Molecular and morphofunctional bases of development of the horse multiple congenital eye anomalies with the silver gene presence on the example of the <i>Soviet draft</i> breed

The article concretizes clinical data on the molecular and morphofunctional foundations of the development of multiple congenital eye abnormalities (MСOA) linked to the silver gene, using the example of the Soviet heavy-duty horse breed. Recommendations for owners on their maintenance and medical support and work with them are provided. The study was conducted on the basis of data from the VNIIK breeding center for the specified horse breed, genetic testing and ophthalmological examination. The focus group included 26 horses of the Soviet heavy-duty breed, examined for the presence of the silver gene. The results of the study showed that horses of the Soviet heavy-duty breed should undergo genetic testing for the presence of a silver gene in the genotype. However, the presence of MCOA linked to the silver gene is not an indication for the culling of horses due to the status of this breed as endangered, if it is necessary to select a mate for mating without genetic abnormalities so that they do not spread during uncontrolled crossing. Regular observation of an ophthalmologist and strict implementation of his recommendations are necessary to prevent the development of infectious complications and rapid progression of the disease with the onset of blindness. Horses homozygous for the silver gene should be kept in conditions that limit the possibility of injury to the eyeballs, including secondary damage to eye structures by the UV spectrum of solar radiation, for which translucent/opaque masks or sunglasses should be used. Working on homozygous horses with partial or complete loss of vision is potentially dangerous and possible only if a number of conditions are met and the owner is ready to bear legal responsibility for possible consequences.