As it is the case with all cattle breeds, there are genetic disorders in Wagyu cattle, too, though as far as the latter is concerned, the whole issue is overvalued and considered a quality criterion at times. When I bought my first embryos from Australian breeders, my concerns about genetic disorders were not really paid attention to. Things should be kept in proportion here... C = genetic carrier ... a thoroughly healthy animal, why not breeding it? In actual fact, some of the best breeders for meat quality and milk yield are carriers of genetic disorders, such as JVP Fukutsuru 068 F11, or Itomoritaka 002 CHS!! Basically, mating two carriers should be avoided. But in our view, breeding will not evolve without the use of certain breeders which are carriers of genetic disorders.
Needless to say, we also examine our animals for genetic disorders before determining a mate and excluding Status (A) animals.
These exams are conducted for us by the company Agrobiogen.
Find an overview/explanation of genetic disorders below.
Factor XI Deficiency (F11) – When Factor XI deficient, the effectiveness of the coagulation factor XI (plasma thromboplastin antecedent), an important blood plasma protein, is reduced. Infected animals suffer from mild hemophilia. The most obvious symptom is continued bleeding episodes or unusual blood plasma coagulation after injuries or surgeries, such as castration or dehorning. It has moreover been found that when mating Factor XI deficiency carriers, more problems with insemination and abortion may occur. This genetic disorder is not lethal. Note – infected animals are viable and may be used for breeding.
Chediak Higashi-Syndrome (CHS) – This genetic disease especially affects macrophages (a type of white blood cells of the immune system that recognize, engulf, and destroy target cells). In affected cattle, the function of these cells (bacteriolysis) is decreased, weakening the protection against infections. This genetic disorder is generally considered not lethal. Affected cattle present an increased susceptibility to bacterial infections. Usually they are light colored and have a tendency to slowed clotting. A first manifestation is unusual umbilical cord bleeding of the calf during birth.
Spherocystosis (B3) – The erythrocyte membrane protein band 3 is responsible for the correct form of the red blood cells’ membrane. Red blood cells of affected cattle are smaller, have a spherical shape, and their function is restricted. The mutation of both copies of the band 3 gene leads to the birth of a calf with pernicious anemia (anemia, underweight, weak constitution, shortness of breath, fast heart rate). This genetic disorder is lethal and mostly results in the animal’s death within the first week post-partum. In some cases, animals grow to maturity, but become severely disabled.
Claudin-16 Deficiency (CL16), also known as RTD (Renal Tubular Dysplasia) – This mutation causes a buildup of fibrous tissue, especially in the kidneys but also in other organs. Affected animals have a higher risk of renal failure, which can develop suddenly during growth. Typical symptoms are growth retardation, elevated urea and creatinine rates in the blood, diarrhea, and excessive hoof growth. This genetic disorder is not lethal; however, animals suffering from CHS have a short life expectancy and do normally not become older than six.
Status C animals are carriers, which means that the animal carries only one copy of the mutated and one of the healthy allele. With this combination, genetic disorders and the related symptoms do not occur. Carriers are phenotypical and unobtrusive and can be distinguished from actually healthy animals by genetic testing.
Sometimes the abbreviation FU can be found in stock papers. It is applied when it is proven that both parents did not have the genetic disorder and it is therefore clear that it will not occur in the offspring.
Animals with this status are affected. This condition is only rarely detected. Affected animals are homozygous, which means that the respective disorder occurs only in case both copies (alleles) of the mutated gene occur.
Animals with this status are free of any genetic disorders, thus not affected by genetic mutations.