Sixty Landrace glits were subjected to the present study on the relationship between the hind exteriors and meat production performance. The gilts were rated into Group A of 10 with rich inward and backward stretches of hind exteriors, Group B of 10 with rich out-stretches but poor backward stretches, and Group C of 10 with poor stretches of hind exteriors, all at 90kg of body weight. In addition, 15 guts each with and without a concavity at the tail head of hind quarters were also subjected to the present study.
The results revealed that glits with rich inward and backward stretches teded to have thin back fat, large loin eye area, and high lean meat and low fat percentages. Gilts with a concavity at the tail head of hind quarters also tended likewise to have high lean meat and low fat percentages.
It was therefore suggested that selection of live bodies with such traits of exteriors as rich inward and backward stretches and a concavity at tail head of hind quarters could possibly contribute to improvement of hind quarters of pigs.

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The ratio between the content of collagen and content of labile collagen, both being basic proteins in the muscular connective tissues which are deemed to be especially related to tenderness of muscles, was determined by the amount of oxyproline. The results were comparatively evaluated with F-test in order to study if there is significance in differences among the breeds, sexes, or weights of carcasses in this conjunction.
It was found out that the total collagen content of Kagoshima Berkshire (621.63μg/g) was less than that of Large White (639.17μg/g), verifying presence of significant differences among various breeds.
It was further realized that the ratio of labile collagen amount against total collagen amount was less in Kagoshima Berkshire (2.81%) than in Large White (3.63%), as with the comparison of the total collagen verifying significant differences among varying breeds also in this respect. Both total collagen amount and the ratio of labile collagen to total collagen tended to be higher in sows than in castrated pigs. On the other hand, both total collagen content and labile collagen content tended to increase in both breeds as their weights gained. It was conjectured from these findings that both collagen content and labile collagen content would increase as age advances.
Finally, the total collagen content and ratio of labile collagen to total collagen in longissimus dorsi muscle, and the correlation among the thickness of muscular fibers, thickness of muscle bundle, and number of muscular fibers in muscle bundle were studied by breeds, and the results were studied of significance, using the t-test. The results revealed that either significant or positive close to significant correlation was noted in Kagoshima Berkshire among the total collagen content, thickness of muscle bundles, and number of muscular fibers in muscle bundles. On the other hand, significant positive correlation was seen between the total collagen amount and thickness of muscular fibers and between the ratio of labile collagen to total collagen and the thickness of muscular fibers in Large White. In other words, as the muscle bundle was thicker and thicker and the number of muscular fibers in the muscle bundle increased in kagoshima Berkshire, the total collagen content increased. The thicker the muscle fibers in Large white, the higher were both the total collagen content and the ratio of labile collagen to total collagen.
Consequently, it was conjectured that there would be variations among varying breeds in terms of tenderness of muscles and that the thickness of muscular fibers, thickness of muscle bundle, and the number of muscular fibers in muscle bundle would have something to do with tenderness, i. e. good taste of pork.

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The Japanese pig progeny testing records in terms of two different feeding systems were analyzed in order to examine whether phenotypic and genetic correlations between growth rate and backfat thickness are affected by feeding conditions.
The test pigs were fed individually a ration according to their weight, about 6 percent at start and 4 percent towards the end of testing period under the old system. In order to save testing capacity and labour, the new feeding system that two littermates of the same sex are fed ad libitum in a pen has been adopted since 1973.
The data used for estimating phenotypic correlations under the old system comprised of 1064, 63, 100, 289 and 87 litters of Landrace, Large White, Hampshire, Middle White and Berkshire, respectively. The data from 707, 73 and 98 litters of Landrace, Large White and Hampshire were used for the same analysis under the new system. These litters were tested at 31 testing stations during the period of 1966-1969 for Middle White and Berkshire and during the period of 1970-1975 for the other breeds. For estimating genetic correlations, data of 590 and 438 litters of Landrace respectively under the new and old systems from 8 leading stations were employed. Only the balanced litter groups of two females and two castrated males with complete records were subjected to the final evaluation. The analyses were made within each seasons, years, stations and sex sub-group. Heritabilities and genetic correlations were estimated by the heirarchical analysis of variance and covariance.
The mean daily gain and coefficient of its variation under the old testing system were greater than the counterparts of the new one. Significant sex difference for daily gain was not found under the old system, but castrated males gained their weight faster than females under the new system.
Heritabilities of daily gain and backfat thickness from sire components were estimated to be 0.61±0.20 and 0.50±0.19 under the old system and 0.35±0.19 and 0.72±0.20 under the new system, respectively.
Sex and breed differences in phenotypic correlations between daily gain and backfat thickness were not significant, but difference between the two feeding systems was significant at 1 percent level. These coefficients in Landrace were -0.16 and 0.13 under the old and new system, respectively, showing a reversed symbol. This tendency was alike noted in other breeds. Phenotypic correlations were also computed from the data of 92 pigs from 23 litters were devided into two groups which could be distinguished from each other by the feeding recipes of the controled and the uncontroled. The estimates pooled for sexes were -0.10 in the restricted feeding group and 0.40 in ad libitum feeding group. Since same number, two litter mates of one female and one castrated male were kept each in a pen in both groups, it was suggested that the changes in the phenotypic correlation could possibly be caused by the level of feeding rather than by the numbers of pigs in a pen.
Genetic correlations estimated from sire components were -0.02±0.20 and 0.28±0.26 under the old and new system, respectively. Although the standard errors were large, a similar tendency to that of the phenotypic correlations could be noted.

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Experiment I:
In order to clarify suitable body weights of swine for admission into cages in cageraising of swine, comparative studies were conducted twice in a year of spring and fall with total 30 swine of Landrace × Large White concerning the relationship between the body weights at admission into cages and the subsequent growths and meat production performance, through limited feeding of formula feed twice a day until each swine reached a body weight of 90kg from the body weight on admission of 20, 30, and 40kg, thus divided into three groups.
(1) The growth in the spring test was best in the swine weighing 30kg at admission. The days required for fattening the swine into 90kg were 108.3 days, and the daily mean weight gain was 617.3g. The feed conversion rate was 3.10. The growth in the autumnal test was best in the swine weighing 40kg at admission, followed by those weighing then 30 and 20kg in this order. Those of 20kg group were the poorest in both spring and autumnal tests in comparison with the other two groups, thus showing considerable influences of the weights at admission upon the subsequent growth.
(2) No significant variation by seasons or groups was seen in the dressed carcasses percentage, lengths and ratios of parts of carcass, and thickness of fat layer, and therefore on effect of body weights at admission was seen upon the meat production performance.
(3) It was conjectured that the body weights of swine suitable for admission into cages would be approx. 30kg, in view of the results of growths and yields of carcasses.
Experiment II:
In order to know the suitable point of body weights for shipment of swine raised in cages, Landrace × Large White swine were subjected to individual keeping in a pen each, to which commercial formula feed for fattening pigs was supplied with designated restrictions, and the growths and meat production performance were comparatively evaluated of three groups of finishing body weights of 90, 95, and 100kg from the start of 30kg, The results were as summarized below.
(1) The group with finishing weight of 90kg was the best among others in terms of days required for fattening and mean daily weight gain, followed by the groups of 95kg and 100kg in this decreasing order. The days required for the fattening were approx. 90 days for the group of 90kg, and each 5kg gain required extension of fattening period of 10 days.
(2) Feed intakes were 179.7kg, 201.8kg, and 219.7kg respectively for the groups of 90kg, 95kg, and 100kg, and the feed conversion rates were respectively 3.00, 3.11, and 3.13, showing the best results of the group of 90kg.
(3) As to the findings on carcasses, the weights of carcasses were less than 70kg in the group of 90kg, which was inferior to those of the other groups. No significant difference was seen among these three groups in terms of body lengths and loin eye area. However, the greater the body weights were, the better the findings on carcasses tended to be.
(4) The thickness (average) of the backfat layer was 3.08cm in the group of 100kg, which was slightly thinner than those of the other two groups. The thickness (average) of the abdominal fat layer was 2.38cm in the group of 90kg, which was the thinnest of all the three groups.
(5) The marks attained at the judging of carcasses were the highest amounting to 78 marks in the group of 100kg, in terms of general external appearances, while the group of 90kg was the most inferior in terms of body length, or lack in firmness or fullness of carcasses. Both of the 95kg and 100kg groups attained as good as 80 marks in meat quality as well as fat quality.

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A series of experiments were conducted on the development and improvement of equipments for separation, accumulation, and transportation of excreta in the course of its disposition in swine raising in cages. The results were as summarized hereinafter.
1. Equipments for separation and collection of excreta
1) It was found out that defecations and urinations by each swine take place several times a day and are concentrated into a range of time shortly before and soon after the feeding. Feces are excreted either onto the front or onto the back of a cage. Care should be taken for separation and collection of excreta of swine in connection with the difference of urination styles of both sexes of swine.
2) It was found out that the angle of slant of the receptacle plate for feces is not a decisive factor for impoving separation of feces from urine, but installation of a net plate is effective for this purpose, which proved to be also effective for preparatory drying of feces.
2. Equipments for accumulation and transportation of feces
1) A polyethylene net with a reticulation size of 6mm was found to attain both a high collection rate and detaching efficiency of feces, along with an extremely good moisture evaporation effect, which were significantly better than those of the control group.
2) A polyethylene net conveyer was developed and installed beneath each cage, with which separation of feces from urine became so efficient that feces were well dried in advance of subsequent disposition. The resulting air-dried feces could be transported and accumulated without untoward aggregation. This facilitated subsequent disposition so well that much energy could be saved in the removal of excreta from the net, attaining extremely good effects. However, further studies are yet to be conducted on the economy of the polyethylene net.
3. Simplified methods for treatment and re-utilization of filthy water with urine
1) It was found out that a water dispenser with minimum spilling in drinking should be used in order to minimize the volume of the filthy water with urine, because water supply to swine through an artificial teat leaves much spilling of water.
2) A step of continuous stirring of a designated quantity of fresh filthy water with urine by using an underwater pump with subsequent exposure to air could attain quick septic ageing with no adverse smell, by which filthy water could be transformed with an extreme ease.
The liquid after the treatment was free from Escherichia coli or odd smell, and was useful for rinsing the floor of cage pigpens.
3) As the nitrogen component of the treated liquid was of ammonia type, its value as a fertilizer was so high as to be effective for growing vegetables. However, it was problematical due to a large amount of labor needed for its transportation and application, and it is important to establish the standards for its application to various types of vegetables in order to further promote the utilization of the liquid as a fertilizer for various crops.
4. Systematization of treatments of excreta in raising swine in cages
1) Pigpens illustrated in Fig. 2 had so many problems for a proposed improvement in the structure of pigpens and raising conditions for swine. Therefore, it was remodelled into the one illustated in Fig. 1.
2) Feces separated from urine through the net could directly be subjected to treatment for fermentation through piling without any specific adjustments of moisture content.
3) Filthy water with urine could be continually treated through two-step exposure (sporadic and continuous) to air each time in 10% volume of capacity of the equipment, through stirring with an underwater pump.
4) Of the measures for utilizing the treated liquid, it proved to be effective to use it for rinsing floor of cage pigpens and for growing vegetables.

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A simplified equipment for treatment of sewage from piggeries with simplified structure, lower installation cost, and easier operation control and yet with a high purification efficiency has been developed.
Conventional facilities operated with an activated sludge system in Saitama and Ibaraki Prefectures were involved for our preliminary study on the development of the new particular equipment. The new equipment can be elucidated as follows.
1. The aeration tank (with an actual volume of 10m³) was a self-developed one in a conical funnel shape with its inner wall directly lined with mortar. A vinyl roof was provided for the tank during the winter time for thermal insulation so as to keep the temperature of water above 10°C.
2. The volume-wise loading of sewage on the tank was designated as less than 0.5kg BOD/(m³ day). If a part of the treated water was utilized as diluent, the new equipment could produce treated effluent with a good quality irrespective of the BOD levels of the original sewage subjected to the operation.
Furthermore, by allowing to pass through the sand bed and volcano ash bed for filtration, the treated effluent with a quality of BOD less than 10ppm could be obtained with our new equipment.
3. If the oxygen supply to the aeration tank was sufficient (DO: 5-8ppm), organic acids with C₂-C₅ could be eliminated within 30 minutes after exposure to air beginning from the order of acids with larger numbers of carbon atoms, leaving only acetic acid after one hour.

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1. The newly developed equipment reported in part I of our present studies with an actual volume of 10m³ was subjected to scale-up into 35m³. No drop of diluting water was newly added into the aeration tank and treated effluend alone was used as the diluent. In other words, the purification effect was attained with the new equipment as originally aimed at and its commercial use could be put in foresight by disposing only sewage of the storage tank into the aeration tank.
2. Amounts of oxygen required by and supplied to the aeration tank were investigated to find that the purification efficiency was good if the amount of supplied oxgen was sufficient for the amount of necessary oxygen.
3. Technics for dehydration and drying of the residues from the activated sludge treatments have not yet been established in using them as one of the recycled resources.
It is not adequate in the treatment of excreta and sewage from piggeries to burn the excreta or to use inorganic and organic high-polymer aggregationagents. Consequently, the simplest possible methods for dehydration and drying with sand bed for filtration were investigated in our study.
The results proved that loading of the sewage and excreta in an amount less than 1.0kg/m²/day against sand bed for filtration could extend the shelf life of the sand bed for filtration and its thickness was about 7mm, and that the moisture content of the treated sludges could be reduced into less than 50% within 2 weeks irrespective of ambient weather.
For presenting the filtration bed from stuffing, the surface of the sand bed was occasionally raked and air-dried for a designated period of time and ten uniformly leveled for re-use. This method proved to be effective for keeping the sand bed for filtration over more than 5 years.

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Porcine Parbo-virus is a highly resistive virus. Its inactivation was achieved by heating at 73°C for 30 minutes or at 70°C for 1 hour.
Its chemical inactivation was conducted with success by allowing 0.5% sodium hypochlorite solution and 0.06% potassium dichlorocyanurate solution to react upon the virus for 5 minutes or by allowing 3% formalin solution upon it for 1 hour.

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Since the report by MAKINO et al on the chromosome constitution of an intersex swine, several cases of intersex swine with or without chromosomal abnormalities have been reported by not a few investigators.
Gonstitution of chromosomes and external genital organs were examined by the leucocyte cueture method with 5 intersex swine with abnormalities in external genital organs. The results of the investigation particularly on the morphology of internal reproductive organs and histology of the testico-ovaroid organ were as described below.
1. Abnormalities of the external genital organs were noted with 4 Landrace and 1 cross breed of Landrace and Large White (L x W).
2. The external genital organs were phenotypically closer to those of a sow in 4 out of 5 swine examined. They had a large clitoris protruding from uprighted commisura labiorum pudendi. In the remaining one swine, the general morphology of the external genital organs was closer to that of a boar, in which the external genital organs demonstrated a penioid organ hanging down between the hind legs (with a length of 7.2cm). In 3 out of 5 swine, a scrotum was seen formed on the left side, of which one showed a testiculoid organ descending and existing in the scrotum.
3. The internal reproductive organs of all of these 5 swine were closer to those of sows, and differentiation of uterine angle, uteri, and vagina derived from Muehller's duct could be clearly noted. Except in one of the five, a testiculoid organ was detected in the ovarylike region of abdomen, in which uriniferous tubules and Sertoli's cells could be found existing in the histology. The degrees of development of these organs were not always in parallel with the age of the tested swine (by month), and had variations with the individual swine for the test.
4. Mosaic patterns of XX/XO, XX/XY, and XX/XXY were noted in the sexual chromosomes through leucocyte culture method. On the other hand, there were some showing no mosaic patterns. On the basis of these findings, it was conjectured that the basic constitution of the sex chromosomes of the swine with abnormalities in the morphology of external genital organs were invariably those of the female type (XX).

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To standardize testing procedures applicable to Japanese field conditions, the method of the halothane test was re-examined using 695 piglets, including 398 Landraces, 108 Durocs and 189 other breeds and crosses, at the age of 50-70 days. The experimental animals were anesthetized for 5 minutes with a halothane concentration of 4% against oxygen. One hundred and thirty-eight animals (19.9%) were scored as positive and 540 (77.7%) as negative. Seventeen animals (2.4%) were scored as doubtful. Reliable discrimination of stress-susceptible animals from stress-resistant ones was reconfirmed based on progressive clonic and particularly tonic spasm appearing in four extremities. Based on the results of this study, criteria for positive reaction to the halothane test were proposed and the points of testing procedures to which special attention should be paid were indicated.

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[in Japanese]

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