Importance of choline in milk production

Choline supplementation: when, and why?

The focus of this webinar is on a single question: when is choline supplementation worth it, and why? We had two experts unpacking the subject: veterinarian and herd management consultant Dr. Heidi Hiitiö and animal nutrition expert Dr. Timurhan Tastutar.

In the EpiHerd results, choline repeatedly emerges as a factor that limits the health and yield of dairy cows.

What is choline?

Choline is a vitamin-like compound whose main function is to enable the transport of fat from the liver to the rest of the body. This occurs through the formation of very-low-density lipoprotein (VLDL) particles. Without sufficient amounts of choline, this process is limited, causing the fat to remain in the liver and not be available for, for example, milk production.

When choline is flagged in EpiHerd results, this is not a theoretical recommendation, but rather, the need for choline is reflected in the cow's metabolism, as detected by the EpiHerd test, and this need is especially increased during the transition period.

In the webinar, Timurhan illustrated the need for choline with a practical example: if you ask a guest to bring champagne to your party, but they bring you a tanker truck of prosecco, that is a gift with good intentions but in the completely wrong form! The same applies to choline; the animal will not be able to utilise choline unless it comes in the right “packaging” (right form) and at the right time. In practice, this means that the usual choline given with the feed is often not the right form, because it is not “rumen-protected”, and rumen microbes break it down before it has time to take effect. Choline rarely needs to be given to cows continuously, either, so the timing is important too.

Why is choline beneficial?

Timurhan and Heidi pointed out that according to studies, the importance of choline is especially noted during the transition period, when the cow's metabolism is under heavy strain.. After calving, the cow is in a negative energy balance, when fat is mobilised from the tissues to the liver. If this fat cannot be moved forward from the liver, it begins to accumulate there, which increases the risk of fatty liver and ketosis.

Therefore, insufficient choline intake during the transition period impairs the export of fat from the liver and can lead to the development of fatty liver. This is seen in practice as increased beta-hydroxybutyrate (BHBA) levels, reduced feed intake, lower milk yield, reduced fertility and an increased risk of culling.

Additionally, choline is part of the same methylation cycle as methionine.The methylation cycle is a fundamental process in the body for basic bodily functions. If choline is too low, the body uses methionine to replace it, which can impair antioxidant systems and immune response, among other things. This explains why choline and protein metabolism often appear in the same EpiHerd results.

How much choline should be given and what else affects its effectiveness?

The rumen microbes break down the choline that comes with the feed before it is absorbed. That is why rumen-protected choline is needed, which is only released in the small intestine. The target level shown to be effective in studies is about 13 grams of absorbable choline per day, targeted at about 21 days before and after calving. In late lactation, more than 150 days after calving, no significant effect has been observed with the supplement. The effectiveness of choline also depends on the balance of the entire diet. For example, methionine, folate and betaine support choline’s function. If the basal diet is not in order, the effect of choline supplementation will be limited.

At the right time, for the right individuals

The greatest benefit from choline is in high-yielding cows, dry cows with excessive body fat, and farms with repeated ketosis, fatty liver or poor lactation initiation. When choline appears in EpiHerd results, it means that the metabolic burden is already underway and support can be targeted at just the right moment before problems develop. It is also essential to note that choline does not work in isolation. Its effect depends on the balance of the entire diet, especially methionine, folate, vitamin B12 and energy intake. If these factors are limiting production, choline supplementation alone will not resolve the situation.