The mean (+/- sd) packed cell volume (pcv) of the lambs in a flock mat
ed by 'out-of-season' breeding methods and housed throughout the last
six weeks of pregnancy and the whole of the suckling period declined t
i, 233 +/- 334 per cent when the lambs were a month old, but recovered
spontaneously to reach values within the normal range (30 to 35 per c
ent) before they were weaned at two months, Clinical signs of anaemia
were observed in only a few lambs at three weeks old but the pcv value
s of all the lambs mere significantly lower at this time than at meani
ng, There was no relationship between the pcv values during the two to
four weeks after birth and the growth rate of the lambs, The administ
ration of 200 mg iron, as iron dextran, by intramuscular injection to
the newborn lambs prevented the decrease in PCV, but had no measurable
effect on the health or growth rate of the lambs throughout the suckl
ing period,