Study of breeding and the methods of eliminating the diseases which hinder the breeding work of domestic animals. 1 Ovulation ratio of right and left ovaries and their diseases of cattle

摘要

1. The author has studied of the ovaries of 145 Kurogewashu (a Japanese black , breed of cattle) female cattle brought from a slaughter house to see the ovulation ratio of both ovaries by the existence of the newly formed corpus albicans. The result of the study was this: 76 cattle (52.4%) had corpus albicans in the right ovary and 69 cattle (47.6%) in the left ovary. This shows that the right ovaries have . ovulated eggs more often than the left ovaries. According to many reports concerning this, the ovulation ratio of right and left ovaries is from 6：4 to 7：3; but the author's study does not show any difference between them in their ovulation ability. It is not clear if it is due to the special type of climate of Okinawa or to the way farmers took care of them. In effort to see the reason, the author will bring out the results of a few studies in the following pages. 2. The average weight of the right ovaries of the 145 cattle was 6.7 grams and that of the left ovaries was 6.5 grams. This shows very little difference in their weight. And further, the author has studied of implantation ratio of fetus number of corpus albicans, the result was that 67 corpuses (49.3%) were in the right ovaries and 69 corpuses (50.7%) were in the left ovaries; which shows very little difference. This should mean that right and left ovaries perform their function with almost the same ability. 3. Out of the 164 female cattle, 13 (7.9%) were infected with ovarial cyst, which seems to be very large proportion. This seems to be due to the facts that farmers kept them in dark houses to control their exercise and fed them rich feed. 4. Out of the 164 female cattle, 22 (13.4%) were infected with Lutein cyst; this means that cattle are more subject to the attack of this disease than are to ovarial cyst. Very little is known how this disease occurs. Graafian follicle occurs more often' in the ovaries which are infected with Lutein cyst than in a mormal ovary (45.4%), and these ovarial follicles have very thick will and will not rupture at all. Some of them look like a normal ovarial follicle. It needs to be studied further, to find out if such ovaries ovulate or not.