ARTICLE 74 FEED & ADDITIVE MAGAZINE November 2022 CHOLINE SUPPLEMENTATION TO TRANSITION COWS: A HEALTHIER LAUNCH OF HER LACTATION “Choline continues to be of great interest to researchers across many species including humans and obviously dairy cattle. Research in just the last few years has shown that feeding rumen protected choline during transition improves milk production over the entire lactation, helps maintain healthier cows and improves calf health and performance.” Choline was identified as a nutrient in the early 1930s when it was shown that lecithin (a source of choline) could prevent fatty liver in rats fed special diets and also in diabetic dogs (Zeisel S.H., 2012). Subsequently, choline has been determined to be an essential nutrient in rats, mice, guinea pigs, dogs, pigs, chickens, trout and fairly recently in humans. In 1998 the US National Academy of Medicine established requirements for choline in humans. Supplemental choline has been shown to improve fetal development, infant cognitive function, improved performance and stamina in athletes, cognitive function in older adults as well as improved liver function to name a few benefits. Over the past 20 years, there has been a growing body of research into the benefits of choline in transition dairy cows. This article will focus on the impact of choline supplementation on transition cow health. As cows approach calving they experience hormonal changes that trigger a dramatic increase in lipid mobilization from adipose tissue. The rapid increase in blood non-esterified fatty acids (NEFA) at calving coupled with a doubling in blood flow to the liver results in a 13-fold increase in liver uptake of NEFA immediately after calving (Reynolds et al., 2003). These NEFA are either used by the liver as an energy source, partially oxidized to ketones, exported as fat via very low-density lipoproteins (VLDL) or stored as fat in the hepatocytes (liver cells). Oxidation of NEFA by hepatocytes and export as fat via VLDL are positive outcomes. Excessive partial oxidation of NEFA can lead to ketosis. Accumulation of lipids in hepatocytes can lead to fatty liver which can have significant negative effects on cow health. Bobe et al. (2004) reported that 50-60% of all transition cows experience moderate to severe fatty liver. Metabolic consequences of excessive fat accumulation in the liver include reductions in gluconeogenesis, ureagenesis, hormone clearance, and hormone responsiveness. Cows that develop fatty liver show nonspecific signs of illness; decreased DMI, excessive weight loss, reduced milk production, are prone to infections such as metritis and mastitis, Marcos Zenobi, MSc, Ph.D. Technical Services Manager Balchem
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