Serum growth hormone and insulin-like growth factor-1 concentrations in Japanese black cattle with growth retardation

Serum concentrations of growth hormone (GH) and insulin-like growth factor- 1 (IGF-1) were determined in 5 calves in the same lineage with growth retar dation. They had normal appetites, activities, body proportion, and laborat ory test results. Calves with growth retardation had higher serum GH concen trations and lower serum IGF-1 concentrations. These findings suggested def ects in the GH-IGF-1 axis, such as in the GH-receptor.