In Hokkaido prefecture, the TMR Center has increased the area where most farmers manage dairy farming. TMR is an abbreviated for“Total Mixed Ration”, and is one of feed to give milk cow. This feed is made to mix grass silage, corn silage, concentrated feed, maize, oatmeal to make from soybean and etc. in accordance with nutrition which milk cow requires. TMR Center is an organization that produces TMR and delivers it to customers. Most TMR Centers in Hokkaido are composed of several dairy farms (in this manuscript, they are referred to as“composing farms”) and are engaged in cultivation and ensilage.

At most TMR Centers, composing farms labor conducts cultivation and ensilage. However, since 2006, an increasing number of Centers have begun entrusting these activities to external contractors. The case that we have analyzed is one where the TMR Center has switched cultivation and ensilage from composing farmers to an external operator. So we use this case to clarify the reasons for making the change away from using composing farmers’ labor, which is linked to rising costs to produce TMR, and calculate the upper cost limit associated with changing to an external contractor.

The results are as follows. First, it is difficult for composing farmer labor to cultivate and ensile forage crops these days, because composing farmers’ labor is weakening due to aging and related factors. Second, if a TMR Center entrusts an external contractor with cultivation and ensilage, the cost to produce TMR rises. The cost of trust accounts for more than 20% of total the cost of the TMR product. Third, entrusting external contractor with cultivation and ensilage has caused product costs to rise to TMR and a corresponding lowering of revenues to composing farms. Therefore, a TMR center needs to establish an upper cost limit for about entrusting external contractors in order to manage the operation smoothly. The higher the production of milk per cow, the higher the upper cost is, so management of a TMR center can become easier.

It is effective to conquer labor restrictions when TMR centers entrust external contractor with cultivation and ensilage. However, this has caused rising costs for producing TMR and lower revenue for composing farms. If composing farms will lack labor in the near future, they will need to entrust more cultivation and ensilage. Under this condition, it is important for a TMR center and composing dairy farms to calculate and establish the upper cost limit for entrusting these operations, in order to establish a target amount of milk per cow for the smooth management of the TMR center and composing dairy farms.

Analyses of Japanese consumption styles based upon household food expenditures, such as for cooking and eating at home, and eating out eating take out foods have suggested a structural change in food demand. Households have exhibited an increased dependence on external suppliers to cook and serve meals, and a desire to reduce meal-preparation time. The reasons behind this change are the increased opportunity costs of home cooking, due to increased incomes, more working women, smaller households, more single-person households, an increasingly aging society, and diversifying lifestyles. People are thus motivated to spend less time on cooking-related housework. The way food is consumed has changed such that eating out and eating take out foods substitute for cooking/eating at home. Households have replaced fresh vegetables with ready-to-eat products, such as cut vegetables for salad, that save cooking time. Young people are more inclined to save food consumption time and to depend more on external food/meal suppliers. So, it is important to study the substitutability between ready-to-eat products, like salad, and fresh vegetables before discussing how fresh vegetables should be supplied. Yet, there are only a few academic studies that give quantitative accounts of the consumption structure of ready-to-eat products and fresh vegetables.

So, to clarify the structure of Japanese fresh vegetable demand, this article analyzes this demand structure by choosing salad as a ready-to-eat product and examining the relationship between the demand structures of four fresh vegetables (cabbage, lettuce, cucumbers and tomatoes) included in salad, and the relationship between the structures and attributes of consumer households. The analysis applied LA/AIDS that took account of zero consumption and looked into monthly data from individual questionnaires filled out for the Family Income Expenditure Survey for the 11 years between 2000 and 2010. Analysis of the survey data in individual questionnaires enables estimations of the relationship between the attributes of consumers and consumption, and short-term demand functions covering specific years, months, etc., although it was difficult for previous analyses of computed data to consider the relationship and functions.

Our analysis revealed the following points about the structure of the consumption of salad and fresh vegetables used in salads.

First, a comparison of the consumption structures between vegetables found that the prices of salad and fresh vegetables were mutually influenced and the consumption amount of salad, a ready-to-eat product, depended on the price of fresh vegetables. Substitutability was observed between salad and tomatoes/lettuce. As the price of tomatoes or lettuce rose, salad was picked as a substitute.

Second, there was a relationship between household attributes and salad consumption. Households in which the wife held a job, urban households, those with fewer children, and those with fewer total members had a higher ratio of salad consumption.

Third, an examination of how the price of salad and the elasticity of attributes changed revealed that the impact of the price of salad on its consumption declined for the eleven years of the survey, that salad accounted for an increasing part of household expenditures, and that households with fewer children and fewer total members spent more on salad.

These findings imply that salad will become a more important means of Japanese vegetable consumption, which will continue to have fewer children and more nuclear families.