[in Japanese]

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[in Japanese]

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Separate-strow method by which storage media and dilueted semen with diluent not to effect the fertility of spermatozoa during deep-freezing and after liquerfing were frozen separately in the same strow, was devised and their storage and fertility tests were carried out. The results obtained were as follow.
1. Freezing speed in this method was fast considerably and the figure of the decreasing curve of temperature in this method showed similar trend as compred with the pellet method.
2. Survival rating of spermatozoa prepaed by separate-strow method contaieieg 0.5ml of six times diluted semen and 0.5ml of storage media was superior to to that 0.25ml of three times diluted semen and 0.75ml of storage media.
3. Higher suvival rating of bull spermatozoa was obtained in this method in comparison to the strow method.
4. Motility and fertility of bull semen containing the strage media with T.T.F.D. were higher than that containing the storage media without T.T.F.D..
5. The pregnancy rates of 61.2 and 75.3 percents resulted in 1, 442 dairy and 178 beef cows inseminated with the sperm produced by this method were higher than that of 47.6 and 60.8 percents resulted in those types of cows inseminated by the same inseminations during last three years.
From this results and with other merits it seems likly that the deep-frozen bull semen produced by Separate-strow method has some practical advantages.

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[in Japanese]

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In order to study effect of hypothalamic lesions on sexual maturation and growth in rats, electric lesions (anodal direct current : 2 mA 15 sec.) were placed in the hypothalamic areas of female Wistar rats at 2 weeks old. All animals were weighed two times a week and checked daily for vaginal opening after weaning. When vaginal opening occured their body weights were recorded and vaginal smears were daily taken onwards. They were killed at the seventh week of age and body weight, body length and weights of uteri, ovaries, adrenals, thyroids and hypophysis were measured. I) In Experiment A, stainless tube was used as electorode. It measured 0.33 mm in diameter and was cleared for a distance of 1 mm from tip. In these series two charactaric phenomena were observed, as follows :
a) Advanced vaginal opening. (30.3 ± 2.6 days in 18 rats accompanied with retarded growth. cf. 40.1 ± 3.2 days in 34 unoperated litter mate rats.)
In this case, lesions were located with anterior area of the hypothalamus including the supurachias-matic nucleus, the paraventricular nucleus and the ventromedial nucleus.
b) Definite inhibition in the development of reproductive organs accompanied with obesity. (3 rats) In this case lesions were extended to the arcuate nucleus and the rostral part of the mamillary body. II) In Experiment B, in which platinum wire was used as electrode, the electrode having 0.30 mm in diamater was cleard only at the bottom of the wire. When small lesions were made in the anterior hypothalamic area using this electrode, earlier vaginal opening was observed. (30.4 ± 1.8 days in 8 rats without significant alteration in growth rate compared with 36.7 ± 3.9 days of unoperated control.)

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