Data on sex ratio in swine were obtained from the Ibaragi Experiment Station of Animal Industry (Ib) and the Livestock Farm, University of Tokyo (Tb), and compared with those given in the authors' three preceding reports¹³⁾. They were collected from 3, 269 head (from 1962 to 1969) at Ib and 1, 509 head (from 1959 to 1971) at Tb and analyzed for sex ratio by the methods described in reportI¹⁾. (The classes which showed a shift of sex ratio to either sex were presented mainly in tables.) The results obtained from all the groups of breed as a whole are summarized as follows.
1) The total sex ratio (Table 1) was significantly high at Ib. No shift of sex ratio was found at Tb. There were significant differences between Tb and Ta, To, Tk or Ib of the nine farms studied.
2) One boar showed a high sex ratio of his offspring at Ib, but another showed a low sex ratio at Tb. Four sows at Ib and three at Tb exhibited high sex ratios. Three sows at Ib and two at Tb, however, showed low sex ratios (Table 2).
3) The sex ratios of litter series (Table 3) were high in two classes at Ib. Two groups of litter series presented high sex ratios, but there was (no significant difference between either of them and any other group. No such shift of sex ratio, however, was seen at Tb.
4) Only one class of litter size (Table 4) showed a high sex ratio at Tb. A shift to male was observed in the grouping of litter size at Ib.
5) A shift of sex ratio to male was seen in summer and winter for primary sex ratio, and in autumn for secondary at Ib. A significant seasonal difference was noticed in secondary sex ratio between autumn and winter at Ib (Table 5).
6) Artificial insenmination induced a shift to male at Ib, but there was no significant difference in sex ratio between it and natural mating at Ib or Tb (Table 6).
7) A high sex ratio was found in only one age class of boars at Ib, but there was no significant difference between age groups of boars at Ib. A shift to male was observed in two age classes of sows at Ib. A shift to male was found in one age group of sows at Ib, but no significant dif-ference was observed between any two age groups of sows (Table 7).
8) No shift of sex ratio was present in any age group of breed as a whole at Ib or Tb. A shift to the sex or the opposite sex of the older parent was seen in some groups of breed at both stations (Table 8).
9) A shift of annual sex ratio to female was observed in only one year at Tb (Table 9).

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An observation was made on the duration of estrus in 50 mongrel bitches, 24 years of age, weighing about 10 kg each. Twenty three of 31 bitches mated in estrus became pregnant but 8 of them were infertile. Ten bitches were mated with vasectomized dog. The remaining 9 bitches were not subjected to mating.
The duration of proestrus was regarded as an interval between the day of vulval bleeding and the day of onset of acceptance of the male, and the duration of estrus was regarded as that of acceptance of the male.
The copulation tests of bitches were carried out with 4 male dogs, two of them had been vasectomized, after vulval bleeding in the morning and evening everyday.
The copulation test was judged to positive when the bitch showed estrous behavior and allowed the mounting of the male or did not reject the introduction of a finger into vagina.
The day of onset or termination of estrus was determined according to the acceptance of the male either in the morning or evening tests.
Results obtained:(1) The duration of proestrus ranged from 3 to 27 days, 8.3± 2.9 days (mean ± S. D.);(2) The duration of estrus ranged from 5 to 20 days, being 10.9± 3.4 days; (3) The duration of proestrus plus estrus ranged from 11 to 35 days, being 19.4± 2.7 days; (4) The duration of vulval bleeding ranged from 4 to 37 days, being 20.5± 5.0 days.

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Ovulation in bitches was studied to confirm the time of ovulation in the estrus. It was a part of studis on the physiology of reproduction in the dog of the laboratory. The time of the onset of acceptance of the male was considered the best point to clarify the relationship between ovula-tion and estrus.
The copulation test of bitches (2-4 years of age, weighing about 10 kg each) with a male dog was undertaken twice a day at 7 : 00 a.m. and 7 : 00 p.m.
To confirm the time of ovulation laparotomy was carried out under local anesthesia (2% procaine hydrochloride) or general anesthesia (pentobarbital sodium), at 24 hours (1 bitch), 36 hours (3), 48 hours (13), 60 hours (12), 72 hours (1), and 96 hours (2) after the onset of acceptance of the male. Laparotomy was restricted once in the bitch to prevent influences to the ovulatory process by anesthetic shock and other effects.
Results obtained were as follows: 1) No ovulation was observed at 24 or 36 hours after the onset of acceptance of the male (4 bitches). 2) Ovulation was observed 7 of 13 bitches at 48 hours, 11 of 12 bitches at 60 hours, and 3 bitches at 72 and 96 hours. 3) From the above men-tioned results, it is suggested that; (1) Ovulation in most bitches onsets at 48 hours and terminates at 60 hours after the onset of acceptance of the male. (2) Ovulation occures in the bilateral ovaries almostly at the same time (within 12 hours). Four to 6 follicles ovulate in a estrous stage.

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Sugar constituents in bovine uterine fluid were studied by gas-liquid and thin-layer chromato-graphies.
The uterine fluid was collected at slaughter from thirty healthy cows during estrous cycle and from four cows at 3040 days of pregnancy. Preparation for the chromatographies was made by deproteinizing and freeze-drying the fluid. Either trimethylsilylation or acetylation was further necessary for the gas-liquid chromatography.
Using columns SE-52, QF-1 and OV-17 in the gas-liquid chromatography and Kieselgel G in the thin-layer chromatography, presence of glucose, fructose, sorbitol and inositol was confirmed in the fluid during estrous cycle and preplacentaion stage of pregnancy. Other carbohydrates such as rhamnose, xylose, galactose, erythritol, xylitol, adonitol and ascorbic acid were not detectable.

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[in Japanese]

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