It seems like you're describing a linear programming problem where the goal is to minimize the total cost of feed while meeting specific nutritional requirements for cattle. You have a system involving three different feeds, each with varying amounts of nutrients, and you need to figure out the optimal blend of these feeds.

Could you please provide the full nutritional information for each of the three feeds and the nutritional requirements (in terms of the desired amounts of each nutrient)? This will allow me to set up the necessary equations and help you solve the problem.

Feel free to upload any relevant data or clarify further if needed!