Clinical responses of cows with ovarian follicular cysts to synthetic LH-RH analog were com-pared with those to HCG.
Twenty three dairy cows with ovarian cysts were given the LH-RH analog. Seventeen cows of them were injected intramuscularly with 300 μg and 200μg LH-RH analog at 90 minutes interval, and the remaining 6 cows were given single intramuscular injection with 1, 000μg LH-RH analog (Table 1). In 16 (69.6%) of 23 cows treated, ovarian cysts recovered, estrus and ovulation occurred 31.0±6.4 [SE] days after the treatment. Although subsequent fertility could not be examined in 3 cows, 10 cows (50.0%; 10/20) became pregnant after 1-2 inseminations (Table 4).
In another group, fourteen dairy cows with ovarian cysts were treated by a single intramuscular injection with 5, 000 iu HCG (Table 2).
In 9 cows (64.3%) the treatment resulted in clinical recovery, estrus and ovulation occurred 31.3±4.2 [SE] days after the treatment, and 7 cows (50.0%) conceived after 1-4 inseminations (Table 2).
The recovery rate in these 2 groups seemed to be almost same, but the LH-RH analog treatment group included 16 cows which had not responded to HCG treatment in the past. In the present experiment, however, 10 (62.5%) of those 16 cows recovered by the LH-RH analog treatment. From these results, it is supposed that the LH-RH analog could be effective to treat ovarian folli-cular cysts of the cow even in the case which has not reacted to HCG treatment, probably because of the anti-HCG formation in such a cow.

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Serum LH levels were determined by radioimmunoassay on samples collected from cows with ovarian follicular cysts and from normal experimental cows.
Blood samples were collected from 40 dairy cows when their ovaries were diagnosed as cystic. Eighteen cows of them were injected intramuscularly with 300 μg and 200 μg LH-RH analog at 90 minutes interval.
In 17 cows of them blood samplings were performed again at the 2nd injection. In one remaining cow the samplings were frequently done till 720 minutes after the 1st injection (Table 1).
In a normal exprimental cow serum LH levels were measured through 3 estrous cycles, and in 2 experimental cows LH responses after the LH-RH analog injection were observed (Tables 2 & 3).
Serum LH levels in cows with ovarian follicular cysts [6.3±1.1 (SE) ng/ml] were higher than those in estrous cycles except estrous periods in normal experimental cows [1.9 ± 0.1 (SE) ng/ml] (Table 4).
In cows with ovarian follicular cysts, serum LH levels increased significantly (p <0.01) 90 mi-nutes after the LH-RH analog injection (Fig. 1). The LH responses after the LH-RH analog injection in cows with cystic ovaries seemed to be similar to the pattern of preovulatory LH surge in normal experimental cows (Figs. 25).
From these results, the mechanism of recovery from ovarian follicular cysts by the LH-RH analog administration is supposed as follows: serum LH levels were increased over a certain thre-shold and maintained for a while, and then luteinization of cystic follicles was induced.

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A seasonal variation was investigated in the characteristics of semen collected from six boars and the fertility of sows artificially inseminated with this semen.
1) In the semen collected in summer, motility and the concentration of spermatozoa decreased by 7.5•55. 0% ( ?? ) and 0.39 0.63 x 103/ml, respectively. Spermatozoa with abnormal head, defective acrosomic system, and proximal cytoplasmic droplet increased by 12. 0 30. 8%, 10.732.8%, and 49.581.0%, respectively. These seasonal changes in semen characteristics occurred in four of the six boars.
2) The conception rate (53.8% or below) showed a tendency to decrease in summer when the semen collected from the six boars had been used. Two of the four boars in which semen characte-ristics were very poor in summer continued to exhibit low fertility all the year round.
3) Significant interrelationships were observed among the motility of spermatozoa, the app-erarance of spermatozoa with the abnormal head, that of spermatozoa with proximal cytoplasmic droplets, and the conception rate. When semen contained spermatozoa of less than 80% (-11f) of progressing motility, spermatozoa with abnormal head at more than 10%, or spermatozoa with proximal cytoplasmic droplets at more than 30%, it was assumed to make the conception rate considerably low.

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Luteinizing hormone (LH) response to the injection of an analog of luteinizing hormone relea-sing hormone (LH-RH), [Des-Gly-NH¹⁰₂, Pro-ethylamide⁹]-LH-RH (EA-LH-RH), was studied in cows with ovarian follicular cyst. Seventeen cows with cystic ovaries were administered intravenously with various doses of EA-LH-RH and the changes in plasma LH level before and after the adminis-tration were examined. Plasma LH level was determined by radioimmunoassay. In the cow given with 1, 10, 100 and 500 μg of EA-LH-RH at 2 hrs intervals, plasma samples were serially collected at 15 min intervals for 10 hrs by an indwelling polyethylene catheter placed in the jugular vein. The LH level was elevated a little by 10 μg of EA-LH-RH, but not by 1 μg. The distinct elevation in the level followed after the administration of 100 and also 500 μg. Another cow was given 100 and 500 μg of EA-LH-RH. Distinct elevation in plasma LH level was found after the administration of 100 μg, and it was further increased by 500 μg; maximal level was obtained at 90 min after injection of 500 μg. All of 9 cows treated with 100 μg of EA-LH-RH showed the elevation in plasma LH level. Administration of 2, 000 μg of EA-LH-RH resulted in remarkable elevation of plasma LH in all 7 cows. Peak level was observed at 90 min and 105 min after an administration in 2 cows in which plasma LH level was determined serially at 15 or 30 min intervals after administration of 2, 000 pg of EA-LH-RH. Two cows, one administered with 100 and 500 pg of EA-LH-RH and another receiving singly 2, 000 pg of EA-LH-RH, both showed nymphomanic tendencies. The response of plasma LH level in these cows to EA-LH-RH was much higher.

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The maternal behavior was studied using IVCS strain mice aged from 24 to 550 days. Three hundred and thirty-four females and one hundred males were used for this experiment. The animals had never been in contact with any pups except for their own litter-mates prior to the experiment. They were housed individually in standard cages and a standard maternal behavior test was started when a 1-or 2-day-old pup was placed about 10 cm distant from the nest. The maternal behavior of each test animal was observed for 5 minutes after contact with the pup. Retrieving and licking the pup, nest-building and adoption of the lactation-position were recorded.
The results obtained were as follows; 1) Mice of both sexes aged 24 to 25 days already showed normal maternal behavior. The ratio of abnormal maternal behavior in mice of both sexes aged 550 days were higher than that in younger ages. 2) The ratio of complex maternal behavior in mice of both sexes aged 70 to 84 days and 280 days were higher than that in other ages. 3) Licking was always shown first in the animals aged 70 to 84 days except one female.

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The activity of prostaglandin dehydrogenase in pig blastocysts at 13 days after mating was histochemically investigated by the NISSEN and ANDERSEN method with a slight modification, using prostaglandin (PG) A₁, PGA₂, PGB₁., PGB₂, PGE₁, PGE₂, PGF_1a and PGF_2a as the substrates, and using NAD and NADP as the cofactors. The composition of the medium was 0.3 mM substrate, 0.75 mM cofactor, 0.075mM nitro-BT and 0.1 M phosphate buffer solution at pH 8.0; the whole amount of the medium was 1 ml.
The activity of NAD-dependent prostaglandin dehydrogenase was found in the trophoblast cells of the blastocyst when PGA₁, PGB₁, PGB₂, PGE₁ or PGE₂ was used as the substrate, but it was not found with PGA₂, PGF_1a, or PGF_2a. The activity of NADP-dependent enzyme was not demon-strated when either of all kinds of any PGs was used as the substrate.

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[in Japanese]

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Genital tract mucosa obtained from eleven cows at various reproductive phase were examined by scanning electron microscopy.
Cows were consisted of Holstein and Japanese black. The specimens dissected from uterus, cervix and vagina were fixed with glutaraldehyde rinsed with phosphate buffer, dehydrated with graded series of alcohol, then transfered from alcohol into isoamylacetate. Air drying and critical point drying from isoamylacetate were applied. Thereafter, dried tissues were coated with carbon and gold, and were subjected to examination with JEOL JSM-35.
During follicular phase, ciliated cells were less abundant in the endometrial surface than in the oviductal epithelium, and the surface of non-ciliated cell was coated with thin mucus. Hexagonal cells and secretion-like structures composed with disc-like units were observed in the endometrium during luteal phase. The cells coated with spares microvilli were located in the endometrial surface at 60 days of pregnancy. In estrus, cervical epithelium was coated with thick mucus, and string-like structures were identified in the mucus. At luteal phase, the cervical epithelium contained ciliated cells and non-ciliated cells with smooth surface or rough surface. In vaginal mucosa, the cells coated with thin mucus and the spongy cells possibly corresponding to degeneration were observed at follicular phase. Squamous stratified epithelium covered the surface of vaginal mucosa at luteal phase.
The surface topology of these genital epithelia was illustrated by photographs and discussed.

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In the grazing heifers with quiescent ovaries, the responses of their ovaries to administration of gonadotropins (Experiment I) and of an LH-RH analogue (Experiment II) were investigated with the check of fertility following the treatments.
1. In Experiment I, 13 animals averaging 18.9 months of age and 299 kg in weight received an intramuscular (i.m.) injection of PMS, 1, 000 IU and HCG, 1, 000 MU. Ovulation was induced in all animals by 35 days after the treatment. The size of corpora lutea formed following the induced ovulation seemed likely normal in 5 animals, whereas those of the remaining 8 animals were a little smaller. Corpora lutea in 12 animals regressed in rather sooner or within 812 days after the treatment, and in one animal, it regressed in the period of the normal estrous cycle length. After regression of these corpora lutea, ovaries of 7 animals (53.9%) showed normal cyclic activity, but in remaining 6 animals, their ovaries returned quiescent state again. Two out of 4 animals received artificial insemination (A. I.) on 2736 days after the treatment, became pregant.
2. In Experiment II, 26 animals averaging 18.5 months of age and 301 kg in weight were alloted to the two groups; i.e. group 1 (13 animals) received an i. m. injection of 200 μg of [Des-Gly-NH¹⁰₂, Pro-ethylamide9]-LH-RH (LH-RH-A), and group 2 (13 animals) received an i.m. injection of 400 μg of LH-RH-A. Ovulation was induced by 24 days after the treatment in ten and seven animals for groups 1 and 2, respectively. Corpora lutea formed following the induced ovulation were rather small in size or hardly noticeable by rectal palpation, and they regressed in rather sooner or within 612 days after the treatment. The ovaries of 4 animals (30.8%) each in both groups showed normal cyclic activity after regression of their corpora lutea, but those in the remaining animals (total 18 in both groups) returned quiescent state again. The ovaries of the 9 animals which had not ovulated by the 4th day after the treatment, did not show and cyclic activity for the following 36 days (8 animals), or in one animal, it turned to be cystic in this period. Three out of 5 animals received A. I. on 934 days after the treatment, became pregnant.
3. The hematocrit value of blood collected at the time of treatment, tended to be lower in the animals with non-responded ovaries (including one which became cystic) than in the animals with ovaries which responded and were activated by the treatment. The result may indicate that the response of quiescent ovaries of the heifers to the hormones administered in this study seemed to depend upon the difference of the physiological condition of each animal, at the treatment given.

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Experiments were carried out to examine "formation of nucleus" and "cleavage" in pig follicular oocytes cultured in vitro. When oocytes with corona cells were cultured in modified Krebs Ringer bicarbonate solution, "formation of nucleus" was observed at 5760 hours, and at 27 hours in the oocytes without corona cells. The predominantly found numbers of "nucleus" in the oocytes were one and two. Extrusion of the second polar body was not observed, but the oocytes having two "polar bodies" were observed. "Cleavage" occurred at 72 hours of culture in modified Krebs Ringer bicarbonate solution. Fragmenting ova which closely resemble segmenting ova were observed, the predominantly found type of "cleaved" ova was 2 "cell", and 3 and 4 "cell" ova were also observed. When oocytes were cultured in Eagle MEM, "formation of nucleus" was observed at 69 hours of culture.

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