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.
|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|
|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|
|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
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:
- Dysplastic (abnormally formed) hairs
- 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)
German study- Is the Curly horse hypoallergenic click title for articles and study results
Curly Coat Gene Study
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
Curly Fiber Studies
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.
*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)
Curly Ancestral DNA Research
GAIT Gene Study
If you would like to take part in the study please see details on our home page- http://ichocurlyhorses.org