Comparison of plasma levels of the gonadotropic hormone FSH, during the first 3 months of life, in male lambs, carrying or not carrying the "F" gene of proliferation

We have found evidence in the male lambs, Booroola x Mérinos d'Arles and Booroola x -Romanov, during the first three months of life, for the expression of the "F" prolificacy gene. More FSH at the peripheral plasma levels is observed in males carrying one copy of the "F" gene as compared to non carriers of the same crosses in the same environment. However the difference is of too small amplitude to be utilised to discriminate male lambs carrying the "F" gene.