FLUSHING TO INCREASE LAMB YIELDS. 11 
number of ewes will lose their lambs and a corresponding number of 
pairs of twins would allow transferring one from each pair of twins 
to a ewe in milk and without a lamb. This would render possible 
the rearing of 100 per cent of lambs. 
There are, also, a few breeders of registered sheep who believe that 
there is no gain in obtaining twin lambs. Their position is based 
upon the fact that some twin lambs do not develop so fully as singles. 
Since a good individual animal sold for breeding purposes may bring 
as much as or more than two inferior ones, single lambs might be an 
advantage, provided they always proved more valuable at selling age. 
At the other extreme are raisers of market lambs in whose hands a 
pair of twins, even though comparatively underdeveloped and sold 
perhaps at a lower price per pound, still will bring a much larger 
amount than the single lamb. 
With ewes lambing for the first time, it is less desirable to have 
twin lambs than with older ewes. Young ewes do not ordinarily 
milk so well nor look after their lambs so faithfully, and thus they 
have a greater rate of loss in twin lambs than older ewes. In most 
flocks, if not all, containing the ordinary proportion of ewes of vary- 
ing ages, the mark can well be set at 150 per cent of lambs in working 
for the greatest net returns. 
Possible disadvantages in twin lambs must come from one or all of 
three causes: (1) Greater rate of loss among twins; (2) slower rate 
of growth as lambs; or (3) inability to reach the same size, weight, 
and breeding value as single lambs. 
As regards the rate of loss, the experience of the Bureau of Animal 
Industry shows no greater losses among twins. In the lambing 
seasons of 1916 to 1920, inclusive, in the two flocks of Southdowns 
used in the experiments a total of 224 single lambs and 290 twin 
lambs was born. Of these, 14.3 per cent of the single-born lambs 
died before reaching the age of 2 weeks, and 13.4 per cent of the 
twins. 
COMPARATIVE WEIGHTS OF SINGLE AND TWIN LAMBS. 
Comparative weights of twins and single lambs at six months old 
show that the milk received by the lambs is more important in in- 
fluencing growth than is birth as a single or twin. 
Records of 184 lambs dropped through three different years are 
grouped to show weights attained by both sexes and by single lambs, 
twin lambs, and lambs born as twins but having all of one ewe's 
milk (twins raised as singles) . The weights of the ram lambs include 
3 or 4 wethers. 
