Fatty liver disease occurs when there is an accumulation of fat in the liver. At the beginning of the dry period, the energy requirement of the cows decreases because they no longer produce milk. When the cows are still receiving an energy-rich ration, this ensures that fat is stored as belly fat at the organs. This fat is easily absorbed into the blood. When there is too much fat in the blood, the liver cannot handle it and becomes fat. In addition to the start of the dry period, the phase around calving is crucial. Cows enter a negative energy balance around calving. This is caused by the growth of the calf, the start of lactation and changes in the hormone balance.
The liver has to work hard during the onset of lactation. The cow will use its own fat reserves in an unhealthy way. This releases ketones into the blood, substances that are harmful to the body. If a cow has too many ketones in the blood, it is called lingering milk fever. Mastitis, uterine inflammation, ovarian cysts and a cow that is stuck with the afterbirth is often the result.
A blood test can determine whether there is fatty liver disease. The blood is examined for NEFA, AST, GLDH, bilirubin and urea. When the liver is fatty, the NEFAs will increase in the first instance. NEFAs are fatty acids which occur from the breakdown of body fat. A high NEFA value (above 600mEq/l) therefore means that the cow lacks energy and uses its body reserves. GLDH, AST and urea are also indicators of fatty liver. Normally, the liver is dark reddish brown in colour. When the liver is fatty, the colour will be pale and pale yellow.
Good feed management is of great importance to prevent a negative energy balance. A cow that is too skinny or too fat will quickly have a problem. A body condition score of 3.5 is desirable during the transition period.
Firstly, a good dry period ration is of great importance. The far-off dry period (generally the first 4 to 6 weeks) compared to the close-up group (generally the last 3 weeks before expected parturition) should be given a different ration. To ensure that the far-off group does not get fat, a structure that is not too energy-rich and sufficient is important. For the close-up group, the concentrate dose can be increased gradually. Provide no more than 0.5 kilogrammes per day.
Secondly, it is important to consider particle size as this can have an impact. Chopping added straw improves absorption.
Finally, cows with a higher risk of fatty liver should receive extra attention before entering the dry period. By giving the animals a kexxtone bolus, fattening can be prevented. The active ingredient in the bolus supports the rumen bacteria in releasing fatty acids from the feed, which are easily converted into energy by the liver.