14 BULLETIN 996, U. S. DEPARTMENT OF AGRICULTURE. 
The practical advantage of flushing lies in the production of twins, 
which in turn depends primarily upon the number of ova produced 
by the ewe. 
Experiments here reported indicate that ewes getting in lamb first 
produce the largest percentage of twins. 
The experimental sheep were divided into 20 lots averaging 18 in 
each lot. Comparisons made with flushed and unflushed lots under 
varying conditions showed that an average increase of 18.7 lambs 
per 100 ewes was obtained as a result of flushing. 
The most pronounced effect occurred with Lots 18 (unflushed) and 
20 (flushed), the latter gaining an average of 8.15 pounds in weight, 
or 6.6 pounds more than Lot 18, and increasing the number of lambs 
dropped by 47 per 100 ewes. 
The data obtained indicate that in order to produce the largest 
number of twins, ewes should gain at least 7 pounds a head during 
the breeding season. 
Comparing grain with pasture as best feed for flushing, the work 
indicates that there is no decided advantage in the kind of feed used 
other than the saving in labor and expense when sufficient good 
pasture is available. ' 
The influence of age of the ewe on twin production shows a gradual 
increase up to 6 years. The rate of lambs dropped by ewes 2 years of 
age was 111.4 and at 6 years 161.2 per 100 ewes. 
The influence of heredity (breed) on twin production is shown by 
records obtained from breeders of 189 flocks representing 9 breeds. 
There is little difference among the Dorset, Lincoln, Oxford, and 
Southdown, these being the 4 highest breeds. 
The mating of rams and ewes themselves born as twins does not 
appear to increase the proportion of births. However, there seems 
to be some increase in per cent of lambs produced by ewes from 
heavy twinning strains in a given breed. 
There is no material difference in the size of twins and singles 
when fully developed. 
Although at market age twin lambs would not weigh so much as 
singles, the difference in weight would be small compared to the 
total weight of the lambs for sale, thus making twins far more 
profitable. 
