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mini Zebu calf-- source: Pinterest
a miniature Zebu calf
miniature Zebu are naturally tiny without dwarfism
photo source: Pinterest

List of DNA tests available for cattle and list of labs that currently offer them: animalbiotech.ucdavis.edu/dna-companies

Dwarfism in Cattle: Most forms of dwarfism are inherited and result from mutated genes. These mutations impair cartilage and bone formation in early development and results in various types of dwarfism. Some forms of dwarfism result from environmental factors that influence embryonic development, such as the BVD virus (bovine viral diarrhea), fungal toxins, plant poisons, or a manganese deficiency, during gestation. However, most forms of dwarfism in cattle occur when a calf receives one or both mutated genes from the parents.

Types of Dwarfism in cattle vary, according to the specific mutation. In general, dwarfism causes shorter stature, and varying degrees of deformities in the limbs, joints, head and spine. Dwarfism can be categorized as either proportionate (an overall size reduction without changes in body proportions) or disproportionate (a size reduction in one or more limbs, with changes in body proportions). Some types of dwarfism can include cleft palate, abdominal hernia or other abnormalities. Some forms of dwarfism are non-viable (lethal).

Chondrodysplasia is one type of dwarfism found in cattle.
Congenital disproportionate dwarfism, designated as chondrodysplasia, achondroplasia or chondrodystrophy, is described in a number of different cattle breeds with varying modes of inheritance. Chondrodysplasia is disproportionate dwarfism that expresses with shortened limbs in cattle.

Bulldog Dwarfism in Dexter cattle is one of the earliest described Mendelian disorders of animals. It affects the aggrecan (ACAN) gene. Dexter dwarfism has incompletely dominant inheritance, leading to a mild form of dwarfism in heterozygotes (carriers of 1 copy). When inherited in homozygous form (carries 2 copies), the lethal expression occurs, and the result is a dead aborted or stillborn calf that physically resembles a bulldog. This version of chondrodysplasia is also known as BD which stands for "bulldog". There are several different mutations of the ACAN gene, as well as other genes, that are associated with the same bulldog-type dwarfism. BD mutations have been found in Nellore cattle of Brazil, and in Holstein of Denmark. Dexter upgrades of New Zealand carry BD2 specifically, along with the original BD1. BD1 has existed in purebred Irish Dexters for centuries.

miniature cow size comparisons

Dwarfism in Miniature Cattle. Most miniature cattle are just small cattle, with no dwarfism. Some miniature cattle are small cattle that carry BD. Those cattle are dwarfs with Irish Dexter DNA in their pedigree.

the inheritance of Chondrodysplasia:

  • Autosomal means it is an inherited trait not related to gender.
  • Incomplete dominant (or semi-dominant) means:
    • It is partially expressed when a single copy is inherited (heterozygous).
    • It is fully expressed when 2 copies are inherited (homozygous).
  • Lethal gene is a gene mutation that is not survivable when inherited in homozygous form.

Miniature cattle carriers have 1 copy of the BD mutation. Since BD is a lethal mutation, if a fetus inherits 2 copies of the mutation, one from each parent, it is not viable.

Most herds of breeding miniature cattle (that are short Dexter-derived breeds) are tested to prevent lethal birth defects. To understand the risk, here are the genetic probabilities that result from breeding 2 chondro positive cattle together (if both the bull and the cow are chondro carriers):

(in this figure we use A to represent the ACAN allele with the BD mutatation;
and we use a to represent a normal, non-mutated ACAN)

risk of prenatal chondro homozygous

25% of the offspring are expected to be bulldog calves ("homozygous" chondrodysplasia), severe
disproportionate dwarfism. A bulldog calf is the non-viable fetus with tiny legs, a protruding tongue and a flat face that look similar to a bulldog. A dead bulldog fetus is usually aborted in mid to late pregnancy. It usually doesn't cause dystocia (calving difficulty), but if carried full term, the risk increases.

50% of the offspring are expected to be short (dwarf) cattle ("heterozygous" chondrodysplasia). 1 ACAN gene allele has the BD mutation, and the calf is affected by mild dwarfism, most notably in height. In miniature and small cattle, mature height can be reduced from 4 to 6 inches. In standard taller breeds, dwarfism can reduce mature height from 8 to 9 inches.

25% of the offspring are expected to be normal cattle (chondro free or non carrier). Since both ACAN alleles inherited are normal, the calf grows to its genetically natural height. Its natural height of course, can genetically be anywhere from short to tall, depending upon its breed and its parents' natural size.

North American Miniature Cattle Breeds:the Irish Kerry cow

  • There are 2 kinds of BullDog dwarf genes; BD1 and BD2.
  • They are two different mutations that do about the same thing.
  • BD1: is found only in Irish Dexter DNA
  • BD2: was discovered in New Zealand Irish Dexter cattle descended from Meadowpark Charles. Read more about BD2 Dexter NZ mutation here: Chondrodysplasia, by Robyn Snelgar, dextercattle.nz.
  • BD2 is not found in North American miniature cattle.
  • When we talk about BD in North America, we are talking about bulldog dwarfism in general, or the BD1 mutation specifically.
  • Compound Heterozygote: Lethal; a fetus that inherits one copy each of BD1 and BD2, will also be a bulldog calf.

There are a number of genetic mutations in cattle that will cause dwarfism.
BELOW: graph illustrating BD dwarfism in Miniature Cattle compared with dwarfism mutations in other N.A. cattle

primary population genetic dwarfism mutation gene mode of inheritance hetero homoz DNA test?
Irish Dexter disproportionate (bulldog) BD1 ACAN semi-Dominant Dwarf Lethal Yes
upgraded NZ Dexter disproportionate (bulldog) BD2 ACAN semi-Dominant Dwarf Lethal Yes
mostly Hereford proportionate (snorter) ? recessive normal Dwarf Yes
Not D2? What is it? (Johnson et al., 1950) where is current research?
mostly Angus proportionate (long headed) D2 PRKG2 recessive normal Dwarf Yes
  Dolichocephalic or Snorter dwarfism was about eradicated in Angus by the 1970s.
Shorthorn (Stonaker and Tom, 1944; Baker et al, 1950)? anything current?   ? Dwarf ?   ?
Florida native (Dollahon et al., 1957; Dollahon and Koger, 1960)?   ? Dwarf ?    ?
Brahman (Florida) proportionate; growth hormone GH1 recessive normal Dwarf   ?
Jersey PB--FBs? proportionate dwarfism in Jersey (Mead, 1942) any current info? is there dwarfism in Jersey?
Fleckvieh what kind of dwarfism? GON4L recessive?   ? Dwarf ?   ? 
Belgian blue proportionate RNF11 recessive?   ? Dwarf ?   ? 
Brazilian Nelore disproportionate (bulldog) (BD3?) ACAN semi-Dominant Dwarf Lethal   ? 
In North America, any miniature cattle that descend from shortie Dexter crossbreeding could carry BD1
Animal Biotechnology > DNA Companies.
List of DNA tests available for cattle and list of labs that currently offer them.

 

Physical effects of BD chondro carrier cattle can include:

  • increase or earlier incidence of arthritis
  • mini shorty calf--picture found on Pinteresta low incidence of mild deformities that can include
    undershot jaw, pug nose, bow legs, enlarged joints

Low birth weight and postnatal growth restriction are the most evident symptoms of dwarfism. Accompanying skeletal aberrations may compromise the general condition and locomotion of affected individuals. Newborn chondro calves normally present with dished faces and loose hips (soft cartilage), which they outgrow (the cartilage firms up to normal), and shorter legs, especially short cannon bones. Chondro positive miniature cattle can be quite small, and are often bred for pets. People who favor and enjoy very small cattle love their chondro carriers. Sometimes the tiniest, fuzziest, fanciest colored dwarf calves fetch high prices due to their "cuteness factor".

 

Armageddon--bucking bull
Armageddon, a condro-carrier 40" tall bucking bull. This bull is an example of a chondro carrier that has no sign of dwarfism other than a short stature; “...he was such a sweet boy, he came when called. He got so excited when he saw the trailer you'd have thought he was wild & crazy, but he just absolutely LOVED loved to go rodeo--he loaded himself in the trailer! He was always a gent in the trailer & loading in the chutes. He begged for treats & back scratches; never ever offered to hurt his rider or any of the clowns or chute help. In this video he was age 9; this was the first time he was ever ridden & the little cowboy scored a 92.5! Armageddon divided his time between the pasture with his girls and the bucking arena. His legs were clean & blemish free as was the rest of him. He never had any symptoms whatsoever that he was chondro-positive except for his short legs.” (~former owner) Editorial comment: Armageddon's breeder has bred short cattle for decades, long before we fully understood the genetics. I am told that all his cattle are about the same size from having been selected small for generations, and he pays no attention to BD. His cattle have been selected for soundness and conformation that apparently works quite successfully with carrying chondro.

 

dwarf mini Longhorn CL Variation of Effect: It is important to emphasize the wide variation in how much dwarfism affects different carrier cattle, and different lines of cattle. In incomplete dominant traits, inheriting one copy causes a partial effect. In the case of BD1 dwarfism, it ranges anywhere from "almost no effect" to "some effect". That is mostly in height, and of course is subjective. But in general, it is fair to say:

  • most of today's carriers that have been selectively bred for generations are not affected much, other than their stature
  • with advanced age, many are negatively affected by arthritis

All Miniature Cattle will probably fare better on small acreages than on large pastures. Little animals will do better when not having to share pasture and physically compete with larger animals over feed or hay. Carrier cattle might not thrive if having to hunt grass and walk all day, which might cause excessive wear & tear on their joints and shorter legs.

MANAGEMENT: Proper management of chondro cattle means taking whatever steps are necessary to prevent two carrier animals from breeding. That can include good fences so that chondro bulls can't get to chondro cows, or, making sure young chondro positive bull calves are castrated or separated from the cow herd well before being able to breed. Some carrier cattle breeders run only chondro negative bulls, and band (castrate) all the bull calves shortly after birth, and market them as pets or butcher steers. With that herd plan, no birth defects are possible. And, the cow herd A Shorty Dexter bulldoesn't need BD testing (a considerable cost saving in larger herds).

Dexter Terminology ~ Short Legged or Long Legged:
The terms “Shorty” or “Short” or “Short-Legged” may be used as a genotype term, or as a phenotype term. These terms were historically used among Dexter breeders in reference to chondro positive cattle (long before the genetics were fully understood). BD(+) cattle are usually recognizable, visibly. They often have broader or larger heads for their stature, and they usually have noticeably shortened legs (most noticeable are their short cannon bones from the knee and hock down to the fetlock). Since only the skeleton and joint cartilage is affected by the BD gene, essentially, the rest of their bodies is actually still normal sized organs & muscles on a reduced frame. This could be one reason why some cattle (herds, bloodlines or composite breeds) fare better when they inherit the BD gene than others do.

Mona, Barbara NettiShort legged and long legged may be used to describe phenotype: thick, beefy cattle (regardless of their genetic makeup) that are shorter and wider compared to taller or narrower framed herdmates. Because mini cattle breeders have been selecting for short cattle for centuries, there are plenty of miniature cattle that are not dwarfed. Herds of crossbred miniature cattle tested chondro free, can lack uniformity and still have both “long legged” and “short legged” cattle. Some untested “short-legged” cattle (that look like chondro carriers), may not have chondro. They may just be genetically short. However, short legged miniature cattle that look chondro positive, usually are. To avoid birth defects, only DNA testing can tell breeders for sure.

Photo above left: A naturally short little red Dexter cow, Legend Red Mona, ADCA No. 15552, who measured 40" hip height at 5 years of age. She tested non-carrier for chondro. Photo courtesy of Barbara Netti, Legend Rock Ranch, Texas, 2015.

miniature Jersey -- PinterestRegistries and Breeding. Most breed associations do not require testing for dwarfism. Whether or not a miniature composite or breed or herd has carrier cattle within its population, is the responsibility of individual breeders, sellers and buyers to test for and manage with honest and ethical practices.

Do All Miniature Cattle need DNA testing for BD? No, not if they have no Dexter in their pedigree. Otherwise, that depends upon what breeds their ancestors are, if known. A lot of today's miniature cattle breeds are composites (crossbred cattle of known breeding) or percentage cattle that were originally developed using short-legged Dexter cattle. A general rule of thumb is, if a miniature cow or bull has, or could have a Dexter ancestor, and is unknown status, it should be tested for BD before being bred to another unknown status animal.

Testing. Calves can be DNA tested by hair samplesending in 30-50 pulled hairs (including the roots) from their tail switch, to a testing lab. The tail switch hairs have the largest root bulbs and in calves, are the easiest to extract DNA from in the lab. You can pull hair from anywhere on cattle, but make sure the root bulbs of the hair are included, and they should be easily seen with the naked eye. Use a pair of pliers, a box of fresh clean plastic sealable (storage) bags, and a flashlight if needed. Be very careful not to contaminate one animal's sample with another animal's hair. As you pull and the cow pulls away, you should get a good sample, and perhaps an annoyed cow but not an upset cow. Hair samples cost less but blood or tissue samples can also be used for DNA testing in most labs.

Parentage Verified. An animal can be proven negative for chondro by parentage verification. Cattle are "obligate negative" if both of their parents are tested negative, and they are DNA parentage verified as their offspring. In other words, two miniature cattle that are tested negative BD(-), will not produce a BD(+) positive calf when bred together. If a BD(+) calf is born from 2 BD(-) (tested or obligate) cattle, then, the only possible reasons for that (listed in order of likelihood) would be if:

    • there was a sneaky chondro positive bull (or bull calf) in the woodpile
      (Did you know bull calves can become fertile as early as 6 months of age?)
    • there was a mixup or contamination in the hair samples when collected
    • there was a mistake in record-keeping in one of the parents' pedigrees
    • there was a mistake made at the DNA testing lab (some labs are more reliable)
    • there was false record-keeping in one of the parents' pedigrees
    • the embryonic calf's own genes spontaneously mutated (like me winning the lottery)

DNA TESTING: The first test for chondrodysplasia became available in 2003 (with the 1st testing license given to SRC Lab in Canada). In 2006 Texas A&M got licensed to test for chondro, then UC-Davis VGL, and in time a few more. Here is a link to VGL's Biotechnology page that stays current with all DNA tests when they become available, and keeps links to all the labs available when they get licensed to perform them. Some breed registries cooperate with certain labs and offer special member discount prices for tests or panels of tests that meet the needs of their breed.


(the down side...)

Patti Adams arthritic Dexter shorty cow
“Many people haven't yet kept a lot of chondro cattle into old age, to see what the eventual damage to the skeleton looks like. This is what old age looks like for a Dexter Chondro carrier. She was 14 years old--we had her euthanized by our vet on the day that this photo was taken. You can see how much the muscles have atrophied in the hind quarters due to her severe arthritis and reduced mobility. Every Dexter chondro carrier that we have owned has eventually developed severe arthritis as they aged out, and that has been the sole reason to remove them from the herd. These females were very productive all through their lives, but it was arthritis that ended them.” ~ Patti Adams, Wakarusa Ridge Ranch, KS

don't worry -- be happy miniature cowFor beginners just starting out with miniature cattle, deciding whether or not to buy or breed carrier cattle is the first decision they might make. When deciding on a breed, learn the differences between crossbred, composite, purebred and fullblood cattle, remembering that BD1 is only found in Dexter DNA. Visit and talk with as many breeders as you can. Visit cattle herds in person. If present, look at carrier and non-carrier miniature cattle of all breeds, and at all ages. You will figure out what will work best for you.

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PHA in Miniature Cattle

PHA occurs in several breeds of cattle. Research by Dr. Jon Beever at the University of Illinois identified the mutations responsible for PHA in cattle. He discovered that there are 2 mutations that cause PHA. The affected gene is the same gene for the different breeds, but the specific mutation associated with PHA·D in Dexter cattle is different from the PHA mutation in Maine-Anjou/Shorthorn. PHA testing became available in the United States in 2009.

Primary breed(s) Genetic dwarf mutation Mode of inheritance heterozygous homozygous DNA testable?
Dexter DNA PHA·D recessive normal Lethal Yes
Maine Anjou PHA recessive normal Lethal Yes
DNA Companies. A current list of DNA tests available for cattle genetic conditions, and list of the labs that offer them.

PHA similarities to BD:

  • There are 2 kinds: PHA and PHA·D
    • PHA: "Pulmonary Hypoplasia with Anasarca" (mostly found in Maine Anjou DNA)
    • PHA·D "Dexter Pulmonary Hypoplasia with Anasarca" (only found in Dexter DNA)
  • both kinds of PHA are similar and do about the same thing
  • PHA is a heritable birth defect that is testable
  • PHA is a lethal gene (in homozygous form it causes a birth defect that is not survivable)

PHA·D, like BD1, is found exclusively in Dexter cattle. PHA is characterized by incomplete development of the lungs and severe subcutaneous fluid accumulation. The "WaterBaby" aborted calf is (in some ways) similar to a "BullDog" aborted calf.

PHA differences from BD1:

  • PHA is a recessive gene. A heterozygous PHA(+) calf is a normal calf, with no visual indications of carrying.
  • PHA is not dwarfism and has nothing to do with frame size.
  • the PHA (homozygous) birth defect is called a "WaterBaby" calf (similar to a huge water balloon, up to 200 lbs.)
  • A PHA "WaterBaby" calf usually results in calving difficulty, while a BD BullDog calf usually doesn't.
  • No one wants PHA in their cattle: With testing PHA·D will be avoided, and can eventually be exterminated. Hopefully, it is getting close to being exterminated now.

All untested Miniature Cattle that are Dexters or could be Dexter composites should be tested for BD1 and PHA·D before being bred, to eliminate the 25% chance of either Bulldog or WaterBaby birth defects. PHA waterbaby calf associated dystocia can lead to death of the cow. A genetic test specific for the Dexter PHA mutation (PHA·D) is available from the UC Davis Vet Genetics Lab (VGL).

The VGL PHA test does not detect the Maine Anjou /Shorthorn mutation. Those breeds can be tested for the non-Dexter PHA through their breed associations, such as the Maine Anjou, Shorthorn, and Simmental registries.

 

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Sources:

dwarf bull--calfology.comBritish and Continental Cattle Breeds. Homestead on the Range, November 28, 2017.

Severe Generalised Chondrodysplasia in Miniature Cattle Breeds. KE Dittmer, KG Thompson & T Hogan, New Zealand Veterinary Journal Vol. 65, Iss. 5, 2017, Pages 282-283 | Published online: 25 May 2017.

AgriGenomics, Inc. offers these livestock genetic tests. 2017

UCDavis VetGen Lab Cattle | Dexter Genetic Tests. The Veterinary Genetics Laboratory offers genetic tests specific to Dexter Cattle. 2017

Animal Biotechnology > DNA Companies. A comprehensive list of DNA tests available for cattle, and list of all the labs that currently offer these tests.

A miniature condition in Brahman cattle is associated with a single nucleotide mutation within the growth hormone gene: Hormonal disruptions are evident in Brooksville miniature Brahman cattle caused by mutations in GH1 and GHR. Miniature Brahman cattle at the USDA ARS Subtropical Agriculture Research Station in Brooksville, FL have normal proportioned growth but are approximately 70% of mature height and weight when compared with Brahman cattle in the same herd. Pedigree analyses suggest that the condition is inherited through a recessive allele.

PRKG2 Gene Mutation for Dwarfism (D2) Fact Sheet. What is PRKG2 Gene Mutation for Dwarfism (D2)? D2 was recognized as a specific strain of dwarfism on September 7, 2007. D2 is caused by a recessive mutation on a single cattle chromosome. Cattle that are homozygous for the mutated gene will exhibit D2. Revised 06/2016. Dwarfism in Angus cattle is caused by a mutation in the GMP dependent, type II protein kinase (PRKG2) gene.

"Dwarfism in other breeds, such as Hereford cattle, is caused by multiple genes." no sources cited; under investigation

Dwarfism in Cattle, video by Karlee Logan published on 20 January 2015.

Mammalian Genome: Bulldog dwarfism in Dexter cattle is caused by mutations in ACAN. Authors: Julie A. L. Cavanagh, Imke Tammen, Peter A. Windsor, John F. Bateman, Ravi Savarirayan, Frank W. Nicholas, Herman W. Raadsma, Springer Science+ Business Media. N.p., 28 June 2007, November 2007, Volume 18, Issue 11, pp 808–814. Web. 27 May, 2014.

Davidson, Carole. Chondrodysplasia. N.p., 2008. Web. 29 May 2014, American Dexter Cattle Association, DexterCattle.org.

Dwarfism in Cattle, By Dottie Love, Fancher Love Ranch, 2014.

Genetic and PathoAnatomical Features of the Bovine Prenatal Lethal Chondrodysplasia Hereditary Genetics ISSN:2161-1041, Genetics an open access journal, Volume 3 • Issue 4 • 1000132. Moura et al., Hereditary Genetics 2014, 3:4. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. http://dx.doi.org/10.4172/2161-1041.1000132. Corresponding author: Dr. Enio Moura, Service of Medical Genetics, Faculty of Veterinary Medicine, Pontifícia Universidade Catolica do Paraná (PUCPR), Curitiba, Parana, Brazil, Tel: 55 41 3274-4501; E-mail: enio.moura@pucpr.br Rec date: Apr 15, 2014. Copyright: ©2014 Moura E, et al., Pub date: Aug 25, 2014.

a bulldog calf, not BD1 but the same result our graph at top of page
Hereditary Genetics: Current Research Genetic and PathoAnatomical Features of the Bovine Prenatal Lethal Chondrodysplasia,
Figure 1: bulldog calf Figure 2: Risk of prenatal lethal chondrodysplasia in a mating of short-legged Dexters.

white Nelore (Nellore) heiferThis article provides an overview of the current state of knowledge regarding the genetics and anatomical pathology of bovine prenatal lethal chondrodysplasia, describing the characteristic phenotype of affected animals and the Mendelian aspect of genetic inheritance. It also is the first record of a spontaneous occurrence of another chondrodysplasia mutation in the Nelore (right), breed of Brazil.
Figure 1 ABOVE LEFT: shows several of the abnormalities in an affected Nellore calf with a gestational age of approximately eight months. This is another BD mutation, but the bulldog calf defect is the same.
Figure 2 ABOVE RIGHT: [BD1] ...in the Dexter is caused by incompletely dominant mutations in the aggrecan gene (ACAN gene). If we represent the ACAN gene as “a” and the mutant allele as “A”, the long-legged Dexter has an “aa” genotype (homozygote), the short-legged Dexter has an “Aa” genotype (heterozygote), and the bulldog Dexter has an “AA” genotype (homozygote). Thus, the homozygosity of the “A” allele causes a defect in the endochondral ossification that is so severe that it is incompatible with life. Therefore, based on the principle of Mendelian genetics, if two heterozygote Dexters are crossed, there is a 25% chance of the offspring having long legs, a 50% chance that it will have short legs, and a 25% chance that it will be affected by BPLC (a bulldog calf), as illustrated in Figure 2. The inheritance pattern that we have described is classically known as incomplete dominance (semidominance). 2014.

Decker, Jared E., University of Missouri assistant professor and beef genetics specialist. “The Truth: Every Living Thing is a Genetic Defect Carrier,” N.p. Web. 06 June 2014.

Chondrodysplasia, by Robyn Snelgar, BD2 NZ Dexter mutation; dextercattle.nz.

Interesting: Birth of a Bulldog Dwarf fetus on a farm in South Africa -- photos.

‘‘Snorter’’ Dwarfism in Herefords. Jones JM, Jolly RD. Dwarfism in Hereford cattle: a genetic morphological and biochemical study. NZ Vet J. 1982; 30:185–189. 22 Aug 22 2013.

Long Nosed Dwarfism in Angus cow Dexter Bulldogs and Waterbabies Belle Fourche Farms, April 5, 2012

Livestock > Genetics > Avoiding The Worst, Joe Roybal, editor & Wes Ishmael, contributing editor | BeefMagazine.com | February 2010

‘‘Long-Nosed’’ Dolichocephalic Dwarfism in the Angus breed. (left) Koltes JE, Mishra BP, Kumar D, et al. A nonsense mutation in cGMP-dependent type II protein kinase (PRKG2) causes dwarfism in American Angus cattle. Proc Natl Acad Sci U S A. 2009; 106:19250–19255.

Bulldog dwarfsm in Dexter cattle is caused by mutations in ACAN Abstract: Bulldog dwarfsm in Dexter cattle is one of the earliest single-locus disorders described in animals. This form of dwarfism (known as bulldog dwarfism) was clearly documented in Dexter cattle in the 19th century (Curran 1990), and its Mendelian inheritance was suspected and discussed as early as 1904 (Seligmann 1904). Affected fetuses display extreme disproportionate dwarfism, reflecting abnormal cartilage development (chondrodysplasia). Typically, they die around the seventh month of gestation, precipitating a natural abortion. Heterozygotes show a milder form of dwarfism, most noticeably having shorter legs. Julie A. L. Cavanagh Æ Imke Tammen Æ Peter A. Windsor Æ John F. Bateman Æ Ravi Savarirayan Æ Frank W. Nicholas Æ Herman W. Raadsma; ©Springer Science+Business Media, LLC. Published online: 22 October 2007.

D2 Dwarfism typesInheritance of proportionate dwarfism in Angus cattle, 122 Australian Veterinary Journal Volume 84, No 4, April 2006

ISU researcher leads effort, develops test to identify dwarfism gene
05-07-08. Iowa State University, James Reecy, Animal Science.

Dwarfism in Cattle. Irish Cattle Breeding Federation

Dwarfism How to Identify it and why it needs to be kept out of your herd.
Information Assembled By: Eric J. Redeker,
The Vertically Challenged Cattle Company, Miniature Texas Longhorns.

Veterinary Medicine on Facebook | Diseases of Cattle | Dwarfism (Chondrodysplasia)
The Vet Book ~ Dwarfism in Cattle

The 5 ‘W’s” of PHA, DexterCattle.ca.

PHA article on Thomas' Dexter's website.

Battle of the Bull RuntsThe Battle of the Bull Runts (Overcoming Dwarfism); by L.P. McCann, 1974.

New Zealand Veterinary Journal, Dwarfism in beef cattle: Diagnosis and control, A.N. Bruere B.V.Sc Ph.D., Pages 205-209 | Received 01 Apr 1969, Published online: 23 Feb 2011

Congenital and Hereditable Defects Which Interfere With The Reproductive Efficiency Of Domestic Cattle (Bos tarus) (pdf) Mylon E . Filkins, Iowa State University, 1965.

The inheritance of Two Different Types of Dwarfism in Beef Cattle, E.J. Turman, B.J. Watkins, Doyle Chambers and Dwight Stephens. Oklahoma Agricultural Experiment Station, Feeder's Day Report, 1962. http://www.beefextension.com/research_reports/research_56_94/rr62/rr62_13.pdf ... The inheritance of 2 different types of dwarfism in beef cattle, the snorter and longheaded types, were studied from the 1955-1961 breeding records of the Project 873 cow herd at Fort Reno. The data indicate that each is a simple autosomal recessive gene. The same gene produces the snorter dwarf in both the Hereford and the Angus breeds. The longheaded dwarf gene is a different gene from the snorter gene. Longhead Dwarfism: found only in Angus cattle. It was not an allele to snorter dwarfism. It may be missed in cattle, since it is realtively harmless, other than a characteristic abnormality in the lumbar vertebrae (identified by xrays) and short legs, and sometimes with larger than normal heads for their body size. It sounds like it is still around, since it is not a real obvious type of dwarfism and is likely not always recognized.

Canadian Journal of Comparative Medicine and Veterinary Science. 1958 Nov; 22(11): 400–403. Dwarfism In Beef Cattle, E W. Stringam Complete Printable Article (554K)

Deletion in the EVC2 Gene Causes Chondrodysplastic Dwarfism in Grey Alpine cattle or Tyrolean Grey Cattle, (Australian Brown Swiss breed) Published: July 11, 2014, Murgiano L, Jagannathan V, Benazzi C, Bolcato M, Brunetti B, Muscatello LV, et al. (2014) and, Deletion in the EVC2 Gene Causes Chondrodysplastic Dwarfism in Tyrolean Grey Cattle. PLoS ONE 9(4): e94861, Editor: Claire Wade, University of Sydney, Australia.

The mammalian growth plate, also known as the physis, is a highly specialized mesoderm-derived cartilaginous structure. Each growth plate is a sandwich-like, multilayer structure divided into 4 functional zones: reserve, proliferative, hypertrophic, and calcified.4 The last zone is then converted into the primary spongiosa, which is remodeled into the secondary spongiosa. Chondrocytes are metabolically active cells that synthesize various elements of the extracellular matrix, including collagen II, which is used as a marker of cartilage differentiation because it is expressed in cartilage matrix. Fibrillar cartilage-specific collagen type II is the major component of the cartilage extracellular matrix. Burdan F, Szumilo J, Korobowicz A, . Morphology and physiology of the epiphyseal growth plate. Folia HistochemCytobiol. 2009;47(1):5–16., and, Mackie EJ1, Ahmed YA, Tatarczuch L, . Endochondral ossification: how cartilage is converted into bone in the developing skeleton. Int J Biochem Cell Biol. 2008;40(1):46–62.

Several types of inherited chondrodysplasia occur in cattle, including “bulldog” chondrodysplasia, Telemark, brachycephalic, dolichocephalic, and rhizomelic types. Japanese Brown cattle with chondrodysplasia present with the rhizomelic type, with lesions confined to the long bones of the limbs, with prominent shortening of the forelimbs. 27 Thompson K. Bones and joints. In: Jubb, Kennedy, and Palmer’s Pathology of domestic animals. 5th ed. Philadelphia, PA: Elsevier Saunders; 2007:13–33.

Breeding Matters – Inbreeding vs. Line Breeding, By Morgan Hartman / October 20, 2014.

Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.

 

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little bullThis Chondrodysplasia Report includes the combined hard work and results of many dedicated researchers and miniature cattle breeders over the years. Much of the information contained in this report was researched and generously contributed by, Carol Davidson (BC, Canada; foremost authority on Dexter cattle in North America), Barbara Netti (TX Dexter breeder), Patti Adams (KS Dexter breeder), Hans Peterson (MI Dexter and mini Scottish Highland breeder), Linda McKay (OK miniature Longhorn cattle) and Kirk Fackrell (WA Dexter and fullblood classic and miniature Belted Galloway breeder). This collection of information is written, compiled and edited by Donna G Vickery. As author I am solely responsible for the content in this report. My sources are not responsible for my findings in this report (since my experience is with genetics and breeding mostly standard breed cattle--I have only owned 2 miniature cows). My sources are not to be held responsible or blamed for any opinions or research conclusions I have come up with. My sources are not necessarily in agreement with some or any of my content, nor each other's findings. But that's OK! What matters is being truthful, informing ourselves and educating each other. And enjoying our cattle!

Donna Grace Vickery, March 2018.

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