ISSUE FOCUS FEED & ADDITIVE MAGAZINE November 2023 39 CHOLINE IS A REQUIRED NUTRIENT FOR FUTURE GENERATIONS Epigenetics is the study of how the in-utero environment can modify gene expression without changing the genes themselves. DNA methylation is a key mechanism of epigenetics and involves adding a methyl group to the DNA molecule. DNA methylation regulates gene expression by effectively turning some genes on or off. One requisite for DNA methylation is the availability of molecules named methyl-group donors, such as choline. Choline is an efficient methyl donor with three methyl groups, in comparison to most others that offer only one. Epigenetic changes during gestation that modify the phenotype of the calf after birth are called fetal programming. The increased demand for choline during pregnancy and lactation represents a threat to the developing fetus. If the supply of methyl group donors is insufficient, gene expression in the calf will be negatively affected. There is abundant evidence that choline deficiency during gestation can also negatively affect placental development, fetal growth, cognitive function, and the offspring’s immune system (Jiang et al., 2014). New research studies conducted at the University of Florida, Michigan State University and the University of Wisconsin are helping to better understand the benefits of fetal programming when choline is supplemented to pre-partum dairy cows. Researchers were able to demonstrate a significant improvement in key immune markers in the newborn calves and saw an improvement in growth of about 45 g per day, resulting in heifers being 36 kg heavier at first calving. These same heifers produced an additional 1,8 kg of milk per day during their first lactation as compared to the calves whose mothers did not receive choline supplementation during the transition period. An unexpected discovery from these same studies is that choline supplementation pre-partum may increase the volume of colostrum produced. In the University of Wisconsin trial, researchers saw a 60% increase in the amount of colostrum produced and in the Michigan State trial they saw an 80% increase in colostrum volume when pre-fresh cows were supplemented with choline. More research is planned to better understand the mechanisms that contributed to these remarkable gains. CHOLINE IS REQUIRED FOR A HEALTHY TRANSITION INTO PROFITABLE LACTATION The transition to lactation is a metabolically challenging period for a dairy cow as they biologically prepare for calving and the onset of lactation. Graphic 1. Effect of feeding ReaShure during the transition period on milk production over the full lactation - Zenobi et al., (2018a)
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