In recent years, the scientific community has become increasingly aware of the potential negative consequences linked to elevated levels of nonesterified fatty acids (NEFA) and beta-hydroxybutyrate (BHBA) in transition cows. Several large-scale epidemiological studies have been conducted to identify a critical blood concentration at which these negative effects might manifest. Given that BHBA is more frequently measured than NEFA, much of the research has focused on BHBA levels. These studies consistently suggest that a blood concentration of 1.2-1.4 mmol BHBA/L could be the threshold where milk production starts to decline. As a result, it is often recommended that if 10-15% or more of the cows tested show levels of 1.2 (or 1.4) mmol BHBA/L or higher, an alarm level has been reached, and the underlying causes should be investigated.
The previous myth-buster article explored the widespread belief within our industry that elevated NEFA and BHBA levels in transition cows are inherently harmful. We debunked this notion by explaining how NEFA and BHBA can actually support lactation by acting as precursors for milk fat synthesis and as energy sources for milk production. However, there are instances when these levels can rise to such an extent that they begin to negatively affect the cow. Traditionally, the strategy to address this issue has involved using feed additives or treatments aimed at inhibiting fat mobilization and reducing NEFA levels entering the bloodstream and subsequently reaching the liver (as illustrated in Figure 1).
Figure 1: The conventional approach to managing fat mobilization, which can inadvertently restrict nutrients available to the udder for milk production.
In some cases, attempts to suppress fat mobilization have led to decreased lactation performance by limiting nutrient availability to the udder (Janovick et al., 2010; Yuan et al., 2012), a topic that will be further explored in a future myth-busting article. Dr. John Newbold succinctly captured the potential downside of this traditional approach:
"The nutritional restriction of adipose tissue mobilization may be necessary, but there's a philosophical issue here. We've bred cows that rely heavily on mobilized body reserves for milk production. The farmer has paid for this genetic advancement—should we now ask him to pay the nutritionist to counteract this? Our priorities seem misplaced. We should first consider how best to help the liver handle mobilized fatty acids before deciding whether we need to reduce the amount of fatty acids supplied to the liver."
Dr. Newbold’s innovative perspective on managing fat mobilization is depicted in Figure 2, contrasting with the historical approach shown in Figure 1. His idea is to leverage the liver to convert NEFA into very low-density lipoproteins (VLDL) and transport them to the mammary gland, thereby avoiding issues like fatty liver and ketosis.
Figure 2: An improved approach to managing fat mobilization. By supplementing rumen-protected choline, you can support lactation without restricting fat mobilization and by facilitating fat export from the liver to the udder.
The take-home message is clear: the initial step in managing fat mobilization should involve aiding the liver. Among known compounds, choline is the only one capable of achieving this. Dietary choline is an essential nutrient, yet it is largely degraded in the rumen. Thus, it must be provided in a form that shields it from ruminal breakdown. Choline works by enhancing phosphatidylcholine synthesis, crucial for VLDL assembly and fat export from the liver (Chandler et al., 2017). Numerous studies demonstrate that feeding rumen-protected choline reduces fat accumulation during intense NEFA mobilization in dry or transition cows (Cooke et al., 2007; Zom et al., 2011; Elek et al., 2013). As Dr. Newbold suggested, choline supports lactation by ensuring nutrient availability rather than restricting it. Two summaries of transition cow trials indicate that feeding rumen-protected choline boosts milk production by 4.9 pounds per day (from 13 studies, Grummer, 2012) or 4.4 pounds daily (Staples, unpublished, Figure 3).
Figure 3: A summary of milk yield responses when feeding rumen-protected choline to transition dairy cows.
Sources:
- CHANDLER, T. L. AND H. M. WHITE. 2017. Choline and methionine differentially alter methyl carbon metabolism in bovine neonatal hepatocytes. Plos One doi.org./10.1371/journal pone.0171080.
- COOKE, R. F., N. SILVA 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.
- ELEK, P., T. GAAL, AND F HUSVETH. 2013. Influence of rumen-protected choline on liver composition and blood variables indicating energy balance in periparturient dairy cows. Acta Vet. Hung. 61:59-70.
- GRUMMER, R. R. 2012. Choline: A limiting nutrient for transition dairy cows. Proc. Cornell Nutr. Conf.
- JANOVICK, N. A., AND J. K. DRACKLEY. 2010. Prepartum dietary management of energy intake affects postpartum intake and lactation performance by primiparous and multiparous Holstein cows. J. Dairy Sci. 93:3086-3102.
- JANOVICK, N. A., Y. R. BOLSCLAIR, AND J. K. DRACKLEY. 2011. Prepartum dietary energy intake affects metabolism and health during the periparturient period in primiparous and multiparous Holstein cows. J. Dairy Sci. 94:1385-1400.
- MCNAMARA, J. P., AND F. VALDEZ. 2005. Adipose tissue metabolism and production responses to calcium propionate and chromium propionate. J. Dairy Sci. 88:2498-2507.
- NEWBOLD, J. 2005. Liver Function in dairy cows. Page 257 in Recent Advances in Animal Nutrition. P.C. Garnsworthy and J. Wiseman, eds. Nottingham University Press.
- YUAN, K., R. D. SHAVER, S. J. BERTICS, M. ESPINEIRA, AND R. R. GRUMMER. 2012. Effect of rumen-protected niacin on lipid metabolism, oxidative stress, and performance of transition dairy cows. J. Dairy Sci. 95:2673-2679.
- ZOM, R. L. G, J. VAN BAAL, R. M. A. GOSELINK, J. A. BAKKER, M. J. DE VETH, AND A. M. VAN VUUREN. 2011. Effect of rumen-protected choline on performance, blood metabolites, and hepatic triacylglycerols of periparturient dairy cattle. J. Dairy Sci. 94:4016-4027.
Related Posts:
Myth #6: If You Are Feeding Rumen-Protected Methionine, You Do Not Have to Feed Rumen-Protected Choline
Choline and methionine are both available in rumen-protected forms. Based on insights from non-ruminant studies...
Myth #5: If You Are Feeding Goldilocks Diets, You Do Not Have to Feed Rumen-Protected Choline
Goldilocks diets are considered beneficial for transition cow health because they moderate fat mobilization...
Gummy Sweet Candy,Season Gummy Candy,Sweet And Sour Gummies,Sweet And Sour Gummy Bears
Montreal Shantou Food Co., Ltd , https://www.montrealsnack.com