Table 3.— Effect of age of eives on per cent of lambs dropped in experimental flocks. 
Age of ewes. 
Cases of 
lambing. 
Lambs 
dropped. 
Age of ewes. 
Cases of 
lambiiig. 
Lambs 
dropped. 
Years. 
2 
79 
63 
67 
62 
Percent. 
111.4 
123.8 
143.3 
143.5 
Years. 
6 
49 
35 
22 
8 
Per cent. 
161. 2 
3 
7 
8 
142.8 
4 . . 
113.6 
9 
162.5 
TWIN PRODUCTION AS AFFECTED BY BREED OF EWE. 
Evidence as to inheritance of fertility makes it appear that vari- 
ous breeds or strains have each an inherited limit of fertility and that 
the obtaining of the full possibility in any one season will be deter- 
mined by the extent to which the conditions and management favor 
the full utilization of the inherited capacity. 
Kecords of actual returns from 189 flocks representing 9 breeds for 
the seasons of 1919 and 1920 were obtained by the Animal Husbandry 
Division through the kindness of breeders who reported. The aver- 
age per cent of lambs in proportion to ewes, lambing in the spring, is 
shown below, also the separate record of the 2-year-old ewes (drop- 
ping lambs the first time) and the highest flock average reported for 
each breed. The table gives the average of the two seasons' reports. 
The high return for the breed is for a single season. 
Table 4. — Record of lamb crops, by breeds, from 189 flocks. 
[Average of seasons 1919 and 1920.] 
Flocks. 
2-year-old ewes. 
Aged ewes. 
Total ewes. 
Highest flock. 
Breed. 
Ewes. 
Lambs 
dropped. 
Ewes. 
Lambs 
dropped. 
Ewes. 
Lambs 
dropped. 
F ! Lambs 
^ es - dropped. 
Number. 
26 
11 
18 
27 
26 
16 
25 
16 
24 
Number. 
215 
40 
96 
138 
549 
91 
167 
84 
186 
Per cent. 
146 
145 
144 
143 
139 
135 
134 
123 
111 
Number. 
566 
106 
214 
378 
857 
190 
402 
184 
667 
Per cent. 
163 
161 
156 
153 
148 
148 
154 
149 
125 
Number. 
781 
146 
310 
516 
1,406 
281 
566 
268 
853 
Per cent. 
158 
157 
152 
151 
144 
144 
149 
141 
122 
Number.Per cent. 
6 1 200 
11 191 
Oxford 
6 1 200 
6 | 200 
6 1 200 
23 | 200 
6 | 183 
Turds 
8 1 200 
Rambouillet 
9 177 
TWIN PRODUCTION AS AFFECTED BY SIRE. 
A study of 334 cases of lambing from the services of 5 rams, none 
of which were used less than three seasons or on less than 20 ewes, does 
not indicate any important variation in proportions of twins that can 
be attributed to the sire. Such differences as were shown in the 
average number of lambs per service for each sire appeared to be due 
to differences in the ewes to which they were bred. Records of 380 
lambings from services of 8 different sires were studied in relation to 
