Seasonal variations in L-carnitine levels in colostrum and milk of Holstein cows
2009
Sato, M., Tokyo Univ. of Agriculture, Atsugi, Kanagawa (Japan). Faculty of Agriculture | Kurosawa, A. | Watanabe, N. | Odo, S. | Ikeda, S. | Sukemori, S.
In this study, we observed the seasonal variations in L-carnitine levels in the colostrum and milk of Holstein strain cows. Milking for L-carnitine analysis was conducted on days 2, 6, and 30 after calving. Because milk composition varies with each cow udder, mixed milk from each cow was prepared for this study. In the chronological variations of L-carnitine values after calving, the highest values were recognized in the colostrum and decreased to their lowest levels in milk. The seasonal variations in L-carnitine levels for each day after calving showed specific patterns, respectively. The L-carnitine level in colostrum increased mildly at the start of summer, and on day 6 after calving at the start of autumn, it increased suddenly. The L-carnitine level in milk remained stable. Differences in these variations in L-carnitine levels during the lactation stage appear to indicate differences in heat stress damage.
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