The role of B vitamins on liver function in transition cows

Transition periods for dry cows can create lots of issues post calving if not managed carefully. Looking at the vitamin balance of the transition diet is one factor that can influence how well fresh cows handle their body’s increased demands for energy.

Why are B vitamins important?

The correct balance of B vitamins in the transition diet will help improve liver function through oxidation of fat (the ability to process fat in the liver converting it to a source of energy the cow can use). If the liver can not function efficiently, this can prolong the cow’s negative energy balance post calving, leaving her susceptible to ketosis.

B vitamins are water soluble and can be synthesised in the rumen. However dietary sources of B vitamins are often rapidly Choline and B vitamin's roles in reducing liver fat infiltrationdegraded in the rumen, but rumen microbes can synthesis their own B vitamins which are then pass through to the small intestine.

There is a concern as cows have been bred to produce more milk intakes have not increased at the same rate and there is a possibility that the ability of the dairy cow to synthesis adequate amounts of B vitamins could be a limiting factor.

Ruminants will use B vitamins for cell function, growth, milk production and fertility.

A combination of folic acid, B12, riboflavin and choline have been shown to have beneficial effects on liver function in dry cows.

Avoid negative energy balance

When a cow is in negative energy balance her body is desperate to get energy from wherever it can. Body fat reserves will be broken down and converted to energy by the liver. This can be seen quite clearly in fresh cows from changes in body condition. The process will also be happening in the close-up period as her DMI reduces in the days leading up to calving.

The mobilization of body fat for energy will produce non-esterified fatty acids, NEFAs. If blood NEFA become high this can have a negative effect on DMI. Falling intakes will result in more body fat being converted to energy and the liver simply can’t keep up. The result is production of (Beta Hydroxy Butyrate) BHB which is linked with Ketosis.

In the fresh period post calving the demand for nutrients increases, such as glucose to meet milk production demands. Having a healthy liver is essential to help with the transition and the needs of lactating animals to ensure they can process nutrients effectively. Choline, Folic acid and B12 can help increase the oxidation and removal of fat by the liver and reduce the levels of NEFAs and BHB in the blood.

The combination will also help improve cell immunity. This is because less oxidative stress is on the liver. The addition riboflavin in combination folic acid and choline can also increase DMI in the dry period which will again have the benefit of less fat tissue being mobilized and lower levels of NEFA in the blood.

The benefots of B vitamins in transition cows

Ketosis and the effects of subclinical ketosis is a costly disease for any dairy cow. Liver function will be one element that will help fresh cows cope with the period of negative energy balance they will encounter. Body condition score at drying off, the environment of the dry cow pen and fresh cow conditions will all effect how well they will transition. But the balance of vitamins in the dry cow diet should not be overlooked or dismissed and will be one key element that is worth considering helping ensure health liver function and preparing for the lactation ahead.

Alasdair Taylor
Dairy Specialist
You can contact Alasdair or the rest of the dairy team here.

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