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, have increased incidence of metabolic diseases (retained fetal membranes, milk fever, and displaced abomasum) as well as poorer reproductive performance. It is not surprising therefore that fatty liver has a significant economic impact on dairies.
It is very important to recognize that NEFA mobilization is essential. Around parturition, all cows experience negative energy balance and mobilize lipids, resulting in increase NEFA in the blood. Without increase blood NEFA there would be less glucose available to the udder for lactose synthesis and milk production would suffer. The key to a smooth transition and high peak milks is to effectively manage the ability of the liver to handle the NEFA surge at parturition, not to prevent mobilization. Feeding and management strategies exist to help mediate declines in prepartum DMI and minimize postpartum negative energy balance and NEFA mobilization during transition, but, these are beyond the scope of this paper. Regardless of those strategies one clearly effective tool is to feed Rumen Protected Choline.
A major functionality of choline is as a precursor for phosphatidylcholine which in turn is a key structural component of VLDL. The rate of VLDL export (and therefore fat export from the liver) depends on the rate of phosphatidylcholine synthesis (Cole et al. 2011). The classic symptom of choline deficiency in many species is fatty liver. It is not surprising then that supplementation of rumen protected choline to cows can help alleviate the degree of fat accumulation in the liver (Cooke et al., 2007; Zom et al., 2011; Zenobi et al., 2018a). Figure 1 shows the results of supplementation of rumen protected choline (ReaShure) at graded levels on liver fat accumulation in restricted fed dry cows (Zenobi et al., 2018a). As choline ion increased liver fat accumulation decreased linearly.
Lima et al. (2012) reported on two studies conducted on large commercial dairies. In the first study 369 animals (primiparous and multiparous) were utilized. Rumen protected choline was fed for 25 days prepartum to 80 days postpartum. Clinical ketosis, mastitis (cases/cow), morbidity, IV dextrose treatments and oral propylene glycol and calcium propionate treatments were all significantly reduced and there was a strong tendency for a decrease in mastitis incidence when choline was supplemented. There was no interaction between parity and treatment. In the second study with heifers, rumen protected choline was only fed for 22 days prepartum. Choline supplemented heifers had significantly lower incidence rate of retained fetal membrane (RP) and fewer mastitis cases per heifer. Metritis and fever incidence rates were actually higher in heifers fed choline. It is important to remember supplementation with choline stopped at calving in the heifer study and potential added health benefits of extended supplementation postpartum cannot be assessed.
Arshad et al. (2020) published the results of a meta-analysis of choline ion supplementation. Statistically, RPs and mastitis incidence, tended to decrease. However, incidences of all diseases monitored were numerically lower with the exception of ketosis.
The costs associated with metabolic and infectious diseases in transition cows are significant to dairy producers. Liang et al. (2017) estimated the cost of 7 common transition diseases in United States dairy herds. Table 1 is adapted from the that study and shows the estimated costs of each disease excluding that associated with lost milk. As strongly supported by the Arshad et al. (2020) study, feeding choline during transition increases milk production. It can be assumed that some of the milk production increase is associated with healthier cows. So, to separate the economic losses due to decreased milk production from the other costs associated with the disease, lost production cost was taken out of the Liang et al. (2017) economic calculations. Using the incidence rates and changes in disease incidence reported in the Lima et al. (2012) study we can get an idea of the potential economic benefits associated with feeding choline pre- and postpartum through improved health independent of improved milk production (Table 2). This data excludes preliminary data (Zenobi et al., 2018b; Bollatti et al., 2020) that suggests that choline may help mitigate the prevalence of subclinical hypocalcemia, an economically important metabolic disease of transition cows (not reported in the Lima et al., 2012 study).
Choline continues to be of great interest to researchers across many species including humans and 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. Much more remains to be understood about how choline supplementation improves cow health and research continues in this arena. What does seem clear is that choline is an essential nutrient that appears to be limiting at least during the transition period when demand is elevated and choline availability is limited.
• Arshad, U., M. G. Zenobi, C. R. Staples, and J. E. P. Santos. 2020. Meta-analysis of the effects of supplemental rumen-protected choline during the transition period on performance and health of parous dairy cows. J. Dairy Sci. 103:282–300.
• Bollatti, J.M., M. G. Zenobi, N. A. Artusso, A. M. Lopez, C. D. Nelson, B. A. Barton, C. R. Staples, and J. E. P. Santos. 2020. Effects of rumen-protected choline on the inflammatory and metabolic status and health of dairy cows during the transition period. J. Dairy Sci. 103:4192–4205.
• Bobe, G., J. W. Young, and D. C. Beitz. 2004. Invited review: Pathology, etiology, prevention, and treatment of fatty liver in dairy cows. J. Dairy Sci. 87:3105–3124.
• Cole, L. K., J. E. Vance, and D. E. Vance. 2012. Phosphatidylcholine biosynthesis and lipoprotein metabolism. Biochim. Biophys. Acta 1821:754–761.
• Cooke, R. F., N. S. Del Rio, D. Z. Caraviello, S. J. Bertics, M. H. Ramos, and R. R. Grummer. 2007. Supplemental choline for prevention and alleviation of fatty liver in dairy cattle. J. Dairy Sci. 90:2413–2418.
• Liang, D., L.M. Arnold, C.J. Stowe, R.J. Harmon, J.M. Bewley. 2017. Estimating US dairy clinical disease costs with a stochastic simulation model. J. Dairy Sci. Vol. 100:1472–1486.
• Lima, F. S., M. F. Sa Filho, L. F. Greco, and J. E. P. Santos. 2012. Effects of feeding rumen-protected choline on incidence of diseases and reproduction of dairy cows. Vet. J. 193:140–145.
• Reynolds, C. K., P. C. Aikman, B. Lupoli, D. J. Humphries, and D. E. Beaver. 2003. Splanchnic metabolism of dairy cows during the transition from late gestation through early lactation. J. Dairy Sci. 86:1201–1217.
• Zeisel, S.H. (2012). “A brief history of choline”. Annals of Nutrition & Metabolism. 61 (3): 254–8.
• Zenobi, M. G., T. L. Scheffler, J. E. Zuniga, M. B. Poindexter, S. R. Campagna, H. F. Castro Gonzalez, A. T. Farmer, B. A. Barton, J. E. P. Santos, and C. R. Staples. 2018a. Feeding increasing amounts of ruminally protected choline decreased fatty liver in nonlactating, pregnant Holstein cows in negative energy status. J. Dairy Sci. 101:5902–5923.
• Zenobi, M. G., R. Gardinal, J. E. Zuniga, A. L. G. Dias, C. D. Nelson, J. P. Driver, B. A. Barton, J. E. P. Santos, and C. R. Staples. 2018b. Effects of supplementation with ruminally protected choline on performance of multiparous Holstein cows did not depend upon prepartum caloric intake. J. Dairy Sci. 101:1088–1110.
• Zom, R. L., J. Van Baal, R. M. A. Goselink, M. J. de Veth, and A. M. van Vuuren. 2011. Effect of rumen-protected choline on performance and hepatic triacylglycerol concentrations in early-lactating dairy cattle. J. Dairy Sci. 94:4016–4027.
About Marcos Zenobi, MSc., PhD.
Marcos Zenobi is originally from Argentina. After receiving his Master of Science degree in 2013, he moved to Gainesville, Florida to start his PhD under Dr. Charles Staples and Dr. Jose Santos in the Animal Sciences Graduate Program at the University of Florida. Dr. Zenobi is a specialist in dairy nutrition and management. He now lives in Cordoba where he leads Balchem Technical Services, mostly in Latin America. He also teaches undergraduate and graduate students in Argentina.