Coat color link to eye issues in French horse breed

A Comtois stallion alongside night chocolate coat as well as flaxen mane as well as tail (black heterozygous Silver).

Chestnut Comtois horses carrying a silvery coat colour mutation cause got been establish to cause got a greater prevalence of optic abnormalities, a written report inward French Republic has revealed.

The Comtois is a lite draft horse, of upward to well-nigh 16hh, as well as are generally chestnut with flaxen manes as well as tails, precisely tin too be bay. Researchers inward French Republic establish that chestnuts of the breed had a higher prevalence of Multiple congenital ocular anomalies (MCOA) relating to the PMEL17 (Silver)  coat color mutation. The bay horses were negative for the mutation.

Comtois foal alongside chestnut coat as well as chestnut mane as well as tail (bay heterozygous Silver).

In the study, 74 purebred Comtois as well as i half-bred, aged 10 days to eighteen years, were examined yesteryear transillumination, straight ophthalmoscopy as well as ultrasonography.

Hair samples were collected from 34 horses for coat color genotyping. Sixty-six horses (88%) revealed cysts (65 horses) or abnormal thickness (one horse) of the ciliary bodies, most of them solely diagnosed yesteryear ultrasonography. Cysts were localised inward the nasal business office of the optic inward viii horses.

All these horses presented the silvery phenotype alongside mane as well as tail beingness white or flaxen, or were chestnut alongside genetic testing confirming PMEL17 mutation. Of these, 39 (58%) showed MCOA-syndrome alongside iridal hypoplasia (100%), cataract (85%), cornea globosa (56%) as well as lens luxation (8%).

Ultrasonography detected cysts inward all Silver carriers apart from one, around of them beingness localised inward the nasal business office of the eye.

Only viii bay mature horses (11%) were classified equally beingness disease-free. Genetic testing confirmed that cyst-phenotype horses were heterozygous carriers for the Silver mutation, MCOA-phenotype horses were homozygous carriers, as well as bay horses were noncarriers.

Bay homozygous carriers had significantly lighter coat color than heterozygous carriers. One foal alongside heterozygous mutation had normal eyes.

Comtois foal alongside white coat as well as mane as well as tail (black homozygous Silver).

The researchers said that MCOA-syndrome related to PMEL17 mutation was overrepresented inward the breed, as well as should hold upward taken into consideration when breeding.

The Comtois  is believed to cause got descended from horses brought yesteryear the Burgundians of northern Germany to France during the 4th century, as well as they cause got been bred at the Franche-Comté as well as inward the Jura Mountains since the 6th century. In the Middle Ages they were used equally state of war horses.

During the 16th century, the Comtois breed was used to improve the Burgandy Horse. In the 19th century, other draft horses such equally the Norman, Boulonnais, and Percheron were bred into the Comtois, as well as to a greater extent than of late the Ardennes was used to attain a stronger Equus caballus alongside improve legs. Today, the Comtois breed is instant solely to the Belgian draft Equus caballus inward number in France.

In the16th century, they were used equally a cavalry and artillery horse, as well as today they are used for hauling wood inward the pine forests of the Jura inward the mountainous regions of the Massif Central, as well as for working inward the vineyards inward the Arbois area. They are too bred for the French horsemeat industry.

 

Phenotypic description of multiple congenital ocular anomalies inward Comtois horses: M. Depecker (Centre International de Santé du Cheval d’ONIRIS (CISCO), LUNAM Université, ONIRIS); E. Ségard and J-L. Cadoré (Université de Lyon, VetAgro-Sup, Campus Vétérinaire de Kyon). DOI: 10.1111/eve.12075

 

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