UC Davis School of Veterinary Medicine Veterinary Genetics Laboratory
Paunch Calf Syndrome (PCS) of Romagnola Cattle

Paunch Calf Syndrome (PCS) is an inherited lethal defect of Romagnola cattle. PCS is characterized by abnormal development of multiple organs, craniofacial deformities, an enlarged fluid-filled abdomen and liver fibrosis. Affected calves are usually stillborn and can present a protruding tongue and cleft palate. PCS is caused by a mutation (c.2503G>A) in the Lysine (K)-Specific Demethylase 2B (KDM2B) gene that affects its normal function. The KDM2B gene is important for development and cell differentiation, including the development of embryonic endodermal- and mesodermal-derived organs and tissues such as liver and bone. Compromised function of KDM2B thus can have multi-organ deleterious effects.

PCS is inherited as an autosomal recessive trait. This means that 2 copies of the mutation (P/P) are required to produce the disorder. Animals with 1 copy of the mutation (carriers, N/P) are normal but can produce 25% affected calves when bred to other carriers. PCS affects both male and female calves. The KDMB2 mutation arose naturally and increased in prevalence in the Romagnola breed as a consequence of close inbreeding and “popular sire” effects which were amplified by the use of artificial insemination. Common ancestors of PCS cases are sires Dritto and Treno.

The Veterinary Genetics Laboratory offers a test for PCS in Romagnola cattle. Test results help breeders determine if the PCS mutation is present among breeding stock, and implement mating strategies to reduce incidence of PCS while retaining genetic diversity in the breed. Carriers can be safely bred to N/N mates as this type of breeding will not produce PCS calves.

Allow 6 - 10 business days for results.

Results reported as:


Normal – no copies of the PCS mutation are present.


Carrier – 1 copy of the PCS mutation is present. Animal is normal but can produce affected offspring if bred to another carrier.


Affected – 2 copies of the PCS mutation.

Testoni S, Bartolone E, Rossi M, Patrignani A, Bruggmann R,  Lichtner P, Tetens J,  Gentile A,  Drögemüler C. KDM2B is implicated in bovine lethal multi-organic developmental dysplasia. PLoS One, 7, 2012, e45634.

Murgiano L, Drögemüler C, Sbarra F, Bolcato M and Gentile A. Prevalence of paunch calf syndrome carriers in Italian Romagnola cattle. The Veterinary Journal 200: 459-461, 2014.

Veterinary Genetics Laboratory, Tel 530-752-2211, Email VGL