Suppression of secondary wool follicle development by
administration of placental lactogen to ovine foetuses
G.A. Wickham, P.A. Schoknecht, W.B. Currie, A.W. Bell, S.N.
McCutcheon
Department of Animal Science, Massey University, Palmerston
North, New Zealand
Proceedings of the New Zealand Society of Animal Production.
1992, 52: 277-280
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.
Keywords: NZSAPAB;
Foetus; ovine placental lactogen; wool; follicle development;
Dorset sheep.
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