Ge et al. [23] reported lower IGF-1 levels in young BB Angus bulls, while Maj et al. [41] and Mirzaei et al. [42] found higher IGF-1 concentrations in BB Polish and Iranian HF cattle, and Ruprechter et al. [29] reported no association in Uruguayan HF cows. The gene discussed is IGF1; the disease is hydrops fetalis.