• Curly Traits
    • Glossary
    • Curly Genes
    • Extremes
    • MicroCurl
    • Minimals
    • SmoothCoats
    • Homozygous
    • Recessive
    • FAQ
  • Research
    • Allergies
    • Ancestral
    • FiberScans
    • CA
    • TestedCA
    • Gait Gene Study
  • Curly Mustang Assoc
  • Gaited Assoc
  • Genetic Testing
  • CurlyHorseHistory
ICHO

                                               RESEARCH                          http://ichocurlyhorses.org

Researching the Curly horse was one of the very first missions of ICHO. From the beginning of ICHO there has always been a research project taking place. Here we will list all the projects past and present.   

Blood Comparisons Study

Results reported January 2001
by Dr. Andrea Schaap, DVM, former director, ICHO Curly Horse Research Council

April 01- 2001: Blood Research: Project completed.

Hypothesis tested:

Curly red blood cell (RBC)concentrations in blood are higher than regular horses.

I have collated the information received on curly horse blood parameters. This is based on 16 pairs of horses. Each pair of horses compared, were one Curly Horse, and one straight other breed horse, (w/ zero curly pedigree) of the same age bracket, same sex and reproductive cycle, and living at the same place & elevation, under the same conditions (together).

The Research Council collected the widest type pairs available, striving for maximum variety of different types of curlies and straights. We paired saddle horses, breeding range stallions, pregnant mares, open mares, young horses, old horses, weanlings, ponies, and drafts (the draft pair was a Belgian mare and a recessive Percheron mare, the only recessive tested in this comparison.) Living elevations ranged from 1000' to 4000'.

Curly horses were so normal in their results that even though the sampling was relatively small (16 curlies, 32 horses) there is no indication that this project should be continued in any direction.

Note, most of the samples are from range horses, many of whom will have little cuts and nicks that are healing which would push up the WBC count.

White Blood Cells
Average #'s Range in low range in high range
Curlies 9.71 4.7 - 13.1 1 horse 7 horses
Straights 9.02 6.9 - 12.6 0 3 horses
(equine) Normal Range   5.3 - 11    
Average difference between the paired samples: -1.16

Red Blood Cells
Average  #'s Range in low range in high range
Curlies 8.33 6.5 - 11.3 0 0
Straights 8.44 6.2 - 12.2 1 horse 1 horse
(equine) Normal Range   6.5 - 11.6    
Hemoglobin average difference between the paired samples: -0.12; + or - 1.39

T4 (thyroid)
Average #'s Range #  horses in low or high range?
Curlies 48.06 12 - 62 none out of normal range
      (1 was 12, next lowest was 39)
Straights 50.31 20 - 75 1 in high range
Normal Range   10 - 70  
Average difference between the paired samples -2.31

Note that although the difference is not significant, Curlies actually had a slightly lower RBC count than straight breed horses at 8.33 compared to 8.44 for the straights. They are right in the mid normal range, and out of the 16 samples tested not one was out of normal range. Also note that the differences within each pair is very tiny at negative 0.12. I think that it would be reasonable to conclude that Curlies have very normal blood parameters. A larger sample would be more significant, but these results don't even hint that there may be something interesting or unusual in curly blood.

I also see no point pursuing the idea that Curlies may be hypothyroid. Not only was the curly average and range quite normal, the most extreme horse in the sample had a T4 of 56, which is mid normal.

I tested several other parameters on liver, kidney, protein levels, hemoglobin levels etc. There is nothing there to induce any interest in following those up with statistical analyses as the curly results were basically all mid normal.


Curly Horse Epidermal Research Project

report by Andrea Schaap, DVM, Guelph, Ontario
August 2005


April 01, 2001.

Skin Research Project started. Fall skin biopsy samples (6mm sized, preserved in formalin) of several Curly horses were sent to Dr. Scott, Cornell University, Ithaca NY.

May 30, 2001.

Initial results received from Dr. Scott: 9 horses were tested ranging from a minimally expressed to an extreme stringtail. On preliminary examination there were two significant types of variation from normal horse skin anatomy.
The two types are:

  1. Dysplastic (abnormally formed) hairs
  2. Follicular keratosis (excessive amounts of keratin in hair follicles)

There was a wide variation in the distribution of variation from normal horse anatomy. Other than the two variations listed below, overall obvious microscopic skin anatomy from these horses looks like that from normal horses.
All four horses who had scanty or stringtails had dysplastic hair. The most extreme horse had both dysplastic hair and follicular keratosis. The other three scanty tails did not have follicular keratosis. One of the scanty tails is heterozygous (unless the one straight offspring is actually a minimal), the other three are believed, but are not proven, homozygous.
The two most minimal horses had follicular keratosis - one was the mother to the most extreme, the other the sister.
The 3 moderately curly horses had normal skin in this sampling, including a recessive with full mane and tail. All three were fairly old horses - at least 10 years older than the next oldest horse.

No definitive conclusions could be drawn from such a small sampling. There was no one common trait to all curly horses and the horses with the most desirable moderate curl had no instantly obvious variation from normal. Because there are two unrelated variations so far, it is probable that there are at least two different genes functioning, which when combined leads to the stringtail extreme.

Dr. Andrea Schaap, DVM (2001)

ADDITIONAL INFORMATION:

Read the official findings of Dr. Scott's research published in the Equine Veterinary Journal
(includes color photographs)

Curly Horse Epidermal Research Project
EVE Vol. 16 (4) 201-206.pdf (119 KB)

Graciously provided by:

Lindsey Abeyasekere
Production Manager
Equine Veterinary Journal Ltd
351 Exning Road
Newmarket
Suffolk CB8 0AU, UK
Tel: +44 (0)1638 666160
Fax: +44 (0)1638 668665
Email: [email protected]

(copies of the article are available for purchase if readers contact EVJ)

Dr. Scott's publications

about Dr. Scott.

Cornell University • College of Veterinary Medicine • Ithaca, New York 14853-6401


Curly Horse Epidermal Research Project
eve_vol._16_4_201-206.pdf
File Size: 122 kb
File Type: pdf
Download File


German study- Is the Curly horse hypoallergenic   click title for articles and study results


Curly Coat Gene Study 

The Curly gene research has been a work in progress for many years between ICHO and Dr Gus Cothran. Sandy Hendrickson worked with Dr Cothran to get the original gene study going and Founding member Lisa Wytiaz was responsible for securing a research grant through the Panoz Foundation.
In Sept 2010, ICHO refunded new work with Dr Cothran for a new complete gene scan of the Curlies DNA in hopes of locating the Curly hair gene. 3/15/15 Update- Additional genetic study is underway for the ongoing hunt for the Curly coat gene/s. Much progress has been made but more genetic study is needed before we know the whole story about our Curly coat genes and what makes our Curly horses curly! 3/5/16 Update- Our next group of test horses is under way to find the Curly gene/s of the Curly Jim gaited line. Stay tuned for more info as it is becomes available.

*December 2017- A Gene has been found! A Missense variant in keratin 25 gene causes dominant gened Curly coats in horses. KRT25 has been found in Native/Warrior, Damele, Canadian, BLM horses. Read the research article below. Also read Dr Mitch Wilkinson's Curly Gene article in the 2017 Fall Gazette linked below. Explains the research in easy to understand terms. ICHO offers a test for KRT25, see our home page for more info.

SP6 Curly Coat gene has been discovered by German Researchers. Dr Gus Cothran is verifying results that this is the Curly Jim line gene. Stay tuned for more info. To read the German Study paper use this link- https://www.nature.com/articles/s41598-018-24865-3 
curlygenekrt25_research_article.pdf
File Size: 5702 kb
File Type: pdf
Download File

2017_fall_gazette.pdf
File Size: 6061 kb
File Type: pdf
Download File


Curly Fiber Studies

The fiber studies were used to determine the hair diameter and curvature of Curly hair using the Fiber testing lab of Yocum-McColl, leaders in fiber testing of all fiber animals. Before these studies, not much had been documented about the physical properties of a Curly horses body coat. The Fiber Lab results were quite interesting.  In the 2006 study, we were looking for the finer spinning quality Curly coats. The lower the micron count number, the finner the hair fiber. Micron count means the thickness of a hairs diameter. The lab report also gives a curvature measurement, which means the amount of bend to a hair. 
Below are the 2006 Lab results. The first report is fiber diameter and the second report gives more detail including curvature measurements. We learned there is quite a wide range of fiber diameter and curvature measurements. The best spinning quality Curlies fall in the 30's range and second best in the 40's range. The fiber studies were conducted by Bunny Reveglia with donations of Curly hair fiber from many members.   
ichosummarybyfiberdiameter.pdf
File Size: 22 kb
File Type: pdf
Download File

icho_ofda_reports_287363-287388.pdf
File Size: 108 kb
File Type: pdf
Download File

The 2007 fiber study looked for certain areas to test, and we also retested horses in the 2006 study to see if fiber measurements changed with age. Also Smooth coats and some other breeds were tested as comparisons. The 2008 report tested more other breeds hair fibers and was a comparison of all lab reports findings for all years. Read the reports below.  
*Click here for:  Fiber Study Scans of horse hairs  
(photos of actual horse hairs, most likely the most intensive photographic study of Curlies and other horse hair of all types for curvature and fiber diameter)
icho_research_dept_fiber_study_2007.pdf
File Size: 1535 kb
File Type: pdf
Download File

2008_fiberstudyreport.pdf
File Size: 191 kb
File Type: pdf
Download File


Curly Ancestral DNA Research

Have you ever wondered who your Curlies ancestors really are genetically? Since we have so many "unknowns" in some Curlies, especially the BLM Curlies, Dr. Mitch Wilkinson has worked out the project details with Dr Gus Cothran of TX A&M and ICHO.  Ancestral DNA research on BLM Curlies  is in progress as well as all other Curlies that owners want tested. The results show you, your Curly's Genealogy DNA findings. Sometimes they are surprising. In my case with WW Thunder Moon, he is half Native Line Curly and we really don't know the background of those horses, so his results showed he carried the highest level of association with the Quarter Horse or breeds that made up the Quarter Horse. His second level of association was New World Iberian breeds and his third association was with North American Gaited breeds. This was surprising since he is by pedigree- 1/2 Native Curly, 1/4 Damele Curly lines and 1/4 Belgian draft. I had my three Curlies Ancestral DNA'd and the results we are now getting results in from the BLM Curlies tested. Very interesting. If you are interested in having your Curly Ancestral DNA tested, please go to forms: Ancestral DNA form or download and print below and there is a place to pay the $25.00 fee on our Payment online link. Hair sample and payment and form must be sent to the ICHO office. Since we really don't know the actual origins of the Curly in North America, all Curlies are welcome to be tested including Damele, Native and Curly Jim line and BLM Curlies as we would like to have a good database full of Ancestral DNA results to compare to. Thanks for taking part! Go to our Ancestral DNA Results page here.
ancestraldnaform.pdf
File Size: 113 kb
File Type: pdf
Download File

Research into CA- Cerebellar Abiotrophy that affects the Arabian horse and horses of Arabian Ancestry including the Curly horse. We will be tracking Curly carriers that have inherited the recessive gene for CA from their Arabian Ancestors. To learn more go here- http://ichopage.weebly.com/ca.html 

GAIT Gene Study

June 1, 2013 thru June 1 2015 This study is to DNA test for the gait gene DMRT3 in Curly horses and Smooth Coat Curlies. All horses tested will be documented so it can be determined how many of the Gaited line Curlies have the gait gene and if they are heterozygous or homozygous for the gait gene. We will also document gaits of the horse and parents to see if there is a relationship to gene copies and gaits performed. This will also help find the gait gene in other lines of Curlies as well. Results can be seen here- Gait Gene Study Results

If you would like to take part in the study please see details on our home page- http://ichocurlyhorses.org
Powered by Create your own unique website with customizable templates.