To prepare models of osteochondrosis and osteoarthrosis as etiological factors for leg weakness, which is frequent among locomotory disorders in pigs, we conducted an induction study using 5% papain solution and examined its clinical symptoms and cartilage lesions.
The body temperature and clinical symptoms subsided after 3 days. Mild lameness persisted until Day 14. However, macroscopically observed cartilage lesions serially deteriorated, and the areas of cracking and erosion expanded.
Experimental models prepared by the infusion of papain solution into the knee may play an important role in the establishment of future techniques to diagnose osteochondrosisor osteoarthrosis-related leg weakness.

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The meat characteristics of the crossbred pigs with Ryukyu native sire (A) and Large White×Landrace (LW), Duroc (D), or Berkshire (B) were examined. Eight DA, 9 BA, 12 LW·A and 12 LW·D (control) crossbred pigs were used. The longissimus thoracis muscle and the inner layer of subcutaneous fat were collected from the 5-6th vertebra of each pig, and the meat quality was evaluated. Compared with LW·D (control), the crossbred pigs with A sire were smaller for loin muscle area (P<0.05) and tended to be thicker for backfat thickness. There was no significant difference in meat color with Japanese pork color standards among the crossbred pigs. However, LW·A was slightly higher in a* with a color meter than LW·D or LW·A, and DA was slightly higher in a* than LW·A and BA (P<0.05). LW·A and BA was slightly lower in b* than LW·D (P<0.05). There was no significant difference in fat color with Japanese fat color standards among the crossbred pigs with A sire. Marbling was lower in LW·A than in LW·D (P<0.05). Ether extracts in longissimus thoracis muscle were lower in LW·A than in BA and DA (P<0.05). No significant difference in fat quality — the melting point, the refractive index, and the fatty acid composition, was observed among the crossbred pigs with A sire. Muscle fiber area was 0.6-0.8μm² for the crossbred pigs with A sire and 0.9μm² for the LW·D pigs, though a significant difference was not seen. The number of muscle fiber was the lowest in LW·D (45.0) and the highest in BA (80.6) and the difference was significant. It was shown that the crossbred pigs with Ryukyu native sire were changed not only for carcass quality the loin area and the fat thickness, but also for meat quality meat color, chemical contents and histological characteristic, by the combination with sow of different breed.

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