Study of breeding and the methods of eliminating the diseases which hinder the breeding work of domestic animals. 2 Ovulation ratio of right and left ovaries and their diseases of Cattle.

A Study was made of the ovaries of 231 Kurogewashu (a Japanese black breed cattle) obtained from a slaughter house to see the ovulation ratio or right and left ovaries and ovarian diseases. The result was as follows: 1. The ovaries of 191 cattle were studied to see ovulation ratio by newly formed corpus luteum. The ovaries of 40 cattle were excluded because of the absence of corpus luteum, pregnancy, and disease infection. The result was that 109 cattle (57.1%) had corpus luteum in the right ovary and 82 cattle (42.9%) in the left ovary. The ratio is 6:4; which means that the more right ovaries ovulated than the left ovaries. 2. By the number of corpus albicans in ovaries, the implantation ratio of right and left kornu uteri was studied of 48 cows. The result was that 61 corpus albicans (56.0%) were found in the right ovaries and 48 (44.0%) in the left ovaries. These results will show that pregnancy will take place more often in right kornu uteri than in left kornu uteri. 3. Furthermore, the ovaries of 191 cattle were studied of their weight. The average weight of the ovaries of heifers was 5.8 grams. and that of the cows ,vas 8.2 grams, which means that the ovaries of the cows 2 grams heavier than those of the heifers. The average weight of right ovaries was 6.6 grams and that of left ovaries was 5.8 grams, the difference was 0.8 grams. This fact might show that the right ovary is performing its function than the left ovary is. 4. Out of 231 cattle 19 cattle (8.2%) were infected with follicular cyst. The proportion was higher when only cows were taken; 13 cows (27.1%) out of 48 cows were infected with the disease. The reason for this high rate of infection seemed to be the fact that among them inclued cows which had stopped breeding for some reason. It might also depend on the fact that those cOvvs were kept in dark places and fed rich feed. Eight cattle (3.5%) out of 231 were infected with lutein cyst. The high rate of occurrence of follicle (1.1－1.3cm) was recognized in those ovaries infected with lutein cyst. Usually, these follicles had thick wall and very hard to rapture. Some of these follicles look like normal follicles. It is not clear if these latter follicles have any ovulation function or not