In addition, SNP hits in the AMPD1, CAPN3, MYF6 and SDR16C6 CGs were monomorphic only to the Polish Red breed, while a SNP hit in the GDP10 CG was monomorphic only to the Polish HF breed, and SNP hits in the GHRHR and IGFN1 CGs were monomorphic only to the Hereford breed. Here, AMPD1 is linked to hydrops fetalis.