{"id":30788,"date":"2026-07-10T11:15:23","date_gmt":"2026-07-10T09:15:23","guid":{"rendered":"https:\/\/www.cpv-ev.com\/?p=30788"},"modified":"2026-07-10T11:24:53","modified_gmt":"2026-07-10T09:24:53","slug":"10-07-2026-the-silver-dapple-coat-colour-by-anette-minarzyk","status":"publish","type":"post","link":"https:\/\/www.cpv-ev.com\/?p=30788","title":{"rendered":"10.07.2026 – The Silver Dapple Coat Colour, by Anette Minarzyk"},"content":{"rendered":"

 Looks Nice, but Fraught with Problems<\/strong><\/p>\r\n\r\n

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\u201eA good horse is never a bad colour\u201c, goes a common saying. Unfortunately, that is not entirely true, because there are indeed bad colours: those associated with such severe impairments of other organ systems that they can reasonably be categorised as \u201edefective breeding\u201c. One of the best-known examples is the Merle factor in dogs, which produces a distinctive, mottled coat and blue or odd-coloured eyes. As long as only a single copy of this gene is present, these dogs are largely healthy. If, however, \u201cMerle\u201d is inherited from both parents, it will produce a range of severe, disabling malformations of the eyes and inner ear. Responsible for these effects is a mutation in the silver locus gene (PMEL17). A missense mutation in the same gene causes the sought-after \u201csilver dapple\u201d coat colour in horses. Unfortunately, this is also associated with severe eye defects in homozygous carriers of the Silver gene, which have been described as \u201cMultiple Congenital Ocular Anomalies\u201d (MCOA) [1, 2].<\/p>\r\n

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What do \u201csilver\u201d horses look like?<\/em><\/p>\r\n

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In Germany the silver dapple coat colour first came to attention through the Icelandic horse community, and eventually certain American breeds, whose breeders traditionally distinguish more coat colour patterns than their German counterparts. Nevertheless, the Silver gene is also present in European breeding programmes. It occurs particularly in Scandinavian and British breeds and their descendants, including, as found recently, the Connemara Pony. Though, silver dapple is not always recognised, and the respective horses likely get classified as \u201cchestnut\u201d or \u201cliver chestnut.\u201d<\/p>\r\n

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At birth, silver dapple foals are recognisable by their light, pale coat colour, blond eyelashes, and striped hooves. They usually darken considerably with their first shedding and develop their final colour over the course of the next years.<\/p>\r\n

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In combination with a black base, \u201cSilver\u201d produces a nice, chocolate coloured coat with a silvery grey or flaxen mane and tail. Along goes frequently a distinct dappling with a silvery hue \u2013 a variation particularly sought after. Black-silver Horses tend to undergo remarkable colour changes over the course of the year. The winter coat is usually much lighter, sometimes to a degree that they could be taken for dapple greys, while their dappling might become less distinct or even invisible in the dark brown summer coat.<\/p>\r\n



If the base colour is bay, mane and tail are diluted in a similar way, while the reddish body is hardly affected. The legs, however, are always significantly darker than the body\u2014chocolate or gray-brown\u2014in contrast to the pale reddish colouration seen in chestnuts. When the Pangar\u00e9 (Mealy) colour modifier is also present, which among other effects turns the backsides of the cannon bones flaxen, this distinction can be difficult to detect, especially in horses with heavy feathering. However, it is usually revealed by a sooty discolouration around the carpal joints and hocks. Since \u201cSilver\u201d affects only black pigment, it has no visible effect on genetically chestnut horses, whose coats contain little or none of it. The same applies to homozygous carriers of the \u201cCreme\u201d gene and other white-born horses. In gray horses, it might still be recognisable in the foal coat, but soon gets concealed as they grey out. Unfortunately, the eye disorders affects all carriers of \u201cSilver,\u201d regardless of their coat colour [3, 4].<\/p>\r\n

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What effect does \u201csilver\u201d have on the eyes?<\/em><\/p>\r\n

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Rocky Mountain Horses, a breed with a high proportion of silver-coloured individuals, were the first to be noted for an increased incidence of eye abnormalities and were subsequently studied scientifically [5]. The same gene and identical eye malformations were later also detected in silver-dapple Icelandic horses [6]. Studies including these and further breeds suggested a causal link between the PMEL17 variant known as \u201cSilver\u201d and both the coat colour and the eye problems [1, 2, 3, 4, 7, 8].<\/p>\r\n

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The Silver trait is inherited in an autosomal incompletely dominant manner. A single copy of the gene is sufficient to produce the desired coat colour. Homozygous carriers may be slightly lighter in colour but otherwise otherwise differ little in appearance. However, there is a marked difference in the severity of MCOA:<\/p>\r\n

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In heterozygous carriers\u2014i.e. horses that inherited the gene from only one parent\u2014cysts were consistently found in the iris, ciliary body, or peripheral areas of the retina. Both eyes were always affected. In few cases no cysts could be detected, even though the Silver gene had been identified in the respective horses. Although, the authors could not rule out the possibility that very small, peripheral cysts were overlooked during the ophthalmological examination. Since these fluid-filled cysts are usually transparent or only faintly pigmented, they generally cause little to no impairment of vision. However, a considerable number of heterozygous silver dapple horses were also found to have retinal folds and scars from retinal detachments in the peripheral retina [3]. Though, both the cysts and the retinal folds may, depending on size and location, create areas of blurred or distorted vision.<\/p>\r\n

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If, however, the Silver gene is homozygous, foals are born with serious manifestations of MCOA. These severely impair the vision of the affected animals and, in extreme cases, lead to complete blindness [9]. Specifically, the following defects and malformations were observed:<\/p>\r\n