Plasma lipid concentrations in holstein steers during growing and finishing stage
Hidari, H.; Sato, Y.; Endo, N.; Hidaka, S.; Okada, M.
Japanese Journal of Zootechnical Science 60(2): 158-165
To investigate the change of the plasma lipid concentrations in beef cattle during growing and finishing stages, the plasma samples from four 9 month and eight 15 month old Holstein steers and eighteen heifers were analysed for lipids concentration. The steers were fed on concentrate diet ad lib for six months. The blood samples were taken from their jugular vein at noon once a month during the experimental period. At the same time of blood sampling from the steers, blood samples were taken as control from four heifers, the same aged and from four having the same weight at that time. The proportions of total cholesterol (TCh) and phospholipid (PL) in the plasma of the experimental animals were 44.1, 45.9% respectivley and did not vary with age and body weight changes. The plasma triglycerides (TG) in the dairy heifers were higher than in the growing steers (P < 0.01). At the beginning of the finishing stage, because the steers were not accustomed to the new feeding system, the plasma non-esterified fatty acid (NEFA) concentrations showed the highest value through the experimental period. The plasma PL concentrations in the growing steers increased with age until 15 months (P < 0.05). In the plasma of finishing steers, however, the TCh concentrations decreased with age (P < 0.01). The plasma TCh in the growing steers gained daily more than 1.4 kg and in the finishing steers gained daily less than 0.75 kg showed significant correlations with their body weight r = 0.896 (P < 0.01) and r= -0.528 (P < 0.01) respectively. The increase in plasma TCh of the growing steers and the decrease in the finishing steers with age and body weight gain seems to be explicable by the levels of TDN intake/BW0.75, the lipogenic capacity in the fat tissues and the hepatic disorders.