As a method for easily detecting a suitable time for inseminating sows in swinebreeding farmers for wider popularization of artificial insemination, pH of vaginal mucus of sows in estrus was determined so as to know whether or not this would serve for grasping the optimal time for insemination.
The results were as follows.
Differences were noted between the determination results with BTB test paper and those with a portable pH meter. The BTB test paper readily reacts with polluted air in piggeries and tends to be inaccurate. It is therefore recommendable to use the pH meter for this determination.
From the results of determination with a pH meter, it was noted that the pH of vaginal mucus on the day of the oncet of estrus is higher than 7.3, slightly alkaline, regardless of breeds and age of tested swine and that during the period of acceptance of boars the pH of vaginal mucus was within the range from 7.2 to 7.3 in all the breeds. This condition seemed to continue during the period of boar acceptance. When the estrus is over and sows no longer accept boars the pH of the vaginal mucus tends to be slightly lower than it is during the boar acceptance.
The relationship between the pH of the vaginal mucus on the day of insemination and the conception rate was investigated to know that the insemination to sows on the day with pH of 7.2-7.3 turned out to be 93.8% in Landrace Breed, 66.7% in Large White Breed, and 92.3% in Hampshire Breed, proving to be good conception results. Considerably good results could be obtained with guts if the pH of vaginal mucus was 7.2-7.3 at insemination, although it was difficult to obtain as good results as in sows.
Generally speaking, the pH of the vaginal mucus turns into slightly alkaline, higher than 7.3, following the oncet of estrus, and subsequently is lowered to 7.2-7.3 in the period suitable for insemination, but tends to be further lower following termination of the estrus after the suitable period for insemination to sows would be the day when the pH of the vaginal mucus shows 7.2-7.3 and the behaviors of sows after the oncet of estrus and the conditions of external genitals are regarded upon inspection as accepting the insemination.

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The relationship between the ovarian cycle and the estrous symptom cycle of sows were investigated by histological observation of sections collected from ovaries and vaginal vestibule of the same animals.
Ovarian and vaginal vestibule tissues were collected from 65 sows at varying stages of their estrous symptom cycles (12 sows in proestrus, 11 sows in estrus, 10 sows in postestrus, and 32 sows in diestrus).
1. The ovarian cycle of a sow was classified by gross and histological observations of the ovaries.
Early follicular stage: Graafian follicles were noted in their growth in the ovaries. The follicles were about 5-7mm in diameter and their granulosa layers were about 50-65μ thick, while their theca interna were about 40-55μ thick.
Late follicular stage: The nearly mature follicles which were noted were about 8-10mm in diameter. The thickness of granulosa layers and theca interna were respectively 35-55μ and 35-45μ.
Ovulatory stage: The follicles at this stage were about 8-12mm in diameter. The ruptured follicles showed hemorrhage at the follicular stigma.
Early luteal stage: The ovaries at this stage are featured by the presence of ruptured follicles, and the hemorrhage at the follicular stigma was found to have disappeared.
Middle luteal stage: Gross findings of ovaries at this stage were the presence of blooming corpus luteum in its size of about 9-14mm in diameter.
Late luteal stage: The ovaries at this stage indicated presence of the regressing corpus luteum and that of growing follicles of 4-6mm in diameter.
2. Of varying thickness of mucosal epithelium of vaginal vestibule in the ovarian cycle and the estrous symptom cycle, the thickest stage was the ovulatory stage amounting to 148μ, followed by the estrus stage amounting to 138μ, while the thinnest stage was the middle luteal stage amounting to 36μ, followed by the diestrus amounting to 39μ.
3. With respect to the relationship between the ovarian cycle and the estrous symptom cycle, correlation was noted between the proestrus and late follicular stage, between estrus and ovulatory stage, between postestrus and early lutel stage, and between diestrus and middle luteal stage.

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Physicochemical characteristics of pork, particularly those showing palatability, such as color hues, water holding capacity, and texture were investigated with longissmus dorsi of 159 pig carcasses which had been selected put of fattening pigs produced for supply to common market due to their identifiable breeds and feeding histories and then slaughtered at nearly the same stage and under the same conditions.
As a result, values comparable to those commonly noted in many reports were obtained with the color values on the basis of UCS photometry, water holding capacity on the basis of pressurized filter paper method or heated centrifugation method, binding capacity on the basis of heated centrifugation method, hardness, texture, and gumminess with a texturometer, and chewability except the “a” component of the color values. On the basis of the sizes of standard deviation and the variation coefficient, these results could be deemed as sufficiently applicable standard values indicating general characteristics of pork.
Standard evaluation was made on the differences among various breeds in terms of these features. It was noted as a result that there were variations with these breeds in terms of most of the characteristics thus investigated. However, the superiority of any breed over others in terms of these features varied with esch of these features, and it was noted that mass inspection of meat resulted only in finding quality features in each of the breeds tested.

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In order to know what values of color hues, water holding capacity, binding capacity, and texture would be indicated by the palatability of pork carcasses generally regarded as prime grade, the characteristics of longissmus dorsi of the prize-winning pork carcasses on the 6th All Japan Fattening Pig Show were investigated.
As a result, it was noted that in comparison with common carcasses available in regular wholesale meat market this type of pork had deeper color of lighter red, and higher water holding capacity and binding capacity; particularly to be noted was that the amount of juice separated from the pork in the determination of water holding capacity and binding capacity with the heated centrifugation method was nearly half of that of pork commonly available on the usual meat market.
Investigation on the texture of this type of pork indicated that the prize winner pork in competitive exhibition had higher values in hardness, gumminess, and chewability. This would suggest that consequently pork of the type with grester hardness and consistency is regarded as of better quality than the regular pork.
Nearly similar trends could be noted with both regular carcasses and prize winner types of carcasses of various breeds in terms of color values, water holding capacity, and binding capacity. However, coincidence could not always be attained between the two types of carcasses in terms of various other values showing texture except the value of aggregation. Therefore, further studies would be needed on the comparison among various breeds in terms of values showing texture of pork.

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1. Fractionated semen was diluted in a ratio of 1:1 or 1:2 with a specially prepared buffer diluent consisted of 3.24g of skim milk, 1.62g of glucose, 0.28g of sodium bicarbonate, 0.36g of Tris, 0.23g of glycine, and 100ml of distilled water, and adjusted to a pH of 7.2 by adding 6% citric acid solution.
The diluted semen was stored in two ways: one being gradual cool-down to 15°C spending 4 hours, by means of immersion in a beaker containing luke-warm water and storage in a low temperature incubator (15°C), followed by further storage at 15°C, while the other being immersion in a thermos containing warm water, followed by storage in a refrigerator (3-5°C) with gradual lowering of temperature down to 5°C spending approx. 24 hours, and then kept stored at 5°C.
The progress in motility change of the sperm was comparatively evaluated with the two sample groups. The test on the activity and livability of the sperm was made by the microscopic examination of the stored semen following warming and shaking for 20-30 minutes at 37°C.
The motility of the sperm stored at 15°C was found to be better than that of the semen stored at 5°C for the initial 3 days of the continued storage, but was sharply lowered on the 4th day.
The semen stored at 5°C were certainly showed less motility for the initial period of storage than that of the semen stored at 15°C, dut further lowering of motility was not noted, maintaining up until the 7th day the active livability of semen which could be used for insemination.
2. The boar semen stored at 5°C for 1-7 days were warmed and shaken at 37°C for 20 minutes in order to infuse the semen which raised the temperature up to 37°C and then restored their motilities.
Of the 17 sows and 13 gilts tested, 13 sows and 9 gilts, 22 in total, were successfully concieved and duly farrowed. The conception rate was 73.3%. The mean litter size was 8.5, 10.8 for sows and 5.2 for gilts, respectively. No trend of reduction in conception rate or litter size was noted with longer storage of the diluted semen.

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In order to investigate the effects of grain sizes of swine feeds upon their digestibility and properties of feces, 3 classes of feeds with the same composition but different grain sizes and a high-energy feed were prepared for the digestibility test as well as other tests. The 3 different groups were the large particles which passed through the sieve for the feed of mature poultry, the moderate particles (which was of the size of so-called Kanagawa Prefectural Authorized size No. 4 for Swine), and the fine particles (which passed through the sieve for later stage of creep feed). The highenergy feed was prepared by adding 5.2% of yellow grease.
1. The amount of excreta increased as the grain sizes were larger. The excretion rate against the ingested feed amount was also higher as the grain sizes were larger. The amounts of drinking water and urination varied very much with individual pigs, showing no significant difference by the grain sizes, but the correlation between the two amounts was extremely deep (r=0.974).
2. The digestibility of each feed component varied considerably with the grain sizes. The digestibility of each component tended to be better as the grain size became smaller. The trend was even more distinct particularly with the crude fibers. The difference in digestibility was smaller between the group of fine particles and that of moderate particles than the one between the moderate particles and the large particles. This meant that the grain size of the large particle group was excessive from the viewpoint of digestibility and utility of swine feed.
3. Gross findings of feces were that those with fine particles and moderate particles had smooth surface and solid appearance with distinct lump shape, whereas that of the large particle group had many large hulls of corn grains and was fragile and easily disintegrated by the exogenous pressure. The properties of feces of the group with addition of yellow grease were similar to those of the large particle group, which was very much different from the findings with the commercial feeds with addition of oils and fats. This difference may be attributed to the difference in the grain sizes of the basic feed.
4. Hardly any differences were noted in the changes by time lapse of the feces in water between the group with fine particles and the group with moderate particles. Both groups maintained their original shapes even after 2-4 hours, but the grnups of large particles and the yellow grease addition group were mostly disintegrated with stirring at 30 minutes
5. with respect to the distribution of particle sizes and separation rate by sieving of undigested solid matters in the feces, the particle sizes of the undigested matters found in feces tended to be larger in proportion to the grain sizes and the sieving rate tended to be higher.
Particularly, most of the hulls of corn grains were excreted with no changes in the group with larger grain size, and it could be assumed that the large grains would have affected the shapes and properties of feces in this group.

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