This investigation was carried out to determine the factors affecting the low rates of implantation and parturition in superovulated adult rats.
The first experiment was made to examine the number of ova shed after treatment with various doses of PMSG and hCG. The rats were pretreated with 10, 20, or 40 IU of PMSG and hCG at 15:00 hours (h) on the day of early or late diestrus, or at 11:00h on the day of late diestrus. Then the same or half dose of hCG was injected 42, 54, or 66 h later corresponding to normal proestrus LH surge, and killed 22h after hCG injection. The number of ova shed increased with increasing dose of PMSG. There were no significant difference in the number of ova shed among time intervals of PMSG and hCG, and between the same and half dose of hCG.
In the second experiment, the rats were treated with 10, 20, or 40 IU of PMSG followed by same dose of hCG 54 h later. The females were placed with male and mating was confirmed the following morning by presence of spermatozoa in vaginal smear. They were killed 24, 48, 72, 96, or 120h after hCG injection, and the ovaries and uteri were washed by physiological saline to examine the fertility, transport and early development of ova and/or embryos. At 72h after hCG injection, the percentage of embryos recovered from uterus were increased with increasing doses of PMSG and hCG. The number of ova and/or embryos recovered were reduced with the lapse of time after hCG injection and increasing doses of PMSG and hCG, and the number of rats with ova and/or embryos were reduced in rats treated with 40 IU of PMSG and hCG 96 or 120h after hCG injection. When rats were examined 72 to 96h after hCG injection, the cleavage rate in gonadotrophin-treated rats was delayed as compared to untreated rats, and with increasing dose of hormone. At 24 to 72h after hCG injection, the fertility was lower in rats treated with 40IU of PMSG and hCG as compared to untreated, 10, or 20IU treated rats.
These results suggested that the low rates of implantation and parturition in superovulated adult rats induced by high doses of PMSG and hCG may be due to a loss of ova and/or embryos from uterus by accelerated transport, although the low fertility and delay of development of ova and/or embryos were observed.

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An investigation was carried out to determine whether a pregnancy diagnosis could be made in swine by the cytological examination of vaginal smears on the basis of the principles of diagnosing pregnancy by the vaginal biopsy method.
Vaginal smear samples were collected from 326 swine of 5 breeds beginning with 17 days after mating. They were taken with a sampling instrument from the dorsal wall of the vagina and smeared on slides with phosphate buffer saline solution. They were fixed, stained with blue polychrome, and analyzed microscopically at 200- to 400-fold magnification.
The accuracy of diagnosis was 63.3% between days 17 and 24, 85.2% between days 25 and 34, 81.5% between days 35 and 44, 72.0% between days 45 and 69 after service. For the whole pregnancy, it was poor, or 78.1%.
In conclusion, this method was technically simpler than the biopsy method and useful for a supplementary diagnosis of pregnancy in gilts to which no rectal examination was applicable. Improve-ment was necessary in sampling technique and instrument to obtained high accuracy of diagnosis.

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At first, linear multiple regression was fitted for the estimation of open days on Holstein cows using 52 parturition records. Independent variables were year (X₁) and month of parturition (X₂), parity (X₃), body weight at conception (X₄), milk production for the first 30 days (X₅), body weight loss from pre-partum to 30th day post-partum (X₆) and a derived variable (X₇=X₅•X₆/1000). The multiple correlation coefficient by the equation was low.
Then, curvilinear multiple regression was fitted taking quadratic and cubic terms of independent variables (X₁, X₂, X₅, X₆, and these derivatives) into account. This time, the regression equation explained over one third of the variation in open days (adjusted R²=0.362). In that equation, the quadratic and cubic effects of year and month of parturition were significant. Milk production (X₅), body weight loss (X₆) and derived variables from these two had a rather complicated effect on open days. The estimated open days by the regression for all possible combinations in value of X₅ and X₆ showed bowl-shaped surface. When X₅ and X₆ took values 550 and 115kg, minimum estimate of open days was obtained as the bottom of the bowl.

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The development of ovarian follicles in adult rats and effect of sodium pentobarbital on the ability of antral follicles to ovulate response to hCG were examined.
Experiment 1: Ovarian follicular development: In rats treated with 40 IU PMSG at 13:00h on the day of metestrus, the number of follicles( ?? 550μm in diameter) showed a peak (about 110 follicles per both ovaries) on the day of expected estrus.
Experiment 2: Effect of hCG in PMSG treated rats: When 40 IU hCG was injected on the day of estrus in PMSG treated rats, the number of ova shed did not increase.
Experiment 3: Effect of sodium pentobarbital: Sodium pentobarbital was injected ip 51h after PMSG treatment. Then 40 IU hCG was injected 27h after the injection of sodium pentobarbital. The number of ova shed increased about 100 ova per both ovaries at 20h after hCG injection.
These results suggest that sodium pentobarbital is effective to maintain the ability of antral follicles to ovulate at least until the day of expected estrus in PMSG treated adult rats.

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The effects of male mouse urine or it's fractions on the advancement of the onset of puberty were examined using post-weanling female mice of ICR strain. The odors of urine of adult male mice could advance the day of the first vaginal estrus of female mice as well as the application of male urine on the philtrum of young females. Both the methylene chloride soluble fraction and the insoluble fraction advanced the day of the first vaginal estrus. Male urine was fractionated by ion exchange resin and each fraction was extracted by methylene chloride. The cation fraction of male mouse urine advanced the day of the first vaginal estrus, but neutral and anion fractions have no effect, suggesting that the active fraction of male mouse urine contained amines. The components of the active fraction were examined by gas chlomatography, comparing with those of the same fraction of the urine of castrated male, of female and of preputialectomized male. Two specific peaks were observed in the fraction from the urine of intact males and of preputialectomized males. By com-parison of the retention time with amine standards, these two peaks were assumed to be isobutylamine and isoamylamine respectively.

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Postnatal development and seasonal changes of accessory sex glands of the male Japanese deer, Cervus nippon (Nara Park) was studied morphologically. Specimens used in this study were; 1) One 2-month old fawn, 2) One immature yearling, and 3) Fourteen adult stags older than 2 years.
Results obtained are:
1. Towards maturity the weight of the seminal vesicle (vesicular gland) increased with the de-velopment of the glandular parenchyma. During the non-breeding season, the gland exhibited narrow crypts, low epithelium and amorphous PAS-positive materials. Many vacuoles were observed in the epithelia. During the rutting season, dilated crypts, tall epithelium and PAS-positive droplets were seen in the gland.
2. The major seasonal changes were seen in the increase of width of the cripts, enhancement of secretion, and denser distribution of the capillaries. Whereas there was no appreciable postnatal in-crease nor a seasonal change with respect to the height of the epithelium. During the non-breeding season many lymphocytes were scattered in the mucosa of the adult deer. These lymphocytes may have a role in eliminating dead spermatozoa and debris.
3. The postnatal development of the prostate was not obvious. The body of prostate is a small parenchymatous gland located on the dorsal surface of the neck of the urinary bladder.
The disseminate prostate was composed of two glands, cranial and caudal. The seasonal change was most evident in the cranial gland of the disseminate prostate among the three of the prostate. The end pieces of the cranial glands obtained from stags in a rutting season, seemed analogous to the bulbourethral gland of other mammals.

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The reproductive organs of 14 female Yezo brown bears (Ursus arctos yesoensis), mauled to death in a bear park, were studied morphologically with respect to thier configuration and seasonal variation.
The ovaries were completely covered with ovarian bursa, and their size and shape were similar to those of a broad bean. The medium sized follicles (size: 0.5-0.7 cm) were observed in bears ob-tained during June and early July, and the corpora lutea (size: 0.7-1.5 cm) were observed in those obtained in and after July. Invaginations of the surface epithelium known as a cortical cords were observed in all ovaries.
The oviducts, uniformly looped and encircling the walls of the ovarian bursae, entered the ovarian bursae through the small orifices. The length and thickness of oviducts were 5.0-7.0 cm and 0.1-O. 3 cm. In each individual case most of the fimbria was enclosed in a bursa, but a part of it pro-truded outwards.
Uteri were bipartite, and the length of the uterine horns ranged between 6.0 cm and 18.0 cm. The proliferation of uterine tissue and the appearence of PAS positive granules in the uterine glands were observed in bears obtained during June and July. The length of uterine bodies and cervices varied from 3.0 cm to 6.0 cm and 3.0 cm to 8.0 cm, respectively. Three annular folds were observed in an uterine cervix.
The length of vaginae and vulvae varied from 9.0 cm to 13.5 cm and 5.0 cm to 6.0 cm, respec-tively.
From these morphological observations, it is suggested that the breeding season of the female Yezo brown bear is a period from June to early July.

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A trial for synchronization of estrus cycle with single or double injection methods of PGF_2α- analogue was conducted in fifteen Holstein heifers. The subsequent variations in levels of plasma progesterone were investigated to assess the correlation between progesterone levels and synchroniza-tion of estrus cycle.
The results obtained were as described below.
1) The profiles of plasma progesterone level in fifteen Holstein heifers following PGF_2α-analogue injection could be classified into five types (type I-V). The type V in which three heifers were in-cluded was considered as abnormal, the other four normal types reflected the ovarian condition of the heifers when PGF_2α-analogue was first injected: two heifers at estrus (type I), two heifers at about 3-4 days after ovulation (type II), four heifers at functional stages of corpus luteum (type III), four heifers either at late stages of estrus cycle or at early stages of luteal phase (type IV).
2) The heifers, which came into estrus after PGF_2α-analogue injection, could be classified into three group: (1) the estrus cycle was induced with PGF_2α-analogue injection, (2) the time of injection was happened to coincident with estrus, (3) injection was done at the late stages of estrus cycle.
3) In all of heifers excluding three heifers which were supposed to be abnormal, the concentra-tions of plasma progesterone at the second PGF_2α-analogue injection increased up to the levels which was almost the same as these of the first PGF_2α-analogue injections.
4) The rate of successive synchronization of estrus cycle after the second PGF_2α-analogue injec-tions in fifteen heifers was 73.3% (11/15). Three heifers which were judged as abnormal based on the levels of plasma progesterone and one heifer failed to synchronize even after the second injection. The conception rate was 72.7% in remaining eleven synchronized heifers.

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Effects of an administration of 750IU pregnant mare serum gonadotropin (PMSG: group I, 13 ewes) and 15 mg prostaglandin F_2α (PGF_2α: group II, 15 ewes) after a progestin treatment with methyl-acetoxyprogesterone (MAP) through vaginal sponge for 9 days on synchronization of estrus and ovulation, and the subsequent fertility were compared with that of cycling ewes during the breeding season. The changes in plasma steroids (estradiol-17β: E₂ and progesterone: P) concentrations were also estimated. All treated ewes showed estrus within 5 days after the treatment and all of the 4 laparotomized ewes in each group were ovulated when examined 8 days after the treatment. The number of ovulations in group I appeared to be greater than that in group II (3.25±0.63 and 1.75±0.25 per ewe), although the difference was not significant. Conception rates were expressed non-return (16-21 days), pregnancy (50-70 days) diagnosed by a Doppler method, lambing rate and number of lambs born per ewe. There was no significant difference in fertility between the two groups probably due to a small number of ewes used. The changing pattern of plasma concentrations of E₂ and P was similar between the two groups. The MAP sponge treat-ment combined with PMSG appears to be more effective than MAP sponge combined with PGF_2α treatment for synchronization of estrus and ovulation in cycling ewes.

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The recurrence of diestrus following removal of pups on day 10 of lactation was studied in lactating rats. Pituitary responsiveness to LHRH, and plasma LH, prolactin and progesterone levels were determined after removal of pups. Diestrous periods following romoval of pups were 8.61±0.36 and 3.33±0.21 days in the females which had been nursing 12 and 2 pups, respectively. Seventy-eight % of animals that had nursed 12 pups exhibited typical vaginal smear of pro-estrus on day 2 or 3 of post-weaning, but none of these animals ovulated on the following day. The number of follicles over 550μm in diameter rapidly in-creased from day 1 (1.7±1.2) to day 2 of post-weaning (7.6±1.9) in females that had nursed 12 pups. On day 2 or 3 of post-weaning obvious LH surge occurred in females that had nursed 2 pups, but not in animals that had nursed 12 pups. The rise of plasma LH levels following LHRH injection was less and the ovulatory responsiveness to LHRH injection was lower in females nursing 12 pups than those in rats nursing 2 pups on day 2 or 3 of post-weaning. High plasma progesterone levels were maintained until day 6 of post-weaning in animals that had nursed 12 pups, while concentration decreased to the basal level within 18 h after removal of pups in females nursing 2 pups. In accordance with the high level of plasma progesterone, the fluctuation of prolactin levels was observed following removal of pups in animals that had nursed 12 pups. It was suggested that the prolongation of the diestrous period following removal of pups in the rats nursing a large litter was attributable to the reduced responsiveness of pituitary to LHRH and to the maintenance of functional corpora lutea formed at post-partum ovulation.

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To examine the suppressive effect of suckling stimulus and ovarian progesterone and their interaction on the resumption of ovarian cyclicity during lactation, peripheral plasma progesterone levels and the length of diestrous periods were studied by using lactating rats of which post-partum ovulation was blocked by anti-LH serum. Plasma progesterone levels were less than 5.6ng/ml in the rats treated with antiserum despite of their size of litter that had been nursed. The diestrous period in antiserum treated rats nursing 12 pups (15.4±1.4 days) was shorter than that in the intact rats nursing the same number of pups (26.2±1.1 days). In the rats nursing 2 pups, antiserum treatment also shortened the di-estrous period (6.5±0.1 days) and this value was the same as those in the intact or anti-serum treated rat of which pups were removed immediately after parturition.
Plasma progesterone levels before and after removal of pups were studied in antiserum treated rats nursing 12 pups up to 10 days after parturition. They were received progester-one injection from 3 to 10 or to 16 days after parturition and were deprived of their litter 10 days after parturition. When progesterone was injected from 3 to 16 days after parturi-tion, the diestrous period following removal of pups was prolonged to 8.7 days. Cessation of progesterone treatment 10 days after parturition markedly shortened the diestrous period following removal of pups (3.4 days) and reduced the plasma progesterone to the basal level on the day following removal of pups.

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