Abstract

The effects of ovine placental lactogen (oPL) on wool follicle development were examined in chronically catheterised singleton Dorset foetuses. From days 122 to 136 of gestation, five foetuses were infused intra-arterially with purified oPL (1.2 mg/day) in a carrier medium consisting of sterile physiological saline plus 15% plasma from non- pregnant ewes while another five were infused with carrier medium alone. Foetal arterial plasma concentrations of oPL were increased six-fold by the infusion compared with those in controls. Foetuses were euthanased on day 136 of gestation and skin samples excised from the midside for histological examination. Treatment of foetuses with oPL did not influence primary follicle density but reduced the ratio of immature secondary follicles to primary follicles (Control, 1.22 vs oPL-treated 1.01, Pooled SE = 0.06, P=0.06). These data provide the first evidence that follicle development in the lamb may be regulated by ovine placental lactogen.

AJ, Litherland, E Sorenson, J Niezen, and D Bishop

Proceedings of the New Zealand Society of Animal Production, Volume 52, , 233-236, 1992