into the herd book. Please allow ample time for the postal service to deliver your certificate. If you do not receive your certificate within 15 days after the animal entered the herd book please contact the registrar here and you may ask for a replacement certificate. Digital Certificates are also available. Please choose to receive a digital certificate if you do not want a paper certificate mailed to you. You will receive a digital certificate much quicker than a paper certificate in the mail. It is important that you enter the correct mailing address and information on your registration applications. Please check to confirm all information is correct before submitting the form.
  • I see my Miniature Zebu in the herd book but I did not get a certificate in the mail.
    Contact the IMZA registrar and please allow time for the mail to be processed and delivered.
  • I lost my registration certificate. How do I get another one?
    Replacement certificates are available by filling out the form for a replacement certificate and paying the appropriate fees. That form is found here REGISTRATION FORMS
  • There is an error on my registration papers. How do I get that corrected?
    The error correction form can be found here. Follow the instructions, fill out the form and submit it to the Registrar. REGISTRATION FORMS
  • What is the difference between an Application and a Registration?
    An animal sold with an application IS NOT registered. The IMZA has no record at all of the animal. The animal may not be able to be registered. A IMZA registered animal can be found in the online herd book and will have a Registration Certificate that matches the Online Herd Book recorded information.
  • I changed the ear tag or other ID for my miniature zebu. How do I update that in the herd book?
    The ID change and update form can be found here. You can only select one of your ID types to be printed on a certificate. That is called Primary ID. Other forms of ID will show in the online herd book. You will find the form to update your ID here. REGISTRATION FORMS
  • How do I hardship a Miniature Zebu with the IMZA?
    Our Hardship Registration Application has been updated to include much more information to help you in getting your miniature zebus registered. Please note that if you do not have a birth date for your animal, it must be estimated by checking with the breeder, former owner, your veterinarian or someone experienced in mouthing bovine to read the teeth for approximate age. The animal must be at least 24 months old at the time of Hardship application. Please note that you will need to do a Registration Application on all Hardship applications under the age of 3 years old when they become 3 years old.
  • How do I measure a my Miniature Zebu for registration?
    Miniature Zebu are the smallest of the miniature cattle breeds and the only naturally occurring miniature breed maturing to heights under 42” at the back and most being 36”-38”. IMZA requires the measurement to be directly behind the hump. Measure from the ground to the back area directly behind the hump.
  • I purchased a bred cow. Do I use the breeders farm prefix or my own for the calf?
    It is common courtesy to give credit to the breeder of the calf so you would use the breeders farm prefix for the calf.
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