In order to study the nutritive levels of feedstuffs which are adapted for fattening of the fattening swine in cages, varying levels of TDN of 64.4, 70, and 74 were provided to tested swine while the levels of proteins were kept almost constant (DCP 12.4-12.9), and the results of growths, utilities of feedstuffs, and findings of carcasses were comparatively examined. The results were as described hereunder.
1. With a feedstuff having a TDN of 64.4%, the growths of the fattening swine were fairly retarded, and the findings on the carcasses were fairly poor, demonstrating that the feedstuff was not suitable.
2. With a feedstuff having a TDN of 74.0%, both weight gain and the feed conversion rate were fairly improved, whereas the findings on carcasses were inferior to those with a feedstuff having a TDN of 70% in terms of loin eye area, thickness of back fat and grading of carcasses. Especially to be noted was that those fattened during summer time demonstrated bigger differences in this respect.
3. Even when a feedstuff having a TDN of 74% was provided at the latter half of the fattening stage, the results were inferior to those of a feedstuff with a TDN of 70% in terms of the findings on the carcasses.
4. The results of weight gains depending on the levels of TDN were in proportion to the differences in the TDN levels between the tested classes of feedstuffs.
5. Changes in TDN levels of feedstuffs could not alter the amounts of TDN which were required for a weight gain of 1kg.
6. From these findings, it was assumed that the best possible TDN level for a DCP of 12.4-12.9 would be about 70% (NR4.4), and that there would be no need to change the TDN levels for the earlier and the latter halves of the fattening stage.

View full abstract

Experiment I: Structure of cage floor: The effects of the longitudinal and lateral types of structures of plastic drainboards in the cages for swine raising upon the growth and meat productivity of swine were studied.
The results revealed that better growths were attained with the lateral type in both seasons of spring and autumn on the basis of average results of a year; the days required for fattening and the mean daily weight gain were respectively 97.4 days and 61.96g, showing slightly better results over those of the longitudinal type. The longitudinal type demonstrated slightly better results in the earlier half of fattening but were poorer in the latter half than the lateral type.
The feed conversion rate of the swine on the lateral type was 3.40, which was slightly better than that of the longitudinal type. The loin eye area of the group with the longitudinal type tended to be slightly better than the lateral type among other findings on the carcass. However, there was no significant difference between the two groups in terms of dressing percentage of carcass, length of carcass, thickness of back fat or ratio of ham.
Summarizing the results of findings on the growths and carcass, it can be claimed that the plastic drainboards for cages should be of the lateral type for attaining better growths, but further studies would be required on the influences of the materials and measurements of the drainboards upon the growths of swine.
Experiment II. Number of swine to be admitted into cages: Group raising methods will have to be studied in the swine raising in cages as costs for facilities are substantial and the animals tend to have weak legs. With 24 crossbreds of LW, we studied on their growth and meat productivity through varying raising numbers of single, two and four animals admitted in cages and through limited feeding of twice a day of the approved feed for the period from the body weight of 30kg up to 90kg. The following results were attained.
1. The single raising group demonstrated the best growth, and a trend was noted that as the number of the animals admitted in a cage increased, the daily mean weight gain and feed conversion rate were less favorable.
2. However, the gross findings on the legs and hooves (weak legs) were in the trend contrary to that of the growth. The motility of the swine raised in the groups of 4 was very smooth and showed least adverse effect, followed by the groups of two and single.
3. The groups of single raising proved to have better loin eye area and thickness of back fat among other findings of carcass, and, as the number of the raised animals incresed in the groups, the fat layer tended to be thicker and more variable in the results, showing somewhat inferior quality of carcass.

View full abstract

I. Method for feeding with quantification by days after birth: The results of our comparative feeding test between the conventional body weight method our newly designed method with quantified feeding by days after birth as a quantitative feeding method for cage swine raising revealed that the newly designed method could attain good results comparable to those of the body weight method and that the new method can be a practically applicable feeding method with quantification.
II. Feeding amount after attaining a body weight of 90kg: In order to design the feeding amount in cage swine raising during the term from a body weight of 90kg up until 100kg, a feeding test was carried out with 3 groups of swine of varying feeding amounts of 3.1kg/day, 2.9kg/day, and 2.7kg/day of a compounded feed which had a DCP of 12.9% and a TDN of 70.0%. The group with 3.1kg/day demonstrated the most favorable results, indicating that this amount was adequate.
III. Effects of limited water supply upon growth: In order to improve the method for water supply in cage swine raising, the effects of limitations in the amount and time (1 hour after feeding) for water supply upon the growth of swine were investigated to attain the following results.
1. The water intake at a body weight of 60kg was 9.5kg per head per day, and the ratios of the intake against body weight and total feeding amount were respectively 15.8% and 3.9 times.
2. The amount of spillt water at water supply to swine was 4.87kg per head per day, and the ratio of the spillt water against the water intake was 51.5%.
3. All the parameters in the results of growth such as days required for designated growth, daily mean body weight gain, and feed conversion rate proved to be the best in Group I (with water supply ad libitum for the term of body weight from 30kg up to 60kg and limited water supply from 60kg up to 90kg), followed by Group II (with limited water supply from 30kg up to 90kg) and the control group (with water supply ad libitum from 30kg up to 90kg), but no significant difference could be noted.
4. No significant difference was observed among the three groups in terms of the results with slaughtered bodies such as yield of carcass, length II of back loin, loineye area, thickness of back fat, or ratio of ham and in terms of gross inspection results such as color shade and quality of pork and the quality of fat. However, the grading results of carcasses of Group II were slightly inferior to the other two groups in terms of yield of better quality pork.

View full abstract

Histological specimens prepared with 70 test samples of muscles comprising 35 samples each of M. longissimus dorsi and M. biceps femoris both collected from total 35 hogs covering 6 barrows and 5 gilts of Kagoshima Berkshire, 6 barrows and 6 gifts of American Berkshire, and 6 barrows and 6 gilts of Hampshire all of which had been raised at the Swine Husbandry Department of Kagoshima Prefectural Animal Experiment Station through the paraffin embedding method in the same manner as in our prior report. These specimens were microscopically inspected and evaluated in order that the muscle fiber diameter, muscle bundle diameter, and number of muscle fibers in muscle bundle could be comparatively evaluated by breeds, sexes, and weights of slaughtered bodies.
The significance of differences in the determined muscle fiber diameters, muscle bundle diameters, and numbers of muscle fibers was comparatively determined with the F-test method by breeds, sexes, and weights of slaughtered bodies. The results revealed that the diameters of muscle fibers of both M. longissimus dorsi and M. biceps femoris of Hampshire were the largest, followed by the American Berkshire, and the smallest was those of Kagoshima Berkshire, and that the diameters of fibers of both muscles of gilts were larger than those of barrows of all the three tested breeds. However, no significant trend was seen in the weights of slaughtered bodies of the breeds.
The significance of correlations among the three parameters of muscle fiber diameter, muscle bundle diameter, and the number of muscle fibers in muscle bundle of both tested muscles was examined with each of the three breeds, and the significance of the correlation was investigated with the t-test. The results revealed that a negative correlation could be noted between the muscle fiber diameter and the numbers of muscle fibers in muscle bundle of M. longissimus dorsi of both Kagoshima Berkshire and American Berkshire and that a positive correlation could be noted between the muscle bundle diameters and the number of muscle fibers in muscle bundles of Hampshire. The results further revealed that positive correlation could be noted between the muscle fiber diameter and the muscle bundle diameter of M. biceps femoris of all the three tested breeds and a positive correlation could be seen between the diameter of muscle bundle and the numbers of muscle fibers in muscle bundle of Hampshire.

View full abstract