Carnitine and Acetylcarnitine in the Milk of Normal and Ketotic Cows

Free and acetylated carnitine was measured enzymatically in the milk of normal cows and cows with clinical ketosis. Free carnitine and acetylcarnitine was 0.062 and 0.057 µmoles per milliliter, respectively, in milk from control animals and 0.031 and 0.219 µmoles per milliliter, respectively, in milk from ketotic animals. These differences for milk carnitine were statistically significant, as was the increase in total daily carnitine in milk of ketotic cows. Change in the ratio of free to acetylated carnitine was shown on two animals which recovered spontaneously from symptoms of ketosis. Changes in milk acetylcarnitine and free carnitine are assumed to reflect similar alterations of these compounds in the mammary cell and are discussed in relation to decreased de novo synthesis of fatty acids and increased rate of acetoacetate synthesis which occur in mammary tissue of ketotic cows.