Fleckvieh haplotype 4 / FH4 (SUGT1-related) - Cattle

Fleckvieh haplotype 4 (FH4)

This DNA test detects the SUGT1 variant c.949T>C that causes Fleckvieh haplotype 4, also known as FH4, in cattle. The variant changes the SGT1 protein, which is important for normal cell division and early embryonic development.

FH4 is a recessive lethal haplotype. Calves with two copies are not expected in practice, because this combination causes very early embryonic loss. Carriers are healthy themselves but can pass the variant to their offspring.

Inheritance and meaning

FH4 is inherited as an autosomal recessive lethal trait. One copy means carrier status; two copies cause embryonic death. In risk matings this can appear as reduced pregnancy success or a cow returning quickly to the next cycle.

Practical value of this test

• Breeding planning: identify FH4 carriers before mating or insemination.
• Fertility management: avoid carrier-to-carrier combinations and reduce embryonic loss.
• Genetic progress: keep valuable carrier lines by pairing them with clear animals.