Insulin-like growth factor I plasma concentrations in newborn healthy donkey and horse foals

In different species the insulin-like growth factor I (IGF-I) is an important regulatory factor in fetal and neonatal growth, especially in skeletal and gut development. This study was carried out to assess plasma IGF-I profile in newborn healthy donkey and horse foals during the first two weeks of age. The study was conducted on 32 horse and 19 donkey foals, born at term, after spontaneous parturition, mature and viable. Blood samples were collected from the jugular vein at 10, 20 and 30 minutes, 3 and 12 hours and at day 3, 7, 10, 14 of life. IGF-I levels were evaluated by RIA. IGF-I showed an increasing profile in both species, with lower levels (P