Skip to main content
Canonical source: the standalone Goat Health & Husbandry KB (herdmate.io ecosystem). Sync changes there to avoid drift.

​
DNA Testing Basics for Goats

DNA testing has become an increasingly accessible and valuable tool for goat producers. From verifying parentage to identifying genetic diseases and optimizing dairy production through casein genotyping, genomic testing provides objective data that supports better breeding decisions. This guide covers the major types of DNA tests available for goats, how to submit samples, and how to interpret your results.

​
Available Genomic Tests for Goats

Several categories of DNA testing are available to goat producers, each serving different management and breeding objectives.

​
Parentage Verification

Parentage testing uses DNA markers (microsatellites or SNP panels) to confirm or determine the sire and dam of an individual animal. This is the most widely used DNA test in the goat industry. Why parentage matters:
  • Accurate pedigree records are the foundation of genetic evaluation and EPD calculation
  • Multi-sire breeding pastures make visual identification of sires impossible
  • Registration requirements for many breed associations include parentage verification
  • Misidentified parentage leads to incorrect EPDs and flawed breeding decisions
How it works: Parentage testing compares the DNA profile of the offspring to the profiles of the alleged sire and dam. Each animal inherits one copy of each genetic marker from its sire and one from its dam. If the offspring’s profile is inconsistent with a potential parent, that parent is excluded. When the profiles are consistent, parentage is confirmed with a probability typically exceeding 99%. ADGA requirements: The American Dairy Goat Association requires DNA parentage verification for certain registration categories and for animals used in artificial insemination programs. ADGA maintains a DNA repository through its approved laboratories.

​
Scrapie Genotyping

Scrapie is a fatal transmissible spongiform encephalopathy (TSE) that affects sheep and goats. While classical scrapie is rare in goats in the United States, the USDA Scrapie Eradication Program encourages genotyping to identify animals with genetic susceptibility or resistance. The genetics of scrapie susceptibility in goats: The prion protein gene (PRNP) contains several polymorphisms associated with scrapie susceptibility. In goats, the most studied variants include:
  • Codon 146: The wild-type asparagine (N) allele is associated with susceptibility, while the serine (S) and aspartic acid (D) variants are associated with increased resistance
  • Codon 142: The isoleucine (I) to methionine (M) substitution has been associated with resistance in some populations
  • Codon 211: The arginine (R) to glutamine (Q) substitution has been associated with resistance
  • Codon 222: The glutamine (Q) to lysine (K) substitution has shown strong resistance associations in European studies
Practical implications:
  • Producers can use scrapie genotyping to select breeding stock with resistance-associated alleles
  • Genotyping supports the USDA’s National Scrapie Eradication Program objectives
  • Animals with resistant genotypes may face fewer movement restrictions in scrapie-affected flocks
  • The University of California Davis Veterinary Genetics Laboratory (VGL) offers comprehensive goat PRNP genotyping

​
Casein Variant Testing for Dairy Goats

Casein proteins (alpha-s1-casein, alpha-s2-casein, beta-casein, and kappa-casein) are the primary proteins in goat milk and are critical determinants of cheese yield, milk processing characteristics, and nutritional quality. The alpha-s1-casein (CSN1S1) gene is the most extensively studied and tested in dairy goats. Alpha-s1-casein variants: The CSN1S1 gene has multiple alleles that produce different levels of alpha-s1-casein protein:
  • Strong alleles (A, B1, B2, B3, B4, C, H, L, M): Associated with high alpha-s1-casein content (approximately 3.5 g/L per allele). Animals homozygous for strong alleles produce milk with the highest protein content and best cheese-making properties.
  • Intermediate alleles (E, I): Associated with moderate alpha-s1-casein content (approximately 1.1 to 1.6 g/L per allele)
  • Weak alleles (D, F, G): Associated with low alpha-s1-casein content (approximately 0.45 to 0.6 g/L per allele)
  • Null alleles (01, 02, N): Associated with virtually no alpha-s1-casein production. Animals homozygous for null alleles produce milk with significantly lower total protein.
Why casein genotyping matters for dairy producers:
  • Milk from goats with strong casein alleles yields approximately 15% to 20% more cheese per gallon
  • Strong casein milk has firmer curd formation and better processing characteristics
  • Casein genotype significantly affects milk flavor profile; null-allele milk tends to have a stronger “goaty” flavor
  • Breeding programs can increase herd casein levels within a few generations through informed sire selection
  • ADGA records casein genotypes and displays them on pedigree documents

​
Genetic Disease Testing

DNA tests are available for several hereditary conditions in goats:
  • G6S (G-6-Sulfatase Deficiency): A fatal lysosomal storage disease in Nubian and Nubian-cross goats. Carriers are clinically normal but produce 25% affected offspring when bred to another carrier. Testing is strongly recommended for all Nubian breeding stock.
  • Beta-mannosidosis: A fatal neurological disease identified in Nubian goats. DNA testing can identify carriers.
  • Myotonia congenita: The condition responsible for the “fainting” phenotype in Myotonic (Tennessee Fainting) goats. While not a disease in the traditional sense, testing can confirm the genetic basis.

​
Coat Color and Pattern Genetics

DNA testing for coat color genes is available and can help breeders predict offspring color patterns. While less economically significant than production or disease tests, color genetics testing supports marketing and breeding objectives for producers targeting specific color phenotypes.

​
How to Submit Samples

The sample submission process is straightforward, but proper technique ensures reliable results.

​
Approved Sample Types

  • Blood on FTA cards: A few drops of whole blood applied to a Whatman FTA card. This is a convenient and stable format for shipping. The card preserves DNA at room temperature.
  • Hair follicles: Pull (do not cut) 20 to 30 hairs with visible root bulbs attached. Hair roots contain the DNA; the shaft alone is insufficient. Place in a paper envelope labeled with the animal’s identification.
  • Tissue samples: An ear notch or tissue biopsy collected in a sterile container or on an FTA card. Often collected at the time of ear tagging.
  • EDTA blood tubes: Whole blood collected in purple-top EDTA tubes. Requires refrigeration and expedited shipping.

​
Submission Steps

  1. Determine which tests you need: Parentage, scrapie genotyping, casein variants, disease panels, or a combination
  2. Order a sample collection kit from the testing laboratory or download submission forms from their website
  3. Collect samples properly: Ensure samples are clearly labeled with permanent identification (registration number, ear tag number, or microchip number)
  4. Complete submission forms: Include the animal’s identification, breed, sex, date of birth, and owner information. For parentage testing, include sire and dam identification.
  5. Ship samples according to laboratory instructions: FTA cards and hair can typically ship at room temperature in a standard envelope. Blood tubes require cold packs and expedited shipping.

​
Major Testing Laboratories

  • University of California Davis Veterinary Genetics Laboratory (VGL): Offers parentage, scrapie genotyping, casein variants, G6S, coat color, and other tests for goats. One of the most comprehensive goat genomics labs in the United States.
  • ADGA-approved laboratories: ADGA maintains a list of approved laboratories for parentage verification that feeds directly into their registration database.
  • Texas A&M Veterinary Medical Diagnostic Laboratory: Offers select goat DNA tests.
  • GeneSeek (Neogen): Provides SNP-based parentage and genomic testing services.

​
Turnaround Time and Cost

  • Parentage testing: Typically 2 to 4 weeks; approximately 25to25 to 50 per animal
  • Scrapie genotyping: Typically 2 to 4 weeks; approximately 20to20 to 35 per animal
  • Casein variant testing: Typically 2 to 4 weeks; approximately 25to25 to 40 per animal
  • Disease panels: Typically 2 to 4 weeks; approximately 20to20 to 35 per test
  • Multi-test discounts are often available when ordering several tests on the same sample

​
Interpreting Results

Understanding your DNA test results is essential for making them actionable in your breeding program.

​
Parentage Results

Results will indicate either:
  • Qualified (confirmed): The tested parent is consistent with being the true parent at all tested markers. The probability of parentage is reported, typically exceeding 99%.
  • Excluded: The tested parent is excluded from being the true parent because of incompatible markers. At least one other animal must be the actual parent.
  • No decision: Insufficient data to confirm or exclude parentage. This can occur if the alleged parent has not been DNA-tested or if the marker panel has insufficient power to resolve closely related potential parents.

​
Scrapie Genotype Results

Results report the amino acid variants found at each tested codon. For example:
  • 146 N/N: Homozygous wild-type (susceptible)
  • 146 N/S: Heterozygous (one resistant allele)
  • 146 S/S: Homozygous for the resistance-associated variant
Work with your veterinarian and breeding advisor to incorporate scrapie genotype into your breeding program. Selecting for resistance alleles while maintaining genetic diversity in production traits requires balanced decision-making.

​
Casein Variant Results

Results report the two alleles an animal carries at the CSN1S1 locus. For example:
  • A/A: Homozygous strong; highest alpha-s1-casein production
  • A/F: Heterozygous; one strong and one weak allele; moderate production
  • F/F: Homozygous weak; low alpha-s1-casein production
  • E/01: One intermediate and one null allele; reduced production
Using casein results in breeding:
  • Breed strong-allele does to strong-allele bucks to maximize the proportion of high-casein offspring
  • Even heterozygous animals (one strong, one weak allele) produce milk with significantly higher casein than homozygous weak or null animals
  • Within 2 to 3 generations of deliberate selection, a dairy herd can substantially shift its casein allele frequencies toward strong alleles

​
Disease Test Results

Results typically classify animals as:
  • Clear (Normal): Does not carry the disease allele. Safe to breed to any animal.
  • Carrier: Carries one copy of the disease allele but is clinically normal. Should only be bred to tested-clear animals to avoid producing affected offspring.
  • Affected: Carries two copies of the disease allele and is clinically affected (or will become affected). Should not be used for breeding.

​
Integrating DNA Testing into Your Breeding Program

​
Priority Testing Recommendations

For most goat operations, the following testing priorities make sense:
  1. All breeding bucks: Parentage verification, relevant disease panels, and (for dairy) casein genotyping. A buck’s genetic influence is amplified across the herd, making accurate genetic information critical.
  2. Replacement doe candidates: Parentage verification and disease panels at minimum. Casein genotyping for dairy does helps optimize mating decisions.
  3. Purchased breeding stock: Require DNA test results before purchase. Reputable breeders should have testing completed on sale animals.
  4. AI sires: Parentage verification is typically required by breed associations for AI sires. Complete genetic profiles add value and marketability.

​
Cost-Benefit Considerations

DNA testing represents a modest investment relative to the value of the breeding decisions it informs. A single misidentified sire can result in years of misdirected genetic selection. A carrier-to-carrier mating producing affected offspring creates animal welfare concerns and economic loss. The cost of testing is almost always justified for animals that will be used in breeding programs.

​
Record-Keeping

  • Record all DNA test results in your herd management system alongside pedigree and performance data
  • Register results with your breed association when applicable
  • Reference genotype data when planning matings
  • Share relevant test results with buyers of breeding stock