Palomino Horse: Genetics, Color, and Health Considerations

The palomino horse displays a golden body coat with a white or light cream mane and tail, a color produced by the interaction of a chestnut base coat with a single copy of the cream dilution allele. This article explains the genetic basis of palomino color, describes the inheritance patterns that breeders must understand, and reviews the health considerations that veterinary professionals and owners should monitor, including skin sensitivity and melanoma risk. The practical outcome is a genetic inheritance chart for palomino color and a list of health screening recommendations that can be applied in routine management and breeding decisions.

At a Glance: Palomino Genetics and Health Overview

The Genetic Basis of Palomino Coat Color

Palomino is not a breed but a coat color that can appear in many horse breeds. The color results from the action of the cream dilution gene on a chestnut base coat. Understanding the underlying genetics allows breeders to predict color outcomes and veterinarians to identify horses that may carry additional dilution or patterning genes with health implications.

The Cream Dilution Allele and Its Location

The cream dilution gene is responsible for palomino and buckskin coat colors. Research published in Animal Genetics mapped the cream dilution locus to horse chromosome 21, with linkage analysis establishing the marker order SGCV16, HTG10, LEX60/COR73, COR68, Ccr, and LEX31. The study also determined that the horse cream locus is not tyrosinase, ruling out one candidate gene for the dilution effect. This chromosomal mapping provided the foundation for identifying the specific mutation responsible for cream dilution.

Subsequent research identified the causal mutation in the MATP gene, also known as SLC45A2. A G to A transition in exon 2 of the MATP gene results in an aspartic acid to asparagine substitution in the encoded protein. This mutation is conserved across mice and humans, supporting its functional significance in pigment dilution. The MATP gene plays a role in melanin synthesis, and the cream mutation reduces the production of dark pigment while leaving red pigment relatively unaffected.

Base Coat Color and the Chestnut Allele

The palomino phenotype requires a chestnut base coat. Chestnut is controlled by the melanocortin 1 receptor gene, commonly abbreviated MC1R. The recessive chestnut allele, designated as "e," produces red pigment when present in homozygous form. A horse with at least one dominant "E" allele at this locus produces black pigment and cannot be palomino, regardless of cream dilution status.

A study of 28 horse breeds investigated allele frequencies for base coat color, dilution, and white patterning variants in 11,281 horses. The recessive chestnut allele was identified in four breeds: Knabstrupper, Paint Horse, Percheron, and Quarter Horse. The estimated allele frequency in Knabstruppers was 0.035, illustrating the importance of genetic testing for mate selection when base coat color is a breeding goal. Breeders seeking palomino offspring must ensure that both parents carry the chestnut allele or that at least one parent is chestnut-based.

The Interaction of Cream Dilution with Base Colors

The cream dilution allele exhibits incomplete dominance. A single copy of the cream allele on a chestnut base produces palomino, with the golden body color and light mane and tail. A single copy of the cream allele on a bay base produces buckskin, where the black points remain visible but the body color is diluted. Two copies of the cream allele produce cremello on a chestnut base or perlino on a bay base, both characterized by cream or nearly white coats with pink skin and blue eyes.

The 2003 study in Genetics Selection Evolution confirmed that the cream mutation causes partial dilution in heterozygous horses and extreme dilution in homozygous horses. This dosage effect is consistent with the incomplete dominance model and explains why palomino to palomino matings produce a predictable ratio of colors.

Historical Understanding of Palomino Inheritance

The genetics of palomino color have been studied for decades, with early research establishing the inheritance pattern that modern genetic testing has confirmed. Understanding this history helps breeders appreciate why palomino registries operate differently from breed registries and why genetic testing has become an important tool.

Early Genetic Studies

The Salisbury-Britton hypothesis proposed that palomino results from a single dilution gene acting on a chestnut base. A 1946 paper in The Journal of Heredity titled "Genetics of the Palomino horse, confirmation of the Salisbury-Britton hypothesis" provided early confirmation of this model. A subsequent 1951 paper in the same journal, "New evidence on the genetics of the Palomino horse," added further support. A 1961 paper in Genetics titled "The palomino horse" continued this line of investigation, and a 1974 study in The Journal of Heredity examined "Inheritance of the palomino color in Icelandic horses," demonstrating that the same genetic mechanism operates across breeds.

These early studies relied on pedigree analysis and phenotypic observation instead of molecular genetic testing. They established that palomino is a heterozygous condition, which explains why palomino to palomino matings do not produce all palomino offspring.

The Palomino Horse Breeders of America and Pedigree Tracing

The Palomino Horse Breeders of America, commonly known as PHBA, maintains a registry for palomino horses. A 2024 study in the Journal of Equine Veterinary Science examined the origins of the modern PHBA stock-type horse through pedigree tracing. Registration numbers for PHBA have risen with the assistance of new registration guidelines that allow registration of any horse with a palomino body color, including those with unknown pedigrees.

The study sampled 460 horses from published entries of the PHBA World Show Championship Horse Show over a 10-year period from 2012 to 2022. Pedigree tracing identified six foundation sires contributing to the modern PHBA stock-type horse, with the majority of horses, 58%, tracing back to a sire named Old Fred. Two identified sires, Yellow Jacket and Cotton Eyed Joe, have conflicts concerning color designation in historical records.

The study authors noted that pedigree tracing is of particular value for color registries because the study of coat color patterns is complicated by pedigrees with inaccurate color designations. They concluded that genetic testing is required to accurately identify the cream dilution allele within registered horses to ensure a phenotype based solely on the cream dilution allele. This finding has practical implications for breeders who rely on registry status as evidence of genetic makeup.

Breeding Palomino Horses: Inheritance Patterns and Predictions

Breeders need a clear understanding of palomino inheritance to make informed mating decisions. The cream dilution allele follows predictable Mendelian inheritance, and the outcomes of specific matings can be calculated with confidence.

Palomino to Palomino Matings

When two palomino horses are bred, each parent contributes either a cream allele or a non-cream allele. The possible offspring genotypes are:

The palomino to palomino mating produces only 50% palomino offspring, which is a common source of disappointment for breeders who expect color consistency. The 25% cremello offspring are homozygous for the cream allele and will have cream coats with pink skin and blue eyes. The 25% chestnut offspring carry no cream allele and will have standard chestnut coloring.

Breeding Strategies for Consistent Palomino Production

Breeders who want to maximize palomino production have two reliable options. The first is to breed a palomino to a chestnut, which produces 50% palomino and 50% chestnut offspring with no cremello risk. The second is to breed a palomino to a cremello, which produces 50% palomino and 50% cremello offspring.

Breeding a chestnut to a cremello produces 100% palomino offspring, which is the only mating that guarantees palomino color. This strategy requires maintaining both chestnut and cremello breeding stock, which some breeders find impractical.

Genetic Testing for Breeding Decisions

Genetic testing for the cream dilution allele provides definitive information about a horse's genotype. The 2022 study of 28 horse breeds emphasized the importance of testing for mate selection for base coat color. Testing is particularly valuable when a horse's pedigree is unknown or when a horse's phenotype is ambiguous.

The 2024 PHBA study noted that genetic testing is required to accurately identify the cream dilution allele within registered horses. This recommendation applies to any breeding program where palomino color is a goal. A horse with a palomino phenotype may carry additional dilution or patterning genes that affect offspring color, and testing can identify these variants.

Health Considerations in Palomino Horses

The palomino coat color itself does not cause disease, but the genetic variants that produce dilute colors can be associated with health conditions that require monitoring. Additionally, palomino horses may carry other color genes with known health implications.

Skin Sensitivity and Sun Protection

Dilute coat colors are associated with reduced pigment in the skin, particularly in areas with pink skin. Palomino horses often have pink skin around the muzzle, eyes, and genital area, and these areas are more susceptible to sunburn than pigmented skin. Owners should provide shade during peak sun hours and consider the use of fly masks and other protective equipment for horses with extensive pink skin.

The relationship between coat color and skin sensitivity is well established in veterinary medicine. The Merck Veterinary Manual provides general guidance on skin conditions in horses, and owners should consult this resource for information about sun-related skin damage. Horses with pink skin require regular monitoring for signs of sunburn, including redness, peeling, and blistering.

Melanoma Risk and the Gray Gene

Melanoma in horses is most strongly associated with the gray coat color gene, not with palomino dilution. Gray horses have a high incidence of melanomas, particularly as they age. A palomino horse that also carries the gray gene has the same melanoma risk as any other gray horse.

The Merck Veterinary Manual provides information on melanoma in horses, including clinical presentation and management considerations. Owners of gray palomino horses should include melanoma screening in their routine veterinary care, with particular attention to the perineal area, tail head, and other common sites for melanoma development.

Veterinarians should distinguish between melanomas associated with the gray gene and other skin masses when examining palomino horses. The presence of the cream dilution allele does not confer melanoma risk, and owners should not assume that a palomino horse has elevated melanoma risk solely because of its color.

Ocular Health and the Silver Dilution Allele

The silver dilution allele, also known as PMEL17, can cause ocular anomalies in horses. A 2011 study in Veterinary Ophthalmology described equine Multiple Congenital Ocular Anomalies syndrome in PMEL17 mutant ponies. The study examined five ponies and found that horses homozygous for the mutant allele had multiple bilateral anterior segment anomalies, including cornea globosa, iris hypoplasia, encircling granula iridica along the pupillary ruff, and cataracts.

Notably, the study described a pony where silver dappling was masked by palomino coloring. This pony was homozygous at the MCOA locus but displayed a palomino phenotype, meaning the silver dilution was not visually apparent. This finding has important implications for palomino breeders, as a palomino horse can carry the silver allele without showing silver coloring.

The 2022 study of 28 horse breeds found that the Rocky Mountain Horse breed had the highest allele frequency for the silver dilution variant. The study suggested that marker-assisted selection in this breed could aid in the production of horses with desirable dilute coats with less severe ocular anomalies caused by the silver allele.

Veterinarians should recommend ophthalmic examination for palomino horses that may carry the silver allele, particularly those with Rocky Mountain Horse or related breeding. Genetic testing for the silver allele is available and should be considered before breeding decisions are made.

Body Condition and Metabolic Health

Body condition scoring is an important component of health monitoring for all horses, including palominos. A 2023 study in Animals examined body condition scores in Danish horses and found that 78.6% of evaluated horses had ideal scores of 5 to 6 on a 1 to 9 scale. However, 16.5% of horses were above ideal body condition, and this was influenced by type, age, and training.

The study found that cold-blooded horses and traditional ponies had increased risk for being above ideal body condition. Horses trained at higher intensities showed a significant protective effect against above-ideal body condition. These findings apply to palomino horses of any breed, and owners should adjust feeding and exercise programs based on individual body condition scores.

The relationship between coat color and metabolic health is not established, but palomino horses are subject to the same metabolic risks as other horses. Owners should monitor body condition regularly and work with veterinarians to address weight management concerns.

Practical Health Screening Recommendations

A structured health screening program for palomino horses should address the specific risks associated with dilute coat colors while also covering general equine health concerns. The following recommendations provide a framework for owners and veterinarians.

Annual Health Examination

Every palomino horse should receive a complete annual health examination from a veterinarian. The examination should include:

The Merck Veterinary Manual provides comprehensive guidance on equine health management, and owners should use this resource to understand the components of a thorough examination.

Genetic Testing for Breeding Stock

Horses intended for breeding should undergo genetic testing for the cream dilution allele and other color variants that may affect offspring health. The 2022 study of 28 horse breeds recommended genetic testing for mate selection, particularly for base coat color and dilution variants.

Testing should include:

The 2024 PHBA study emphasized that genetic testing is required to accurately identify the cream dilution allele within registered horses. This recommendation applies to all breeding programs, regardless of registry affiliation.

Melanoma Screening for Gray Palomino Horses

Palomino horses that carry the gray gene require regular melanoma screening. The Merck Veterinary Manual provides information on melanoma in horses, and owners should discuss screening frequency with their veterinarians.

Screening should include palpation of common melanoma sites, including the perineal area, tail head, lips, eyelids, and parotid gland region. Any new or changing masses should be evaluated promptly. Early detection allows for more treatment options and better outcomes.

Sun Protection Measures

Owners of palomino horses with pink skin should implement sun protection measures during peak sun exposure. These measures include:

The Merck Veterinary Manual provides guidance on skin conditions in horses, and owners should consult this resource for information about sun-related skin damage.

Records and Measurements for Palomino Horse Management

Accurate record keeping supports informed management decisions and provides valuable data for veterinary care. Owners should maintain comprehensive records for each palomino horse.

Essential Records

The 2023 body condition study used a modified Henneke scoring system with scores of 5 to 6 regarded as ideal. Owners should learn to score body condition accurately and record scores consistently to track changes over time.

Photographic Documentation

Photographs provide valuable documentation of coat color and physical condition. Owners should take standardized photographs at regular intervals, including:

Photographs are particularly useful for documenting changes in coat color over time, which can occur with seasonal shedding and aging.

Common Failure Patterns in Palomino Breeding and Management

Understanding common mistakes helps owners and veterinarians avoid problems in palomino breeding and health management.

Breeding Failures

The 2024 PHBA study documented the importance of accurate color designation in pedigrees. Historical records may contain errors, and genetic testing provides definitive information.

Health Management Failures

The 2023 body condition study found that veterinarians attended more horses with body condition scores above and below ideal values, while farriers mostly saw horses that were above ideal body condition. This finding suggests that owners may not recognize body condition problems until they become severe.

Limitations of Color-Based Health Assumptions

Owners and veterinarians should recognize the limitations of making health assumptions based on coat color alone. The palomino phenotype provides information about the cream dilution allele but does not reveal the presence of other color genes or health-related variants.

Masked Genetic Variants

The 2011 MCOA study demonstrated that silver dappling can be masked by palomino coloring. A palomino horse can carry the silver allele without showing silver coloring, which means the horse can produce affected offspring when bred to another silver carrier. This finding highlights the importance of genetic testing for breeding stock.

Similarly, the gray gene can be present in palomino horses, and gray horses lighten with age. A young palomino horse may not show gray coloring, but the gray gene will eventually affect the coat color. Owners should be aware that a palomino horse can carry the gray gene and should include melanoma screening in their health program.

Color Registries and Genetic Accuracy

The 2024 PHBA study noted that new registration guidelines allowed registration of any horse with a palomino body color, including those with unknown pedigrees. While this promoted registry growth, the study authors emphasized that genetic testing is required to accurately identify the cream dilution allele within registered horses.

Registry status does not guarantee genetic makeup. A horse registered as palomino may carry additional dilution or patterning genes that affect offspring color. Breeders should use genetic testing instead of registry status as the basis for breeding decisions.

Breed-Specific Considerations

The 2022 study of 28 horse breeds found significant variation in allele frequencies across breeds. The Rocky Mountain Horse breed had the highest allele frequency for the silver dilution variant, while the chestnut allele was identified in only four breeds. These breed-specific differences affect the likelihood of encountering specific genetic variants in palomino horses.

Owners should understand the genetic background of their horse's breed when making health and breeding decisions. A palomino horse of Rocky Mountain Horse breeding has a higher likelihood of carrying the silver allele than a palomino of another breed.

Welfare and Safety Context

The management of palomino horses involves specific welfare considerations related to coat color and genetic health risks. Owners have a responsibility to provide appropriate care that addresses these considerations.

Sun Protection as a Welfare Issue

Pink skin areas on palomino horses are susceptible to sunburn, which causes pain and can lead to more serious skin conditions. Providing shade and protective equipment is a welfare obligation for owners of horses with extensive pink skin. The Merck Veterinary Manual provides guidance on skin conditions in horses, and owners should seek veterinary care for sunburn that does not resolve with basic management.

Genetic Testing as a Welfare Tool

Genetic testing for the silver dilution allele can prevent the production of foals with severe ocular anomalies. The 2011 MCOA study described horses with cornea globosa, iris hypoplasia, and cataracts, conditions that can affect vision and quality of life. Testing breeding stock before mating is a welfare-conscious approach that prevents the birth of affected animals.

The 2022 study of 28 horse breeds suggested that marker-assisted selection could aid in the production of horses with desirable dilute coats with less severe ocular anomalies caused by the silver allele. This approach balances color preferences with health considerations.

Body Condition and Welfare

The 2023 body condition study found that 16.5% of evaluated horses were above ideal body condition. Obesity in horses is associated with multiple health problems, including laminitis and metabolic syndrome. Owners should monitor body condition regularly and adjust feeding and exercise programs to maintain ideal scores.

The study also found that a large proportion of geriatric horses were both above and below ideal body condition. Older palomino horses require careful monitoring to maintain appropriate body condition as their nutritional needs change.

Professional Escalation Criteria

Owners should seek veterinary care promptly when specific signs or situations arise. The following criteria provide guidance for escalation to professional care.

Urgent Veterinary Care

The 2023 fracture study in Thoroughbred racehorses identified genetic factors associated with catastrophic fracture risk. While this study focused on racehorses, the findings highlight the importance of prompt veterinary evaluation for any horse with lameness or musculoskeletal concerns.

Routine Veterinary Care

The Merck Veterinary Manual provides comprehensive guidance on equine health management, and owners should use this resource to understand when veterinary care is needed.

Decision Framework for Palomino Breeding and Health Management

Breeding palomino horses and managing their health requires a structured approach that integrates genetic knowledge with practical farm management. A decision framework helps owners and veterinarians move from theoretical understanding to consistent, repeatable actions. This section provides a practical framework that can be applied to individual horses and breeding programs, with emphasis on record keeping and troubleshooting.

The Palomino Breeding Decision Matrix

Before any mating decision, breeders should work through a systematic evaluation of both the mare and the stallion. The following matrix organizes the information needed to make a confident breeding decision.

The 2024 study of the Palomino Horse Breeders of America registry emphasized that genetic testing is required to accurately identify the cream dilution allele within registered horses. This applies to all breeding decisions, regardless of whether the horse is registered with PHBA or another organization.

Step-by-Step Breeding Decision Process

The breeding decision process should follow a consistent sequence that prevents overlooked factors. Start with base coat color, then move to dilution status, then consider health-related variants.

Step 1: Test the mare and stallion for base coat color. Both parents must contribute the chestnut allele for palomino offspring. A horse with a dominant black allele at the MC1R locus cannot produce palomino foals, regardless of cream dilution status. The 2022 study of 28 horse breeds identified the chestnut allele in Knabstrupper, Paint Horse, Percheron, and Quarter Horse populations, but the allele can appear in any breed.

Step 2: Test both parents for the cream dilution allele. A palomino horse is heterozygous for cream, meaning it has one cream allele and one non-cream allele. The 2003 study in Genetics Selection Evolution identified the causal mutation as a G to A transition in exon 2 of the MATP gene. Testing confirms whether a horse with a palomino phenotype actually carries the cream allele or whether the color has another cause.

Step 3: Test for the silver dilution allele. The 2011 study in Veterinary Ophthalmology demonstrated that silver dappling can be masked by palomino coloring. A palomino horse can carry the silver allele without showing silver color, and breeding two silver carriers can produce foals with severe ocular anomalies. Testing identifies carriers before mating decisions are made.

Step 4: Test for the gray gene. The gray gene is associated with melanoma risk and progressive coat lightening. A palomino horse carrying the gray gene will eventually show gray coloring, and the horse requires melanoma screening as part of routine health care.

Step 5: Review the expected offspring color ratio. Use the known genotypes of both parents to calculate the probability of each offspring color. Document this calculation in the breeding record so the expected outcomes are clear before the mating occurs.

Record System for Palomino Breeding Programs

A functional record system tracks genetic information, health data, and breeding outcomes for each horse. The system should be simple enough to maintain consistently but detailed enough to support decision making.

The 2023 body condition study in Danish horses used a modified Henneke scoring system with scores of 5 to 6 regarded as ideal. Owners should record body condition scores monthly and track changes over time to identify trends before they become problems.

Troubleshooting Unexpected Breeding Outcomes

When a foal is born with an unexpected color, the first step is to confirm the genetic status of both parents and the foal. The 2024 PHBA study noted that pedigrees with inaccurate color designations complicate the study of coat color patterns. Historical records may contain errors, and genetic testing provides definitive information.

The 1946 and 1951 papers in The Journal of Heredity confirmed the Salisbury-Britton hypothesis that palomino results from a single dilution gene acting on a chestnut base. These early studies established the inheritance pattern that modern genetic testing has confirmed, and unexpected outcomes are almost always explained by the known genetics of the parents.

Health Monitoring Decision Points

Health monitoring for palomino horses should follow a structured schedule that addresses the specific risks associated with dilute coat colors and other color genes.

The Merck Veterinary Manual provides guidance on skin conditions and melanoma in horses. Owners should consult this resource for information about specific conditions and discuss any concerns with their veterinarian.

Common Failure Patterns in Decision Making

Several recurring mistakes undermine palomino breeding and health management programs. Recognizing these patterns helps owners avoid them.

Failure to test for masked variants. The 2011 MCOA study demonstrated that silver dappling can be masked by palomino coloring. A breeder who relies on visual assessment alone may breed two silver carriers without knowing it, producing foals with severe ocular anomalies. Genetic testing is the only reliable way to identify these carriers.

Reliance on registry status instead of genetic testing. The 2024 PHBA study noted that new registration guidelines allowed registration of any horse with a palomino body color, including those with unknown pedigrees. Registry status does not guarantee genetic makeup, and breeders should use genetic testing as the basis for breeding decisions.

Assumption that palomino to palomino produces all palominos. This mating produces only 50% palomino offspring, with 25% chestnut and 25% cremello. Breeders who expect color consistency from this mating are frequently disappointed.

Inadequate sun protection for pink skin. Palomino horses often have pink skin around the muzzle, eyes, and genital area. Owners who do not provide shade or protective equipment risk sunburn and more serious skin conditions.

Inconsistent body condition monitoring. The 2023 body condition study found that 16.5% of evaluated horses were above ideal body condition. Owners who do not record body condition scores regularly may not recognize weight gain until it becomes a health problem.

Escalation Criteria for Professional Consultation

Owners should seek professional consultation when specific situations arise during breeding or health management.

The World Organisation for Animal Health provides international standards for animal health and welfare. Owners and veterinarians should be aware of these standards when developing health management programs for breeding horses.

Integrating the Decision Framework into Farm Management

The decision framework works best when it is integrated into regular farm management routines. Schedule genetic testing before the breeding season, record body condition scores on a fixed monthly date, and review health records at each veterinary visit.

A practical approach is to create a breeding and health calendar for each horse that includes testing dates, examination dates, and monitoring points. This calendar ensures that no step is overlooked and provides a clear record for veterinarians and future owners.

The 2023 fracture study in Thoroughbred racehorses identified genetic factors associated with catastrophic fracture risk, highlighting the importance of genetic information in health management. While this study focused on racehorses, the principle applies broadly: genetic information supports better management decisions across all horse types.

Frequently Asked Questions

What causes the palomino coat color in horses?

Palomino results from the interaction of a chestnut base coat with a single copy of the cream dilution allele. The cream dilution allele is a mutation in the MATP gene that reduces dark pigment production while leaving red pigment relatively unaffected. A horse must be homozygous for the chestnut allele at the MC1R locus and heterozygous for the cream allele to display the palomino phenotype.

How is palomino color inherited?

Palomino color follows an incomplete dominance pattern at the cream dilution locus. A palomino horse has one cream allele and one non-cream allele. When two palominos are bred, the offspring are 25% chestnut, 50% palomino, and 25% cremello. Breeding a palomino to a chestnut produces 50% palomino and 50% chestnut offspring, while breeding a chestnut to a cremello produces 100% palomino offspring.

Is palomino a horse breed?

Palomino is a coat color, not a breed. Palomino horses can appear in many breeds, including Quarter Horses, Thoroughbreds, and Icelandic Horses. The Palomino Horse Breeders of America maintains a color registry that accepts horses based on palomino body color, but this registry does not define a breed.

Do palomino horses have more health problems than other horses?

The palomino coat color itself does not cause disease. However, palomino horses may carry other color genes with health implications. The silver dilution allele can cause ocular anomalies, and the gray gene is associated with melanoma risk. Genetic testing can identify these variants and guide health monitoring.

Are palomino horses more sensitive to sunlight?

Palomino horses often have pink skin around the muzzle, eyes, and genital area, and these areas are more susceptible to sunburn than pigmented skin. Owners should provide shade and consider protective equipment for horses with extensive pink skin. Sunburn should be treated promptly to prevent more serious skin conditions.

What is the relationship between palomino color and melanoma?

Melanoma in horses is most strongly associated with the gray coat color gene, not with palomino dilution. A palomino horse that also carries the gray gene has the same melanoma risk as any other gray horse. Owners of gray palomino horses should include melanoma screening in their routine veterinary care.

Should palomino horses be genetically tested before breeding?

Genetic testing is recommended for palomino horses intended for breeding. Testing for the cream dilution allele confirms the palomino genotype and allows accurate prediction of offspring color. Testing for the silver dilution allele identifies carriers of ocular anomaly risk, and testing for the gray gene identifies melanoma risk.

Can a palomino horse carry the silver dilution allele without showing silver color?

Yes. A 2011 study described a pony where silver dappling was masked by palomino coloring. This pony was homozygous at the MCOA locus but displayed a palomino phenotype. Genetic testing is the only reliable way to identify silver dilution carriers in palomino horses.

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References and Further Reading

• Merck Veterinary Manual. Merck Veterinary Manual.
• Animal Health and Welfare. World Organisation for Animal Health.
• The palomino horse.. Genetics, 1961.
• Pedigree tracing to determine the origins of the modern Palomino Horse Breeders of America stock-type horse.. Journal of equine veterinary science, 2024.
• Genetics of the Palomino horse, confirmation of the Salisbury-Britton hypothesis.. The Journal of heredity, 1946.
• New evidence on the genetics of the Palomino horse.. The Journal of heredity, 1951.
• The cream dilution gene, responsible for the palomino and buckskin coat colours, maps to horse chromosome 21.. Animal genetics, 2001.
• Inheritance of the palomino color in Icelandic horses.. The Journal of heredity, 1974.
• A Functional Single-Nucleotide Polymorphism Upstream of the Collagen Type III Gene Is Associated with Catastrophic Fracture Risk in Thoroughbred Horses.. Animals : an open access journal from MDPI, 2023.
• Equine Multiple Congenital Ocular Anomalies (MCOA) syndrome in PMEL17 (Silver) mutant ponies: five cases.. Veterinary ophthalmology, 2011.
• Animal-Assisted Therapy in palliative care: a scoping review.. 2024.
• Connections Between Gene Polymorphism and Fetlock and Hock Measurements in Polish Sport Horses.. 2025.
• Investigating the Market Value of Brumbies (Equus caballus) in the Australian Riding Horse Market.. 2023.
• Body Condition Score in Danish Horses Related to Type, Use, and Training Level: Patterns, Risk, and Protective Factors.. 2023.
• Breed Distribution and Allele Frequencies of Base Coat Color, Dilution, and White Patterning Variants across 28 Horse Breeds.. 2022.
• Disease investigations for equine infectious anemia in Canada (2009-2012) - Retrospective evaluation and risk factor analysis.. 2019.
• The palomino horse.. Genetics, 1961.
• A mutation in the MATP gene causes the cream coat colour in the horse. Genetics Selection Evolution, 2003.
• Diluted colours exemplified in Fjord horses. Medycyna Weterynaryjna, 2001.

This article is educational and is not a substitute for veterinary diagnosis or treatment. Contact a veterinarian for advice about an individual animal.