10 
BULLETIN 996, U. S. DEPARTMENT OF AGRICULTURE. 
There does not appear to be any connection between lamb produc- 
tion and the fact of sires and dams having been singles or twins. 
Table 5. — Effect of breeding on twin production of Southdown ewes in Government flock. 
Ewes' breeding. 
Lambs 
dropped 
Born twins: 
Sires twins, dams twins... 
Sires singles, dams twins . . 
Sires twins, dams singles. . 
Sires singles, dams singles. 
Average for twin ewes . . 
Born singles: 
Sires twins, dams twins . . 
Sires singles, dams twins. . 
Sires twins, dams singles . . 
Sires singles, dams singles . 
Average for single ewes . 
136.2 
A safer way of appraising the possibility of increasing twin pro- 
duction by selection is to take into account the full records of female 
ancestors rather than a single birth in which the particular sire or 
particular dam was produced. 
VALUE OF TWIN LAMBS IN COMPARISON WITH SINGLES. 
Sheep raisers differ in their ideas of the desirable size of the lamb 
crop. At one extreme are ranchmen chiefly interested in wool pro- 
duction who consider twins as undesirable because feed conditions 
are unfavorable to a ewe's furnishing more than sufficient milk for 
one lamb. Even in such cases, however, it is always likely that a 
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 
