Dapples, the fascinating spots that add a unique pattern to a horse’s coat, have long captured the attention of equestrians, breeders, and horse owners.

Dapples are rounded areas on a horse’s hair coat that appear lighter or darker than the surrounding color. Dappling is associated with beauty, good health and optimal nutrition in horses.

But what exactly causes dapples on horses, and can every horse develop these eye-catching spots? While the science behind dapples is not fully understood, certain genes linked to coat color are known to influence their appearance.

Various factors, including feeding and management, physical condition, age, and breed also impact the presence of dapples. Continue reading to learn more about how to bring out dapples in a horse’s coat.

Dapples on Horses

Dapples on horses are distinctive patterns characterized by circular or irregular regions of hair that feature a different color or shade than the surrounding coat. This spotting can occur over the entire body or in specific areas.

The appearance of dapples varies among horses, depending on the underlying coat color and other factors. Some horses have large, pronounced dapples, while others have small, less noticeable ones.

Dapples can also come and go based on the horse’s overall health. A horse that is not in good physical condition, or is not receiving a balanced diet, can experience poor hair growth which could result in loss of dapples.

However, a horse’s dappling should not be used as the sole determinant of its health and wellbeing. Not all healthy horses exhibit dapples; the presence of these spots also does not guarantee that a horse is in optimal health.

Can all Horses get Dapples?

Not all horses are capable of developing dapples. The potential to form dapples on a horse’s coat is primarily determined by genetics.

Dapples are more commonly seen in certain coat colors and breeds, but they may not be present in all individuals within those groups. Some horses only get dapples at certain times of the year, such as when the hair coat sheds out.

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Genetics of Coat Colors

Dapples are patterns created by variations in hair pigmentation within a horse’s coat. To explain how dapples occur, it’s important to first understand the genetics of coat colors in horses.

Color Pigments

Coat colors and patterns are influenced by specific genes that regulate the expression of pigments in hairs. The two primary pigments responsible for hair color are:

  • Eumelanin: This pigment is responsible for black and brown colors in hair.
  • Phaeomelanin: This pigment is responsible for red and yellow colors in hair.

The amount and combination of these pigments within the hair shaft determine the hair color. For example, Haflinger horses known for their distinctive chestnut or sorrel coat color, have high levels of phaeomelanin in their hair coat. In contrast, Friesian horses are famous for their stunning black coat color, primarily produced by the pigment eumelanin.

White-Base Colors

Horses with predominantly white or grey coloring are said to have white-base coat colors. Unlike other coat colors that result from the presence of specific pigments, white-base colors arise from a genetic variation that inhibits the production of these pigments.

In other words, the genes for white and gray coat color mask other inherited colors. [1]

Other Colors

All other coat colors and patterns arise either from a lack of pigmentation, genetic dilutions, or specific patterns of gene expression. [1]

For example, dilution of the basic eumelanin/phaeomelanin coat colors results in cream, dun, champagne, and silver colors. The most common dilution in horses produces the golden palomino or buckskin color. [2]

Cause of Dappling

Deviations in the intensity and distribution of pigments within the hair produces dapples on a horse’s coat. For most coat colors, dapples result from variations in patterns of red and black (eumelanin and phaeomelanin) pigments along the hair shaft.

Factors that influence the development and visibility of these pigmentation variations include genetics, age, overall health, and nutrition.

Interestingly, this also explains why chestnut color horses cannot develop dapples. These horses only produce the pigment phaeomelanin and cannot produce eumelanin, making it impossible for dapples to form.

Other factors are responsible for dappling in grey and silver horses.

Grey Dapples

Grey is a progressive coat color in horses, meaning these horses are typically born with another coat color. Soon after birth white hairs will begin to appear, beginning around the eyes and progressively spreading. [2]

As their coat lightens, original color hairs are replaced with grey hairs, often resulting in the development of dapples on their coat. Dapples usually become more noticeable as grey horses progress through the stages of greying.

The formation of dapples in grey horses is not fully understood, but it is believed to result from variations in the arrangement of pigment-producing cells (melanocytes) in the skin and hair follicles.

Silver Dapples

Silver dapple is a specific coat color variation found in horses that affects the distribution of pigment in their hair coat.

This unique coloration results from the presence of the silver dapple gene, which alters the way black (eumelanin) pigment is expressed in the hair, but doesn’t affect red (phaeomelanin) pigment.

Silver dapple is a dilution gene that lightens black hairs. Horses with the silver dapple gene typically have a chocolate or reddish-brown coat color with a silvery or grayish mane and tail.

The silver dapple gene is inherited in an autosomal dominant manner, meaning that a horse only needs one copy of the gene from either parent to express the silver dapple coat color. Horses with two copies of the gene (homozygous) may have a more pronounced silvering effect.

This pattern can occur in the following breeds: [3]

Nutrition for Dapples

Your horse’s diet has a significant impact on their skin and hair quality. While the expression of dapples is strongly determined by genetics, nutrition also plays a key role in the development of these attractive patterns.

To increase the likelihood of dapples appearing in your horse’s coat, ensure that all their dietary requirements are met. Coat growth and appearance is influenced by protein, vitamin, trace mineral and fat intake in the diet. [4]

Work with a qualified equine nutritionist to help you design a balanced feeding program for your horse. Your nutritionist will help you select the appropriate forage to meet your horse’s needs, and then consider additional feeds or supplements to balance the diet.

In healthy horses with the potential to display dapples, these distinctive patterns often become apparent once the horse’s diet is properly balanced and nutritional deficiencies are addressed.

Trace Minerals

Trace minerals are essential micronutrients that horses require in relatively small amounts, but are critical for various physiological functions.

Horses on forage-only diets are often deficient in one or more trace minerals. This can contribute to hoof issues, reduced immune function, poor hair coat condition and even coat fading due to sun bleaching. [4]

Six of the most important trace minerals in the equine diet include: [4]

Many ration balancers and supplements contain trace minerals, but not all provide these nutrients in the correct amount to balance your horse’s diet. Moreover, while many products include inorganic mineral sources, studies indicate that chelated or organic trace minerals are more readily absorbed by horses. [4]

Copper and Zinc

Copper and zinc are two trace minerals that need to be appropriately balanced in the diet to maintain healthy skin, coat, and hooves. The ratio of zinc-to-copper in the diet should be between 3-4:1.

Horses that do not get enough of these minerals in their diet can experience slower hair growth or even hair loss. Deficiency can also result in a lackluster, coarse, or brittle coat that may be more susceptible to damage.

Zinc is important for proper enzyme function and is involved in the synthesis of keratin, a protein that makes up the structure of hair. Adequate zinc enhances the shine and luster of the hair, making the coat look healthy and vibrant.

Copper contributes to the formation of cross-linkages in the proteins that make up hair, strengthening the hair’s structure and reducing the risk of breakage and damage. [4]

Copper is an essential component of melanin, the pigment responsible for the coloration of hair. Horses with a copper deficiency may exhibit faded or dull coat colors, in addition to depigmentation of the skin around the eyes and muzzle. [4]

Research shows that feeding horses diets with higher levels of copper and zinc can significantly improve features of hair coat appearance. In one study, yearling thoroughbred horses were provided with feeds enriched with 5% higher levels of organic zinc and copper. The study reported improvements in hair structure and composition compared to a control group. [4]

Sulfur and Silicon

Sulfur and silicon are two additional minerals that play a role in maintaining the structure and function of hair.

Sulfur is required to form disulfide bonds within keratin, contributing to the structural strength of the hair shaft. This mineral also influences the texture of hair, such as whether the coat is coarse or fine.

This essential mineral is a component of pheomelanin, the red and yellow pigment. While sulfur deficiency hasn’t been observed in horses, when horses consume excessive selenium, it can substitute for sulfur in keratin and presumably pheomelanin. This can lead to weakened hair and hair loss. [8]

Silicon, in the form of orthosilicic acid (OSA) or dietary silicon, is a trace element that is important for various aspects of equine health. [7] Because it plays a role in collagen synthesis, it may impact coat quality.

Collagen is a protein found in skin, hair follicles, and connective tissues. It enhances hair strength and elasticity, and may contribute to softer and more manageable coats. [7]

Iron Overload

Another trace mineral that can influence the presence of dapples on your horse’s coat is iron, but its effects are detrimental rather than beneficial. While iron is important for oxygen transport and enzyme function, getting too much of this mineral has negative effects.

Excessive iron intake, especially from forages grown in iron-rich soil, can interfere with the absorption of copper and zinc from the diet. All three minerals are absorbed in the small intestine through similar sites, and an excess of iron can compete with copper and zinc for absorption. [11][12]

Signs of iron overload in horses may include lethargy, changes in coat color or texture, hoof problems, weight loss and joint stiffness. [10]

If you suspect your horse has high iron in their diet, consult with an equine nutritionist or veterinarian for help with formulating a balanced diet. Feeding organic zinc and copper supplements can counteract some of the harmful effects of iron overload.

Horses should not be supplemented with iron unless under a veterinarian’s supervision. Only horses with chronic blood loss are considered at risk for iron deficiency. [5]

Macro Minerals

The macro minerals, or major minerals that are required in the equine diet in larger quantities include: [9]

  • Calcium (Ca)
  • Phosphorus (P)
  • Magnesium (Mg)
  • Potassium (K)
  • Sodium (Na)
  • Chloride (Cl)

These minerals are involved in bone health, muscle function, electrolyte balance, and various metabolic processes. While they are not directly linked to the expression of dapples, deficiency in these nutrients can negatively impact the overall health and condition of the horse’s skin and coat. [4]

Protein

Hair consists primarily of the protein keratin. Poor coat quality and slow hair growth are signs of low protein intake in your horse’s diet. [8]

Proteins are made up of building blocks called amino acids. Horses require a balanced intake of essential amino acids to support various bodily functions, including tissue repair, enzyme synthesis, and the production of hormones.

Certain proteins (enzymes) are involved in the production of coat color pigments. While the primary factor influencing coat color is genetics, protein can indirectly influence the vibrancy and expression of coat colors, including dapples.

Most horses can meet their protein requirements with good quality pasture or hay. However, horses in heavy work, growing horses, pregnant and lactating mares, senior horses and those recovering from illness or injury may require additional protein sources in their diet. [4][8]

Vitamins

Vitamins are essential organic compounds that play critical roles in the health of all animals, including horses. Several vitamins are essential for skin health and a shiny coat.

Vitamin A:

Vitamin A is essential for maintaining healthy skin and mucous membranes. A deficiency in vitamin A can lead to dry, flaky skin and dull hair, which may affect the overall appearance of the horse’s coat. [9]

Vitamin E:

Vitamin E is an antioxidant that helps protect cell from damage caused by free radicals. Adequate vitamin E can contribute to healthy skin and hair, potentially supporting the expression of dapples by keeping the coat in good condition. Horses on hay-only diets and those in heavy work need additional vitamin E. [8]

Vitamin D:

Vitamin D is essential for the absorption of calcium and phosphorus, which are important minerals for overall health. While it doesn’t directly impact dapples, ensuring a horse has sufficient vitamin D is crucial for overall well-being. [5]

B-Complex Vitamins:

Several B vitamins, such as biotin, are important for overall skin and coat health. Biotin is involved in keratin synthesis, which supports the structural integrity of the hair shaft. Biotin also helps prevent dryness, flakiness, and skin conditions that can affect hair growth. [6]

Fatty Acids

Fatty acids, particularly essential fatty acids like omega-3 and omega-6, are also important for the healthy appearance of your horse’s skin and hair coat. [4]

Dietary fat helps moisturize the hair shaft, preventing hair from drying out and becoming brittle. When the hair is well-hydrated, it appears smoother and shinier, enhancing the overall luster of your horse’s coat.

Omega-3 fatty acids have additional benefits for regulating inflammation and maintaining healthy skin. [14]

Oils and fat sources commonly used in the equine diet include:

Mad Barn’s W-3 Oil is a fat supplement enriched with the omega-3 fatty acid DHA, as well as natural Vitamin E. Feeding your horse W-3 Oil can support their overall well-being and contribute to a healthy, gleaming coat.

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Grooming for Dapples

Regular grooming and proper care of your horse’s hair coat can enhance the appearance of dapples. Grooming removes dead hair, skin cells and debris from your horse’s coat, while presumably distributing natural oils from the horse’s skin to make the coat shinier. [13]

Grooming also stimulates blood circulation in the horse’s skin and helps to reduce stress.

Ideally, horses should be groomed on a daily basis. If this is not possible, aim for ten to fifteen minutes several times per week to improve the appearance of your horse’s hair coat. Start with a rubber curry comb, followed by a stiff brush. In the summer months, you may also want to use a soft brush.

Don’t forget to clean your brushes frequently to avoid brushing dirt back onto your horse. Follow our grooming guide for more advice on grooming tools and important steps to follow.

Contrary to common belief, frequent bathing can have a negative effect on a horse’s coat by drying out the skin and hair. Limit bathing to once or twice a month, as required.

Summary

  • Dapples are distinct circular or irregular patterns on a horse’s coat that appear lighter or darker than the surrounding color.
  • The potential for a horse to develop dapples is primarily determined by genetics, with certain coat colors and breeds being more prone to display these patterns.
  • Dapples are the result of variations in the intensity and distribution of pigments (i.e. eumelanin and phaeomelanin) within the hair shaft.
  • Grey horses develop dapples as they progress through the stages of greying, while silver dapple horses have a specific genetic variation affecting their coat color.
  • The appearance of dapples is associated with good health and nutrition. Ensuring your horse gets a balanced diet with adequate trace minerals can support the expression of dapples.

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References

  1. Melvin, K. et al. Equine Genetics Basic Coat Color Inheritance. University of Tennessee Institute of Agriculture. Accessed Oct 19, 2023.
  2. Thiruvenkadan, A.K. et al. Coat colour inheritance in horses. Livestock Science. 2008.
  3. Brunberg, E. et al. A missense mutation in PMEL17 is associated with the Silver coat color in the horse. BMC Genetics. 2006. View Summary
  4. Marycz, K. et al. The correlation of elemental composition and morphological properties of the horses hair after 10 days of feeding with high quality commercial food enrich with zn and cu organic forms. Electronic Journal of Polish Ag Universities. 2009.
  5. Ralston, S.L. Nutritional Requirements of Horses and Other Equids. Merck Veterinary Manual. Accessed Oct 19, 2023.
  6. Proud, V.K. et al. Fatty acid alterations and carboxylase deficiencies in the skin of biotin-deficient rats. Am J Clin Nutr. 1990.
  7. O’Connor, C.I. et al. Mineral balance in horses fed two supplemental silicon sources. J Animal Physiol Anim Nutr. (Berl). 2008. View Summary
  8. National Research Council Nutrient Requirements of Horses: Sixth Revised Edition. 2007.
  9. Kline, R.C. Horse Nutrition. Ohio Cooperative Extension Service; Ohio State University. 1988.
  10. Theelen, M.J.P. et al. Chronic iron overload causing haemochromatosis and hepatopathy in 21 horses and one donkey. Equine Vet J. 2019. View Summary
  11. Cherukuri, S. et al.Unexpected role of ceruloplasmin in intestinal iron absorption. Cell Metab. 2005.
  12. Solomons, N.W. and Ruz, M. Zinc and iron interaction: concepts and perspectives in the developing world. Nutrition Res. 1997.
  13. Heusner, G. Horse Ownership: Obligations, Costs and Benefits. University of Georgia. Accessed Oct 19, 2023.
  14. Sawada, Y. et al. Omega 3 Fatty Acid and Skin Diseases. Front Immunol. 2020.