Bone fracture in fattening swine has become a subject of concern in some central wholesale markets in Japan in recent years. The details of the troubles and etiological factors of the bone fracture have been investigated in the present study. The frequency of bone fracture in fattening swine in major meat wholesale markets over half a year since October 1978 has been investigated. The results revealed that the frequency of the bone fracture in all the commercial carcasses in Kyoto market amounted to 0.88% and the regions of the fracture were fourth lumbar vertebra or femur, whereas the frequency of bone fracture in Tokyo wholesale market was so low as 0.06% of all the slaughtered number and the regions of the fracture were concentrated into four extremities. There has been no incident of bone fracture in the carcasses in Osaka wholesale market, which was therefore out of question there.
The findings on the fracture in Kyoto market suggested an overload upon carcasses by a high-speed rolling of slaughtered body in a large heavy duty depilation machine during the skinning in hot water, whereas it was assumed in the cases of skinning for Tokyo wholesale market that the lesser incidents of fracture and its concentration into the legs may be attributable to the different type of skinning machines in Tokyo and the incidents in Tokyo would be attributable to the manner of handling and transportation of fattening swine.
The frequency of incidents of fracture in fattening swine shipped into and slaughtered at the Kyoto central market varied with the eight swine operation areas in the range from 0.11 up to 3.22%. The survey on the rearing conditions of fattening swine in these operation areas in terms of the causes for the differences in the incidents of fracture revealed that the frequency of bone fracture was higher in fattening swine where garbage containing as much as 30% stale bread or bread sippets in the dry matter of feeds are fed, and besides that excessive amount of sweetened bread was being supplied to the swine. It was assessed that excessive ingestion of sugars, shortage in calcium and much higher ratio of phosphorus to calcium in feedstuffs must have caused fragility of bone. It should be further pointed out that elasticity coefficients of bone vary with individual fattening swine even though they are kept under the same conditions. It was therefore assumed that, of the fattening swine with generally poorer skeletal structure due to inadequate feeding conditions, those under some aggravated, conditions may have developed the bone fracture when subjected to skinning with hot water and with high-speed rotations by the skinning machines after the slaughter.

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The utility of whole crop corn silage in fattening swine was investigated in the present study. The pigs were given the silage and the conventional compounded feed in ratios of 6% and 3% to their body weights, respectively. Intake, weight gains, traits of carcasses, and the changes in the composition of ingested silage following selective ingestion by the fattening swine were determined.
1. Total intakes of the silage and of the compounded feed amounted to 283.9kg and 224.4kg, respectively, during the growth from 20kg to 90kg of body weights. An equation of Y=0.037X+0.250 (X: kg of body weight, Y: fresh matter in kg of daily silage intake) could be obtained between the mean body weight (X) and the mean daily silage intake.
2. It was observed that the pigs tended to ingest certain parts of the corn silage selectively. The percentages in the composition of the ingested silage were higher in crude fat and NFE and lower in crude fiber and crude ash than those of the silage offered throughout the experiment period.
3. Mean daily gains during the growing period amounted to 373g from 20 to 55kg, 663g from 55 to 90kg, and 485g from 20 up to 90kg, respectively.
4. It was recognized that the weights of stomach were larger and the melting points of fat in carcasses were lower among other characteristics of the carcasses in the swine subjected to the present study than the regular carcasses, and that the development of the tissues of salivary gland was remarkable.

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The report is presented on the construction of selection index for use in the selection of young boars and guts at around 90kgs. of live body weight in this experiment.
The selection index was to make use of such informations as daily gain of weight (X₁) and thickness of backfat (X₂), both measured on the animals subject to the selection, and the average area of eye muscle (X₃) and average percent ham (X₄) of the carcasses of littermate (full-brother) hogs.
Two selection indice were constructed in order to take care of the both cases where the young boar or gilt had two littermate hogs and where it had only one.
As for the genetic parameters necessary for construction of selection index, reliable estimates thereof neither for these particular experimental herds nor for any other Landrace herds in this country were available in time for the start of experiment, and the values assumed on the basis of the analysis of the performance test data for Middle Yorkshires accumulated for several years were used.
The selection indice constructed follow:
I₂=0.0127X₁-4.008X₂+0.187X₃+0.358X₄ for the case of two littermate hogs, and I₁=0.0129 X₁-4.077X₂+0.116X₃+0.209X₄+C for the case of only one littermate hog, where
C=(0.0127-0.0129)X₁-(4.008-4.077)X₂+(0.187-0.116)X₃+(0.358-0.209)X₄, X₁-X₄ denoting the herd averages for the respective traits.
These selection indice, as mentioned in the preceeding report, were to be in use for two generations from the start of the experiment, and then to be revised, with new estimates of parameters and from a new methodological viewpoint, for application from the third generation on.

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The present study was conducted to comparatively examine the characteristics of reproduction in sows which had protease antibody produced by Corynebacterium pyogenes and to examine the changes in the titer of the antibody in sera of their piglets.
The protease antibody was checked by the gel precipitation reaction by TAKEUCHI et al6).
No difference was seen in the characteristics of reproduction, litter sizes, number of still-births, or survival rates after birth between the sows which had and those which had not the protease antibodies.
It was therefore realized that unless any special disturbance is manifested even though the sows had the antibodies, there are no difference between the two groups of sows in terms of the functions as the sows for reproduction.
The check of the blood samples collected in time lapse from the piglets farrowed by sows with and those without CP protease antibodies for the transfer of the antibodies revealed that the antibodies were found transferred from the sows with the antibodies into the piglets via milk, but were eliminated from the bodies after weaning.
It was judged that there would be no specific tendency in the susceptibility of the piglets to CP subject to positivity or negativity of the antibodies in sows, because all the piglets remained negative up until 8 months of their age.

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The authors have devised a simple equipment with open-circuit system for measuring the respiratory energy metabolism of piglets and growing pigs, and performed some experiments to judge the practical adaptability of the system.
1. Two kinds of respiratory chambers of the simple equipment for measuring the respiratory energy metabolism were made of transparent acrylic resin. For growing pigs, the size of the chamber was 100cm long, 45cm wide, and 70cm high, while, for the piglets, it was 58cm long, 30cm wide, and 44cm high.
2. The respiratory chamber for growing pigs was equipped with two air inlets on the frontal wall and three air outlets on the rear wall, while the chamber for piglets was provided with two air inlets on the frontal wall and with one air inlet on the rear wall.
3. Two kinds of swine-keeping cages were made with angle steel. For growing pigs, the size of the cage was 85cm long, 35cm wide and 61.5cm high, and was equipped with small wheels at the bottom for moving. For piglets, it was 50cm long, 23cm wide, and 25cm high.
4. The upper part of the respiratory chamber was equipped with a meandering copper pipe to cool down the rising temperature in the chamber, and the copper pipe was 18.0 meters long for the growing pigs and 5.8 meters for the piglets.
5. The ventilator of the system was composed of a wet type gas meter, a vacuum pump, a thermometer holder, and a ventilation controlling pipe. The gas meter and the vacuum pump were connected with each other via a hard rubber duct. Two three-way cocks were devised on the rubber pipe for air sampling and the air flow rate was controlled by the distribution cock.
6. The comparison of CO₂ gas concentrations in various parts of the respiratory chamber when a pig was brought in revealed no significant differences among the individual parts of the chamber.
7. The determination of the air temperature at different parts in the chamber when a pig was brought in revealed that the temperature was the highest at the side wall and the lowest at the air inlets. Accordingly, the thermometer in the chamber was equipped on the side wall.
8. In order to know the actual effective volume of the chamber when a pig was brought in, specific gravity of 12 pigs was each determined, which turned out as 0.987 on the average.
9. The CO₂ concentration in the air of the chamber had to be kept on 0.8-1.0%. It is therefore necessary to designate in advance the time up to the launch of ventilation and the ventilation speed for each of tested swine subject to their sizes.
10. Comparison was made in terms of environmental factors between the test group without cooling of the respiratory chamber during hot summer time and the test group with cooling revealed that the ambient temperature, relative humidity and absolute humidity were higher by 14%, 0.7%, and 29% in the group without cooling than in the group with cooling, respectively.
11. When the ambient temperature in the chamber was 29°C, the heat production of the pigs with a mean body weight of 1.9kg was 7.36Cal/kg^{0, 75}hr and that of the pigs with a mean body weight of 2.6kg was 7.61Cal/kg^{7, 5}hr. When the temperature in the chamber was 25.6°C, that of the pigs with a mean body weight of 3.8kg was 6.51Cal/kg^{0, 75}hr.
12. As the conclusion of the above experiments, the simple equipment for the respiratory energy metabolism of swine devised by the authors was found to have utility due to simplified operation, feasibility of contunued measurement in lapse of time, easy motility, and low cost for its preparation.

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