The influence of energy content during the rearing period on physiological markers and milk yield: A study at monozygotic twins

Abstract

Using 15 pairs of female monozygotic Holstein Friesian twins that received diets containing different energy contents we repeatedly detected blood biomarkers (insulin, glutamate dehydrogenase, aspartate aminotransferase) and body traits (back fat thickness, daily weight gain). The study reached until the age of 660 days. No effect of a different feeding on milk yield was found. However, the different diet caused effects on daily weight gains, back fat thickness and insulin levels (p<0, 0001). Insulin reached much sooner higher concentrations in the group with intensive feeding than in the group with moderate feeding. Comparing pairs of twins with high (10323 kg) and low (7857 kg) milk yield during the rearing period we found to 37% higher insulin and to 27% lower aspartate aminotransferase levels in the high performance group than in the group with low milk yield. Probably these effects are genetically determined.