[in Japanese]

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Fertility and hatchability were compared among eggs laid by pure bred hens of White (W), Leghorn New Hampshire (N), and Barred Plymouth Rock (B) and eggs produced by New Hampshire hens mated with White Leghorn cocks (WN), White Leghorn hens mated with New Hampshire cocks (NW), and Barred Plymouth Rock hens mated with White Leghorn cocks (WB). A total of 1, 597, 683 eggs were incubated at the Tsudanuma Hatchery from 1952 to 1961. The results obtained are as follows.
1. There were seasonal differences in fertiliy in pure bred fowls. The highest fertility occurred in the spring (W : 91. 31%, N: 89.57%, B: 86.32%), the second highest fertility in the winter (W: 85.09 %, N: 84.72%, B: 84.65%), and low fertility in the summer (W: 77.65%, N: 83.33, B: 82.85%) and in the autumn (W: 74.77%, N: 83.99%, B: 81.04%). When matings were carried out to produce crossbred fowls, the highest fertility occurred in the spring (WN: 89.68%, NW: 87.59%, WB: 89.21%), the 'second highet fertility in the summer (WN : 86. 33%, NW : 86. 27%, WB : 83. 12%), and low ferti-lity in the autumn (WN : 81. 41%, NW : 79. 97%, WB : 84. 53%) and in the winter (WN : 80. 48%, NW : 80. 50%, WB : 84. 52%).
2. The hatchability of (or the percentage of normal chicks hatched to) fertile eggs was 86.40 (79.93), 85.55 (78.99) and 82.76 (77.79) per cent in the W, N, and B, respectively. On the other hand it was 87.37 (84. 61), 86. 37 (82. 85), and 84. 87 (81.05) per cent in the WN, NW, and WB, respectively.
These results show that the hatchability of (or the percentage of normal chicks hatched to) fertile eggs was higher in crossbreeding than in purebreeding of each breed, and also higher in the WN than in the NW (P<0.01). The facts mentioned above indicate that embryonic mortality in the middle and later periods of incubation and the percentage of weak chicks hatched were lower in crossbreeding than in purebreeding.
3. The hatchability of, and percentage of normal chicks hatched to fertile eggs were high in the spring (89.32%, 86.09%) and winter (88.18%, 84.83%), and low in the autumn (82.33%, 78.52%) and summer (80.78%, 77.11%).
4. Males were found in 50.47% of 1, 130, 629 chicks observed.

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[in Japanese]

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We have been interested in the facts that there are many cases of reproductive disorders in the bulls probably caused by hormonal disturbances. Some of those bulls showed a marked increase of estrogen in urine and in blood. It is still unknown whether those reproductive disorderes in the bulls are caused by endogenous or exogenous estrogen, or by the unbalance between estrogen and androgen. Besides these facts, few reports have dealt with the effects of estrogen on the reproductive function of the bull. We made, therefore, an attempt to produce the experimental damage of reproductive function with estrogen to observe the effect of estrogen on the reproductive disorders.
The data presented here were obtained from 5 bulls. The first bull was injected subcutaneously with 2. 5 mg of diethyl-stilbestrol (DES) daily for 110 days. The second one was treated with 5 mg of DES daily for 35 days. The third one was treated with 5 mg of DES daily for 30 days, and 33 days after the last treatment, he was treated additionally with 10 mg of DES daily for 14 days. Remaining 2 bulls were used as controls. The results of the experiments are as follows.
1) There was no remarkable change in the testicular volume of experimental bulls, but swelling and edema of ostium prepuce were observed only in the third bull.
2) Libido was normal or increased in early stage of.the treatment, but decreased in the latest stage of the treatment, and 2 of the treated bulls showed low libido for long time after the treatment. The ability of ejaculation became poor from the middle stage of the treatment and it took a long time befor ejaculation. They showed poor erection and could not ejaculate before they devoted themselves to mount 5-10 times, and one of them leaked out his semen without manifesting a characteristic thrust.3) The decrease in the volume of semen was observed from the middle of the treatment and it lastedto the last stage of the treatment. 'pH of semen inclined slightly to alkaline at the last stage of thetreatment.
4) The sperm motility gradually became poor and the poorest motility or necrospermia was observed at the last stage of the treatment. The recovery of the sperm motility depended on the period of the treatment, and there was a case that poor motility continued for more than 3 months after the treatment.
5) Decrease of sperm count depended on the doses of DES administrated, but at the last stage of the treatment, it was very remarkable in all treated cases. The time for recovery was controled by the degree of damage in the testicular tissue, and 6 months were necessary for the recovery in case of severely damaged one, but only 3 weeks were enough to recover in case of slightly damaged one.
6) Abnormal sperms increased after the treatment of DES. The rate of abnormal sperms became the highest at the last stage of the treatment and the highest rate continued after the final treatment.In case of the treatment of 5 mg, or 10 mg, most of the abnormal sperms were oflooped tail. In case of the treatment of 2 mg, there were many cases of abnormal head sperms and tailless ones, but few looped tail ones.
7) The contents offructose in semen increased at the beginning of the treatment, but decreased repidly at the last stage of the treatment, and kept its lower value for more thanone month. The contents of 17-ketosteroids in blood showed a similar tendency to that of fructose in semen.
8) Normal semen added with the semen plasma ofa treated bull after going removed its plasma and flushing with glycocitrate, showed the decrease its motility and livabi.lity.

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[in Japanese]

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[in Japanese]

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