Composition of free amino acids in the uterine fluid and cervical mucus collected from eighteen cows was examined.
Uterine horn was washed with a Tris-buffered solution which is free from sodium and potassium. Samples obtained by flushing were processed as follows; they were deproteinized with T. C. A. or picric acid, desalted with ion exchanger, and concentrated by evaporation. Ion exchange chromato-graphy for the concentrated samples was attempted by Hitachi amino acid analyzer. The original concentration of free amino acids in the uterine fluid was calculated as described in the previous paper.
A total of eighteen free amino acids was identified in the uterine fluid and cervical mucus. Histidine, methionine, tyrosine and phenylalanine were detectable in some samples while the other amino acids were detected consistently. In general, amino acid concentration was higher in the uterine fluid than in the blood plasma. Glutamic acid, glycine and alanine were predominant in the uterine fluid at luteal phase. Content of valine and leucine was significantly lower in the uterine fluid at estrus than in the plasma while the content of glutamic acid and glycine was significantly higher in the uterine fluid than in the plasma. The results obtained here were discussed in relation to the possible role of the uterine fluid on the embryonic development.

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The pH and the electric conductivity of the bovine cervical mucus during estrous cycle were measured in vivo by a pocket-type pH meter and a handy type electric conductivity meter, respectively.
The pH values fluctuated during the estrous cycle. Mean values from day -10 to day -1 and day 2 to day 11 ranged between 6.83 and 7.40. On day 0 and day 1, the pH fell to 6.49 and 6.52, respectively. The minimal pH was observed on day 0 (the day of estrus).
The electric conductivity values also fluctuated during the estrous cycle. On day -3, the electric conductivity values began to rise. The maximal value (1.05) appeared on day 0 (the day of estrus), followed by rapid decrease to basal levels. Levels from day -10 to day -4 and from day 3 to day 11 ranged between 0.24 and 0.58.
The changes of the ratio of the electric conductivity to the pH during estrous cycle were also investigated.

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1. Twenty dairy cows with quiescent ovaries were given synthetic LH-RH analog for inducing ovulation at 1253 days (av. 26.1 days) postpartum. Intramuscular injections with 200 μg and 100 μg LH-RH at about 90 minutes interval were performed in these cows except 2 animals in which 2000 μg of LH-RH were administered by single intramuscular injection. Ovulation was induced 723 days (14.9±4.8 (SD) days) after the treatment in 15 (75.0%) of 20 cows. The ovulation was preceded by estrus in these cows except 1 animal of silent ovulation. Eight (66.7%) of 12 cows which were served by 12 inseminations during the induced estrus became pregnant (Table 1). Mean days from the last calving to the 1st ovulation for 10 cows treated with LH-RH (treatment period: 40.4±11.5 (SD) days) were significantly shorter (P<0.05) than those from former calving to the 1st estrus for the same cows (control period: 104.2±78.1 (SD) days) (Table 2). From these results it seems that LH-RH is effective to induce estrus and ovulation in postpartum dairy cows.
2. Eleven dairy cows, exhibiting estrus for 23 days, diagnosed as delayed ovulation or un-ovulation were treated with a single intramuscular injection of 100300 μg LH-RH. The treatment was followed by artificial insemination in 10 cows. Ovulation was induced within 12 days after the injection in all of the treated animals. Five cows (50.0%) conceived after the 1st insemination and 2 cows became pregnant by the 2nd insemination performed during the next untreated estrous period (Table 3). Ovarian responses to LH-RH in 2 cases of unovulation are shown in Fig. 1. The results indicate that LH-RH is effective to treat ovulation failure in dairy cows.

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Ovulation inducing experiments in the cow by administration of a synthetic LH-RH analog were performed. The ovarian reactions to LH-RH were observed and photographed by endoscopy with the aid of a fiberscope.
Three cyclic cows and 2 anestrous cows with quiescent ovaries were given a single intramuscular injection of 1, 0004, 000 IU of PMS for causing multiple follicular developments. The preliminary treatments were followed by intramuscular injections with 600 μg and 300 μg or 300 μg and 200 μg at 90 minutes interval within 14 days when some follicular developments were noticed by rectal palpation (Table 1). The endoscopy revealed that 38 ovulations were induced 12 days after the LH-RH analog injection as shown in Fig. 15 and Plate: Fig. 613. From these results, the ovulation inducing effects of the LH-RH analog on the cow observed in the previous report were confirmed experimentally.

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The egg recovery from the vagina was conducted 1 to 48 hours after administration of 2 or 5 mg/kg of body weight of prostaglandin F_2α(PGF_2α) in rabbits. The majority of eggs were recovered within 24 hours after treatment, especially more than 30% of the eggs were recovered by 2 hours after treatment, when a single administration of PGF_2α was made 20 to 28 hours after mating. A high recovery rate (82.7±5.3%) was obtained by a subcutaneous injection of 5 mg/kg of PGF_2α 22 hours after mating. The earliest eggs were recovered from the vagina at the first vaginal washing 1 hour after treatment.
Multiple administrations of 2 or 5 mg/kg of PGF_2α 72 to 114 hours after mating were applied to recover the blastocysts. However, only a scant number of eggs were recovered following the PGF_2α administrations. Only 28.1±16.4% of the eggs were recovered from the vagina following the injections of 5 mg/kg of PGF_2α at 96, 99 and 102 hours after mating. High implantation rates were demonstrated in spite of the multiple injections of PGF_2α except in one group in which 5 mg/kg of PGF_2α were applied at 108, 111 and 114 hours after mating. This fact indicates that the treatments with PGF_2α on and after 3 days after mating have a lesser effect on the intrauterine egg transport than the early treatments 20 to 28 hours after mating.

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Follicular development, maturation and ovulation of ooeytes were studied in adult female rats treated with human chorionic gonadotrophin (HCG). A total 360 rats of Wistar-Imamichi strain were kept under artificial lighting conditions (14L/10D) and treated with 20i. u. of HCG 12 to 78 hours before anritime of ovulation (-12 to -78h). The time of ovulation was estimated to be 8 h after the beginning of darkness on the day of estrus. All the rats were killed 12 to 30 h after HCG tretyent, except those treated at -12 h after the treatment. At autopsy, the number of ovasked was counted, and the ovaries were fixed its Bouin's solution and stained with Heidenhain iron hematoxylin. Follicles over 250 μ in average diameter (length plus width/2) were classified into groups at intervals of 50 μ in average diameter. At the same time, oocytes were examined for the stage of maturation division. The results obtained are as follows.
1. When rats were treatedexith 20 i. u. of HCG at -66 to -78 h, no induced ovulation was observed. When are treatment was-dam at -24 h, ova were obtained from 50 to 60% of the number of normal ovulation. After treatment at -24 to -36 h or -12 h, the normal number of ova was found 18 to 24 h or 12 h, respectively, after the treatment.
2. In untreated rats, the average number of follicles over 250 μ in average diameter was 74.5 to 108.1 (normal: 65.8 to 82.1; atretic: 8.7 to 27.5). The number of follicles over 500 μ in average diameter per head was about 5 at -54 to -78 h and increased to 11 to 14 at -36 or later.
3. As compared with untreated rats, HOG-treated rats had 83.4 to 141.3 (normal: 67.9 to 117.5; atretic: 18.0 to 35.1) follicles. The number of follicles over 500 p in average diameter per head was 12.9 to 19.6 after the treatment, except in those females 12 h after the treatment at -66 to -78 h (6.5 to 7.1).
4. Maturation division of ooeytes took place in follicles over 500 μ in average diameter in un-treated rats in the following manner: About half of the oocytes in the transitional stage and metaphase I at•h; almost all the oocytes in metaphase I at -6h; most of the ooeytes in late telophase I and metapase II at -3h; ovulation at -0h (an estimated time of ovulation).
5. In rats treated with 20 i. u. of HCG atf -54 h or later, the various number and stages of ooeytes were observed in follicles over 500 μ in average diameter. The results explain the process of induced ovulation, as shown in Table 1.
6. From these results, it is suggested that HCG may stimulate maturation division of the oocytes in the large follicle. HOG had a little effect on follicular development, while it accelerated follicular atresia.

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Experiments were performed to clarify the effects of anaerobic conditions with inert gases on viability and motility of bull spermatozoa. The influence of inert gases was also compared with that of nitrogen gas.
1. Either treatment with argon, helium, nitrogen or carbon dioxide gas was slightly effective on viability of bull spermatozoa when semen was preserved at 4°C and 15°C. But no significant differences were observed among treatments with various gases.
2. Motility of bull spermatozoa either in undiluted semen, diluted semen or washed sperm suspension rather rapidly decreased under various gases such as argon, helium, nitrogen, carbon dioxide and nitrogen with oxygen absorbent than under condition of air atmosphere. Decrease in motility of spermatozoa was greater under argon, helium and nitrogen gas than air, and motility of sper-matozoa decreased more rapidly under nitrogen gas with oxygen absorbent than nitrogen gas. However, differences in motility observed among treatments with various gases were not significant statistically.
3. The results obtained from these experiments suggested that nitrogen gas was not effective chemically and biologically to bull spermatozoa under the conditions adopted at the present experiment, and that the effect of inert gases and nitrogen gas on viability and motility of spermatozoa may be derived from the reduction of oxygen tension in sperm suspension, but not directly from the gas itself.

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The sperm-rich fraction of semen was collected from two Landrace boars by the manual method. After removal of seminal plasma by centrifugation at room temperature spermatozoa were resuspended in ETCG-catalase diluent (Table 1) to give a concentration of 1-2 × 10⁸ cells per milliliter, then cooled and stored in a cold room (4°C) for 1014 days. The sperm suspension (50100 ml) was inseminated in the normal way on the 2nd day of estrus. Of the two gilts inseminated, one farrowed 11 normal piglets following single insemination with sperm suspension stored for 12 days and the other gilt returned to estrus 19 days after insemination. Of the three sows, two returned to estrus 4966 days and one sow 22 days after insemination.

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