Diet and the fatty acids in the plasma of lambs during the first eight days after birth

This study reports the plasma lipid changes in lambs receiving either ewes' milk or a reconstituted low fat milk powder during the first eight days after birth. The liveweight gains of the lambs on the artificial diet was less than half that observed in the lambs on the natural diet. The plasma lipid levels in the lambs on the natural diet increased considerably after birth due to large increases in the concentrations of the cholesteryl ester, triglyceride and phospholipid fractions. For the lambs on the artificial diet these fractions remained similar to those observed at birth. In both groups unesterified fatty acid fractions decreased after birth. The main difference between the two groups of lambs was the large increase in C18 polyunsaturated fatty acids observed after birth in the lambs on the natural diet. The triene‐tetraene ratio of the fatty acids in the lambs on the natural diet decreased from 1.0 at birth to 0.08 after eight days whereas in the lambs on the artificial diet the ratio increased to 2.9. These composition changes are discussed in relationship to the metabolism of essential fatty acids in monogastric animals.