Advice on supporting liver health in high-yielding cows

We are all familiar with the challenges posed by the transition period in high-yielding dairy cows.

However, ongoing research is demonstrating the value of more specific support for liver function during this time.

The inclusion of rumen-protected choline and methionine – either in feed rations or via boluses – helps the liver and improves energy balance.

See also: How three dairy farmers maintain high-yielding herds

At transition, cows experience physiological changes that can strain liver function, increasing the risk of metabolic disorders such as ketosis and fatty liver disease.

Proper nutrition is crucial for minimising disease around calving, supporting liver health and optimising milk production.       

Why does the liver struggle to function properly?

As a cow moves from the dry period to lactation, her energy demands increase significantly.

However, dry matter intake often declines before calving, leading to a negative energy balance.

This energy deficit forces the cow to mobilise body fat reserves, increasing non-esterified fatty acids (Nefas) in the bloodstream.

Excess Nefas can overwhelm the liver, leading to the accumulation of triglycerides and causing fatty liver disease.

If the liver cannot efficiently process these fats, ketone bodies build up, leading to ketosis.

This condition reduces milk yield, immune function and reproductive performance, as well as predisposing cows to conditions such as left displaced abomasum (LDA).

James Dixon © Peakfield Farm Vets

How can the energy gap be filled?

Maximising feed intakes in the pre- and post-calving period is a key strategy to limit the impact of this energy gap.

It can also reduce the risk of diseases such as milk fever and retained foetal membranes, which can impact feed intakes and lead to ketosis as a secondary condition.

As yields (and milk quality) continue to increase, cows need to consume and metabolise increasing levels of energy to meet the demands of production.

In these high-production situations, the benefits of more specific support for the liver are becoming clear.

How do choline and methionine help?

Choline is a vital nutrient that plays a key role in the liver, particularly in fat mobilisation and transport.

Choline has been shown to prevent fat accumulation in the liver by promoting the formation of very low-density lipoproteins (VLDL).

These lipoproteins transport triglycerides out of the liver and into the bloodstream, where they can be used as an energy source by other tissues.

Studies have shown supplementing transition cows with choline reduces liver fat accumulation, lowers blood ketone levels, and improves overall energy balance.

Cows supplemented with choline also show increased milk yield and improved reproductive performance, likely owing to better liver function and metabolic efficiency.

It is important to feed choline in a rumen-protected form, because free choline is rapidly degraded in the rumen before reaching the intestine for absorption.

Methionine also plays a crucial role in lipid metabolism. Rumen-protected methionine enhances VLDL synthesis and works synergistically with choline.

Options for supplementation

Rumen-protected choline and methionine are available in bags and can be added to the total mixed ration (TMR), with good results seen when included from three weeks pre-calving to three weeks post-calving.

For more targeted use, such as prioritising high-risk cows, or where fresh cows are integrated into the main herd, a bolus is available containing rumen-protected choline and methionine.

This is designed to be given pre-calving to prepare cows for the subsequent lactation.

That said, for herds already supplementing dry cows in their feed, but where continued in-feed supplementation is not practical post-calving because there is not a separate group for fresh-calved cows, a bolus given post-calving can fill that gap.

Supplementation rates

Exact feed rates will depend on the product used, its level of rumen protection and its degradation rate.

In all cases, work closely with the farm nutritionist to ensure the ration is correctly balanced and delivering what is required.

For choline, an inclusion rate of 30-45g/day of rumen-protected choline can be fed (from three weeks pre-calving to three weeks post-calving) to give 12-15g/day of usable choline.

This is when fat mobilisation is at its highest and there is increased demand on the immune system.

For methionine, the feed rate will depend on the amino acid profile of the ration. The aim is to achieve a lysine-to-methionine ratio of about 3:1.

Again, this is primarily around transition but can be throughout lactation if the amino acid profile of the available forages demands it. Seek advice from the farm nutritionist.

For both products, consistency of delivery is key – they should be properly mixed into the TMR, or delivered via bolus, to ensure each cow gets the correct allocation.

Importance of monitoring

As with any intervention, it is important to monitor the outcomes to assess its success.

Milk yield, milk protein, body condition score and incidence of transition disease (for example, retained foetal membranes, ketosis, LDA) can all be useful in establishing whether what has been put in place has been beneficial.