Relationships between Plasma L-Carnitine Levels and Genetic Characteristics of Japanese Black Steers

The calving transition period, which lasts several days before and after calving, is a time of high stress for cows, and this stress affects not only cows but also the possibility of calves receiving milk with damaged composition. Some treatments, such as glucose precursors, minerals used as an oral drench solution, L-carnitine or administration of rumen-protected amino acids, have been examined as methods to minimize the negative effects caused by calving [1-6]. In studies of the nutritional role of L-carnitine supplementation on growth performance and meat characteristics, early postnatal skeletal myo-fiber formation in lightweight piglets from large litters was reported by Lösel D et al. [6,7] and Madsen JG et al [8] with L-carnitine supplementation occurring during suckling. These authors reported increases in myo-fiber number, but growth performance was not influenced. Meat production performance of Japanese Black cattle requires large carcass size, i.e., beef cattle strains that show high daily gains preferred by farmers. In contrast, beef with fine marbling texture generally is preferred by consumers [8,9] but preference for beef with coarse marbling has recently increased, as this type of beef is considered a healthier option by older consumers.