Breed Page

Biewer Terrier — BetterBred Breed Page – BetterBred.com
BetterBred Breed Profile

Biewer Terrier

Temperament: Affectionate, loyal, energetic and brave, high grooming needs
Height: 7-11 inches
Weight: 4-8 lbs
Life Span: 12-15 years
Outlier Index ?
0.30
Born before 2016: 0.30 Born after 2024: 0.29
Avg Genetic Rel. ?
0.00
Born before 2016: -0.01 Born after 2024: 0.02
Internal Relatedness ?
0.01
Born before 2016: 0.00 Born after 2024: 0.02
Biewer Terrier
#NameGender OIAGRIR
1 Zinna Belle of Ameican Biewers F 0.27 0.04 -0.20
2 Lordy Logan of American Biewers M 0.21 0.02 0.29
3 The Rooster of American Biewers M 0.23 0.10 -0.12
4 Cool Luke of American Biewers M 0.29 -0.01 0.03
5 Whisper F 0.31 -0.01 -0.05
6 Grand Prince Snow Avalanche M 0.32 0.03 -0.10
7 Donday Dandy M 0.30 0.05 -0.21
8 Donday Greta F 0.44 -0.03 -0.04
9 Donday Bo Jangle's M 0.32 0.03 -0.12
10 Cooper of American Biewers M 0.23 0.03 0.12
Biewers go by many names: such as Biewer Terriers, Biewer yorkshire terriers, or just Biewers. They originated from a yorkshire kennel in Germany in the 1980s. They appeared to be produced between two parents, with a lot of influence from an imported UK stud named Streamglen Richard. It is believed the tri colored patterning evolved from a potential spontaneous mutation, latent mutation, or outbreeding to another breed; Werner and Gertrud Biewer claimed that the latter was not the case. The biewer kennel continued to breed for the type they liked for 5 years before bringing in new genetics. Their dogs were highly sought after. In the 2000s, breeders in America and Germany continued to breed into German yorkshire terriers as was the practice of the Biewer kennel. This practice was ended in 2007. Biewer terriers are currently accepted as a new breed in AKC that may register as a FSS (foundation stock service) and are considered a breed in development.
UC Davis tested Biewers from different backgrounds to see if they were genetically different from one another. While there was variation in the breed, they were found to be one breed. Based on values for all currently tested 104 Biewers, the mean number of alleles found at each locus is 6.39, which is similar to many pure breeds. The number of the alleles (Ne) that contribute the most to overall heterozygosity is 3.35, which is also in line with a number of pure breeds. This indicates a need to redistribute the alleles and the presence of a breedwide bottleneck, likely due to the Founder Effect. The adjusted IR curve for Biewers finds them to be highly inbred, close to that of a litter of full siblings’ breeding, like many breeds, when compared to village dogs.

Average metrics by birth year for dogs with recorded birthdates in the BetterBred database.

A 3D genetic map of enrolled Biewer Terrier dogs in the BetterBred database, based on allele-sharing distance across 33 STR loci. This is not a complete picture of the breed — it reflects only dogs whose owners have enrolled them. Drag to rotate · scroll to zoom · hover for dog names (public profiles only).

Historical founders — oldest 25% of enrolled dogs     Current gene pool — most recent 50% of enrolled dogs
Building plot… this may take a minute for larger breeds.

The Dog Leukocyte Antigen (DLA) region controls immune function and is the most polymorphic portion of the canine genome. Every dog carries two sets of DLA haplotypes — one from each parent — which almost never recombine across generations. Frequency percentages reflect how often each haplotype appears across all allele copies in the breed, not the percentage of dogs carrying it.

Class I Haplotypes

HaplotypeFrequency
1030
47.7%
1012
23.0%
1040
8.8%
1019
7.1%
1014
4.8%
1005
2.1%
1046
1.8%
1104
1.1%
1131
0.9%
1008
0.7%
1016
0.7%
1043
0.5%
1105
0.4%
1117
0.2%
1115
0.2%

Class II Haplotypes

HaplotypeFrequency
2023
47.9%
2003
26.8%
2016
7.7%
2013
6.6%
2037
4.8%
2040
2.7%
2005
1.8%
2081
1.1%
2083
0.4%
2074
0.2%
2084
0.2%

Class I & II Combinations

Class IClass IIFrequency
1030 2023
47.7%
1012 2003
22.9%
1019 2016
7.1%
1040 2013
6.6%
1014 2037
4.8%
1005 2003
2.1%
1040 2040
2.0%
1046 2005
1.8%
1104 2081
1.1%
1131 2003
0.9%
1016 2040
0.7%
1008 2003
0.7%
1043 2016
0.5%
1105 2083
0.4%
1040 2084
0.2%
1012 2023
0.2%
1115 2003
0.2%
1117 2074
0.2%

The Canine Diversity Test from UC Davis Veterinary Genetics Laboratory is the foundation of BetterBred’s breed management tools. Testing your dog adds to the breed database and gives you access to the full suite of breeding analysis tools.

Order from UC Davis VGL →
Sonza
Australian Capital Territory, AUS
Visit Website →
Donday
Washington, US
Visit Website →
OI
Outlier Index

The Outlier Index (OI) measures how unusual a dog’s allele combination is relative to the tested population of its breed. A higher OI means the dog carries alleles at lower frequencies across the breed — genetic variants that are underrepresented in the population as a whole.

Dogs with high OI are genetically valuable because they carry diversity that most other tested dogs don’t share. Breeding them thoughtfully into the broader population helps redistribute lower-frequency alleles rather than allowing them to become even rarer over generations.

The breed average shown here reflects all dogs tested in the BetterBred database. The senior and youngster comparisons show whether diversity is trending up or down in recent generations.
AGR
Average Genetic Relatedness

Average Genetic Relatedness (AGR) measures how similar a dog’s DNA is, on average, to every other tested dog in the breed. It reflects the dog’s mean kinship — how closely related it is to the population as a whole.

A lower AGR means the dog is more genetically distinct from the majority of the breed. Dogs with low AGR carry alleles at lower frequencies across the tested population, making them higher-priority candidates for inclusion in a well-managed breeding program.

AGR is conceptually related to mean kinship used in conservation genetics for managed species populations. A declining AGR average in younger dogs suggests the breed is successfully redistributing genetic diversity across generations.
IR
Internal Relatedness

Internal Relatedness (IR) measures how much identical genetic material an individual dog inherited from both parents. IR is a useful indicator of inbreeding: lower IR generally reflects lower inbreeding, and it is widely used and reported in the scientific literature.

A high IR is not the cause for alarm it might appear. Elevated IR can often be resolved in a single generation by pairing with a dog whose ancestry is less represented in the breed. It is a signpost, not a sentence.

BetterBred reports IR for reference, but it is not our primary breeding guidance tool. OI and AGR together give a more complete and actionable picture of a dog’s genetic value to the population.

AGR tells you which dogs are genetically unusual relative to the population. OI tells you which dogs are most valuable to preserve. OI specifically weights mid-frequency alleles, identifying dogs whose ancestry is underrepresented in a way most likely to benefit the breed.