Process for producing fatty acid salt and livestock feed containing the fatty acid salt

A method for producing a fatty acid salt, which comprises reacting a fatty acid having a melting temperature of −50° to 40° C. with a metal oxide or a metal hydroxide by use of an extruder having at least a stock supply zone, a kneading/reaction zone, and a cooling zone, with kneading being performed in each of said stock supply zone, said kneading/reaction zone and said cooling zone,

• wherein the method is carried out at a temperature of the stock supply zone of 20 to 80° C., at a temperature of the kneading/reaction zone of 80 to 200° C., and at a temperature of the cooling zone of −20 to 5° C., and
• wherein the water is supplied to the stock supply zone in an amount of 1.0 to 4.0 moles based on 1 mole of the metal oxide except in the case of aluminum oxide, the water being supplied to the stock supply zone in an amount of 3.0 to 12 moles based on 1 mole of the metal oxide in the case of aluminum oxide, and in an amount of 0.2 to 1.0 moles based on 1 mole of the metal hydroxide except in the case of aluminum hydroxide, the water being supplied in an amount of 0.6 to 3.0 moles based on 1 mole of the metal hydroxide in the case of aluminum hydroxide.