An investigation of the possible effects of subclinical iodine deficiency on ewe fertility and perinatal lamb mortality.
A controlled supplementation trial was performed in an assumed iodine-deficient Romney ewe flock in the Manawatu. Significantly more twin litters were born to iodine-supplemented ewes than to control ewes. Furthermore, the perinatal mortality rate in lambs born to iodine-supplemented dams was significantly lower than in lambs born to control dams. Ewe age and the use of different lambing paddocks for iodine-supplemented and control ewes may have been confounding factors. In both iodine-supplemented and control ewes, serum T3, and T4, concentration values remained above the currently used normal range throughout the trial period.
Sargison
N D
ND
Department of Veterinary Clinical Sciences, Massey University, Palmerston North, New Zealand.
West
D M
DM
Clark
R G
RG