Leg weakness is one of the most serious problems in pig farms, because leg weakness is one of the most common reasons for involuntary culling of breeding pigs. Various factors have been suggested to be important in influencing leg weakness. Genetics is a main cause of leg weakness. Leg weakness has to be recorded and scored objectively if we want to cull on leg weakness. Leg weakness can be scored by many different methods. Scoring systems are classified to a binary type of scoring system and a linear scoring system. The binary type of scoring system indicates whether the pig has a certain and the level of problem. The linear scoring system evaluates all pigs for certain leg locomotions. Although both types of scoring systems are used in practical breeding programs, the linear scoring systems is considered the superior method for leg evaluation in swine. Heritability estimates for leg score traits are low or moderate. Heritability estimates for osteochondral lesions are also low or moderate. High genetic correlations among leg score traits are high and favorable genetic correlations between leg score traits and osteochondral lesions are estimated in many reports. In general, unfavorable genetic correlations between leg soundness and growth and meat production traits are estimated. More research is needed to develop methods for improving leg soundness, for example, to standardize for scoring leg exterior traits and to study relationships between leg scores and lifetime prolificacy. After them, leg soundness can be genetically improved.

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Effects of marbling, fat color, ‘rice fed pork’ labeling, and price on consumers' choice of pork were investigated by using score-based conjoint analysis. Eight profiles of retail pork packages were prepared by using the following four attributes : marbling (2 levels), fat color (2 levels), ‘rice fed pork’ labeling (2 levels), and price (3 levels). The questionnaire was carried out on April 2008 in National Institute of Livestock and Grassland Science, Tsukuba, Ibaraki, Japan. Answers from 277 respondents were applied to conjoint analysis to determine the importance of the attributes and the utility of levels for each participant. Respondents were classified into 4 groups by cluster analysis according to the utility of levels of package profiles. Each participant group was characterized by the importance of attributes and the utility of levels. Willingness to pay for ‘rice fed pork’ labeling was 6.9 -61.2 yen per 100g pork in 4 participant groups. Furthermore, the utility of ‘rice fed pork’ labeling was significantly correlated with consideration for the self-sufficiency ratio of pig feed in each questionnaire respondent.

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