Genetic conditions are inherited traits caused by changes in an animal’s DNA. While many carrier animals show no signs of a condition and can be healthy and productive, certain genetic conditions can affect fertility, animal health or survival when inherited in particular combinations.
For most recessive genetic conditions, animals are generally described as free, carrier or affected.
- A free animal has two normal copies of the gene and does not carry the mutation.
- A carrier animal has one normal copy and one copy of the mutation; carriers usually appear healthy but can pass the mutation on to their progeny.
- An affected animal has inherited two copies of the mutation and may show clinical signs, reduced performance, reproductive loss or reduced survival, depending on the condition.
Why Monitoring Genetic Conditions Matters
Genetic testing allows breeders to identify carriers, make informed mating decisions, and reduce the risk of producing affected animals. Understanding these conditions supports improved herd health, fertility, productivity, and genetic progress.
Annexin A10 (ANXN10)
Annexin A10 (ANXN10) is a genetic variant associated with embryonic mortality in cattle, particularly during the early stages of pregnancy. It is considered a maternal-effect genetic factor, contributing to early pregnancy loss, reduced embryo viability, and lower reproductive performance.
Animals that inherit two copies of the ANXN10 mutation are considered unlikely to survive to term. Female carriers may experience increased embryonic loss and reduced reproductive performance, making ANXN10 an important consideration in breeding and reproductive management programs.
Importantly, the mutation does not appear to negatively affect economically important production or carcase traits. Its impact is primarily on reproductive performance, with the potential to reduce fertility and calving rates within affected herds.
Spherocytosis (B3)
Spherocytosis (B3) is a serious recessive genetic disorder affecting the membrane of red blood cells. A mutation in the B3 gene causes red blood cells to become abnormally shaped and fragile, making them more susceptible to rapid breakdown.
Animals that inherit two copies of the mutation develop severe anaemia due to the accelerated destruction of red blood cells. Most affected calves die within the first week of life, although rare survivors may exhibit significant growth retardation, poor performance, and reduced productivity.
As an inherited recessive condition, Spherocytosis can be passed on to future generations by carrier animals that show no clinical signs.
Claudin 16 Deficiency (CL16)
Claudin 16 Deficiency (CL16) is an inherited genetic disorder that affects kidney function and mineral regulation, particularly the body’s ability to maintain normal calcium and magnesium balance. The CL16 gene plays an important role in kidney function, and mutations in this gene result in the excessive loss of these minerals through urine.
Animals that inherit two copies of the mutation may develop progressive kidney dysfunction, leading to poor growth, reduced performance, dehydration, and a decline in overall condition. The condition is considered terminal, with most affected animals not surviving beyond approximately six years of age.
Physical symptoms alone are not sufficient to reliably identify CL16, and DNA testing is required to accurately identify affected animals and carriers. As an inherited condition, CL16 can be passed on to future generations, making it an important consideration in breeding programs.
Chediak-Higashi Syndrome (CHS)
Chediak-Higashi Syndrome (CHS) is a recessive inherited genetic disorder that affects the function of white blood cells. As these cells play a critical role in fighting infection, animals affected by CHS have a reduced immune response and an increased susceptibility to bacterial and respiratory disease.
Animals that inherit two copies of the mutation may show a range of clinical signs, including excessive umbilical cord bleeding at birth, delayed blood clotting, pale coat colour, light-coloured eyes with increased sensitivity to light, and recurring bacterial or respiratory infections.
As an inherited recessive condition, carrier animals typically show no clinical signs but can pass the mutation on to their offspring. Avoiding carrier-to-carrier matings helps reduce the risk of producing affected calves and supports long-term herd health and productivity.
Factor XI Deficiency (F11)
Factor XI Deficiency (F11) is an inherited blood-clotting disorder caused by a mutation in the Factor XI gene, which is responsible for producing a protein essential for normal blood clotting. Animals with this mutation have reduced clotting ability, leading to prolonged bleeding times.
Animals that inherit two copies of the mutation may experience excessive or prolonged bleeding following injury, procedures such as castration or dehorning, or calving. While the condition is generally considered mild and non-lethal, severe bleeding events can impact animal welfare and management outcomes. Affected animals are typically able to live and breed under normal conditions.
Carrier animals generally appear healthy but can pass the mutation on to their offspring. Some evidence also suggests that carrier-to-carrier matings may be associated with reduced reproductive efficiency, including lower embryo viability and increased returns to cycle.
Factor XIII Deficiency (F13)
Factor XIII Deficiency (F13) is a rare inherited blood-clotting disorder that affects the body’s ability to form stable blood clots. Factor XIII plays an important role in strengthening and stabilising clots, and animals affected by this condition are unable to clot blood effectively.
Animals that inherit two copies of the mutation may experience severe or prolonged bleeding. One of the most noticeable signs is bleeding from the umbilical cord at birth that is slow to stop. Affected animals may also be prone to internal bleeding or excessive bleeding following injury or routine procedures. Due to the severity of impaired clotting, many affected calves do not survive beyond the early stages of life.
As a recessive genetic condition, carrier animals typically show no clinical signs but can pass the mutation on to their offspring. Although the frequency of F13 within the Wagyu population is considered low, it remains an important consideration in breeding programs.
Hepatic Fibrinogen Storage Disease (HFSD)
Hepatic Fibrinogen Storage Disease (HFSD) is a recessive inherited condition that affects liver function due to the abnormal accumulation of fibrinogen protein within liver cells. Fibrinogen plays an important role in both liver function and blood clotting, and the build-up of abnormal fibrinogen can interfere with the liver’s ability to process toxins, nutrients, and clotting factors.
Animals that inherit two copies of the mutation may develop progressive liver dysfunction and exhibit a range of health problems including poor performance, reduced health and condition, abnormal bleeding, thrombosis, and liver cirrhosis. Clinical expression can vary considerably, with some animals showing few obvious signs while others develop severe disease.
As an inherited recessive condition, carrier animals typically show no clinical signs but can pass the mutation on to their offspring.
Isoleucyl-tRNA Synthetase (IARS) Disorder
Isoleucyl-tRNA Synthetase (IARS) Disorder is a recessive genetic condition caused by a mutation in the IARS gene, which plays a critical role in protein synthesis. The mutation reduces the activity of a key enzyme required for normal embryo development and early calf growth, affecting reproductive performance, calf survival, and overall development.
Animals that inherit two copies of the mutation may die during gestation, shortly before birth, or within the first few days of life. Those that survive to term often exhibit signs associated with perinatal weak calf syndrome, including weakness, anaemia, poor nursing ability, reduced vitality, poor growth, variable body temperature, and increased susceptibility to infection.
As an inherited recessive condition, carrier animals typically appear normal but can pass the mutation on to their offspring. Carrier-to-carrier matings have been associated with increased embryonic and foetal loss, higher rates of return to cycle, and a greater risk of producing affected calves.
Due to its impact on both reproductive performance and calf survival, IARS is an important consideration in breeding programs.
Genetic Conditions Results
Animals that have been tested will receive a definitive result of Free, Carrier, or Affected. Animals that have not been tested may display an estimated carrier probability through GeneProb or be reported as Free Untested (FU) based on pedigree information.
| Result Code | Description |
| _ _ F | Free – Tested and confirmed free of the mutation (homozygous normal) |
| _ _ C | Carrier – One copy of the mutation present (heterozygous) |
| _ _ A | Affected – Two copies of the mutation present (homozygous recessive) |
| _ _ #% | Estimated probability of being a carrier (untested animal) |
| _ _ FU | Expected to be free based on pedigree, but not directly tested |
| NR | The sample was tested; however, no result was able to be obtained. Please collect a new sample and submit a new DNA test request form. |
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